THE 
MICROSCOPE 
AOT 
MICROSCOPICAL TECHNOLOGY 
A TEXT-BOOK FOR PHYSICIANS AND STUDENTS 
HEINRICH FREY 
BY 
Professor of Medicine in the University of Zurich 
TRANSLATED AND EDITED BY 
GEORGE R. CUTTER, M.D. 
Surgeon New York Eye and Ear Infirmary ; Ophthalmic and Aural Surgeon to the 
St. Catherine and Williamsburgh Hospitals, Etc., Etc. 
Illustrated by Three Hundred and Eighty-eight Engravings on Wood 
Seconb (Sbition 
WILLIAM WOOD & COMPANY 
NEW YORK 
1880 Copyright by 
WILLIAM WOOD & COMPANY. 
1880. 
Printing and Booki jing Company, 
201-213 East xitk Street. 
TrowV 
NEWYORK. CONTENTS. 
PAGE 
Translator’s Preface v 
PAGE 
Introduction *x 
Theory op the Microscope 1 
SECTION FIRST. 
Apparatus for Measuring and Drawing 33 
SECTION SECOND. 
The Binocular, the Stereoscopic, and the Polarizing Microscope.. 46 
SECTION THIRD. 
SECTION FOURTH. 
Testing the Microscope 58 
SECTION FIFTH. 
Use of the Microscope—Microscopic Examination 83 
SECTION SIXTH. 
The Preparation of Microscopic Objects 103 
SECTION SEVENTH. 
Fluid Media and Chemical Reagents—Titrition 117 
SECTION EIGHTH. 
Methods of Staining—lmpregnation with Metals—The Drying and 
Freezing Processes 147 
SECTION NINTH. 
Method of Injecting 173 IV 
CONTENTS. 
SECTION TENTH. 
The Mounting and Arrangement op Microscopic Objects 207 
PAGE 
Blood, Lymph, Chyle, Mucus, and Pus 233 
SECTION ELEVENTH. 
Epithelium, Nails, Hair 256 
SECTION TWELFTH. 
Connective Tissue and Cartilage 274 
SECTION THIRTEENTH. 
Bones and Teeth 296 
SECTION FOURTEENTH. 
Muscles and Nerves 316 
SECTION FIFTEENTH. 
Vessels and Glands 381 
SECTION SIXTEENTH. 
Digestive Organs 422 
SECTION SEVENTEENTH. 
Pancreas, Liver, and Spleen . 459 
SECTION EIGHTEENTH. 
Respiratory Organs 485 
SECTION NINETEENTH. 
Urinary Organs 502 
SECTION TWENTIETH. 
Sexual Organs 533 
SECTION TWENTY-FIRST. 
Organs op Sense 554 
SECTION TWENTY-SECOND. 
Index. 607 
Price-Lists of Microscope-Makers 627 TRANSLATOR’S PREFACE. 
Any attempt on my part, by way of introduction or 
commendation of Professor Frey’s work, must, I feel, be 
altogether misplaced and unnecessary. Although the 
treatise has been but a few years before the public, four 
large editions have already been issued, and a copy is 
always found on the table of those microscopists who are 
able to read it in the original. 
I have been induced to undertake the arduous labor of 
preparing a translation of the work by the hope that it 
might stimulate and facilitate the study of this important 
branch of science in this country. 
An apology may be thought necessary for the style of 
the translation,—in having followed the German so liter- 
ally. The nature of the subject, however, involving as it 
does such very minute descriptions, and the frequent repe- 
tition of the same terms, added to the impossibility of doing 
justice in any other way to the author’s condensed style, 
have necessitated a rigid adherence to the original text. 
The few additions which have been made are enclosed 
within brackets. 
George P. Cutter, M.D. 
New York, October, 1873. TRANSLATOR’S PREFACE TO THE SECOND EDITION. 
In preparing tills edition, tlie work has been thor- 
oughly revised, a large amount of new matter and many 
new illustrations have been added; a bolder-faced type 
has been used, and the size of the page increased. 
It is hoped that the very favorable reception ex- 
tended to the previous edition by the profession at large, 
and by the medical press, will also be granted to the 
present. 
George R. Cutter, M.IX, 
No. 312 Second Avenue, New York. 
January, 1880. INTRODUCTION. 
“ To endeavor to discover new methods of investigation appears to me to be one 
of the most important duties of every observer. To communicate these to his pupils 
must be the desire of every teacher of any branch of natural science. (L. Beale . 
How to Work with the Microscope, p. 3.) 
Within the last ten years the Microscope, that instrument which has 
conquered a new world of minuteness for natural science, has become 
widely known. Already a considerable number of these instruments are 
yearly issued from the large and celebrated establishments of Europe ; 
and not less noticeable is the number of those which are constructed and 
sold by less renowned opticians. The opinion is now admitted that the 
microscope is quite as indispensable for the scientific, as the stethoscope 
and pleximeter for the practical requirements of the physician. 
Through Schwann’s classical work we have learned that the human 
body is formed, in all its parts, from cells and their derivatives, and that 
the cell is the ultimate organized unity of animal life. As in the province 
of anatomy we cannot understand the structure of any portion of the 
body without this little microscopical foundation-stone, even so little do 
we succeed in comprehending the physiological action, if we disregard 
the isolated action of these ultimate organized unities. The united action 
of an organ is only the result of all the single actions of cells, of the 
“ elementary organisms,” as they were afterwards called. Thus, Histology 
has become an indispensable member in the series of anatomico-physiolo- 
gical sciences. 
Health and disease appear, in the ingenuous view of man, to be sepa- 
rated by a wide abyss ; an opinion which, in the domain of science, is 
drawn like a red thread through so many nosological systems of X 
INTRODUCTION. 
former days. The recognition of the contrary is properly greeted as a 
great advance in physiological opinion. The processes which take place 
in the diseased body are actually, for us, but modifications of those -which 
occur in the normal; the same physiological laws obtain in the one case 
as in the other ; and those also which, in a material regard, occur in the 
diseased body, the metamorphosis, separation, and new formation of its 
elements, obey the same laws of cell-life which we recognize in the normal 
organism. The eminent significance of pathological histology requires no 
wider discussion, nor is it necessary further to recommend the instru- 
ment by means of which histology is chiefly created. 
Microscopy is, however, as some of our readers will have already expe- 
rienced in their first attempts, delicate work. How many a student, how 
many a physician, impelled by the great value of such studies, has pro- 
cured a microscope only to perceive, to his great dissatisfaction, how little 
he is qualified to use it. Here, as in all departments of human efficacy, a 
period of apprenticeship is necessary,—an arduous season of sowing before 
attempting to reap the plenteous harvest. 
The microscope is a delicate implement; like other complicated in- 
struments, its use must be learned. The faculty of seeing with it must 
likewise be acquired, which also requires some perseverance, if we would 
attain to the accurate vision which is here indispensable. 
The art to observe and investigate requires the employment and 
knowledge of many small, and therefore, at first, apparently unimportant 
accessories. The time is past when it was thought possible to fathom the 
finer textural relations of a piece of fresh tissue by picking, and, perhaps, 
the assistance of pressure and a little acetic acid. Modern chemistry, to 
which medicine is extremely indebted, has also furnished the microsco- 
pist with a series of the most important accessories. Thus, now-a-days, 
knives and needles, the syringe, the scales, and many other artifices are 
employed in the investigation of the tissues of the body. 
We shall readily comprehend, from what has been said, that our so in- 
dustrious epoch in a microscopical regard, among many sound investiga- 
tions, also annually produces over-hasty performances which show how 
little their authors have learned to overcome the most elementary difficul- 
ties. 
This remark, however, is not written to discourage ; it should, on the 
contrary, only indicate that the most complete familiarity with the instru- INTRODUCTION. 
ment and witli the entire technique should be the indispensable prelimi- 
nary of every microscopical investigation. 
Though that school which offers the practical instruction of a teacher 
is always the best, it is not permitted to every one to walk in this path to 
learning. Here written directions find their place, and, provided they are 
judicious and practical, may afford a sufficient compensation, and make a 
microscopical observer out of the beginner. 
The literature of the microscope is already voluminous. Admirable 
and copious works exist in the German, Hollandish, and English lan- 
guages, such as those of Mold, Harting, and Carpenter. But in the Ger- 
man there is a great deficiency of concise works especially adapted to the 
practical wants of the physician, as we have only the obsolete work of Vo- 
gel. L. Beale has produced two able text-books for the English. 
May our little work serve as a guide for students and physicians till 
the time, at least, when a better pen shall produce a better substitute. 
That we premise the mechanism of the instrument and the use of its 
several parts is obviously necessary ; for a knowledge of the implements 
must always precede the labor which they are to perform. That we 
limit ourselves, in this section, to that which is most important and in- 
dispensable, and touch but lightly the difficult, and in all its parts by no 
means definitely settled, optical theory, requires no further justification. 
Another portion of our work treats of the various methods of investiga- 
tion at present in use. A third part, finally, completes the directions for 
investigating the various tissues and parts of the body in a normal and 
pathological condition. Possibly, in the department of pathology we 
may have been too concise for a portion of our readers. The investiga- 
tion of sputum, pus, urinary sediment, and tumors usually occupies a 
much larger space in books on this subject. But, true to our maxim, 
that the most accurate knowledge of the normal relations should precede 
every investigation of their pathological condition, we endeavor, first of 
all, to make the former clear and then join the latter supplementarily. 
As every pathological new formation repeats, more or less, the type of the 
normal structure, so are the methods of investigating diseased tissues 
and portions of the body almost the same. 
V\ ith regard to the literature of the microscope, we would particularly 
mention the following works ; 
J. Vogel, Anleitung zum Gebrauche des Mikroskops, Leipzig, 1841. XII 
INTRODUCTION. 
—H. y. Mold, Mikrographie, Tubingen, 1846.—C. Robin, Du micro- 
scope et des injections, Paris, 1871.—P. Harting, Das Mikroskop, 2. 
deutscbe Originalausgabe, besorgt von Tbeile, 3 Bde., Braunschweig, 
1866. —W. Carpenter, The Microscope, 4th Edition, London, 1868. 
L. Beale, How to Work with the Microscope, 4th Edition, London, 
1867, and, The Microscope in its Application to Practical Medicine, 4th 
Edition, London, 1877.-—H. Schacht, Das Mikroskop, 3. Auflage, Berlin, 
1862.—C. Nageli und S. Schwendener, Das Mikroskop, Leipzig, 1867.— 
L. Dippel, Das Mikroskop und seine Anwendung, Braunschweig, Bd. 1, 
1867, und Bd. 2, 1872.—L. Ranvier, Traite d’histologie technique, Paris, 
1875. octtion .first. 
THEORY OF THE MICROSCOPE. 
hat wonderful organ, the human eye, has often been com- 
paied to the camera obscura, and the comparison is, indeed, 
an excellent one. As the collective lens projects an inverted 
Hninished image at the background of the latter apparatus, 
WlO 1 received on the ground-glass plate, so the collective 
ie racting media of the eye produce the same inverted dimin- 
is e image at its profundity, which is received on the retina. 
_ robably all of our readers are aware that the dimensions 
w iic i an object appears to the eye to possess, depend upon 
coiiil1'28' an^e yisi°n ;an angle which one receives by 
urnnflnif a through straight lines, the corresponding terminal 
s ® le object, and of the image received in the eye, 
g ance at fig, i will render this intelligible. The curved 
Fia. 1. Visual angle and apparent magnitude of the object. 
ocuv f a rePresents the image, projected upon the fundus 
•g \ 0 le arrow AB, placed before the organ of vision; a 
tfi m-0C a ne a second one to B. Thus arises 
V ISLlal angle AoB = ~b oa. All bodies whose terminal 
pom s touch the lines A a and B h, appear to the eye to be of 
o same A needle held close before the eye may, under 2 
SECTION FIRST. 
these circumstances, have the same apparent dimensions as a 
long pole which stands in the distance. When the arrow is 
brought nearer to the eye, to A' B7 for instance, it projects the 
image Zr* a*, causing the angle of vision A' o B7; the arrow, 
however, appears to be larger. If the angle of vision falls be- 
low a certain size, the object ceases to be visible. A thick wire, 
for example, if considerably removed from our eye, is no longer 
perceived. If we bring the wire nearer and nearer, whereby the 
visual angle is also increased, it appears at first as a fine thread, 
then with increasing diameter. We therefore instinctively ex- 
amine small objects at a certain proximity. 
But a continued approach also finds its limit at last; the 
wire, which was still distinctly seen, becomes indistinct, and 
finally, having been brought quite close to the eye, becomes 
entirely invisible. 
On what does this last condition depend ? 
It is known that the image of an object projected by a col- 
lective lens alters its position according as the object is removed 
from or brought nearer to the lens. In the first case the image 
approaches the lens, in the latter, it recedes farther behind it. 
ISTow, as the human eye acts in the same manner as a lens, and 
accurate vision only occurs when the rays of light, coming from 
any point of an object, are so refracted as to be again united at 
the retina, so, in reality, a distinct image can only be possible 
at a certain distance. But daily observation teaches us some- 
thing further; we see remote and near objects, one after an- 
other, with equal accuracy. The eye must, therefore, possess 
a correcting apparatus, in order to adjust its refracting media 
for proximate and remote bodies; it accommodates, as the 
physiologists say. 
This process of accommodation is, however, disregarding in- 
dividual variations, limited. The image of an object, brought 
more and more near to the eye, falls at last behind the retina. 
In our fig. 3, the arrow placed at A would give a distinct image, 
the rays of light diverging from a point p being united at a 
point r on the retina. 
Should the arrow, however, be brought so near as B to the 
organ of vision, this union can no longer take place at the 
retina. The rays of light proceeding from p* come together 
farther behind this membrane, at r*. 
Very small objects, therefore, when brought too near to the THEORY OF THE MICROSCOPE. 
3 
human eye become invisible ; here, as we shall soon see, other 
accessories are necessary. 
The distance from the eye at which objects of medium size 
Pig. 2. Position of an object, and union of the rays which proceed from it in the eye. 
tan be most sharply discerned, is called the mean distance of 
visum. This is usually considered to be from Bto 10 inches, or 
0 centimetres, for the normal eye. The closest proximity at 
an object is still visible is called the near point. Near- 
Slghted eyes permit of a few inches nearer approach, far-sighted 
ones find their limit sooner; the first refract more, the latter 
loss strongly. 
Such a small body may, however, readily be made visible 
y placing a convex lens between it and the eye. The reason is 
onsily understood. The point placed at O, fim 3. produces its 
image at r, and is 
t lerefore no longer 
Perceptible to the eye. 
f we now place the 
ens L, whose focus 
is at P5 between, the 
lays of light receive 
io direction indicat- 
od by the dotted lines, are less divergent on reaching the eye, 
cl.nd are, consequently, united on the retina at R. Thus a dis- 
ln°t image is formed, 
. L will also be observed, that by the use of such a lens the 
Ullage thus received is enlarged. 
-Now whence does this arise ? 
Let us suppose that the object is placed at A B, fig. 4, and 
_ a convex lens is brought between it and the eye. The 
c°ne of rays which proceeds from any point of the arrow, for 
example from A, projects its rays A b, A C, A c on to the lens, 
ail(i these, with the exception of the rays A C, are refracted by 
Pig. 3. Action of a convex lens when an object is brought near 
the eye. 4 
SECTION FIRST. 
the lens in the direction h I and ci; receiving a slight diver- 
gence, as if they proceeded from the more distant point A*, 
Fig. 4. An object magnified by a convex lens. 
they arrive at the eye and are nnited on the retina. The same 
is repeated for the cone of rays B, etc.; thus an inverted image 
of the arrow is formed in the eye. The object appears to the 
organ of vision to be placed, not at A B, but at A* B*, and 
therefore enlarged. As a proof that the image caused by a 
convex lens is always apparently more remote than the object 
itself, look at a piece of paper through the lens, and attempt 
to touch the edge of it with the point of a needle. The needle 
will invariably be directed some distance beneath the paper. 
Such convex lenses are usually called loups, so long as their 
magnifying power does not exceed 15 or 20 diameters, and so 
long as during their use they can be guided by the human 
hand. When the magnifying power of such lenses is greater, 
so that a stand is necessary 
to support them during 
their use, the combination 
is called a simple micro- 
scope. The impossibility of 
making a sharp line of de- 
marcation between the two 
kinds of instruments is self- 
evident, as weak convex 
lenses are also fastened to a 
stand, and numerous so- 
called loup-supporters are also employed (fig. 5). 
There are many varieties of loups, but we must refer to more 
detailed works for their description. Their value and applica- 
Fig. 5. Nachet’s simple loup-stand. THEORY OE THE MICROSCOPE. 
5 
bon in natural philosophy is also too well known to render it 
Accessary for us to say more on the subject. A good loup, 
Magnifying 10 or 15 times, is indispensable. 
The simple microscope of Plossl, of Vienna, is seen in fig. 6. 
nietal bar (a) supports, at half its height, a horizontal plate 
which is bored through its centre, the stage (6) of the micro- 
scope. This can be elevated or depressed by means of the rack 
V)- The movable mirror {/) placed beneath, serves to reflect 
the light on to the object to be examined, which is placed on 
riG. 6. Plossl's simple microscope. 
tle stage. If, instead of transmitted light, it be desired to ex- 
arnine the object by reflected light, after the manner of our 
asual vision, the mirror is thrown out of action, or an opaque 
P ate is placed on the stage. The horizontal arm (d), on the 
Ppper extremity of the stand, carries the magnifying glass, the 
118 (e)- It can be removed from the opening in the arm and 
lePlaced by another. 
The simple microscope of Nachet, of Paris (fig. 7), likewise 
a convenient form. The movement is made by a rack, 
nch elevates or lowers the lens, in contradistinction to the 
ana of Plossl, in which the stage moves up and down. Two 
ditional plates on the stage, bent downwards, serve as sup- 
P°Us for the hands during the manipulation. Both instru- 
-11!,‘llts Pave clamps on the stage, for the purpose of fixing the 
ob3ect. 
Fig. 7. Nachet’s simple microscope. 6 
SECTION FIEST. 
The simple microscope is now-a-days indispensable to the 
natural philosopher, as an instrument for dissecting. It is, 
however, no longer, or but little, employed for scientific inves- 
tigations. 
When a tube is placed over the magnifying-glass of the 
simple microscope, and the object is placed somewhat beyond 
the focus of the lens, an 
enlarged, inverted image 
of the same is projected 
within the tube. In fig. 8 
we can readily perceive 
this relation. If we con- 
nect the lens L with a fun- 
nel, whose diameter ex- 
tends from e* to d*, we 
may receive the image on 
a ground-glass plate. 
When this aerial image 
is again enlarged by means 
of a convex lens, we have 
the compound dioptrical 
microscope. The differ- 
ence between these two in- 
struments consists in this, 
that in the simple micro- 
scope the object itself, in 
the compound, on the con- 
trary, the enlarged image 
of the object is seen. Our 
fig. 8 may represent the 
compound microscope in 
its simplest form. The 
united cone of rays c* a* 
h* diverge from the eleva- 
tion e,c w* to tlie upper lens, from whence, after their refrac- 
tion, they arrive, under a slight divergence, at the human eye. 
At the same time, however/ we find that the cone of rays which 
proceed from the terminal points d and e of the arrow, are 
united at d* and e*, they do not arrive at the upper lens. We 
perceive, therefore, in our example, only the length h-c of the 
arrow. A smaller arrow, circumscribed in this dimension (see 
Fig. 8. The compound microscope in simplified form. THEORY OF THE MICROSCOPE. 
7 
lower part of fig. 8), would, on the contrary, be distinctly seen, 
idle dotted lines, which pass to c** and ft**, the prolongation 
of the rays refracted by the upper lens, give, at the same time, 
the apparent size under which the arrow b c is seen. 
An explanation of the image c* a* b* of the arrow is neces- 
fary, in one other regard ; it appears curved, while the arrow 
itself is straight. If we hold it as established that the point of 
union of a cone of rays falls farther behind the lens from a near 
object than it does from one lying more remote ; and if we re* 
member that b and d, c and e are situated farther from the op- 
tical middle point than a, then we can readily understand why 
the surface of the image is curved. 
The knowledge of magnifying-glasses and the art of grind- 
lng them already existed in antiquity and the early middle 
ages. The invention of the compound microscope occurred, on 
the contrary, at a considerably later epoch. There is no longer 
any doubt that an humble Hollandish spectacle-grinder, Zach- 
arias Janssen, of Middelburg, probably about the year 1590, 
Produced the first instrument of this kind. Other authorities 
mention, without sufficient foundation, the Netherlander, Cor- 
nelius Drebbel, Galilei and another Italian, Fontana, as the 
discoverers. Harting, with his usual carefulness, investigated 
this question of the invention several years ago. 
The oldest compound microscopes were, however, very in- 
c°mplete instruments, and were encumbered with great optical 
Teficiences. These imperfections rendered themselves suffi- 
ciently perceptible with weaker powers, and attained, with 
somewhat stronger glasses, such a rapid increase as to render 
the whole combination nearly useless. 
In order to understand this, we must recall to our minds a 
few well-known optical principles. 
The term angle of aperture of a lens denotes the angle which 
ls formed by the 
f°cus and the two 
terminal points of 
the diameter of the 
;ens- Thus, g f 7i 
18 the angle of aper- 
ture of our fig, 9. 
Only so long as this angle remains small, do the peripheral and 
central rays actually reunite in a point, as we have thus 
Fig. 9. Spherical aberration. 8 
SECTION FIRST. 
far, for the sake of greater simplicity, assumed. When the 
angle of aperture is greater, only those rays of light (BB) 
which are nearly parallel to the axis (A) of the lens, and which 
pass through its central portions, are united at the focus F, 
while those rays (CC) which pass nearer the periphery of the 
lens are more strongly refracted and find their focus already in f. 
This property of refraction is called the spherical aberration. 
If we cause the rays which proceed from a small luminous 
body to pass through such a lens, we receive at F the image 
projected by the central rays. It is not sharp, however, but is 
surrounded by a halo or circle of diffusion, caused by the periph- 
eral rays, which have become divergent again. If we apply 
a dark disk with a circular opening, a so-called diaphragm or 
stop DD, the peripheral rays are intercepted, and we receive 
a distinct though faintly illuminated image at F ; also at f, 
when we obstruct the central rays, and thus permit only the 
peripheral rays to pass through the lens. Such annular dia- 
phragms are extensively employed in practical optics, for the 
purpose of improving the images. 
We here mention another, for the theory of the microscope, 
important effect of this spherical aberration. When very small 
cones of rays arrive at a convex lens of considerable diameter, 
as is the case with the ocular 0 in fig. 8, those which pass 
through the periphery of the lens necessarily receive a stronger 
refraction than the more central ones. The peripheral points 
of the image must, accordingly, appear nearer each other than 
Fig, 10. Quadratic net-work. 
Fig. 11. Image distortion. 
Fig., 12. Image distortion. 
the internal portions. A wire net-work, fig. 10, presents an 
aerial image, such as is represented by fig. 11. If we observe 
the quadrangular net-work through such a loup we receive a 
diametrically opposite phantom, after the manner of our fig. 
12. In both cases arises, therefore, a distortion of the image. THEORY OF THE MICROSCOPE. 
9 
A second not less palpable inconvenience in the use of such 
lenses arises in consequence of their chromatic aberration. 
A ray of white light (fig. 13, B or C), in passing through a 
Fig. 13. Chromatic aberration. 
convex lens would not be refracted as a whole, but would be 
decomposed into rays of various colors, which suffer deviation 
m varying degrees in the direction of the plane of refraction, 
ail(l thus form a spectrum, at one extremity of which the 
strongest refracted, the violet («), and at the other, the least 
deviated, the red ray (r) appears. 
Prom what has just been said it follows, that with ordinary 
convex glass lenses we perceive the object indistinctly defined 
and surrounded with colored borders. Both faults increase 
rapidly with the increase of curvature of the lenses. The 
older microscopes, therefore, produced images which were 
fnintly illuminated, insufficiently defined, and surrounded 
'With colored borders. The image projected by an imperfect 
object lens was still further magnified by the likewise imper- 
fect ocular lens. 
Achromatic lenses have now taken the place of the old use- 
less glasses. By this name is indicated such with which the 
foci of the various colored rays of light are united, in other 
words, those which show the object free from colored borders. 
The powers of refraction and of dispersion are not united in 
equal proportions in any single refractive medium, as has been 
known for a long time. One medium gives, in the same power 
°f refraction, a greater deviation to the colored rays than an- 
other. There are two different kinds of glass which act in this 
Planner with regard to each other—crown-glass and flint-glass. 
he latter is partly composed of lead, and has a considerably 
greater power of dispersing the colored rays than the former. 
If we combine a bi-convex crown-glass lens with a plano- 
concave flint-glass lens (both are generally cemented together 
Wlth Canada balsam) we obtain a combination in which the re- 10 
SECTION FIRST. 
fraction of tlie convex crown-glass lens is lessened, but not de- 
stroyed, by tlie dispersive action of the flint-glass lens. At the 
same time, however, the color dispersion {v r, fig. 14) of the 
crown-glass lens is 
neutralized by the 
contrary action of 
the flint-glass lens, 
so that the violet and 
red rays are accu- 
rately united in F, 
at the central focus of the lens. The image here produced 
will either be colorless or have its natural color. 
Such a combination presents, at the same time, an expe- 
dient by which the spherical aberration may also be substan- 
tially improved. 
A double lens, with which the spherical as well as the chro- 
matic aberration is annulled, is usually called aplanatic. But 
in reality it is impossible to completely obviate either the 
spherical aberration (for reasons, to discuss which here would 
lead us too far) or the chromatic, for even when the violet and 
red marginal rays are made to unite, the ratio of the disper- 
sion of the various colored rays of the spectrum is never en- 
tirely equal. 
Should, therefore, even with a double lens, the violet and 
red rays of light be united, the edges of the image would still 
exhibit traces of the ununited central rays of the spectrum. 
The edges appear greenish yellow. It is customary, therefore, 
in the construction of double lenses for the microscope, to give 
a slight preponderance to the flint-glass lens, so as to obtain a 
bluish tinge, which is more agreeable to the eye; the double 
lens is then said to be over-corrected. A double lens is under- 
corrected when a reddish border is perceptible. 
As, in regard to color dispersion, one speaks of over- and 
under-correction, the same mode of expression is also used in 
speaking of the correction of spherical aberration. 
While the discovery of achromatism had already, in the 
middle of the previous century, led to the production of im- 
proved telescopes, the smallness of the object lens discouraged 
the microscope-makers from making the same experiment on 
the latter. 
According to Harting’s statement, the Hollander, Hermann 
Fig. 14. Achromatic lens. THEORY OF THE MICROSCOPE. 
11 
Van Deyl, produced the first achromatic microscope, in a very 
satisfactory manner, in the year 1807. Four years later, 
Fraunhofer, the renowned optician of Munich, supplied achro- 
matic instruments. In the year 1824 the two Chevaliers of 
Paris, under the direction of Selligue, combined for the first 
time several achromatic objective lenses into one system. The 
Italian Amici, of Modena, then acquired an immortal renown 
in the sphere of microscopical improvements. Other opticians 
followed him with worthy emulation, among which, for the 
end of the first half of the present century, we will particular- 
ize only Pldssl, of Vienna; Schiek, of Berlin; and Oberhau- 
ser, of Paris. The instrument soon became as useful and com- 
plete as that of the eighteenth century was unserviceable and 
incomplete. The commencement of the great and brilliant era 
of modern microscopy is cotemporary with these improvements 
of the instrument. But the recent past has also presented 
many permanent and important improvements, as we shall 
hereafter see. 
Let us return, however, to the mechanism of our instru- 
ment. 
If we glance at fig. 8, we shall perceive that the image of 
the arrow produced by the achromatic lens is now free from 
colored borders and the spherical aberration essentially cor- 
rected, but the incurvation and distortion of the same, as well 
as the diminutiveness of the field of vision, that is, the plane 
surveyed by the eye-piece, remains as before. 
Among the accessories which are employed for further cor- 
rection is a very old one, namely, the introduction of another 
convex lens into the tube of the microscope. This, fig. 15, C, 
is placed between the objective L and the ocular O, so, how- 
ever, as to occupy a position beneath the point of union c* a* b* 
°f the cones of rays refracted by the objective lens from the 
object. 
The advantage obtained by the introduction of such a con- 
vex lens or field-glass is manifested in various ways. Firstly, 
Lie rays proceeding from the points b and c of the arrow are 
refracted by the convex lens towards its axis, as be seen 
m the figure. Without the field-glass the image would be pro- 
jected at c* a* b*, too much extended to be surveyed from the 
ocular lens. An image is now projected at c** afk* b** which, 
though not so large, still comprises the entire arrow. Secondly, 12 
SECTION FIRST. 
the clearness of the image is increased by the tield-giass, as all 
the rays, which, without this lens, would have produced the 
image (fk a* b*, are now united in the smaller space of the 
image c** a** Ir**. Thirdly, such a field-glass, in connection 
with the ocular, may serve to improve the correction of the 
spherical and chromatic aberration. Fourthly—and in this lies 
Pig. 15. The compound microscope with a field-glass. 
a great advantage—the field-glass obviates the distortion of the 
image and the unequal enlargement of the various portions of 
the field of vision connected with it. As we have already 
learned, the rays passing through the marginal portions of the 
lens are more strongly refracted than those passing through its 
central portions, in consequence of the spherical aberration, THEORY OP THE MICROSCOPE. 
13 
and the axial and peripheral points of the image approach each 
other proportionately (fig. 11). Now, as the ocular lens, for 
observing the aerial image c** a** &**, exerts exactly the con- 
trary effect (tig. 12) by its considerable diameter, the entire 
correction may be obtained by the proper use of an ocular and 
a field-glass (tig. 10), 
These various, and, for the most part, highly important ad- 
vantages secured by the addition of a field-glass render it 
appreciable that the latter is no longer omitted in any of the 
compound microscopes of the present time, and that it has be- 
come an integral element of all its combinations.* 
We have remarked above that, since the year 1824, the in- 
dividual achromatic double lenses are combined with each 
other into, so-called, systems. Various advantages are thereby 
obtained. It is very difficult to construct a double lens of 
crown and flint glass with a short focus, while several weaker 
ones combined give the same magnifying power as the 
simple objective, and are much easier to make. Then, 
as we have also seen, by the combination of a single 
crown and flint glass lens, whereby, also, a small 
angle of aperture must always be given to the lens, 
tfie spherical and chromatic aberration are essen- 
tially lessened, but not entirely obviated. By a suit- 
able combination of several double lenses, where the 
aberrations of one lens are made to correct the op- 
posite ones of another, a considerable further cor- 
rection is obtained, and a much larger angle of aper- 
ture may be used ; in this manner the greatly im- 
proved lenses of our microscopes of the present day 
are produced. In these only two, or, at most, three double 
lenses are combined with each other (tig. 16). 
The earlier opticians generally designated the several double 
lenses by a series of numbers, 1, 2, 3-6, the weakest bearing 
the lowest number, and screwed them together into a system 
(for example, 1, 2, 3, and 4, 5, 6). In this way, with a moder- 
ate number of single lenses, a series of systems may be con- 
structed, it is true ; but two things which are of greater impor- 
Fig. 16. An 
achromatic ob- 
jective and its 
angle of aper- 
ture. 
_ * E. Abbe, of Jena, has recently attempted to modify the theory of the compound 
horoscope. He divides the total effect of our instrument into a lower loup action 
and an upper telescopic action. For many purposes this plan is certainly convenient; 
"We doubt, however, that it will accomplish much. 14 
SECTION EIEST. 
tance, the accurate centering (that is, the falling together of the 
axes of the lenses in a single straight line) and the proper dis- 
tancing of the single lenses from each other, cannot be so ac- 
curately accomplished as where these are permanently com- 
bined with each other in systems. The preference has, there- 
fore, very properly been given to the latter arrangement, and, 
though the former is the least expensive, it should be entirely 
discarded. The permanent systems are variously designated by 
the opticians ; either by numerals increasing with the strength 
of the combination, or by a series of letters. The manner of 
expression of the English opticians is peculiar. They speak of 
-g--, TV-, of an inch combinations of lenses, making the in- 
crease of the strength of their systems the same as that of a 
simple lens of i, •§-, TV, inch focus. 
The stronger modern lens systems are, at present, differ- 
ently arranged. The lower, nearly semiglobular crown glass 
lens (with the plane surface turned downwards) is combined 
generally with two, more rarely three strongly over-corrected 
crown-flint glass lenses. 
The combination of the lenses with each other is arranged 
so that the strongest, smallest lens (end or front lens) turns 
downwards, the weakest upwards (fig. 16). A somewhat 
greater focal distance is thus obtained, and such angles of aper- 
ture may be given to the lenses, that all the rays of a cone of 
light c ah received by the lower lens may also pass through 
the entire combination of lenses. Only in this way has it been 
possible to give the above-mentioned high angle of aperture to 
the objectives, which must naturally increase the brightness of 
the image, and besides, as we shall see hereafter, considerably 
increase the intrinsic power of the combination also. 
The ordinary eye-piece of our microscopes (fig. 17, 0), also 
called the Huyghenian or negative eye-piece, consists of a 
longer or shorter tube carrying at its upper end the plano-con- 
vex lens A, whose plane surface is turned towards the eye of 
the observer, while the plano-convex lens C, with its curved 
surface also turned downwards, is screwed into the lower end 
of the tube. The aerial image P* falls, as we have seen, be- 
tween the field and ocular glass. Every microscope is supplied 
with several such eye-pieces of various strengths, designated 
by numbers. The eye-pieces become shorter in proportion to 
the increase of their magnifying power. Another form is called THEORY OF THE MICROSCOPE, 
15 
the Ramsden, or positive eye-piece. It also consists of two 
plano-convex lenses ; but their curved surfaces are turned 
towards each other, and they lie nearer together. Here the 
image does not fall between 
the field and ocular glasses, 
hut lies at a short distance 
beneath the former. The 
latter eye-piece is, however, 
but little used. 
Kellner’s orthoscopic eye- 
piece is a modification of that 
°f Huyghens, or the nega- 
tive ; its field-glass is bi-con- 
vex. It presents a very large 
held free from image distor- 
tion, without, however (and 
111 this I must agree with 
Harting), appreciably in- 
creasing the optical power. 
Hartnack has recently 
constructed a new, strong 
eye-piece, the oculaire Jiolos- 
tere. It consists of a sin- 
gle conical-shaped piece of 
glass, after the manner of the 
hoddington lens, and mag- 
nifies about ten times. It has 
thus far, however, presented 
roe no considerable advan- 
tages. 
In order to render the 
Huyghenian eye-piece as free 
as possible from spherical 
nnd chromatic aberration, it 
las been proposed to make 
n aplanatic and to combine 
1t with an aplanatic objective 
system. Such aplanatic eye- 
pieces are to be found with 
niany instruments. Their magnifying power is weak and the 
eld of vision small. 
Pig. 17. The compound microscope. 16 
SECTION FIRST. 
The usual arrangement is different. It consists of the use of 
eye-pieces which are by no means entirely aplanatic, and the 
aberration present in the eye-piece is made to correct the oppo- 
site aberration of the lens system. Objectives of somewhat 
over-corrected chromatic, and also spherical aberration are 
combined with under-corrected eye-pieces. An objective which 
was rendered as aplanatic as possible would, on the contrary, 
if combined with one of the ordinary eye-pieces, produce an 
imperfect image. While therefore aplanatic lenses are neces- 
sary for the loup and the simple microscope, the art in the 
production of a compound dioptrical microscope rests directly 
in the removal of the aberrations of the objective by means of 
the contrary aberrations of the eye-piece. It is only thus that 
an image free from defects may be obtained, in a manner sim- 
ilar to that already mentioned of correcting one double lens of 
an aplanatic system by means of the other. 
In eye-pieces the distance of the field-glass from the oculal- 
iens is of importance. If the former glass is made to approach 
the latter, the aerial image is greater; if the latter glass be 
made to approach the former, it is smaller. The opticians, as 
a rule, fix both the glasses of an eye-piece in an unchangeable 
position; they select the ones offering the most advantageous 
action. The length of the tube of the microscope, which in 
increasing also increases the magnifying power, is likewise of 
importance to the advantageous combined action of the ocular 
and objective systems. Less increase in the length of the 
microscope tube is permissible with a higher degree of over- 
correction of the lenses than with a weaker one. 
Still another element is associated with the optical relations 
enumerated, for a knowledge of which we have to thank Amici. 
At the present time it receives due attention, whereas for a long 
time it was entirely ignored. We refer to the thickness of the 
scale of glass with which it is customary to cover the object for 
microscopical examination. The thickness of the glass cover 
exerts considerable influence on the sharpness of the image, 
especially when strong lenses are used. An object which, un- 
covered, or with a very thin glass cover, presents a sharp image, 
becomes somewhat dim and foggy, and the appreciability of its 
details diminishes, if a thicker cover be used. Inversely, many 
lenses only manifest their highest capabilities when a covering 
glass is used. THEORY OF THE MICROSCOPE. 
17 
ow, on what does this influence of the cover depend, and 
wliat are the means for its correction \ 
Let P, fig. is, be a thick glass plate, and a a point of light 
10111 which proceeds a cone of rays. The rays on entering the 
B'lass will be re- 
dacted in various 
degrees. The ex- 
ternal, most ob- 
-11 finely incident 
lays a f and a g 
"dl be the most 
strongly refracted 
arid will assume 
die directions ff* 
and g g*' tlie more 
Hiternal rays a d and a e will be less influenced, and the 
central rays a b and a e will be still less deflected from 
leir course. On emerging from the glass the most external 
lays are refracted in the direction f*f** and g* g**, the more 
diternal ones in the direction d* d** and e* e**, and those most 
eternal in the direction b* b** and c* c**. The luminous spot 
Wlll appear to the eye as though it were seen nearer in the 
£ a§s, and instead of one luminous point a series of points lying 
°Ver each other will seem to be present; as h for the rays b 
aad c, i for d and e, Jc for f and g. If, instead of a point, we 
c ave an object, it will make an impression as if it consisted of 
a series of images lying over each other. We receive, therefore, 
0 same effect as from spherical aberration, and in a degree 
hich increases with the thickness of the glass covers. It will 
before be appreciable how imperfect such a course of the 
la?.S dght must render the image of an object with a lens 
11011 is arranged for uncovered objects ; for the same reason, 
au objective constructed by the optician for a covered test ob- 
Ject will only develop its perfect action when a suitable cover 
Used. Weaker combinations manifest this influence of the 
ss covers only in a minor degree, however; stronger ones, on 
contrary, in a very appreciable manner, 
in ls lnHuence °i- cover may be counteracted by chang- 
Ig the length of the microscope tube, and also by altering the 
between the ocular and field glasses. It is advisable, 
a practical point of view, to use a system with its appropri- 
-2 
Fig. 18. Effect of the covering-glass. 18 
SECTION FIRST. 
ate covers only, and to have special thicknesses of glass for 
each system. 
Another method is now becoming more generally adopted. 
By changing the position of the individual lenses of a combina- 
tion this action of the glass cover may be obviated, and thus 
one and the same system may be employed either for uncovered 
objects or for such as have covers of various thicknesses. For 
this purpose the individual double lenses of a system are ar- 
ranged so that their relative positions may be changed by means 
of a fine screw; thus the observer is enabled to make the neces- 
sary change at any moment. Such combinations are called 
objectives with correcting apparatus. They are naturally more 
expensive than ordinary objectives and require in their use a 
certain amount of practice and some outlay of time, but the 
arrangement is almost indispensable for very high powers. 
The rule is, that with increasing thickness of the cover the 
individual lenses of the system must be brought 
nearer to each other, while for very thin covers 
they must be moved farther apart. In fig. 19, 
the objective represented with a correcting ap- 
paratus has a small metallic slider, which, mov- 
ing up or down, indicates the various positions 
of the lenses. 
Having familiarized ourselves with the objec- 
tive and the eye-piece, we are now in condition to 
examine more closely the construction of a mod- 
ern compound microscope. 
The optical portion is of the greatest importance ; the 
arrangement of the stand is, on the contrary, of much less con- 
sequence. Good lenses with suitable eye-pieces, placed on a 
very imperfect stand, would enable an observer to recognize 
subtile structural conditions which would be concealed from 
another, whose instrument combined an imperfect optical ap- 
paratus with a very superior mechanism. Nevertheless, dis- 
regarding the tediousness of the manipulation, poor, incomplete 
stands exert an immediately injurious effect on the optical per- 
formances of a microscope, by not permitting of the necessary 
modifications of the illumination. 
Every modern instrument requires several objectives ; name- 
ly, a weak, a medium, and a strong one ; the combinations of 
each should, preferably, be permanent. Large microscopes 
Fig. 19. Achro- 
matic objective with 
correcting appara- 
tus. THEORY OF THE MICROSCOPE. 
19 
have a more abundant supply of objectives, five or six, and 
even more, and among them the most powerful ones, in the 
production of which great proficiency has been developed of 
late, as we shall see further 
°n. These very high powers 
are not required for ordina- 
ry investigations, and can, 
therefore, be more readily 
dispensed with than combi- 
nations of medium strength. 
A few eye-pieces, at least 
two, are necessary; a weak 
°ne, magnifying about three 
or four times, and a stronger 
°ne of double that strength. 
It might readily be be- 
lieved that a considerable 
number of eye-pieces with 
increasing, and, finally, with 
vei‘7 high magnifying power, 
w°nld be of advantage to 
°ur instrument. But this is 
erroneous. Let us remember 
Ihut an enlarged image 
be projected by the 
objective L, fig. 20, into the 
tube R, and would not be 
without defects, as it is im- 
possible to produce mathe- 
matically correct lenses. The 
jniage would be magnified 
y the eye-piece, and, nat- 
nially5 imperfections in 
e sanie proportion also. 
le eye-piece does not, 
iciefore, like the objective, 
Peimit us to penetrate more 
t-Ply into the structure of 
6 ob.le°t; it only enlarges the images of the latter. The 
nse of somewhat stronger eye-pieces has the advantage, how- 
ever, of enabling us to recognize many things more readily, 
Fig. 20. 20 
SECTION FIRST. 
because they are more enlarged. But in using still stronger 
eye-pieces, we soon arrive at a limit where the image is impaired. 
The most beautiful and elegant images are obtained with very 
weak eye-pieces. Nevertheless, many of the more modern 
lenses bear considerably stronger eye-pieces than those of a 
former epoch, which must always be regarded as a proof of 
superior optical perfection. 
No further observations are necessary, therefore, to show 
that it is impossible to compensate for the poverty in lenses of 
a microscope by a profuse endowment of eye-pieces. It is also 
evident that the value of an enlargement, obtained with a 
stronger objective and a weaker eye-piece, stands higher than 
that of another, where a strong eye-piece is used with a weaker 
objective. Older German microscopes frequently have only 
weak objectives, but are, on the contrary, furnished with sev- 
eral eye-pieces of too great strength. This is to be regarded 
as a fault. At the commencement of the fifth decade of this 
century, for example, the instruments of Schiek compared very 
disadvantageously, in this regard, with those of Oberhauser. 
The tube of the microscope, as well as that of the eye-piece, 
has its inner surface blackened, and is either in one piece (fig. 
20, R), and therefore incapable of extension, or it is composed 
of two pieces which glide over each other, after the manner of 
the telescope. That the latter is to be regarded as the better 
arrangement is proved by several previously mentioned optical 
principles. 
An immoderate elongation of the ocular tube is likewise 
attended with optical disadvantages. 
The objective (L) is to be fastened on to the lower end of 
the tube by means of a screw. 
The stage (T) is the metal plate perforated in its centre, 
already described in speaking of the simple microscope, for 
the reception of the object (P. E.) to be examined. The stage 
shordd not be too small, and especially not too narrow. 
Objective and object must be capable of being moved from 
or towards each other, as circumstances may require. All com- 
pound microscopes have arrangements for this purpose, that is, 
for focussing the object. Shoving the microscope tube with 
the hand through a metal sheath is a very primitive contriv- 
ance, and is only practicable with weak powers. 
Y arious expedients are employed for more accurate altera- THEORY OF THE MICROSCOPE. 
21 
tion of the focus. This may be accomplished, to a considerable 
extent, by means of a single mechanism, when the latter is 
carefully constructed. In fact, the older instruments fre- 
quently have no other. As a rule, the tube of the microscope 
is made to screw up and down on its support; less frequently 
employed, and still less to be recommended, is a movable 
stage, the tube being immovable. 
With the more carefully constructed modern stands a 
double mechanism is provided, one of which serves for the 
coarse, and the other for the fine adjustment. Such a distri- 
bution of the work naturally deserves the preference. The 
coarser movements are made either by machinery, or, what 
answers just as well and is more practicable by reason of its 
greater simplicity, the tube of the microscope may be moved 
in a sheath which surrounds it, by the hand. The finely con- 
structed micrometer screw, which moves the microscope, is 
used for more accurate focussing; the practised observer 
almost never removes his hand from it in making delicate in- 
vestigations and when using the higher powers. 
Ordinary incident light is rarely used for the illumination 
of the object, and then only when the lowest powers are em- 
ployed. When strong illumination is required, a convex lens 
ia) fig. 21) with a long focus is employed. It 
should be movable in various directions, and 
placed either on a stand d h c, or on a ring which 
18 to be shoved over the tube of the microscope. 
Objects are most frequently illuminated by 
uieans of transmitted light, the light being re- 
ceived on a mirror (fig. 20, S) placed beneath the 
stage, and reflected through the opening to the 
object (P). 
The mirror must be fastened to the stand in 
such a manner as to permit of the greatest free- 
dom of movement. The arrangement of many of 
the smaller instruments, permitting the mirror to 
uiove around its horizontal axis only, is an impor- 
tant imperfection. Small microscopes have only 
a c°ucave mirror, by which the incident rays {a a) 
aie reflected in a convergent direction (5 h) to the hole in the 
®tage. Larger instruments have a mirror with one of its sur- 
aces concave and the other plane. The latter surface gives a 
Pig. 21. Illumi- 
nating lens. 22 
SECTION FIEST, 
less intensive illumination than the former, and is, therefore, 
more frequently used with the weaker powers. 
Careful illumination is a very important accessory in micro- 
scopical examinations, and is not to be obtained with the above- 
mentioned contrivances alone. Other special apparatuses are 
consequently necessary. For many examinations, especially 
of delicate, finely bordered objects, the light reflected through 
the opening of the stage would give a much too dazzling illumi- 
nation. A portion of the rays must therefore be cut off. This 
is accomplished by diminishing the opening of the stage; for 
this purpose the so-called screens or diaphragms are used. 
Two forms are employed; the rotary and the cylindrical 
diaphragm. The rotary diaphragm (a, fig. 22) has a circular 
form and is fastened under 
the stage by means of a 
button, A series of circu- 
lar openings diminish, with 
the exception of the largest, 
the aperture of the stage. 
The smallest holes are em- 
ployed with the highest 
powers. 
Cylindrical diaphragms 
are cylindrical tubes which 
have at their upper ends a 
circular disk with an opening of varying size (fig. 22, b, c). 
They are inserted into the opening of the stage, either imme- 
diately or by means of a socket. To develop their complete 
action, some contrivance is necessary, by means of which they 
can be raised or lowered. 
Both arrangements accomplish their objects ; but the cylin- 
drical diaphragm deserves the preference, as it permits of finer 
gradations of illumination. On many of the older instruments 
we find both these kinds of diaphragm combined. 
For many purposes, instead of the ordinary illumination, 
generally called central light, it is necessary to reflect the light 
from beneath in a more or less oblique direction on to the ob- 
ject, called oblique illumination. For this purpose, the mirror 
should have the utmost freedom of motion, because it is some- 
times necessary to give it a very lateral position. 
A further modification of the illumination is obtained by in- 
Fig. 22. Diaphragms, a, the rotary diaphragm; 6, c, 
cylindrical diaphragms. THEORY OF THE MICROSCOPE. 
23 
serting a convex lens or a combination of lenses into tlie aper- 
ture of tire stage. By elevating or depressing the lens, we may 
cause the rays of light coming from the plane mirror to unite 
in a focus at the object, or to arrive at it in a divergent direc- 
tion, either before or after their union. A concave mirror, 
combined with such lenses, sometimes affords very good illu- 
mination. 
Such an illuminating apparatus, consisting of achromatic 
lenses, was made many years ago by Dujardin. Considerable 
attention was afterwards directed to these, especially by the 
English opticians, who called them condensers, resulting in 
their essential improvement. A condenser of perfected con- 
struction is sliown in fig. 23. Below 
it is a rotatory diaphragm which is 
capable of covering a greater or lesser 
portion of its margin and, by means 
of several openings, darkening the 
central portion of the lens, which 
causes peculiar effects, resembling 
many of those of oblique light. 
I have recently received from 
Hartnack an efficient condenser, quite 
similar to the illuminating apparatus formerly constructed by 
Bujardin, consisting of three achromatic lenses. Diaphragms 
may be screwed on to the upper lens. The apparatus is to be 
inserted into the stage in the same manner as a cylindrical 
diaphragm. 
It has subsequently been still further improved. Seibert 
aud Krafft also furnish very good ones. 
As an achromatic condenser is expensive, it may be substi- 
tuted, to a certain extent, by an 
ordinary plano-convex lens. Fig. 
24, 1, shows such an one inserted 
into the tube of an ordinary cylin- 
drical diaphragm. In 2, it is cov- 
ered by a black ring, so that only 
the central portion remains free for 
the passage of the rays of light ; 
while in 3, a small black disk obscures the central part of the 
lens, leaving only the peripheral portions free. The latter ar- 
rangement is to be recommended to those whose microscope 
Fig. 23. Achromatic condenser of 
Smith and Beck. 
H 24- Ordinary condenser; 1 in sec- 
’ ~ covered by a black ring; 3 with a 
central disk. 24 
SECTION EIKST. 
Fig, 25. Microscopes of Merz, of Munich. 111. smallest, 11. medium, I. large instrument. 
Fig. 26. Small micro- 
scope of Schiek. 
Fig. 27. Small microscope 
of Leitz. 
Fig. 28. Small micro- 
scope of Hartnack. THEORY OF THE MICROSCOPE. 
25 
does not permit the mirror to be placed obliquely. The whole 
arrangement is, besides, one of the cheapest. 
As we shall see hereafter, such convex lenses are necessary 
for investigations with polarized light, as well as when the mi- 
croscope is used as a micro-photographic apparatus. 
At the close of this section it may be expedient to glance at 
several microscopes, and thus obtain a few examples of the va- 
rious methods adopted by opticians for fulfilling the various 
indications. 
Fig. 25, 111. shows a microscope of the smallest sort made 
by Merz, of Munich. The coarse adjustment is made by shov- 
ing the tube through a spring sheath, the fine movement is (in- 
expediently) accomplished by the elevation and depression of 
the stage. The concave mirror permits of central illumination 
only. 
Fig. 26 represents a smaller instrument of Schiek’s, with a 
simpler but more convenient stand, and one which suffices for 
most observations. Here, also, the stage moves up and down. 
Similar arrangements, but with immovable stages, also ob- 
tain in the smaller instruments of modern firms, such as Leitz, 
in Wetzlar (fig. 27), Hartnack (fig. 28), Nachet (fig. 29), Cheva- 
lier in Paris (fig. 30), Zeiss in Jena (fig. 31), and Seibert and 
Krafft in Wetzlar (fig. 32). Here, also, the microscope tube is 
shoved up and down in a spring sheath, and thus serves as a 
coarse adjustment. The fine adjustment is made by a screw 
head placed at the upper end of the stem. The stage is suffi- 
ciently wide, and there is generally beneath it a rotary disk for 
moderating the illumination. Several clamps are occasionally 
added to the stage. They are intended for holding the glass 
slides and may be removed if necessary. The mirror is fastened 
to the foot or the stem, and permits of great freedom of move- 
ment (the best is seen in fig. 33), It may be moved away from 
the axis, and thus be employed for oblique illumination. The 
illuminating lens serves for illumination with incident light in 
many of these instruments, as in figs. 33 and 34. The rotary 
diaphragm is, as a rule, flat ; in fig. 31, on the contrary, it has 
a convex surface turned upwards, so that the diaphragm aper- 
ture may be as close as possible to the object. 
Such instruments, among which the medium-sized micro- 
scope of Merz, fig. 25, 11., is also to be reckoned, have very 
suitable stands, which are frequently imitated by other micro- 26 
SECTION FIRST. 
Pig. 29. Small microscope of 
Nachet. 
Fig. 30. Small microscope of 
Chevalier. 
Pig. 31. Small microscope of 
Zeiss. 
Fig. 32. Medium micro- 
scope of Seibert and Krallt. 
Pig. 33. Smaller microscope of 
Nachet, with, oblique position. 
Fig. 34. Smaller microscope of 
Hartnack, arranged for inclining. THEORY OF THE MICROSCOPE. 
scope-makers with slight modifications. Naturally a stand 
may be still further simplified, but its adaptability to various 
kinds of examinations is impaired, for example, when the ob- 
lique illumination is omitted. Nachet’s stand, fig. 88, and that 
of Hartnack, fig. 34, are of somewhat more complicated con- 
Fig. 35. Large, older horse shoe microscope of Oberhauser and Hartnack. 
struction to permit of an inclination and turning of the stage 
and tube. 
The large horseshoe miscroscope (fig. 35), invented by Ober- 
hauser, of Paris, has one of the most efficient stands. It has 
been more frequently imitated than any other with which I am 
acquainted, and combines the advantage of the greatest adapta- 
bility with simplicity of construction. SECTION FIRST. 
In the old stand, the coarse adjustment is also made by slid- 
ing the tube in the spring sheath, but his latest instruments are 
furnished with a mechanism for this purpose. The tube itself 
is capable of being shortened. The fine adjustment is made 
with a micrometer screw which projects beneath the stage and 
runs in a hollow tube containing a spiral spring. The screw 
Fig. 36. The same with oblique illumination, a, cylinder for the diaphragm ; b, slide. 
moves a second tube which surrounds the former and is joined 
to the sheath of the microscope tube. The diaphragms, sur- 
rounded by a cylinder (fig. 36 a), are carried by a so-called 
sliding plate (£), and are adjusted by raising or depressing the 
cylinder. When one diaphragm is to be replaced by another, 
the cylinder is to be drawn out, armed with a new diaphragm, THEORY OP THE MICROSCOPE. 
29 
PiG. 37. Small horseshoe 
microscope of Hartnack, 
with the tube pushed in. 
Fig. 38. Large microscope of Seibert 
old Krafft. 
Fig. 39. Large microscope of Smith and Beck. 30 
SECTION FIEST. 
and replaced from beneath the stage. If oblique illumination 
is necessary (fig. 86), the sliding plate with its entire apparatus 
is to be removed. 
With the latter illumination the stage may be rotated, so 
that the obliquely incident rays of light may come from all 
sides on to the object. The mirror works on a square piece 
fitting into the embrasure of the double bar which supports the 
Fifi. 40. Kachot’s large microscope, most recent pattern. 
instrument, and permits of the most varied changes of position. 
The large, heavy horseshoe foot supports the whole. An il- 
luminating lens on a separate stand (after the manner of fig. 
21) may be placed before the instrument. 
A smaller form of the same stand (fig. 87) dispenses with 
the rotary stage, and does not permit the mirror to be moved 
up and down in a slit, though the oblique position is still pos- THEORY OF THE MICROSCOPE. 
31 
sible. This stand of Hartnack’s is very good and at the same 
time exceedingly cheap. 
Both stands may also be obtained at a moderate price, fur- 
nished with a hinge for inclining. 
Merz’s large instruments, and those of Seibert and Krafft, 
are also quite similar to these, as is shown in figs. 25, 1, and 38. 
We also notice a large microscope, fig. 89, of Smith and 
Beck, of London, as an example of an instrument which is much 
more complicated (too much so, according to our Continental 
notions) in its structure. Much is here allotted to screws 
which, in Oberhauser’s stand, is done by the human hand. 
The instrument hangs between two pillars and can, therefore, 
be given an oblique or horizontal position. The mirror per- 
mits of a pretty free movement. The stage is too profusely cov- 
ered with appurtenances, but permits (and in this lies a great 
advantage over Oberhauser’s instrument) of the introduction 
of a perfected condenser. 
Nachet’s large microscope of latest construction (fig. 40) 
is likewise remarkably complicated, but its mechanism is 
admirable. Section Second. 
APPARATUS FOR MEASURING AND DRAWING. 
It is unnecessary to mention liow important the measuring 
of objects seen under the microscope is for scientific work. In 
fact, various and, in part, ingenious methods were proposed in 
the infancy of microscopy for determining the size of objects. 
The reader will find more on this point in the excellent work 
of Harting. 
At the present time, we have measuring apparatus of rela- 
tively greater accuracy. Two forms of micrometers are to be 
particularly discriminated; namely, first, the screw microme- 
ter, and, second, the glass micrometer. 
The screw micrometer is a somewhat complicated but, when 
the workmanship is good, very accurate, and, therefore, also 
very expensive implement. Its arrangement rests upon the 
following. If a cobweb thread is drawn across the eye-piece, it 
is self-evident that a microscopical object may be so guided 
through the field of vision, by means of a stage moved by 
screws, that its anterior border first cuts the thread, and then 
gradually passes beyond it, till at last only the posterior mar- 
gin of the object exactly touches the thread. Now, the screw 
micrometer is such a movable stage. It has a double plate, 
the upper one of which is movable, by means of a very fine 
micrometer screw, over the lower one, which is fastened to the 
stage of the microscope. A partial view of this arrangement 
is afforded by fig. 25, 1. The extent which it is necessary to 
turn the screw, in order to move the object, in the manner in- 
dicated, through the field, may be read from the index of the 
upper plate and the divisions on the drum of the screw. The 
unities of these screw micrometers vary. Those of Plossl give 
yq-qo"o of a Vienna inch, those of Schiek, aud Toooo of a 
Parisian line. The ocular screw micrometer is an advantageous APPARATUS FOE MEASURING ANB DRAWING. 
33 
modification of the screw micrometer, especially the improved 
form described several years ago by Mohl. 
Nowadays, however, the expensive screw micrometers are 
rarely used ; the much simpler and less expensive glass micro- 
meters are used in their stead. 
It is well known that the art of engraving fine divisions on 
a glass plate, by means of the diamond point, has made great 
strides, and in a later section we shall see the marvellous mani- 
festation of this skill in Nobert’s test plates. 
The line is now divided, with the greatest elegance, into 100, 
500, and 1,000 parts. In some of these micrometers the lines 
are all of equal length ; those are better in which the greater 
divisions are indicated by longer lines, as is the case with our 
ordinary rules. A modification, which is convenient for many 
purposes, consists in the crossing at right angles of one series 
of lines by a second series, generally so that quadratic spaces 
result. 
Now, such micrometers are capable of the simplest appli- 
cation as object bearers. Let us assume that we have a divi- 
sion where the value of each space is -yj/", it is self-evident, 
that a microscopical object which occupies two of these spaces 
is g-L/", and another, which covers five, is I^/// in size. 
However efficient these methods may seem, at the first 
glance, to be, they are nevertheless very inconvenient, and it is 
therefore no longer customary to use them. First, because the 
minuteness of many objects requires a very finely divided and 
therefore very expensive micrometer. Then, in cleaning them 
they become injured in a comparatively short time, and gradu- 
ally become seriously impaired. Further—and this is of much 
greater moment—the objects to be measured very often lie 
obliquely, and not parallel to the lines, however fortunately 
they may be placed on the micrometer. Finally, the case of- 
ten arises where it is necessary to estimate the value of a frac- 
tion of a space, whereby the eye may be deceived. 
From the above mentioned it will be conceivable that the 
glass micrometer, in the form of an object bearer, has been dis- 
carded except for certain special purposes. 
These micrometers are now placed in the eye-piece, as ocu- 
lar micrometers, in the form of circular glass plates. They lie 
on its diaphragm, between the field glass and the ocular lens 
(fig. 20, B). SECTION SECOND. 
Snell ocular micrometers (fig. 41) have naturally quite a dif- 
ferent action. When the glass plate lies on the stage, the 
divisions and the object are equally enlarged by the entire 
dioptrical apparatus of the instrument. In 
the latter case, that is, when placed in the 
eye-piece, the micrometer is enlarged by the 
weak ocular lens only, and appears to the 
eye simultaneously with the image of the 
object to be measured, which is enlarged by 
the objective and again somewhat diminished 
by the field glass. This may be accomplished 
with glass micrometers which are coarser, 
and therefore more accurate, and also less expensive to con- 
struct, They do not wear out, and any object in any position 
on the slide may be instantaneously measured, so soon as the 
eye-piece containing the micrometer has been substituted for 
the ordinary one, and adjusted by turning it in the tube. But 
with more opaque objects an inconvenience arises in the diffi- 
culty of seeing the micrometer divisions over the object to be 
measured. No microscope should be without such a microm- 
eter, which may be obtained for a few (4-5) thalers. In con- 
sequence of the unequal visual distances of different observers, 
it is necessary to vary the adjustment of the ocular micrometer 
by means of a screw arrangement, so that it and the object 
may simultaneously appear alike distinct to any eye. 
It should not be forgotten, in using the eye-piece microme- 
ter, that its value is a relative one, depending on the strength 
of the objective used (therefore variable with immersion lenses), 
and the length of the microscope tube, which always determines 
the size of the image. It is most advantageous to have the lat- 
ter completely drawm out when measuring. 
We have a very simple procedure for determining the value 
of the micrometer in the eye-piece; we avail ourselves of the 
aid of a glass micrometer on the stage. Assuming that it has 
a Paris line divided into 100 portions ; with the objective A, 
perhaps five spaces of the eye-piece micrometer will exactly 
cover one space on the stage micrometer; the value of one of 
its spaces for the objective A is therefore -gfa/". To obtain 
greater accuracy, various portions of the stage micrometer 
should always be used for the measurement, and the mean of 
10-15 single measurements drawn. Always keep in the middle 
Fig. 41. Eye-piece mi- 
crometer. APPARATUS FOR MEASURING AND DRAWING. 
35 
of the field to avoid any distortion of the image that may be 
present. In this manner the value of the eye-piece micrometer 
for the various objectives of a microscope is reckoned and tab- 
ulated. 
Besides this most simple eye-piece micrometer, serving 
completely nearly all the purposes of measurement, various 
other modifications have been produced, but we cannot at 
present enter into their consideration. Those who are inter- 
ested in the subject may read the respective section in Kar- 
ting’s work. 
All statements as to the size of microscopical bodies natur- 
ally depend upon the unity of measure on which they are 
based. Microscopists, as a rule, use the measure in general 
use in their country; those of England use the English inch, 
which is divided into decimal and duodecimal lines ; those of 
France use the Paris line or the millimetre. In one 
of the two last mentioned unities of measure is generally used, 
though the Vienna and Rhine lines are also used. The Paris 
measure is most convenient, and the millimetre deserves the 
preference. It is very convenient to use the thousandth part 
of a millimetre as a unity, under the name of micromillimetre, 
mmm or [i, as proposed by Karting. There is no actual ad- 
vantage in this ; it is merely convenient from its brevity. 
A millimetre is 0.4438 of a Paris line. 
0.4724 of an English duodecimal line. 
0.4587 of a Rhenish line. 
0.4555 of a Vienna line. 
The Paris line is 2.2558 millimetres. 
“ English “ 2.1166 “ 
“ Rhenish “ 2.1802 “ 
“ Vienna “ 2.1952 “ 
For further comparison we give a small table for reducing 
Paris lines to millimetres and vice versa. 
1. 
Millimetre. Paris lines. 
1. = 0.4433 
0.9 = 0.3990 
0,8 = 0.3546 
0.7 - 0.3103 
0.6 = 0.2660 
0.5 = 0.2216 
Millimetre. Paris lines. 
0.4 = 0.1773 
0.3 = 0.1330 
0.2 = 0.0887 
0.1 = 0.0443 
0.01 = 0.0044 
0.001 = 0.0004 SECTION SECOND. 
2. 
Paris lines. Millimetres. 
1. = 2.2558 
0.9 = 2.0302 
0.8 = 1.8047 
0.7 1.5791 
0.6 = 1.3535 
0.5 = 1.1279 
Paris lines. Millimetre. 
0.4 = 0.9023 
0.3 = 0.6767 
0.2 = 0.4512 
0.1 = 0.2256 
0.01 = 0.0226 
0.001 = 0.0023 
The goniometer is an apparatus used for measuring the 
angles of crystals. A simple and efficient arrangement (fig. 42), 
contrived by C. Schmidt for this 
purpose, consists of the following : 
—A circular plate, ab c, divided 
into thirds of a degree, is placed 
around the (fixed) microscope 
tube, at its upper end. To the 
outer edge of an eye-piece {p), 
provided with a crossed thread, a 
vernier {d) is fastened. The an- 
gle of the crystal to be measured 
is brought to the centre of the 
cross, and the threads are made 
Fig. 42. O, Schmidt’s goniometer, ab c, 
graduated disk; d, nonius at the border of the 
eye-piece p ; e, lens for reading off. 
to cover both sides of the angle in succession. The extent 
which it is necessary to turn the eye-piece in order to effect 
this is read off at the vernier, above which a plano-convex 
lens (e) is placed. 
Drawing the investigated object is not less important than 
its measurement with the microscope. It would appear to be 
superfluous to speak further of its value. It is, indeed, gener- 
ally acknowledged in the study of all branches of natural his- 
tory, and a successful illustration is often much more rapidly 
comprehended than the most detailed description. 
Every one occupied with natural science, and especially 
with medicine, should, therefore, be able to practise this art, 
at least in a slight degree. This qualification is all the more 
necessary in consequence of the peculiar nature of microscopi- 
cal vision. While an object which is perceived by the naked 
eye may be grasped and portrayed by an artist who is expe- 
rienced in the guidance of pencil and brush, seeing correctly 
with the microscope is itself an art which must first be learned 
before thinking of making a successful drawing. Although the APPARATUS FOE MEASURING AND DRAWING. 
37 
inquirer wlio understands liis specimen, even though no great 
master of the art of drawing, would be able to produce a toler- 
able and useful representation of the object, this would not be 
the case with a much more proficient artist who ventures, for 
the first time, to represent a microscopical image. Misunder- 
standings and errors would not be wanting. The latter is defi- 
cient in comprehension, while the microscopist is often enough 
in the fatal position of understanding his specimen thoroughly, 
and yet not able, with his unpractised hand, to reproduce it 
faithfully or with artistic conception. 
The simpler accessories for drawing, such as the pencil, the 
rubber, and water-colors, are generally sufficient for the micros- 
copist. Much that one draws to assist the memory during an 
investigation has only the character of simple sketches; like- 
wise, many things that are only incidentally noticed, are con- 
sidered worthy of being drawn in a note-book. It is not advis- 
able to draw everything, on account of the great outlay of time 
which would be necessary. Since we have learned to preserve 
specimens in fluid, in such a manner as to retain their natural 
appearances, they will render better service during a prolonged 
investigation than a volume filled with simple sketches. One 
should be particular in selecting drawings for publication. 
Not every preparation, not every view is characteristic. A 
well-selected representation is of more service than a whole 
series of less pregnant ones. 
More explicit directions as to details would here be out of 
place. Rough paper may be used for the larger sketches; a 
very fine English drawing-paper is necessary for the reproduc- 
tion of very delicate textural relations. A series of various 
sorts of pencils, of the best manufacture, should be selected. 
One should become accustomed to trace the first outlines as 
delicately as possible, then proceed to the darker shades, and 
only at last bring in the strong shade lines. The greatest care 
should be devoted to keeping the point of the pencil in order, 
for which purpose a file is best, if it be desirable to make any 
approach to the delicacy and fineness of many microscopical 
preparations. The use of the rubber should be learned from 
an expert teacher, thereby saving much consumption of time in 
shading. It should not be forgotten to lay in the shading sym- 
metrically on the right side, as it is only thus that elevations 
and depressions can be brought forward in the picture. The SECTION SECOND. 
intensity of the same is to be kept carefully in mind, and ren- 
dered as faithfully as possible, as this is the essential founda- 
tion of the natural disposition of many microscopical appear- 
ances. 
In using water-colors, the more transparent ones are, as a 
rule, employed ; more rarely those of a thicker consistence. 
Their application is soon learned. Too dazzling colors are not 
to be used; one should accustom one’s self to make fine col- 
ored lines with the point of a brush, which, for many purposes, 
are preferable to lines made with a lead pencil. 
In the course of time many kinds of apparatuses have been 
invented for rendering assistance in making drawings from the 
microscope, and, in fact, it is necessary for the microscopist to 
have such an appropriately constructed arrangement, especially 
when laying out a somewhat complicated figure, and for accu- 
rately rendering the various relations of form and size of its 
constituent parts. 
All the respective apparatuses aim, by means of special 
contrivances, to throw the microscopical image on to a sheet of 
paper, placed near the microscope, where its outlines may be 
traced with the point of a pencil. 
Glass prisms are generally used for this purpose. The sim- 
ple drawing prism may be placed over the eye-piece by means 
of a ring which fits over the tube of the microscope. It must 
be movable over the former so that it can be approached to- 
wards, or removed farther from the eye-piece. The paper may 
be placed on a drawing-desk, similar to a note-desk, behind 
the microscope. 
The camera lucida of Chevalier and Oberhauser is more con- 
venient than the simple drawing-prism for our vertical instru- 
ments, but is also somewhat more expensive, costing from 30 
to 50 francs. It consists of a complicated eye-piece, which con- 
tains two prisms, and causes a complete inversion of the image. 
A glance at fig. 48 will readily enable us to comprehend the ar- 
rangement of this instrument. A tube A, bent at right angle, 
has at cl a prism. In front of it is placed the eye-piece B, with 
the field-glass f and the ocular lens e. At a short distance 
from the latter is the small glass prism C, surrounded by a 
black metal ring. The course of the rays of light is clear. 
They pass through the external prism to the eye of the observ- 
er. The latter sees not only through the small prism, but also APPARATUS FOR MEASURING AND DRAWING. 
through the opening of the ring, a paper placed beneath, where 
the microscopical image is projected, and can be easily traced 
with a pencil. 
The camera Incida, when used, takes the place of the eye 
Fig. 43. Camera lucida of Chevalier and Oberhauser. The'piece Bis turned 90°. 
piece, and is fastened on to the microscope tube with the screw 
c. The illumination must be carefully regulated, so that the 
point of the pencil may be accurately seen, which is indispen- 
sable, A black pasteboard screen, placed in front of the draw- 
ing-paper, has a good effect. 
The place where the image is received, that is, where the 
paper lies, is naturally of importance. The farther from the 
instrument this takes place, of course, the larger it will be. It 
should be made a rule to have the drawing-paper placed at as 
nearly the same elevation with the stage as possible, that is, 
about 25 centimetres beneath the prism. If the magnifying 
power of the objective and of the camera lucida be ascertained, 
by shortening the microscope tube and raising the drawing- 
desk, round numbers may be obtained, which is certainly con- 
venient. The camera lucida, however, cannot readily be used 
with advantage for more than tracing the outlines. It is very 
convenient to use the knee-shaped tube with the prism, after 
replacing its eye-piece with another, thus converting the micro- 
scope into a horizontal one, though there is a loss of light. 
The magnifying power used when drawing should always be 40 
SECTION SECOND. 
noted, preferably near the drawing in the familiar way ; as 
(20 diameters), WS -S-fS etc. It is only practicable in a very 
few cases to draw everything with the same enlargement, as has 
been proposed by many persons. What pictures would often 
result; dwarfs by the side of giants ! 
We can readily conceive that photography, that grand dis- 
covery of modern times, has not been ignored by the microsco- 
pist: its value for giving a true objective representation of a 
microscopic specimen must be self-evident. Nevertheless, the 
number of observers who have worked at it, either for them- 
selves alone or, which has generally been the case, in connec- 
tion with a professional photographist, has not, as yet, been 
very considerable. The greater part have been deterred by the 
want of familiarity with the technology of photography, and 
the generally very much overrated difficulties of micro-photo- 
graphic manipulation. What may be thus accomplished, what 
a future photography also has in store for microscopical inves- 
tigations, is shown by many examples of the present time. 
As early as the year 1845, Donne, a French observer, pub- 
lished an Atlas cV anatomie micros copique, the illustrations for 
which were copied from those taken on Daguerre’s metal plate 
by means of the sun-microscope. In more recent times an im- 
mense progress has been made in photography by taking the 
negative on a glass plate covered with iodized collodion. We 
have received from Paris many beautiful micro-photographs, 
which were taken, in part, with very high powers. Within a 
few years Tlessling and Kollmann, in connection with Albert, 
the renowned photographer of Munich, have commenced the 
publication of a folio of photographs deserving, in every re- 
spect, the highest encomiums. Unfortunately, it remains un- 
completed. Professor Gerlach, of Erlangen, whom we have to 
thank for a number of valuable contributions to microscopical 
technology, has published a small but interesting guide to mi- 
cro-photographic manipulation. (Die Photographic als Hulfs- 
mittel mikroskopischer Forschung. Leipzig, 1862.) Beale and 
Moitessier have more recently treated of the same theme in a 
very thorough manner. B. Benecke published Moitessier’s 
work, enriched by many additions of his own, in the German 
in 1868. (Die Photographic als Hulfsmittel mikroskopischer 
Forschung. Braunschweig.) It is the best work that we have 
on this subject at the present time. APPARATUS FOR MEASURING AND DRAWING. 
41 
The ordinary compound microscope may be readily and, as 
G-erlach informs ns, with very slight outlay of money, turned 
into a micro-photographic ap- 
paratus working with sunlight 
(fig. 44). 
Concentrated parallel light, 
which is afforded by the concave 
mirror (q) in connection with a 
plano-convex condensing-lens, is 
used for the illumination. Cylin- 
drical diaphragms with small 
apertures are to be used with the 
stronger powers. The ordinary 
objectives are used, but they 
must be scrupulously cleaned be- 
fore taking the impression, as 
every particle of dust will cause 
a spot on the negative. The eye- 
piece is to be removed and the 
photographic apparatus placed 
on the tube of the microscope and 
held by a ring (f). A tube (g) 
supports a wooden case (d), in 
the upper end (c) of which the 
sensitive glass plate may be in- 
troduced (at 5). It is better that 
the wooden frame (b) of the focus- 
sing screen should contain paper 
rendered transparent by oiling 
instead of the ground-glass plate 
of the ordinary apparatus. The 
usual black cloth, thrown over 
the head, serves to darken the 
same while focussing; the cone 
(g) on the chest contains a mag- 
Fig 44. G-erlach’s micro-photographic appar- 
atus : a, hollow cone, to be placed on 6, the 
focussing screen ; c, projection at the upper 
part of the case d ; e, metal ring at its bottom; 
f, metal ring at the upper part of the wooden 
tube g ; h, metal plate at the lower end of the 
same; i, ring at the upper end of the metallic 
tube ;k, screw of the metal ring I. which serves 
to clamp the spring sheath m ; n, tube of the 
microscope with the objectives; o, stage; p, the 
metallic cylinder for carrying the diaphragm 
and illuminating lens ; q, the mirror; r, the 
metallic bar which supports the stage ; s, the 
horseshoe foot; t, the micrometer screw. 
nifying glass, to permit of the most accurate focussing. In 
order that the weight of the chest may not depress the micro- 
scope tube (a) in its sheath (m), a ring (I) surrounds the latter, 
and may be tightened by means of the screw (7r). The brass 
capsule which covers the objectives of the ordinary appa- 
ratus is replaced by a black, horizontal tablet, which may 42 
SECTION SECOND. 
be placed between the mirror (q) and the condensing lens 
(P)- 
That this apparatus, afterwards still further improved by 
the inventor, suffices for obtaining excellent representations, 
may be learned from Gerlach’s beautiful photographs. How- 
ever, it is still of a somewhat primitive character, and has 
many defects. The illumination is not sufficient for strong 
magnifying powers, and, as the length of the tube is unalter- 
able, the magnifying power of an objective cannot be changed. 
The tube of the microscope is 
too heavily loaded, which re- 
stricts and endangers the work- 
ing of the micrometer screw. 
A similar, but improved ar- 
rangement of Moitessier’s ap- 
pears, therefore, to be more 
suitable (fig. 45). 
A folding camera (B) is sup- 
ported by a strong three-legged 
wooden stand (A), which rests 
on a small table. The camera, 
like the bellows of an accordion, 
is capable of being lengthened 
or shortened, so that the im- 
pression may be taken at vari- 
ous distances from the objec- 
tive. A sheet of white paper, 
stretched in the frame (D), 
which may be seen from be- 
neath at the side, when the door 
is open, takes the place of the 
usual ground - glass plate, 
which, as I know from per- 
sonal experience, renders the 
Fig. 45. Moitessier’s Apparatus. A, pillars of 
the folding camera B ; C, its door; D, frame. 
accurate adjustment of the focus very difficult. The tube 
of the microscope projects freely into the camera, through the 
opening in its bottom. This aperture should fit closely around 
the tube. The illumination is obtained from a silvered mirror 
and a condensing lens, both of which play through a sliding 
arrangement on a horizontal wooden ledge. The light from 
the mirror is concentrated by the lens on to the mirror of the APPARATUS FOE MEASURING AND DRAWING. 
43 
microscope, into the stage of which an achromatic condenser is 
to be inserted. 
Another arrangement (fig. 46) appears to be still more effi- 
cient, although it can only be accomplished with a microscope 
which is capable of assuming a horizontal position. The re- 
Pig. 46. Horizontal apparatus. A, folding camera ; B, microscope; C, achromatic condenser; M, the 
mirror of the microscope turned aside; H, the silvered mirror; P, the diaphragm; E, convex lens; D, 
ground-glass plate. 
moral of the mirror from the microscope permits of the em- 
ployment of direct sunlight. The illumination is obtained 
from the silvered mirror H, the diaphragm F, the convex lens 
E, and a plate of very delicate ground glass D, which are 
placed in a sliding arrangement. The ground-glass plate 
should have such a position that a small circle of light will 
be thrown on it. 
A temperature of 14-18° R. is best suited for taking the im- 
pression. Natural light is used to produce the photographic 
picture. The duration of the exposure, naturally varying ac- 
cording to the intensity of the light, increases with the strength 
of the magnifying power employed, and with full sunlight lies, 
according to Gerlach’s observations, between five seconds for a 
magnifying power of 5-25 diameters, and 40 seconds for one of 
250-800 diameters. Among the methods of artificial illumina- 
tion, that with magnesium light deserves mention above all 
others. A photogenic lamp, together with some additional 44 
SECTION SECOND. 
contrivances, also affords good illumination (S. T. Stein). The 
duration of the exposure depends on the manner of treating the 
sensitive glass plate. The wet method with collodium requires 
the shortest time ; the dry method and that with albumen re- 
quire a much longer time. 
Gerlach, Beale, Moitessier, and Benecke have entered fully 
into all the remaining details of the process. The limits of our 
little work prevent us from noticing the subject further, and 
we must therefore refer to those authorities. 
It is self-evident that the trouble of photographing should 
only be bestowed on preparations which are irreproachable and 
free from every contamination. It is important to have but a 
small number of bodies in the field; for example, only a few 
blood-corpuscles, or a few epithelial cells. Compact tissues 
require the thinnest sections. Pale-bordered objects require 
stronger shading. Therefore, Canada balsam preparations are 
less suitable, as are also objects mounted in glycerine, though 
some assistance may be rendered in such cases by tinging them 
with carmine. Preparations injected with carmine or Prussian 
blue afford admirable pictures, and Gerlach has reproduced 
them even with a repetition of their colors! 
If a micrometer of known value is photographed at the 
same time and with the same enlargement, the size of the object 
represented may be ascertained by measurement with a pair of 
compasses with exceeding facility and accuracy. 
Such micro-photographs are less adapted for furnishing 
large works to be issued in large numbers, as a certain inequal- 
ity of the positive prints is unavoidable. They are admirable, 
on the contrary, for purposes of instruction.* Judging from 
the photographs we have seen of microscopic objects, we must 
doubt whether such photographs as are now made will be use- 
ful for deciding subtle questions of texture. Only a few 
French and American representations of diatomacese make an 
exception. 
In recent times, as is well known, such extraordinarily 
small photographs have been produced, that the picture can 
only be recognized with a strong magnifying glass or a micro- 
* Another excellent use has recently been made of microscopic photographs on 
glass, as well as of macroscopic ones. The enlarged image is thrown on a white 
screen with an improved magic lantern. The instrument is called a “ Sciopticon.” 
Two petroleum flames serve for illumination. APPARATUS FOR MEASURING AND DRAWING. 
45 
scope. Here the silver precipitate is of such fineness that 
a considerable magnifying power is necessary to render it 
visible. 
These minimal photographs have led Gerlach to make a 
peculiar application of photography to microscopical pur- 
poses ; to an increase of the enlargement by photographic 
means. 
The first negative of an object obtained by means of the mi- 
croscope is hereby subjected to a new enlargement. A second 
negative is thus obtained, which presents light and shadow in 
the same manner as the object, and therefore cannot be con- 
verted into a useful positive image. This is quite possible, 
however, when the second negative is exposed to a new enlarge- 
ment and the tertiary is thus obtained, which corresponds to 
the light and shadow of the first one. The enlargement may 
be increased till the silver precipitate becomes visible. By di- 
luting the photographic solutions, as well as by a peculiar treat- 
ment of the sensitive glass plate, this visibility may be very 
much deferred. In Gerlach’s work three such photographs of 
the scale of a butterfly (Papilio Janira) by 265,670, and 1,460 
fold enlargement may be found. Parisian and North American 
photographs of the pleurosigma angulatum, which I have ob- 
tained through Lackerbauer and Woodward, show the hexago- 
nal areolations very beautifully, enlarged to 2,000 and 2,500 
diameters. Impressions of the latter with 19,050 fold enlarge- 
ment I certainly do not comprehend. It remains for the future 
to show what practical advantages such applications of the 
micro-photographic apparatus may present, that is, how far 
structural relations, which by the first impression are not rec- 
ognizable by the eye, can be made visible by the following ones. 
Bo not expect too much, however. Section (Jlitrii. 
THE BINOCULAR, THE STEREOSCOPIC, AND THE POLARIZING 
MICROSCOPE. 
The idea of producing microscopes through which several 
persons are able to observe simultaneously one and the same 
object is sufficiently obvious, and, without doubt, such instru- 
ments must be very convenient for a teacher in his demonstra- 
tions. 
By the application of prisms over the objective, the rays of 
light which pass through it may be divided into two, three, or 
four bundles. This is accomplished either by dioptrical means, 
through an achromatic compound prism (fig. 47), or by catop- 
Fig, 47. 
Pig. 48. 
trical, by total reflection, as, for instance, the prism combina- 
tion shown in fig. 48. If several microscope tubes, each pro- 
vided with its own eye-piece, and corresponding to the number 
of bundles into which the rays are divided, be placed over the 
prism, it will be possible for a number of persons to observe THE BIXOCULAK, ETC., MICEOSCOPE. 
47 
simultaneously. The eye-piece must be movable in its tube, 
by means of a screw, to permit of individual focussing. 
The division of the rays which have passed the objective 
into two, three, or four bundles, is naturally combined with a 
corresponding diminution of the intensity of the light; there 
is also some loss of light in the prisms. Only the weaker ob- 
jectives can therefore be employed with such multocular mi- 
croscopes, as they have been called, and the images leave, 
as a rule, much to be desired. Such binocular, triocular, and 
quadrocular microscopes have recently been constructed and 
brought into commerce, especially by hfachet, of Paris. 
They have no future. 
The binocular microscope may also be so constructed that 
its two tubes can be used 
for both eyes of one and 
the same observer. When 
they are so placed as to 
correspond to the conver- 
gence of the optic axes, 
the two images cover each 
other, and the conse- 
quence must necessarily 
be that the object no 
longer seems flattened, 
but assumes a corporeal 
appearance. In this man- 
ner is constructed the 
stereoscopic microscope, 
the only efficient applica- 
tion of the binocular prin- 
ciple. We have to thank 
Piddell, an American, for 
the production of the first 
Fig. 49. Wenham’s arrangement of the stereoscopic mi- 
croscope. 
instrument of this kind. Since that time, English opticians 
especially, such as the firm of Ross & Co., of London, have, 
with a certain predilection, constructed these microscopes, and 
have contrived arrangements by means of which ordinary mi- 
croscopes may be readily converted into stereoscopic instru- 
ments. Wenham’s very excellent arrangement, in general use 
there at present, is represented by our fig. 49. With the main 
tube A 1 of the instrument is movably connected—that is, 48 
SECTION THIRD. 
capable of being approximated towards, or separated from it— 
the secondary tube 2. A small prism a projects as far as the 
optical axis of the tube 1; its form may be recognized more ac- 
curately in the enlarged drawing B. Each bundle of rays is 
so divided, after its passage through the objective, that the one 
passes unbroken through the tube 1, the other through the 
prism B, in the direction ah c d, into the secondary tube 2. 
Nachet has also, for years, supplied such stereoscopic micro- 
scopes ; likewise Hartnack, whose stereoscopic eye-piece is rep- 
resented by our fig. 51. Opinions are divided with regard to 
Fig. 51. Hartnack’s stereoscopic 
eye-piece. The two tubes b may be 
adjusted according to necessity by 
means of the button c; a, for insertion 
into the tube of the microscope. 
Fig. 50. Crouch’s stereoscopic microscope. 
the utility of these instruments ; they have certainly been over- 
estimated by many. We must leave it for the future to decide 
whether science is to derive any benefit from them. As exam- 
ples, we have represented in our fig. 50 such an instrument by 
H. and W. Crouch, of London, and in fig. 53 one by Nachet. 
The examination of tissues by polarized light has, on the 
contrary, a high scientific value, as, by this means, molecular 
relations become evident, which, by investigation with ordinary 
light, remain entirely concealed. The interpretation of what 
is seen is, in many cases, difficult, and generally lies within the 
province of optics, with which the medical observer is usually 
but little familiar. THE BINOCULAR, ETC., MICROSCOPE. 
49 
Every ordinary instrument may be changed to a polarizing 
microscope, in a very simple manner, by adding to it a polari- 
zer and an analyzer. For tins purpose Mcol’s prisms, consist- 
ing of double refracting calcareous Iceland spar, are used. They 
are so constructed as to 
transmit only one of the two 
rays into which a beam of 
ordinary light is made to 
separate on passing through 
this substance, while the 
other is lost by reflection. 
The polarizer is placed 
close beneath the object, 
preferably in the opening of 
the stage with the addition 
of a convex lens (fig. 54). 
The analyzer, on the con- 
trary, receives various, and 
by no means equally good 
positions. As a rule, it is 
placed by the opticians over 
the objective in the tube of 
Fig. 52. The prisms in Hartnack’s stereoscopic eye- 
piece. 
the microscope ; an arrangement, however, which causes too 
great loss of light, which becomes very unpleasant in investiga- 
tions where the double refraction is weak. It is much more 
advantageous to place the analyzer over the eye-piece, enclosed 
in a metallic tube. Although by this means the field is extraor- 
dinarily diminished, especially when the Mcol is small, it pre- 
sents much more light than the larger field obtained by the first- 
mentioned arrangement. Hartnack has recently placed a plano- 
convex flint-glass lens of short focal distance (fig. 54) over the 
polarizer. The analyzer (fig. 55) he has placed in the eye-piece 
(5) and the latter is made to rotate within a graduated disk (a). 
By this means he has essentially increased the efficiency of 
his polarizing apparatus. 
The two Nicols are to be, at first so arranged that their 
polarizing planes are parallel to each other, which gives an 
illuminated field. This cannot be made too intensely bright, 
especially with weak double refraction. A condenser, such as 
we have mentioned above, placed over the polarizing calcareous SECTION THIRD. 
spar prism, is very serviceable, as was pointed out years ago 
by H. von Mold. 
When the polarizing planes are placed at right angles to 
-each other, by turning the analyzer 90°, the held is darkened 
(it should appear entirely dark with a good apparatus), and 
doubly refracting bodies appear either illuminated or in colors. 
The rotation is made in various ways : either the analyzer 
Fig. 54. Polarizer. The tube a 
fitted into the stage; 6, convex lens 
of flint-glass. 
FIG. 55. Hartnack’s analyzer, new 
construction. The eye-piece b c 
turns in a sheath, which is to be 
fastened to the microscope by means 
of the screw at the right; it (also 
has a graduated circle a; d, vernier. 
Fig. 53. Nachet’s stereoscopic microscope. 
placed upon or within the eye-piece is rotated, or the stage is 
rotated, if capable of that motion. When the stage is immov- 
able and the analyzing prism is placed within the tube over the 
objective, the opticians introduce an especial mechanism, by 
means of which it may be rotated in its sheath. 
The objects to be investigated should be made as transpar- 
ent as possible, when the recognition of weak double refraction 
is in question. Mounting with Canada balsam, which would 
perhaps render the object so transparent as to be totally unser- THE BINOCULAR, ETC., MICROSCOPE. 
51 
viceable for the ordinary methods of examination, would here 
render excellent service. 
In delicate investigations, the incident rays of light must be 
carefully excluded, by placing a hood over the stage. 
Thin scales of selenite or mica, of various thickness, placed 
over the polarizer, are the means generally used for developing 
a lively play of colors with polarized light, and for deciding as 
to the character of double refracting animal tissues. They are 
examined at an angle of 45°. A film of selenite produces more 
lively colors than one of mica. In using these plates, it is pref- 
erable to have them of the thickness which gives a red of the 
first order. At the same time, the sharpness of the microscopic 
polarizing apparatus may also be increased by the introduction 
of a film of such thinness as not to cause any coloring of the 
field. 
Spectral analysis lias also been recently rendered feasible 
with the aid of the microscope. A special spectral eye-piece 
serves for this purpose. 
Its simplest form is seen in fig. 56. There is a changeable 
Aig‘ Simple spectral eye-piece 
of Merz. 
Pig. 57. Complicated spectral eye-piece of Hart- 
nack. 
slit aperture (d) at its image plane, and over the ocular lens 
there is a so-called Amici’ s prism d vision directe, consisting 
of three crown- and two flint-glass lenses (c). 
A similar apparatus of Hartnack and Prazmowski (fig. 57) 
is somewhat more complicated. The slit arrangement and SECTION THIRD. 
Amici's prism are the same, but there is a vertical plate added 
at the side with clamps, for the purpose of holding an object 
with known absorption stripes, which may be used for com- 
parison. 
This is illuminated by the small mirror, and the rays pass 
to a simple prism placed beneath the slit. The prism extends 
half the length of the slit, and conducts the rays to the Amici’s 
apparatus. 
Such spectral eye-pieces are rather expensive, and have not 
thus far produced completely satisfactory effects. Section Jonrtl). 
TESTING THE MICROSCOPE, 
Testing the mechanical part, the screws, the mechanism of 
the mirror, etc., requires no guidance. If a microscope with a 
cylinder diaphragm has been acquired, the centring of the lat- 
ter should first be tested, by focussing a weak objective on the 
aperture of the diaphragm. I have often found new and other- 
wise excellent instruments very defective in this regard. 
In testing and critically examining the optical performances 
of a microscope, with which, naturally, the extent of its mag- 
nifying power must also be included, a number of things have 
to be taken into consideration ; and when the appreciation of 
very fine distinctions, especially with the stronger objectives, 
is concerned, it becomes a difficult business. 
To ascertain the magnifying power of a microscope, the 
focal length of the objective and that of the lenses composing 
the eye-piece may be measured, and from this the enlargement 
reckoned. This subject is further elucidated in the text-books 
on physics. 
It is much more convenient, however, to measure directly 
the joint magnifying power of the several combinations. 
For this purpose, an ordinary glass stage-micrometer with 
fine divisions is used; a rule is also placed on the stage. By 
means of the power of double vision, which, however, requires 
practice, that the head and eyeball may be kept quiet, the 
image of the micrometer divisions will be seen projected on to 
the rule which lies on the stage, and the relative size of their 
spaces may be thus compared. Granted the rule is divided 
into millimetres, and that the micrometer has one such milli- 
metre divided into 100 parts. Two of the divisions of the rule 54 
SECTION FOURTH. 
are covered by one space of the micrometer image. The mag- 
nifying power of the microscopic combination measured is, 
therefore, 200-fold. 
The distance of the eye-piece from the stage must also be 
taken into consideration in order to obtain a precise expression 
corresponding to the visual distance accepted as the normal 
medium, which is, as was already remarked, from 8 to 10 
inches, or 25 centimetres. Let us accept the latter as the visual 
distance. If now, for example, the distance between the image 
and the eye over the eye-piece is 20 centimetres, the magnify- 
ing power, with a visual distance of 25 centimetres, would be 
250-fold. 
It is necessary to determine in this manner the magnifying 
power of the various eye-pieces with one and the same objec- 
tive. It is then only necessary to obtain the magnifying power 
of each of the remaining objectives with one of the eye-pieces, 
—for instance, the weakest one,—to lind by calculation that of 
the others. 
In making this measurement, only those divisions lying in 
the middle of the field should be used, to avoid any incidental 
distortion of the image. 
The image of the micrometer projected on to the stage may 
be readily measured with the points of the compasses, and its 
size determined with the rule. 
It is also convenient to employ the various projecting appa- 
ratuses, especially prisms on the eye-piece. 
Every serviceable modern instrument should have received 
a careful correction of the spherical aberration of its lenses. 
Various means have been used for testing this. They are more 
fully treated of in the larger works on the microscope by Mold 
and Harting. A slide thickly smeared with India ink, in 
which small circles or other figures are scratched with the point 
of a fine needle,* may be recommended, when it is desirable to 
make a few rapid tests of the lenses. If the instrument is ad- 
justed with transmitted light for such a circle, it should appear 
sharply cut on the black ground, and not surrounded by a 
halo of light. If the circle is then brought out of focus, it grad- 
ually enlarges, while its sharp borders disappear, without 
* A glass plate, with a fine coating of silver or gold through which groups of lines 
have been scratched with the dividing machine, is still better. TESTING THE MICROSCOPE. 
55 
spreading a strong lialo of light either inwards or outwards 
over the black field. 
Secondly, adequate correction of the chromatic aberration 
should be observed. This cannot be complete, because there 
is no means by which the secondary spectrum can be removed. 
Therefore, reference is here made only to 
a correction which is as complete as prac- 
ticable. Modern objectives are, for the 
most part, over-corrected with regard to 
chromatic aberration, and show a bluish 
border. Under-corrected lenses present, 
under the same conditions, a reddish mar- 
gin, which is less agreeable to the eye, 
though the sharpness of the image re- 
mains the same. 
The flatness of the field is of great im- 
portance to the advantageous use of the 
instrument. Here, as we have already 
found, two things are to be separately con- 
sidered, namely, the incurvation of the 
field, and the distortion of the image. 
If we strew a very fine powder over a 
flat plate of glass, we should, if the field 
is flat, be able to see the molecules at the 
centre and at the periphery equally dis- 
tinct and simultaneously. If there is any 
incurvation present, deeper focussing is 
requisite to see the molecules at the peri- 
phery of the field. 
A glass micrometer divided into quad- 
ratic fields, placed on the stage, should ap- 
pear as fig. 58, a, if the image is not dis- 
Fig. 58. Quadratic glass 
micrometer. 
torted ; while, on the contrary, if any distortion is present, the 
squares assume the appearances represented in our figure at h 
and c, according as the enlargement from within outwards ip- 
creases or diminishes. 
If restrained by purely practical considerations in testing a 
microscope, regard must always be paid, in deciding on the 
merits of an objective, to the purpose for which the optician 
has constructed it; whether for incident light or for light re- 
flected from the mirror; and, when the latter is the case, 56 
SECTION EOUETH. 
whether for central or oblique illumination. An objective 
may, for example, perform very well with the latter, and yet 
be very indifferent with central illumination ; inversely, many 
opticians construct objectives which are very good in the latter 
regard, but are defective with oblique illumination. It is quite 
impossible to construct a combination which will be equally 
serviceable for all the different requirements, resting, in part, on 
opposite physical conditions. The testing of an objective should, 
therefore, never be restricted to the use of a single test object. 
Two attributes may be distinguished in an object glass; 
first, its defining, and second, its penetrating or resolving 
power. Mold was right in saying that on the first depends the 
distinct recognition of the outlines and forms of bodies ; on the 
latter, the appreciation of its finer structure. 
1, The defining power of an objective depends upon the 
complete correction of its spherical and chromatic aberration. 
Such an attribute, and of adequate extent, must be expected 
from every superior modern objective, for whatsoever purpose 
it may have been constructed. Good definition may be more 
easily obtained with lenses of small or moderate than with 
lenses of larger angles of aperture; and by aiming to extend 
the aperture, the perfection of the definition is not unfre- 
quently impaired. 
A certain amount of practice is necessary to recognize a 
good defining objective. The outlines of the image obtained 
by it appear fine and sharp ; objects lying near each other, and 
those which are pushed over each other in the same optical plane, 
show their individual outlines distinctly and may be readily 
appreciated ; the entire image has something clear and elegant 
about it, like a good copper plate or a print with sharp letters. 
To recognize the opposite condition, it is only necessary to 
furnish the microscope with a pretty strong eye-piece. Thick, 
confused contours and diminished distinctness of the image 
would be met by the observer ; the whole would appear like a 
print with dull, disconnected letters. It is just this sharpness 
and neatness of the image which at first prepossesses one in 
favor of such an objective, whereas an objective with greater 
penetrating power usually gives paler, more milky images, and 
only unfolds its high superiority to the connoisseur. 
The best defining objectives are a prime necessity for all 
microscopes intended for scientific work. TESTING THE MICKOSCOPE. 
57 
2, The penetrating or resolving power of an objective de- 
pends on its capability of bringing the very fine details of the 
surface and interior of an object into view. Its perfection has 
become the aim and the pride of the microscope-makers of the 
present day, and to it is due, in a great measure, the calling into 
existence of the superior objectives of modern times. 
The resolving power of a combination depends, however, on 
the extent of the angle of aperture, and, consequently, on the 
obliquity of the rays of light which the system is capable of re- 
ceiving from the various points of the surface of an object. In 
regarding a transparent surface containing lines placed close to 
each other, whether these appearances be due to elevations or to 
furrows, we are made to appreciate the value of oblique illumi- 
nation. It is clear that rays of light which are transmitted 
axially through the object would yield less information with 
regard to such inequalities than those which fall on its surface 
obliquely. Thus, by means of objectives of medium power, but 
with considerable angles of aperture, one may see with oblique 
illumination things of which no trace can be recognized with 
central illumination. An object-glass of very wide aperture, 
however, will receive, even with ordinary illumination, so many 
rays of great obliquity that the same kind of effect will be pro- 
duced as by oblique illumination with an objective of smaller 
aperture ; but when with such an objective oblique illumination 
is used, a greater resolving power is obtained than any combi- 
nation of smaller angular aperture can possess. 
It will be appreciable, from the remarks which have just been 
made, why it is just this enlargement of the angle of aperture 
which has been, of late, the chief aim of the optician. 
Thus we see that older instruments have only the slight 
angle of 50° or 70° in their strongest systems. But, even as 
early as the year 1851, the renowned London house of Andrew 
Ross had given their strongest systems an aperture of 107° and 
IBs°, a few years later 155°. But the limit was not yet reached; 
for more recently apertures of 160, 170, and even 176° have been 
obtained, in which the actually available portion remained at 
about 130 to 146°. 
Such objectives are of the greatest value when penetrating 
power is required ; but the defining power is usually relatively 
greater with a combination having a smaller angle of aperture. 
We have already (p. 16) mentioned the influence which the 58 
SECTION FOURTH. 
thickness of the covering glass exerts on the sharpness of the 
microscopic image. It is customary to combine with all of the 
stronger objectives the apparatus for correction, fig. 59, which 
was spoken of in a preceding section, so that the 
lenses may be brought nearer together or moved 
farther apart, as necessity may require, accord- 
ing to the thickness of the covers used. Some 
of these objectives are only to be used dry, that 
is, with a stratum of air between the upper sur- 
face of the glass cover and the lower surface of 
the lower lens ; others, only with a stratum of 
water in the place of the stratum of air, and 
paratus. 
are then called immersion lenses. Other modern combinations 
can, however, be used in both media. 
These immersion lenses are properly greeted as a great 
advancement, and Hartnack, of Paris, has obtained a brilliant 
reputation within a few years by producing excellent combi- 
nations of this kind, of very high power and very low price. 
The immersion lenses of Hartnack may be divided into those 
with single and those with double correction. In the first, 
the two lower lenses, fixed with regard to each other, are 
shoved up towards the upper one (the one turned towards the 
eye-piece). In those produced more recently, with apparatus 
for double adjustment, the middle lens also changes its relative 
position to the lower lens in a determined ratio during the 
turning.* 
Here, also, lens combinations similar to those of the stronger 
or ordinary dry systems are used ; but the radii of curvature of 
the several lenses must necessarily be changed. 
* A few additional remarks on the use of immersion lenses may here be in place. 
With a glass rod or a camel’s-hair pencil a drop of water is placed on the cover- 
ing glass, and a second one on the under surface of the lens. The lens is then 
carefully approached towards the object till the two drops flow together and the 
focus is accurately adjusted. By turning the screw, it will soon be ascertained 
whether the image assumes sharper or less delicate contours, and thus the best ad- 
justment will soon be found. With Hartnack’s arrangement, after each correction 
of the objective, the focus is naturally to be readjusted; this is not the case, how- 
ever, with those of the English opticians, in which the position of the lowermost lens 
remains unaltered during the correction. The middle position of the correcting 
apparatus of Hartnack’s immersion system corresponds to a thickness of the covers 
of about 0.1 mm. The newest objectives have a graduated quadrant and a mark on 
the stationary portion of the brass mounting. After being used, the under surface 
of the objective is to be carefully dried with a fine cloth. TESTING THE MICJROSCOPE. 
59 
[lmmersion lenses are now made by Tolies wliicli may be 
used with water, glycerine, or oil, and will also work dry.] 
In indicating the basis on which the optical advantage of 
such an immersion system, in contradistinction to the ordinary 
“dry” combinations, is founded, we will permit one of the 
greatest authorities to speak. Karting, in an interesting paper, 
remarks as follows ; 
“As the water is a stronger light-refracting medium than air, 
the reflection of the rays of light is much diminished at the 
npper surface of the cover and at the under surface of the 
objective, indeed, it almost entirely ceases. Hence, more rays 
of light pass into the microscope, and the thin stratum of water 
has nearly the same effect as an enlargement of the angle of 
aperture. This favorable modification influences chiefly the 
peripheral rays, which fall most obliquely. The peripheral 
i‘ays have most influence on the formation of the image, which 
takes place in front of the eye-piece ; and as, by their passing 
through a transparent object, they are for the most part de- 
flected from their course, and the slight deviations thus caused 
become visible in the image, the defining power of the micro- 
scope must necessarity be increased by the stratum of water.” 
As this stratum of water exerts the same effect as an in- 
creased thickness of the glass cover, it must produce an entire 
change in the spherical and chromatic aberration. We also notice 
that objectives intended for immersion give only inelegant and 
obscure images when used without the stratum of water. The 
intercalated stratum of water is, therefore, an integral con- 
stituent, a new optical element of the combination, and may 
exert an advantageous influence in the removal of the residuary 
secondary aberration. 
In a third manner, finally, the optical power of an objective 
system is increased by the stratum of water. As the latter acts 
like a covering glass, and, as we have seen above, the lenses 
ninst approach each other in proportion to the increase in its 
thickness, the magnifying power and the angle of aperture are 
thereby also increased. 
Karting shows what may be obtained by this means. In 
testing one of Hartnack’s objectives, made in the year 1860, he 
obtained, with the various adjustments of the apparatus for 
correction, an angle of aperture of 166 to 172°, with an avail- 
able portion of 185 to 140°, and a focal distance of 1.8 to 1.6 60 
SECTION FOURTH. 
mm. A stronger objective of Powell and Lealand, of London, 
bad an angle of aperture of 175 to 176°, with an aperture of 
145°, and a focal distance, with the closest approximation of 
the lenses, of 1.36 mm. Its performance was the same as Hart- 
nack’s objective, and if any difference, however slight, existed, 
Powell and Lealand’s objective was, according to Harting’s test, 
the strongest. 
Twenty years have passed since that time, and meanwhile 
many changes have taken place. Hartnack’s immersion objec- 
tives Nos. 9 and 10, with angles of aperture of about 170 and 
175°, and the nominal focal distance of TV and Aof an inch, 
have obtained the most universal acceptance. A still stronger 
system, No. 11, T\/;, with a total angle of aperture of 176°, was 
soon afterwards introduced by this optician. Hartnack has re- 
cently constructed an entire series of very powerful objectives. 
No. 12 corresponds to ■fa". No. 16 to A" > and the highest, No. 
18, to A;/? of the English. 
Still stronger systems have been recently constructed in 
England, according to our views, without benefit; for with a No. 
11 or 12 of Hartnack’s establishment we have arrived toberably 
near the present limits of practical optics. 
It is, self-evidently, of great practical value to find objects 
which are as homogeneous as possible, and of such delicate and 
fine texture that, in their resolution, the optical, or, more cor- 
rectly speaking, the penetrating power of a lens may be accu- 
rately estimated. They are called “ test objects.” Their study 
is of interest and importance. To the beginner, who is desirous 
of ascertaining the capacity of the instrument which, perhaps, 
he has but recently obtained, such test objects are to be recom- 
mended as discipline; since their resolution is by no means 
easy, and with them the accurate adjustment of the focus, and 
the skilful application of the illumination, may be learned. 
Some of these test objects, the finer ones, are so difficult as to 
occupy the beginner for hours in vain, and may occasion much 
labor even for the practised. By careful practice one may 
arrive at a certain virtuosoship, and thus, in a few minutes, 
appease the novice, who possibly begins to despair of his instru- 
ment, by showing him an example of what it is capable of per- 
forming in skilful hands. Then the endeavor to discover fin el- 
and more difficult test objects, thus always holding a higher aim 
before the optician, has led to the great emulation existing at TESTING THE MICROSCOPE. 
61 
the present time in the construction of objectives. It is there- 
fore unjustifiable to regard the study of such tests with con- 
tempt, as is occasionally to be observed among notable micro- 
scopists.* 
In the course of time, such test objects have been frequently 
highly commended and, with the increasing perfection of prac- 
tical optics, again abandoned. Therefore, all those which were 
recommended before 1840, all the various hairs and scales of 
butterflies and wingless insects,f may be regarded as conquered 
territory. To attempt to test a first-class modern microscope 
with these expedients of a former epoch, would be an insult to 
the optician from whose establishment the instrument has pro- 
ceeded. 
In the year 1846, H. von Mold, one of the first judges of the 
microscope, called attention to the brighter scales of the 
anterior wing of the Papilio JaniraQ, a knowledge of which he 
had obtained through the Italian, Amici, the most renowned 
constructor of microscopes of that epoch. Together with the 
familiar longitudinal lines, fine, ciosely approximated (y^Vo 
mm. apart), sharp, and not granular transverse 
lines appear, fig. 60. Mohl remarked, at that 
time, that with a magnifying power not exceed- 
ing 200, nothing was to be seen of these trans- 
verse lines, and that it was necessary to have 
an instrument with very strong and very good 
lenses to recognize the transverse markings, 
sharply and distinctly, with 220 to 300 fold 
linear enlargement. He cited only the micro- 
scopes of Amici, Plossl, and a single one of 
Oberhauser, as at that time standing the test 
thoroughly, I still remember very well how I, as a student, with 
a, for that time, very serviceable Schiek’s microscope,—my com- 
panion for many years,—was obliged to vex and trouble myself 
to obtain only a passable view of these transverse markings. 
Pig. 60. Scale of 
Papilio Janira. 
* M. Schiff has expressed the same sentiments with regard to the value of test 
objects. We cannot agree, however, with many of his views regarding the diatoma 
scales. 
I It is well known that the trichina disease has, in our day, led to the production 
oi an innumerable quantity of cheap instruments, intended only for the microscopic 
examination of meat. The well-known scales of the Lepisma Saccharinum, a wing- 
less insect, are useful for testing them. We shall refer to this subject at the exami- 
nation of the muscles. 62 
SECTION FOURTH. 
Nowadays an instrument would be called bad which, with 
a magnifying power of 200, left anything to be desired in re- 
solving a Janira scale. By means of a large Hartnack instru- 
ment, made in the year 1861, I see them (in a test object coming 
from Kellner) without any precautionary measures, even with 
120-fold enlargement (objective No. 6, eye-piece No. 2). At 
the present time, the scales of the Papilio Janira deserve to be 
regarded as a means of testing objectives of medium strength 
only. 
The silicious envelopes of the Diatomacese have taken the 
place of the butterfly scales; those with the finest and most 
closely placed markings are employed/* 
The fineness of the markings may be represented in a table 
collated by Harting from English sources. 
The Pinnularia nobilis has from 4to 6 striations in the juo of a millm. 
“ Pleurosigma formosum “ “ 12 to 14 “ “ “ “ 
“ “ attenuatum “ “ 15 to 16 “ “ “ “ 
“ u angulatum “ “ 23 to 23 “ “ “ “ 
“ Grammatophora marina “ 25 “ “ “ “ 
“ Nitzschia sigmoidea “ “ 30 to 31 “ “ “ “ 
“ Navicula rhomboides 
(affinis, Amicii) “ 30 u u “ “ 
“ Surirella gemma (lon- 
gitudinal lines) “ “ 30 to 33 “ “ “ “ 
“ Grammatophora subti- 
lissima “ “ 33 to 34 “ “ “ “ - 
“ Frustulia Saxonica “ “ 34 to 35 “ “ “ “ 
Of the numerous Diatomacese there are several which de- 
serve mention as being of particular importance; namely,— 
the Pleurosigma angulatum and Nitzschia sigmoidea, already 
mentioned in the table ; then, the Navicula Amicii, Surirella 
Gemma, and the Grammatophora subtilissima, made known 
by the deceased Professor Bailey, of North America. The 
last two objects (we have these always in mind, as they are to 
be obtained from Bourgogne of Paris) are extremely difficult, 
* Abbe has endeavored to show the effect produced here by the curving or diffrac- 
tion phenomena of the light. According to his views, such test images are not 
conformable to reality, and some modern lenses of gigantic power, of A to A-" focus, 
are superfluous articles of luxury. lam much inclined to admit that he is right, 
although I would place the effectiveness of our best lenses somewhat higher than he 
has done. According to my experience, we arrive at the limits by using a combina- 
tion which magnifies with a weak eye-piece 1000-fold. TESTING THE MICROSCOPE. 
63 
and in resolving them the microscope withstands a hard trial. 
Reinicke (Beitrage zur neueren Mikroskopie, 3. Heft. Dres- 
den, 1863) has called attention to the Frnstnlia saxonica, 
mounted in Canada balsam, as a very subtile 
test object. Its transverse lines do not stand 
very close to each other, but are very delicate 
and difficult to perceive. At the last London 
Industrial Exhibition the Navicula affinis, 
mounted in Canada balsam, was used as a test 
object. Their longitudinal striations are re- 
solved without difficulty, while, on the con- 
trary, their transverse lines are very sharp and 
fine, so that I must pronounce their solution 
(in Bourgogne’s preparations) more difficult 
than the Surirella Gemma and Grammatophora. 
Bailey has also recommended the Hyaloidiscus 
subtilis.* 
The Pleurosigma angulatum, fig. 61, fur- 
nishes, with oblique light, an excellent means 
of testing the resolving power of good objec- 
tives of medium and greater power, but should 
Fig. 61. Pleurosigma 
angulatum. 
expose all its delicate markings with a good immersion lens 
with simple central illumination. With oblique light this 
test object is entirely too easy for immersion lenses. 
If the examination of the Pleurosigma angulatum is com- 
menced with a weak objective, it appears smooth and without 
markings. Passing, together with the application of oblique 
illumination, to stronger lenses, a period arrives when systems 
of lines sparkle forth, which run, in part, diagonally over the 
scale, in part obliquely and crossing each other. Sometimes 
* J- D. Moller, of Wedel, Holstein, has recently produced a very excellent but 
expensive Diatom test-plate. Each one contains 20 Diatoms, arranged according to 
their value as test objects, as designated by Dr. Grunow, namely: 1. Triceratium 
Pavus; 2. Pinnularia nobilis; 3. Navicula Lyra var.; 4. N. Lyra; 5. Pinnularia in- 
terrupta var.; 6. Stauroneis Phcenicenteron; 7. Grammatophora marina (more 
coarsely marked than Bourgogne’s variety); 8. Pleurosigma Balticum; 9. P. acu- 
minatum ; 10. Nitzschia amphioxys; 11. Pleurosigma angulatum; 12. Grammato- 
phora Oceanica subtilissima (marina); 18. Surirella Gemma (transverse lines) ; 14. 
itzschia sigmoidea; 15. Pleurosigma Fasciola var.; 16. Surirella Gemma (longitu- 
inal lines); 17. Cymatopleura elliptica; 18. Navicula crassinervis, Frnstnlia Sax- 
°nica; 19. Nitzschia curvula; 20. Amphipleura pellucida. Rodig, of Hamburg, 
also issues a similar Diatom plate. 64 
SECTION FOURTH. 
the one, sometimes the others of these lines are most distinct, 
according as the oblique light passes through the scale. 
They come forth gradually and quite sharp, and in fortu- 
nate cases one may distinguish all three—the two oblique ones 
cutting each other at angles of nearly 60° (not 53)—at the same 
time with perfect distinctness, all lying, according to my view,, 
in the same plane. It is still believed that we have here to do 
with perfectly straight lines. 
By using an immersion lens with central illumination, they 
appear to surround a series of extremely small and very delicate 
hexagonal areolations in close approximation, fig. 62. These 
Fig. 62. Areolations of the Pleuro- 
sigma angulatum; from a photograph. 
Pig. 63. Areolations of the Pleurosigma angu- 
latum. 
appear, according as the focus is altered, either dark and sur- 
rounded by bright margins, fig. 68, or bright, with dark mar- 
gins, fig. 62. So much may be stated with entire certainty. 
Now arises, however, the difficult and by no means definitely 
settled question :—Are the areolations concave and their mar- 
gins or, on the contrary, are the latter furrows be- 
tween projecting arem ? Both propositions have been sus- 
tained by distinguished observers. I formerly regarded the 
depression as probable, and also that the focus was correctly 
adjusted when the areolations appear dark. M. Schultze has 
also expressed the same opinion, in accordance with certain 
rules (see below) established by Welcker. I afterwards adopted 
the contrary view. This does not appear to be the place to 
enter farther into this subject. 
A good objective, magnifying about 80 or 100 times, should, 
with the proper oblique illumination, enable one to recognize 
the systems of lines sharply and distinctly on all the scales ; 65 
TESTING THE MICROSCOPE. 
while weaker objectives, magnifying 40 or 50 times, should 
show something of the lines. When it is found impossible to 
obtain oblique illumination, this inconvenience may be reme- 
died by means of a condenser, with its central portion obscured. 
Oblique illumination and a stage capable of rotation are of 
great assistance. Hartnack’s immersion lenses Nos. 9, 10, or 
11 show the arege very distinctly and beautifully, with central 
illumination, and even with an unfavorable sky. Other opti- 
cians, Amici, Nachet, and some English and German artists, 
have also been able to resolve them with their strongest lenses 
in the manner last mentioned. Hartnack’s newly constructed 
objective No. 9, not intended for immersion, accomplishes the 
same, as I have myself witnessed, likewise his latest No. 8 ; 
even an excellent No. 7, received several years ago, gives the 
same result, with similar central illumination and elevated con- 
cave mirror. 
The other test objects already mentioned, Nitzschia sigmoi- 
dea, Surirella Gemma, Grammatophora subtilissima, andNavi- 
cula rhomboides are much more difficult, and can only be re- 
solved by means of suitable oblique illumination and very ac- 
curate correction of the objective. The first is the easiest; the 
last three, on the contrary, serve to test the best and most 
powerful modern immersion lenses. 
As was just mentioned, the Nitzschia sigmoidea is the easiest 
of these objects to resolve. With oblique illumi- 
nation, the long and narrow valve shows a series 
of very fine and compact transverse lines. Bour- 
gogne’s preparations of the Nitzschia sigmoidea 
are mounted dry. 
The Surirella Gemma, fig. 64, is a very delicate 
test object, and only to be mastered with much 
pains. Seen from its broad surface, the oval disk 
shows parallel ridges running as far as the cen- 
tral line. Between these appear very readily a 
series of fine, but distinct, transverse lines. It is 
these latter lines, cutting the transverse ones at 
right angles, which give the Surirella Gemma 
its value as a test object of the first class. Undu- 
lating curved lines of extreme fineness should 
Fig. 64. Surirella 
Gemma. 
appear, which give to the whole an interwoven appearance 
like basket-work (fig. 65). With the aid of his best lenses, 
5 66 
SECTION FOURTH. 
Hartnack even succeeded in resolving these undulating lines 
into a series of very narrow hexagonal areolations (fig. 66). 
Bourgogne’s preparation is also mounted dry. 
The Grammatophora subtilissima, mounted by Bourgogne 
Fig. 65. Longitudinal lines on the aili- 
cious envelope of the Surirella Gemma. 
Fig. 66. The same, resolved into areola- 
tions. 
in Canada balsam, is equally difficult. Ido not know whether 
it is identical with the species first used by the American mi- 
croscopist, Professor Bailey, of West Point, U. S. Besides, it 
seems that two kinds of valves of unequal difficulty have there 
been pronounced to be Grammatophora subtilissima. 
Seen from its broad surface, the silicious envelope presents 
the appearance of an oblong square, with blunted corners (fig, 
67, 1). It is divided into three regions by the two peculiarly 
curved longitudinal furrows. The two lateral regions {a) of 
every valve should exhibit very fine and compact transverse 
lines (2a), with the aid of good oblique illumination. The cen- 
tral portion does not show any markings. 
This is, however, only a portion of the markings we are at 
present able to recognize. Other sharper and more coarsely 
marked species of the genus Grammatophora show these trans- 
verse lines, intermingled with a double series of oblique lines 
crossing each other at an angle of 60°, so that exactly the same 
markings result which we have previously described in the 
Pleurosigraa angulatum. These oblique lines of the Grammato- 
phora subtilissima also appear to be quite separated. Hart- 
nack informs me that he has succeeded in resolving them with 
one of his strongest objectives, and I believe that I have myself 
caught at least a glimpse of them, with an immersion lens 
No. 10. 
We add, finally, a few remarks on the Navicula rhom- 
boides, sporangial form* (fig. 68). Its somewhat undulating, 
* The Navicula in question was used at the last London Industrial Exhibition, 
as N. affinis, and was given to me in the form of a preparation by Bourgogne, as 
N. Amicii. I have to thank Th. Eulenstein for the definition given in the text. 67 
TESTING THE MICROSCOPE. 
longitudinal lines (a) may be recognized with oblique light and 
a good immersion lens, without much trouble. They may be 
from 0.0002 to 0.00018 of a Paris line distant from each other. 
Fig. 67. 1, Grammatophora subtilissima. 
2, transverse lines of the same. 
Fig. 68. Navicula rhomboides. a, longitu 
dinal, b, transverse lines. 
The elegant transverse lines (b) of the specimen in Canada 
balsam appear much more compact and extremely delicate. 
To recognize them, very oblique light and the most accurate 
correction of the immersion objective is necessary,* 
All organic test objects have, as a fault, the peculiarity that 
they are not exactly alike, but are, in the most fortunate cases, 
only very similar. It was, therefore, a fortunate idea of No- 
bert’s to produce glass plates with bands of parallel lines, the 
distances between the lines constantly decreasing. The oldest 
of these plates, made about 1845, presented ten bands. In the 
first band, the distance between the lines was twto'", in the 
last 40W". At the present time, with the progress of practical 
optics, such plates would no longer afford a means of testing 
first-class microscopes. Robert afterwards made plates with 
30 bands; but these marvelous productions of art cost 30 
thalers. Quite recently he has issued a plate with 19 bands ; 
the lines in its last division are Tofor of a line apart. Thus 
markings as fine as those of the Diatomacese have been made 
hy art. Nevertheless, these wonderful plates of Nobert’s also 
have the fault of not being identical, although, in the most 
I‘ecent ones, the differences are almost imperceptible. Diversity 
of opinion still prevails regarding the resolution of the last 
* The recognition of these transverse lines may be accomplished almost instantly 
by an expert, with a Hartnack No. 11 immersion objective. I have succeeded in 
doing this, though with some trouble, even with a No. 9of this optician. Let me 
remark, incidentally, that the latter combination should also resolve the Surirella 
Gemma and Grammatophora subtilissima. 68 
SECTION FOURTH. 
bands, and tins is connected with the still unsettled question, 
as to where the limits of accurate vision with our modern mi- 
croscopes lies. We here introduce a table of the divisions of 
the last two test plates : 
Plate with 30 hands. 
1. Band 0.001000 of a Paris line. 
5. “ 0.000550 
10. “ 0.000275 
15. “ 0.000200 
20. “ 0.0001G7 
25. “ 0.000143 
30. “ 0.000125 “ 
Plate with 19 bands. 
1. Band roVo of a Paris line. 
2- U TsW 
8- '* SToVo 
2600 
5 ‘1 i «‘ 
3000 
r, “ _X— t‘ 
O. 3600 
7U J. Li 
TDoo 
8U L L L 
• TS(To 
Q t‘ _l_ U 
*'• 6 0 00 
in u _i— “ 
6 6 00 
11- ' ‘ FchTo 
12. “ bmJo 
13. ‘ ‘ ToVo 
14. ‘ ‘ nhio 
15. “ Winr 
16. “ -g-sVo- 
-17. “ soVo 
18. “ 95V0 
19- '1 TTTotTo 
The resolution of these lines with oblique light has been 
employed as a means of testing objectives. Harting was able, 
years ago, with a Hartnack’s immersion lens No. 10, to recog- 
nize the lines in the 30th band of the older plates, and the res- 
olution of the 25th, 26th, and even the 27th band is not an un- 
usually great achievement. M. Schultze succeeded in resolving 
the 15th band of the more recent plate, and I afterwards re- 
solved the 17th band with objective No. 11. In the year 1869, 
an American, Woodward, whom we have to thank for excellent 
photographs of test objects, also mastered the 19th band of 
this wonderful test plate. 
Several years since, Schultze tested a series of the best mod- 
ern objectives with central illumination. The highest perform- 
ance consisted, at that time, in resolving the 9th band with an 
immersion lens No. 10 of Hartnack, and one of Merz ’s -ij". i 
have repeated this experiment. My immersion objective No. 
11 resolved the 12th, less distinctly the 13th, No. 10 the 11th, 
and the combination No. 7 of most recent construction, the 7th 
of this test plate. TESTING THE MICKOSCOPE. 
69 
We have, finally, to discuss the question as to what precepts 
and advice are to be given to those who desire to procure a 
microscope; how should, the instrument be constructed, and 
which optical establishment deserves, at present, to be most 
recommended. 
He who desires to possess a first-class instrument will gen- 
erally select one of the large 
microscopes with a horseshoe 
stand, fig. 69, as constructed 
by Oberhauser and imitated by 
other opticians. Its conveni- 
ence of manipulation, com- 
bined with a certain simplicity, 
render it a truly model stand. 
The large stage, its capability 
of being rotated (which, how- 
ever, requires very accurate 
workmanship, and is therefore 
expensive), the micrometer 
screw for the fine adjustment, 
and the mobility of the mirror, 
are extraordinary advantages. 
The illuminating apparatus 
might, it is true, be improved, 
still it suffices for most pur- 
poses. When the stands which 
the English opticians select for 
their larger instruments (see 
page 29, fig. 39) are compared 
with it, they appear to be un- 
pleasantly loaded with screws 
and unessential appurtenan- 
ces, which inconvenience one 
who daily works with the in- 
Pig. 69, Hartnack’s large horseshoe microscope. 
strument, as it is better to do with the human hand much which 
is there allotted to mechanical contrivances. 
For medical purposes the rotary stage may be readily dis- 
pensed with; less readily the oblique illumination ; and this, 
which may be added with little expense, should, indeed, no 
longer be omitted from any instrument of medium class. 
Smaller horseshoe stands, similar in construction to the larger 70 
SECTION FOURTH. 
stand, but without the rotary stage, deserve, therefore, to be 
especially recommended. Still smaller stands should possess a 
plane and concave mirror, and at least a rotary diaphragm to 
regulate the illumination, or, which is better, several cylindrical 
diaphragms, as well as a stage an inch and a half wide. When 
there is no oblique illumination, a simple condenser, similar to 
the one represented in tig. 24, may be used as a substitute. 
When there is but a simple mirror, no rotary diaphragm, and 
the stage is very narrow, as is the case in Hartnack’s older 
microscope a I’hospice, the stand is certainly deficient. 
Nevertheless, the mechanical portion of a microscope is a 
secondary consideration and of minor importance ; in the opti- 
cal apparatus is founded the actual value of the instrument. 
One or the other form of instrument will be selected, ac- 
cording as a greater or lesser price can be afforded. Beginners, 
especially, should not have recourse to the largest, most expen- 
sive microscopes, as their manipulation is more difficult, and 
considerable practice is required before very powerful first-class 
lenses can be used. 
The strangest notions not unfrequently prevail with regard 
to the optical portion. How often is the question still heard: 
How much does this instrument magnify % How often are mi- 
croscopes ordered from an optician, with a magnifying power 
of from 5-600 diameters. Nothing shows a greater misconcep- 
tion of the optical performance of our instrument, as it is only 
necessary to add a perhaps uselessly strong eye-piece, to change 
a serviceable magnifying power of 400 diameters into a com- 
pletely unserviceable one of 800, and, therefore, of no value to 
the instrument. 
The individual objectives with the various eye-pieces form, 
each for themselves, a particular microscope. For this reason, 
one should have at least a twofold combination of lenses, if 
possible, three,—a weak, a medium, and a strong one. A 
double combination of lenses may be obtained from one system, 
in the most economical manner, by removing its lowermost 
lens. Many of the most simply constructed instruments have 
only one such objective, with two eye-pieces. Good micro- 
scopes of this kind may be obtained for 20 thalers. It is better 
to have several objectives with inseparable lenses. 
We would here call to mind what we have previously said 
with regard to the great value of weaker powers. They should TESTING THE MICROSCOPE. 
71 
never be wanting. At least one objective of medium strength 
is also a valuable addition. Finally, a stronger objective, 
which, with a weak eye-piece, magnifies from 200 to 250 times, 
and, with a stronger one, affords a good and thoroughly ser- 
viceable magnifying power of 300 to 350, should not be wanting 
on any microscope. 
These, usually, completely suffice, especially if another eye- 
piece with a glass micrometer is added. Such instruments are 
to be purchased for 30, 40, and 60 thalers, according to the 
stand, and, when obtained from the best modern establishments, 
stand higher, as to their capabilities, than the large micro- 
scopes constructed thirty years ago at three or four times their 
price. 
naturally increases the cost considerably. For 
the commencement we would advise the omission 
of the very strongest objectives, especially those 
with apparatus for correction which are delicate 
to manipulate, as well as immersion lenses (fig. 
70), and to select in their place a combination 
which works dry. With this, the magnifying- 
power might be increased to 450 or 600, and 
rarely, even in extended scientific researches, 
Stronger objectives are very seldom required ; their addition 
I’ig. 70. Hart- 
nack’s immersion 
objective No. 9. 
would a higher magnifying power be missed. Such instru- 
ments, of excellent quality, may be bought on the continent 
for about 70 or 80 thalers. 
Other more or less expensive accessories, such as drawing 
and polarizing apparatuses, are, as a rule, added to the larger 
instruments only. 
The value of a microscope being founded on its optical por- 
tion, on the excellence of its lenses, the question here arises as 
to the present productions of the various optical establishments. 
It is very difficult to render an impartial decision on this point. 
Disregarding a certain amount of odium in which one would be 
placed with the opticians not accorded the first rank, one should 
have just made a long journey, instituted for this purpose, 
through Germany, France, England, and North America, for 
in this department our industrial epoch exhibits a steady prog- 
ress, one maker being surpassed by another. 
The problem of the construction of weak, medium, and or- 
dinary stronger objectives has been solved in a perfectly satis- 72 
SECTION FOURTH. 
factory manner by a considerable number of modern opticians, 
so that every year a large number of excellent microscopes, 
thoroughly adequate to all the requirements of the physician, 
are put in the market. It is true that certain objectives of one 
maker are superior to the same lenses of another maker ; but 
these differences do not appear to exert any great influence on 
their practical requirements, and are only to be discovered by 
the practised eye. The effort to obtain a large angle of aper- 
ture has stamped modern objectives with a peculiar character. 
We would give the practical advice, not to purchase an instru- 
ment of an unknown optician, or, at least, not without having 
it tested by an expert, and to have the greatest mistrust of all 
charlatanical recommendations, whether they come from the 
optician himself or from a writer glorifying him. 
The various optical establishments differ greatly in the con- 
struction of very powerful, or the most powerful combinations, 
as to the greatest excellence which may be accomplished in this 
department. Therefore, he who would procure a first-class in- 
strument should proceed with circumspection. 
Twenty-five years ago several large firms in England main- 
tained a higher rank in this department than the Continental 
opticians had obtained, if we disregard the Italian savant and 
distinguished microscope-maker, Amici (f 1863). No impartial 
person, who knows how to test a microscope, could deny this, 
if he were to compare first-class instruments originating in that 
epoch. Since that time the emulation of the Continental opti- 
cians has spurred the most skilful on to even higher produc- 
tions ; the difference has become less and less, and has finally 
disappeared. Indeed, a few which have been produced among 
us of late deserve, perhaps, to be placed higher. At the same 
time there is a very considerable difference in price between the 
larger kind of English instruments and those of Germany and 
France. For example, a single objective with a nominal focus 
of A inch, made by Powell and Lealand, of London, costs 
somewhat more than 16 pounds, while Hartnack, of Paris, fur- 
nishes a combination equally strong, No. 10 a immersion, for 
200, and a still stronger one, No. 11, for 250 francs. The strong- 
est objective, -A inch, of the London firm mentioned is charged 
at 31 pounds 10 shillings in the price-list; in that of the Pari- 
sian optician, at 500 francs. 
Large modern microscopes of the most renowned English TESTING THE MICROSCOPE. 
73 
makers have not been accessible to me. I am, therefore, un- 
able to say how far the achievements of former years have been 
surpassed. Several years ago, Harting, one of the first and 
most profound judges of the microscope, passed the highest 
encomiums on the powerful and most powerful objectives of 
Andrew Ross, as well as of Powell and Lealand. Several years 
ago, the p-g- inch objectives of the latter tirm became quite nu- 
merous in England, and obtained great appreciation at the In- 
dustrial Exhibiti9ii in 1862. Another of gV inch is announced 
in the new price-current. Beale has praised it very highly. I 
became acquainted with it in the year 1866 ; so slightly, how- 
ever, that I am unable to express an opinion. 
Among the Continental opticians, Hartnack, of Paris, the 
successor to Oberhauser (Place Dauphine, No. 21), stands first, 
according to my views. Not only that his immersion lenses 
have not as yet been equalled by any Continental microscope- 
maker, but the weaker objectives, which are so very important, 
have also been very much improved, and from the industr}7 and 
carefulness of this highly accomplished artist, further improve- 
ments are to be expected. Thus, objective No. 5 has already 
an angle of aperture of about 80°. Hartnack’s Nos. 7 and 8, 
especially, are excellent, and, like all of his apparatuses, to be 
recommended for their slight expense. The former has within 
a few years been brought to an ever higher stage of consumma- 
tion, as well in penetrating as in defining power, as I know 
from numerous comparisons and tests, and with an angle of 
aperture of about 100°, forms a wonderful combination for his- 
tological investigations. No. 8 has 125-130°, No. 9 (dry), 155- 
160° total aperture. 
The smallest microscope a I’hospice, with objective No. 7 
and a sufficiently broad stage, may be obtained for the low 
price of 65 francs ; though deficient with regard to the illumi- 
nating apparatus, it is nevertheless very serviceable for medical 
purposes. 
A somewhat larger instrument with a rotary diaphragm 
and a wide stage, with a weak objective and the No. 7 just 
mentioned, together with several eye-pieces, costs 115 francs, 
which is increased, when the objective No. 8 is added, to 165 
francs. Disregarding the absence of oblique illumination, we 
should scarcely wish for anything further. It is very con- 
venient for travelling, on account of its small size. 74 
SECTION FOURTH. 
Tlie small horseshoe microscope, No. viii., is a very conve- 
nient stand, permitting of oblique illumination. With three 
objectives, 4, 7, and 8, together with the necessary eye-pieces, 
it costs 275 francs. During a series of years a considerable 
number of instruments of this kind have passed through my 
hands, and I know of no other modern microscope which I 
should be more inclined to recommend to physicians and stu- 
dents who are able to afford the moderate price. If, instead 
of a No. 8, an immersion lens No. 9 is taken, the price is in- 
creased to 390 francs. Besides this stand, Hartnack has 
recently introduced a still more simplified form, with a rotary 
diaphragm and a bronzed foot. With objectives 4 and 7, and 
two eye-pieces, it costs 140 francs. If the foot is replaced by a 
simple slab, the price is reduced to 120 francs. 
Hartnack makes his large microscope only in the larger 
form, and with a rotary stage; together with four ordinary 
objectives it usually receives a No. 9 immersion lens, costing, 
with this addition, 750 francs, at present the best Continental 
instrument. 
Nachet, of Paris (Nachet et fils, Rue St. Severin, No. 17), 
has also obtained a considerable reputation as a microscope 
constructor. Several large microscopes, constructed several 
years ago, resembling the English pattern, capable of being in- 
clined, and furnished with a condenser, were very good for 
that time. What progress Nachet has since made in the con- 
struction of the most powerful objectives, I have unfortunately 
not become sufficiently informed. I had recently in my hands 
an immersion objective No. 7, a little weaker than Hartnack’s 
No. 10 ;it was very good. Several small microscopes which I 
formerly tested were, as well in their mechanical as in their 
optical portions, excellent and very cheap, costing only 200 
francs. Nachet’s prices are as follows;—The large stand, fig. 
40, fashioned after the English microscopes, and arranged for 
inclining, with very numerous accessories and seven objectives, 
costs 1,800 francs; the older large instrument 1,150, and more 
simply furnished 650 francs. Smaller instruments, with various, 
in part very convenient stands, may be obtained from Nachet 
for 500, 380, 200, 160, 125, and 70 francs. 
Hartnack’s pupil, C. Yerick, Rue de la Parcheminerie, No. 
2, Paris, is a very skilful optician. Several instruments, which 
I have accurately tested, varied from 700 to 900 francs. They TESTING THE MICROSCOPE. 
75 
are of the first rank, are equal to the best of modern micro- 
scopes, and are superior to many which, in Germany, espe- 
cially, have been lately so loudly trumpeted. 
The older firm of Chevalier has recently taken a new start, 
through the son, Arthur Chevalier (Palais Royal, No. 158). A 
competent Judge, von Heurck, has recently given prominence 
to Chevalier’s optical productions. Unfortunately, I have not 
as yet seen anything from this establishment. 
Among the purely German opticians, if one may use the 
expression, I mention first Zeiss, of Jena. lam indebted to 
this optician for the opportunity of seeing his most recent len- 
ses. Zeiss has at present nine different efficient stands, worth 
from 18 to 150 marks. His twelve dry lenses are marked ac- 
cording to their strength with the letters A to F; some of them 
have two letters. The first costs 12 marks, the others vary 
from 27 to 66 marks; No. F costs 84 marks. All these lenses 
are of excellent workmanship. No. F, a dry lens, with 160° 
aperture and the nominal focus of yV', is such a strong and ex- 
cellent combination that a higher power will rarely be necessary. 
A few years ago he reconstructed all these lense combina- 
tions on formula computed by Professor Abbe, of Jena. He 
also made three immersion systems with 180° aperture, which 
perform exceedingly well. The strongest of these systems with 
a perfected correcting apparatus corresponds to 2y' of the 
English. It costs 270 marks. 
The former establishment of Gundlach, in Berlin, has passed 
into the hands of Seibert and Krafft, and removed to Wetzlar. 
Seibert, an excellent optician, placed all his lenses in my hands 
at Zurich, two years since. They were all very good, the 
stronger and strongest ones excellent. The most recent im- 
mersion systems, No. 7, ■£s", No. 8, , and No. 9, which 
I recently received, are among the best I have ever seen. I 
would, therefore, at present, give the palm to Hartnack and 
Seibert. The prices of the distinguished technician are rela- 
lively low. 
In Munich, G. and S. Merz, into whose hands the renowned 
institute of Fraunhofer-Utzschneider has passed, produced ex- 
cellent instruments ten years since. Unfortunately, many of 
their lenses have, in consequence of an unfortunate selection of 
the kinds of glass, proved undurable, so that many complaints 
have arisen. 76 
SECTION FOURTH. 
In Wetzlar, about 1840, C. Kellner supplied instruments 
which were excellent for that time. His immediate successors, 
Belthle and Rexroth, have in their price-currents microscopes 
from 35 to 120 thalers. Belthle showed me good instruments 
years ago. Since Belthle’s death, the business has passed into 
the hands of Leitz. His productions merit entire recognition. 
Another establishment in the same place is that of Engelbert 
& Hensoldt, Their instruments are likewise very good. 
Moller and Emmerich, of Giessen, have supplied micro- 
scopes for several years. 
F. W. Schiek (Halle’sche Strasse, No. 14) is the oldest firm 
in Berlin. Some of his productions, which I have recently 
seen, were equal to any made at the present time, being very 
good, at a moderate price. The stands and objectives resemble 
those of Hartnack in form and designation. 
In Gottingen, R. Winkel has recently produced instruments. 
One, which I saw several years ago, was very good. How far 
Merkel was justified in giving unfounded praise to this micro- 
scope, lam unable to decide. It is, unfortunately, impossible 
to get a sight of anything from that place. 
S. Plossl (alte Wieden, Theresianumgasse, No. 12) was the 
first maker in Vienna. 
The excellent instruments of Amici, of Italy, have obtained 
great renown. They were the best Continental microscopes 
from 1840 to 1850, the deceased Amici having at that time 
acquired the greatest merit in the construction of improved 
microscopes. I know nothing further of his instruments pro- 
duced more recently. 
The three most renowned London firms are ; Powell & Lea- 
land (170 Euston road), Andrew Ross (7 Wigmore street, Ca- 
vendish square, W.), continued, since the death of the founder, 
by the son, Thomas Ross, and Smith, Beck & Beck (6 Coleman 
street). Among the remainder we will also mention Pillischer 
(88 New Bond street), W. Highley (70 Dean street, Soho square, 
10), and Baker (44 High Holborn). It is highly commendable 
that, for a series of years, the English have endeavored to pro- 
duce instruments which might be as cheap as possible and, at 
the same time, good. Thus, for example, a number of estab- 
lishments furnish very fine instruments even for £5, as 
Pillischer, Smith, Beck & Beck. 
Among the microscope-makers of North America, the most 77 
TESTING- THE MICROSCOPE. 
important are Spencer, Tolies, and W. Wales. Zentmayer lias 
recently produced very good stands. The optical perform- 
ances do not surpass those of our best European instruments ; 
the prices, however, are enormous (H. Hagen). 
[The history of the microscope as an American instrument 
commences at a very recent date. 
I am informed by Mr. T. H. McAllister, optician of this city, 
that in the year 1840, when the United States Exploring Ex- 
pedition to the South Seas, under Commodore Wilkes, was 
fitting out, it was thought necessary to have a microscope. It 
was then discovered that none was to be had. The various 
makers of scientific and philosophical instruments were applied 
to, but none of them could furnish the expedition with the 
desired microscope. In this dilemma a private individual was 
applied to, and an instrument was finally obtained from Dr. 
Paul Goddard, of Philadelphia. It was a French microscope, 
which would now be considered very inferior, but was the best 
instrument then to be had in this country. 
Since that time the instrument has come into general use, 
and in certain departments of the manufacture of microscopes 
this country has become pre-eminent. Scarcely had the English 
microscope-makers published those inventions and discoveries 
which rendered achromatic microscopes really possible, and 
elevated the instrument from the position of a mere scientific 
plaything to that of an instrument calculated for the most 
accurate investigations, before Charles A. Spencer, of this State, 
succeeded in producing lenses which at once took a front rank 
among the art productions of the world. Spencer and his 
pupil Tolies, Wales, Grunow, Zentmayer, and perhaps a few 
others, have since that time kept up the reputation of the 
American lenses, and to-day there is no country in the world 
in which are produced finer object glasses than those of domes- 
tic make. 
Previous to Spencer’s time, some few microscopes and objec- 
tives had been constructed by amateurs, but their authors have 
never become celebrated in this department. 
Spencer was induced, while still a lad, by the perusal of the 
article on optics in the “Edinburgh Encyclopaedia,” to construct 
a compound microscope. His first lens was made when he was 
about twelve years of age ; this first attempt wras followed by 
others, at intervals, during subsequent years. After making 78 
SECTION FOURTH. 
several compound microscopes, and a reflecting one upon the 
original plan of Prof. Amici, lie constructed several Gregorian 
and Newtonian telescopes with specula of six and eight inches 
diameter, some of which were quite successful. 
It was not till the publication of the “Penny Magazine ” and 
the “Library of Useful Knowledge,” however, that he became 
aware of the improvements which had been made in Paris and 
London in the achromatic microscope. The results obtained by 
Goring and Pritchard in both the achromatic and reflecting 
microscopes excited his attention especially. The discovery by 
the former of the effects of angle of aperture was a powerful 
inducement for Spencer to perfect himself more thoroughly in 
this branch of optical science. About this time he also learned 
of the successful researches of Guinaud, Fraunhofer, and Fara- 
day in the manufacture of optical glass. By laborious and pro- 
tracted experiments, frequently working over the furnace for 
eighteen consecutive hours, he succeeded in improving the 
homogeneousness and other qualities of the glass considerably, 
which enabled him to make an evident advance upon his pre- 
vious efforts in constructing lenses. 
A few instruments were made for personal friends, but it was 
not till later, about 1847, that Spencer became a professional 
microscope-maker. About this time he visited New York City, 
and was introduced by Dr. John Frey to the late Prof. C. R. 
Gilman. Dr. Gilman had a microscope, constructed by Cheva- 
lier, of Paris, which he showed to Spencer and induced him to 
make one like it. The result was, that Prof. G. sold his Cheva- 
lier instrument and replaced it with the one made by Spencer. 
This instrument was completed in November, 1847. In bring* 
ing it to New York, Mr. Spencer stopped at West Point, and 
showed his microscope to the late Prof. Bailey, then the ac- 
knowledged chief of microscopical observers of this country. 
It was with this instrument that Prof. Bailey resolved the Na- 
vicula Spencerii, noticed in the first edition of Quekett on the 
Microscope. This author, at page 440, in speaking of the N. 
Spencerii, says : “that an object glass, constructed by a young 
artist of the name of Spencer, living in the backwoods, had 
shown three sets of lines on it, when other glasses of equal 
power, made by the first English opticians, had entirely failed 
to define them.*’ 
The information which Quekett’s treatise contained concern- TESTING THE MICROSCOPE. 
79 
ing the discoveries of Lister and the labors of Amici and Ross, 
was extremely useful to our “ Yankee backwoodsman.” In the 
account given of Ross’s discovery of the effect of thin glass 
covers upon the correction of an objective, the announcement 
was made that “ on several occasionst he enormous angle of 135° 
had been obtained,” and that, “135° is the largest angular pen- 
cil that can be passed through a microscopic object glass.” 
This statement, coming from a source so generally considered 
authoritative, arrested Spencers attention and led to an imme- 
diate theoretical and practical examination of its validity. 
The supposed theoretical grounds of the assumption not 
having been found to sustain Mr. Ross’s position, conclusive 
evidence of its incorrectness was speedily obtained by the 
construction of a W in. objective, having an angle of aperture 
of 146°. 
An increase of the angle of aperture of the higher powers 
had been made from time to time, until the maximum angle of 
178°, for the XV, was obtained in June, 1851; and subsequently 
the medium and lower powers were correspondingly improved. 
An investigation into the practicability of so far increasing the 
defining and resolving powers of the objectives of medium 
focal lengths was made, and results have been obtained which 
could not, d priori, have been expected. The angle of aperture 
of the \ has been increased to 175°, and its defining and resolv- 
ing powers are such that it bears oculars bringing its amplify- 
ing powers up to twelve hundred diameters, without any con- 
siderable deterioration in the sharpness of its images. With it 
the 19th band of Robert’s test plate has been resolved with or- 
dinary daylight illumination and with artificial light. The 
residual errors have been the subject of continued investigation 
since then, and they afford an ample field for the exercise of 
the highest mental powers and manual skill, 
We have now to speak of another Automath, Mr. J. Grunow, 
who came from Berlin to this country in 1849, and settled in 
Yew Haven, Conn. He was induced by Hrs. Henry Van Ars- 
ffale and C. R. Gilman to study optics and to commence the 
manufacture of microscopes. Grunow was his own teacher, 
and had been engaged in an entirely different business previous 
to his arrival in this country. He constructed his first micro- 
scope for Dr. Van Arsdale in 1852, and soon afterwards a 
second one for Prof. Gilman. About this time Grunow’s SECTION FOURTH. 
brother became associated with him and constructed the stands, 
which were models of good workmanship. 
It may be interesting in this connection to remark that 
Prof. Riddell of this country, the inventor of the binocular 
microscope, used for his experiments in this direction prisms 
made by Fitz, of New York. The first binocular microscope, 
however, was constructed for Prof. R., in 1853, by Grunow. 
A very valuable improvement, made by Grunow, consists in 
letting the rotary diaphragm into the upper surface of the (im- 
movable) stage in such a manner that it is just below the level 
of the same, and can be rotated without disturbing the slide 
on which the object is placed. In this way the full optical 
effect of the diaphragm is obtained exactly at the point where 
it is needed. 
Mr. R. B. Tolies became a pupil of Spencer in 1843. In 
1856 he commenced business for himself, and after several years 
removed to Boston, Mass. 
Mr. Tolies is the author of a number of valuable improve- 
ments in microscopical accessories; among these his stereo- 
scopic binocular and solid eye-pieces, his method of adjusting 
for cover by making the front lens stationary and no back lash, 
as well as his method of making two fronts to an objective— 
one immersion, and one dry—deserve especial mention. The 
excellent quality of his objectives has earned him a world-wide 
reputation. 
Mr, J. Zentmayer, of Philadelphia, was introduced to the 
American microscopic public by Mr. T. 11. McAllister. The 
first instrument which he made was for Dr. Paul Goddard, of 
that city, in the year 1858. This instrument is now in the pos- 
session of Dr. Squibb, the Chemist, of Brooklyn, N. Y., and is 
almost identical with the present “Grand American 
Stand.” 
Zentmayer is the inventor of several valuable improvements 
in microscopical accessories, which will be mentioned in the 
price-list, at the end of this book. The elegant workmanship 
of his stands is unsurpassed by those of any other maker. 
Mr. Win. Wales was a pupil of Smith and Beck, in Lon- 
don. He came to this country about 1862. After remaining 
here for a few months, he went back to England, but soon re- 
turned to Port Lee, N. J. Since this time his lenses have con- 
stantly improved in quality, and are considered by many com- TESTING THE MICROSCOPE. 
81 
petent judges to be equal to, if they do not excel, those of any 
other maker in the world. 
Mr. L. Miller was formerly in the employ of Tolies, but 
commenced business for himself in 1868. Some of his lenses 
which I have seen were very good. 
In addition to the firms above mentioned, excellent instru- 
ments are also furnished by McAllister, Queen, Bausch and 
Lomb, and W. H. Bulloch. 
The microscopes made in this country are generally to sup- 
ply the home demand, and but few have been exported. Some 
have found their way to Europe, where they have been criti- 
cally examined by the French and English makers, and various 
important improvements, which originated with American 
makers, have been appropriated by them. For instance, in 
“Carpenter on the Microscope,” London, 1868, will be found, 
on page 68, a description of a piece of microscopic apparatus, 
invented by Zentmayer in 1862, but which was copied by a 
Paris maker, to whom Dr. Carpenter gives the credit of being 
the inventor. 
In speaking of this instrument (Kachet’s student’s micro- 
scope), Dr. Carpenter says :—“ The chief peculiarity of this in- 
strument, however, lies in the stage, which the author has no 
hesitation in pronouncing to be the most perfect of its kind 
that has yet been devised.” The instrument from which Na- 
chet copied the circular stage was made by Zentmayer in 1864 
for Dr. W. W. Keen, of Philadelphia, who showed it three dif- 
ferent times to M. Nachet, and had it packed by him, in the 
spring of 1865, for transportation. 
The American microscopes are characterized by extreme 
simplicity, combining all that is necessary for a good working 
instrument, and rejecting numerous complicated movements 
and much superfluity of workmanship which some foreign 
makers seem to consider essential. 
Tlie form of stand which has found most favor in this coun- 
ty is the one devised by Mr. G-. Jackson, of London. It con- 
sists mainly of a stout bar which carries the body, stage, acces- 
sory box, and mirror; securing steadiness, equal distribution 
of tremor, and facilitating the centring of the accessories and 
achromatic illumination. It will be found, on examination, 
that modifications of this principle have been applied in nearly 
all of our American microscopes. 82 
SECTION FOURTH. 
As complete descriptions of the various instruments, objec- 
tives, and accessories will be found in the price-lists of the dif- 
ferent makers, at the end of this book, it is unnecessary to 
allude to them in this place. 
Microscopes of American manufacture, from their com- 
parative cheapness—to the cost of importation must be added 
the duty, which is 45 per cent, ad valorem—and the facility 
with which they can be obtained, offer inducements to stu- 
dents and others to procure their instruments at home, and 
thus save time to themselves, while they stimulate the manu- 
facturers to make increased efforts to attain even greater excel- 
lence.] Section Jftftl) 
USE OF THE MICROSCOPE.—MICROSCOPIC EXAMINATION. 
Practical directions for learning to work with the micro- 
scope may be given pretty rapidly and without difficulty, while 
it is painfully troublesome for the beginner to acquire this 
from written instructions. We shall therefore limit ourselves 
to rendering some of the chief points prominent, and must 
leave many other things for the microscopist to study out for 
himself. 
Suitable illumination is of great value for microscopic work. 
As most examinations are made with transmitted light, and the 
application of natural light is, in this case, to be preferred to 
any artificial illumination, the selection of a working room is 
not a matter of indifference. When possible, one should be 
selected which lies towards the northwest or northeast, and 
affords an outlook, so that a larger portion of the sky may be 
used for the reception of the rays of light. In the narrow 
streets of cities, only the upper stories of the houses can gen- 
erally be used. It is convenient to have windows on two sides 
of the room; but those of the side opposite to the windows 
which are in use should be closed by a dark curtain or shutters. 
For ordinary investigations, one may without disadvantage 
place the instrument on a table standing near the window, and 
thus make the preparations and examine them on one and the 
same table. But when the best possible illumination is re- 
quired, such a position should not be selected for the micro- 
scope ; the instrument should be placed at a considerable dis- 
tance, from six to nine feet or more, from the window. A dark 
shade, which can be placed over the stage by means of a ring 
fastened to the microscope tube, will shut off all incident light 84 
SECTION EIETH. 
from the object, and essentially improve the image. Such 
shading of the stage should never be neglected when making 
observations with polarized light, or resolving very difficult test 
objects with oblique illumination. 
The condition of the sky is of importance for the illumina- 
tion. A clear blue sky gives a very fine, soft light which does 
not tire the eye, and is sufficiently bright for all but the very 
strongest objectives. A dull, white, uniform cloudiness is still 
more preferable. Bright white clouds, which lie near the sun, 
should not be selected, on account of their dazzling light. The 
rapid passing of white clouds over a blue sky, when the atmos- 
phere is strongly agitated, is very unpleasant and troublesome. 
When the sun shines through the window, a white curtain 
drawn over it or lowered from a roller is of service. 
To illuminate the field, the microscope is turned towards the 
window, and the mirror is rotated and moved with one hand, 
while the observer is looking through the instrument. When 
the best light has thus been found, the object to be examined 
is placed on the stage of the microscope and the further correc- 
tion of the field is commenced ; for example, lowering the cy- 
lindrical diaphragm or slightly altering the position of the mir- 
ror, the object being constantly kept in sight. When the 
mirror is freely movable, it is unnecessary to alter the position 
of the instrument; but the limited movement of the mirror 
which many of the smallest microscopes permit, often requires 
a turning and moving of the microscope. 
The beginner generally thinks that he can accomplish most 
with a brightly illuminated field, and thus he works, dazzled 
by a sea of light, with weeping, rapidly tiring eyes. The ex- 
perienced observer is accustomed, as a rule, to diminish the in- 
tensity of the light considerably. Together with the protection 
of the organ of vision, it is only in this way that the finest de- 
tails of the microscopic image can be perceived. The skilful 
application of the illuminating apparatus and the use of the 
diaphragm should therefore at once be practised by the begin- 
ner as much as possible. When the instrument has a mirror 
with plane and concave surfaces, the former is used with the 
weaker objectives and a bright light, the latter with the stronger 
objectives and a light which is less intense. A very perceptible 
deficiency is always connected with instruments not having 
such an arrangement. This may be remedied in a measure, it USE OF THE MICROSCOPE. 
85 
is true, by turning the microscope, or by holding the hand in 
certain positions before it. 
Considerable practice is requisite with the oblique illumina- 
tion (fig. 71). The aperture of "the stage must be freed from 
diaphragms, or any other apparatus which may be under the 
stage, and the various positions of the mirror are to be tried 
Fig. 71. Oblique position of the mirror on the horseshoe stand. 
while the eye is looking into the microscope. Ac the same 
time, while the mirror is brought up close beneath the stage, 
the illumination is made as oblique as possible. Truly diabol- 
ical illumination is thus sometimes obtained, which, however, 
shows many fine details in an astonishing manner. When the 
microscope has a well-centred rotary stage, its rotation is of 86 
SECTION FIFTH. 
great importance with this illnmination. An observer who is 
familiar with his instrument and well versed in this department 
of microscopical technology, will be able to show many things, 
to the astonishment of the unpractised investigator, which the 
latter was unable to accomplish after hours of unsuccessful 
labor. The resolution of the systems of lines of the Pleuro- 
sigma angulatum into areolations, with strong objectives, and 
the exhibition of the markings of the Surirella gemma and 
Grammatophora subtilissima by means of the strongest immer- 
sion lenses, may be designated as specimens of the art of ob- 
lique illumination. This is, however, only of minor value for 
our purposes. 
No one should make any protracted microscopic investiga- 
tions by the aid of the artificial light of a lamp or gas flame if 
he can possibly avoid it, or would spare his 
eyes. In Northern Europe, during the 
winter, there are days when the natural 
light is entirely unserviceable, and, vexed 
by the miserable light, one finally has re- 
course to artificial illumination. When it 
is necessary to resort to artificial light, an 
ordinary moderateur, which should not be 
too high, an Argand or a petroleum lamp, 
with a globe of opalescent glass, is worthy 
of recommendation. A petroleum lamp 
(fig. 72), provided with a large condensing 
lens, recently constructed by Hartnack, is 
very convenient; it should also have a 
shade. Properly constructed gas lamps 
may also be employed with advantage. A 
number of these, with very Judicious ar- 
rangements, have been invented and recom- 
mended by English microscopists. 
Fig. 72. Hartnack’s micro- 
scope lamp. 
A proper moderation of the light is here urgently necessary. 
The illumination may be essentially improved by placing a co- 
balt-blue glass of greater or lesser intensity between the lamp 
flame and the object. It may be placed on the mirror or, 
better, on the stage. A black pasteboard screen with apertures 
of various sizes, which may be placed in front of the micro- 
scope parallel with the mirror, and on which the blue glass 
may be fastened with wax, forms a cheap accompaniment of 87 
USE OF THE MICROSCOPE. 
the large Oberhauser-Hartnack microscope, and deserves to be 
highly recommended for its important action. A rotary dia- 
phragm should be placed behind the screen. In place of the 
above, blue glasses of various sorts, which can be shoved into a 
metallic ring, may be inserted into the stage, as necessity may 
require. Such an arrangement may be readily applied to all 
of the larger stands. 
[A very ingenious arrangement of the illumination has been 
contrived by my friend, Dr. Edward Curtis, of this city. 
A small lamp, similar to the one represented in fig. 72, is 
placed in a cigar-box, which stands on one of its ends. On one 
side of the box is cut a small aperture, in which is placed a 
piece of blue glass, to soften the light as it passes to the micro- 
scope mirror. Another larger opening is made in the front of 
the box and is occupied by three different glasses. The one 
nearest the lamp is a square piece of ground glass ; the next 
one is also square and flat, but colored blue. Finally, a plano- 
convex glass lens of long focus is placed at such an inclination 
as to condense the rays of light, thus softened, on to the work- 
table for use in dissecting or arranging preparations.] 
Although direct sun and lamp light is to be entirely rejected 
for ordinary investigations, these most intense of all illumi- 
nating methods must, on the contrary, be selected for many 
investigations with polarized light. 
Opaque objects require illumination by incident light with 
seclusion from transmitted rays. Ordinary daylight is suffi- 
cient for very weak powers ; with stronger ones, more intense 
illumination is necessary. 
Sun-light may be used in certain cases. Numerous contriv- 
ances are in use for concentrating the light on the object. A 
plano-convex lens of large focus (fig. 21), which is placed be- 
fore the instrument, is generally sufficient; this may also be 
accomplished with a glass prism. Lieberkuhn’s illuminating 
apparatus also deserves mention as a good and very suitable 
contrivance, although it is rarely employed in medical investi- 
gations. 
The object to be examined will have to undergo a prelimi- 
nary preparation, if it be not already a permanent preparation. 
This process, which naturally varies considerably according to 
circumstances, generally rendering the examination possible 
with transmitted light, however, we shall soon treat more in 88 
SECTION FIFTH. 
detail. Let the remark here suffice, that the preparation is to 
be made with care and the observance of the greatest cleanli- 
ness ; and then, on the other hand, we would say, not to do 
too much of a good thing, that is, not to select too large pieces 
for examination. Beginners fail in this very generally, and 
place under the microscope masses which, divided, would have 
furnished a dozen serviceable preparations. One rarely exam- 
ines with incident light alone, in which case the object can be 
placed uncovered and dry on the stage of the microscope. As 
a rule, it is necessary to moisten the preparation (with water, 
preserving fluids, glycerine, etc.; see below). With weak 
powers the object may still remain uncovered, and, in fact, 
many things are thus examined, although the preparation is 
generally placed in a watch-glass, a glass box, or a cell, instead 
of on a simple slide. 
If, however, one has recourse to higher powers, it will be 
necessary to cover the object with a plate of glass. This should 
be thin, and as clean as possible. All fluids must be prevented 
from running over its free surface, as the image becomes some- 
what dim and indistinct with ordinary objectives, although, as 
previously mentioned, with the new immersion systems a drop 
of water must be placed on the upper surface of the covering 
glass. In the application of the covering glass, all contact of 
its surfaces with the fingers is to be avoided; held by its sides, 
it is to be laid over the object. Some caution is necessary 
with very delicate objects ; for example, a primitive mammalial 
ovum might be crushed by covering it awkwardly ; the ele- 
ments of the fresh retina might have their connection destroyed, 
etc. Simple contrivances serve for the protection of such prep- 
arations ; a piece of hair or bristle, or the fragment of a thin 
film of glass, may be placed between the slide and the covering 
glass. 
A large drop of the fluid medium may also be used, so that 
the covering glass swims over it. Inversely, a narrow strip of 
blotting-paper may be shoved under the covering glass, and 
thus gradually diminish the fluid medium. In this way the 
pressure of the covering glass may be increased at pleasure. 
The adjustment is made, while looking through the micro- 
scope, by sinking the tube. This is done either by simply 
shoving it down through its sheath with the hand, or, when 
there is a coarse screw, by moving it downwards with the lat- 89 
USE OF THE MICEOSCOPE. 
ter. In doing this, thrusting the lens against the preparation 
is to be avoided, because the latter may be spoiled and its 
covering glass broken, and in certain cases the lens may also 
be injured. It is well for beginners to make this movement in 
the contrary direction, that is, elevating instead of depressing 
the tube, which is to be so adjusted that there is only a small 
space between the covering glass and the lens, and then moved 
upwards. Accurate adjustment requires some practice, and is 
not very easy with strong objectives. That the correct adjust- 
ment has been made, is shown when the contours of the object 
are sharpest and finest. Here the fine adjusting screw comes 
in play. 
The preparation is to be first examined with low powers and 
transmitted central light, gradually passing to higher powers ; 
very weak eye-pieces being constantly employed. In some 
cases the tube of the microscope may be shortened with advan- 
tage. 
[The changing of the objectives is facilitated by the employ- 
ment of a “ nose-piece.” This is an apparatus having two or 
more arms capable of revolving and carrying the objectives at 
their peripheral extremities. The mechanism is to be screwed 
on to the lower end of the microscope tube, the same as a sim- 
ple objective. The various objectives are brought into position 
successively by simply turning the arms. Further movement 
and accurate centring is controlled by means of a catch. The 
original “nose-piece,s’ invented by Brooke, of London, re- 
volved on a horizontal plane, but by a more recent improve- 
ment the objectives which are not in use are elevated obliquely, 
and only become vertical at the moment they are adjusted to 
the axis of the microscope tube, so that they do not in any 
manner interfere with the manipulation of the stage. This ac- 
cessory is almost indispensable for those who work much with 
the microscope.] t 
It is a general mistake of beginners, who under-estimate the 
value of low powers, to use high powers at the very commence- 
ment of the examination. As, however, only the weak objec- 
tives afford a somewhat extended field of vision, while with 
stronger lenses it is extremely small, it results that the employ- 
ment of weak combinations is of great importance for the si- 
multaneous survey of the whole, as well as to give the observer 
the first ideas as to the relation of its several parts. 90 
SECTION FIFTH. 
One then gradually passes to the employment of stronger 
objectives ; at first, always with very weak eye-pieces. When 
working with cylindrical diaphragms it is necessary to vary 
them, exchanging those with large apertures for those with 
smaller ones, likewise occasionally exchanging the plane mir- 
ror for the concave, and in all cases adjusting as accurately as 
possible with the micrometer screw. 
When the observer has found it necessary to make use of 
his higher powers, he may proceed to employ somewhat strong- 
er eye-pieces; but he should be sparing in their use. One is 
soon convinced that less is obtained with them, which results 
from their optical nature, than would be at first believed. The 
image is larger, whereby some points may at first appear more 
distinct. An enlargement is soon arrived at, however, which 
does not show any more, but rather less, than the weaker of 
the previously employed eye-pieces, the brightness of the field 
and the sharpness of the image having considerably diminished. 
Very strong eye-pieces, which are added to the larger instru- 
ments as an optical supplement, are articles of luxury, and are 
scarcely of any use. 
Objectives which are well made as to their optical portions 
bear stronger eye-pieces than those which are less fortunate in 
their construction, Nevertheless, even in this case, one should 
be careful of forcing the magnifying power by means of the 
eye-piece. The latter, it is true, might be still more improved, 
and it is to be wished that capable opticians might turn their 
attention to this subject. The orthoscopic eye-pieces which, so 
far as I am aware, were first constructed and sold by the unfor- 
tunately so early deceased Kellner, of Wetzlar, give a very flat 
image, but have shown me nothing further, even in their 
stronger numbers. 
It follows from what has Just been said, that he who can ob- 
tain about the same magnifying power in a double manner, 
that is, by means of a weak objective and a strong eye-piece, 
or by means of a strong objective and a weak eye-piece, should 
always have recourse to the latter. The effort of the older op- 
ticians to combine weaker objectives with relatively stronger 
eye-pieces cannot, therefore,—we repeat it,—be approved of, 
and is at present being more and more abandoned. 
The ojects of histological and medical investigations will 
seldom require the application of oblique illumination. If it be USE OF THE MICROSCOPE. 
91 
desired to learn the effects of the latter, the directions given 
above are to be followed. 
When reagents are to be used, it is customary, as a rule, to 
add a drop of them to the preparation by means of a pointed 
glass rod, either by removing and replacing the covering glass, 
or by placing the drop at its edge, so that it may flow under 
the cover and unite at this point with the fluid in which the 
specimen is mounted. A gradual streaming in of the reagent 
may be obtained by means of a thread of lint which lies half 
under the glass cover, half free on the slide where it receives 
the drop. 
A better way is to place an evenly cut strip of blotting- 
paper close to one side of the covering glass, and then add the 
reagent at the other. In this manner the change of fluids 
takes place with rapidity, and one soon learns to control it at 
pleasure. 
For the protection of the instrument, it is necessary to ob- 
serve due caution with reagents, especially when using strong 
acids, alkalies, and all substances which attack the lead of the 
flint glass. Concentrated muriatic and nitric acids are to be 
avoided as much as possible, and care should be used with vol- 
atile acids and ammonia. Sulphuretted hydrogen should never 
be used. All of these reagents require the use of the largest 
possible covering glasses. If a lens should unfortunately be- 
come moistened with the reagent, it must be immediately 
dipped into distilled water. Chemical processes which develop 
vapors should in no case be undertaken in the microscopic 
work-room. The destructive effects of such influences are best 
shown by the unfortunate condition in which the microscopes 
°f chemical laboratories are usually found. 
The repeated packing and unpacking of the microscope is 
too troublesome for those who use it daily, and not at all bene- 
ficial to the mechanism of the stand. It is therefore preferable 
to place the instrument on a thick piece of cloth, on the work- 
table, and under a bell-glass or a glass case, which affords suf- 
ficient protection from dust. The eye-pieces, the objectives 
shut up in their case, and such other things as are daily used 
may be kept under a second smaller bell-glass. It is advisable 
to heat the room during the winter, to prevent dampness. 
The instrument should be re-examined every time that it is 
used, especially by the beginner, before being replaced under 92 
SECTION FIFTH. 
the glass case. Stains are to be removed from the brass work 
with a linen rag; dust which has settled on the mirror, eye- 
piece, etc,, by means of a fine camel’s-hair brush. Although 
these procedures consume some time, they are still of great 
value for the protection of the instrument and the preservation 
of its original power of performance, especially if the objectives 
are also examined each time they are used. 
The objectives are best cleaned, after removing the dust with 
a camel’s-hair pencil, by means of a piece of fine linen rendered 
soft by frequent washing. Fine leather or elder pith may also 
be used. Some stains are to be removed with distilled water ; 
others, as glycerine for example, require a cloth freshly moist- 
ened with alcohol. A larger quantity of alcohol is to be 
avoided, as the fluid might possibly get into the setting of the 
lens and reach the Canada balsam which cements the crown and 
flint glasses together. 
This wetting of the lenses rarely happens to the more ex- 
pert. It is obvious, that where reagents are being used it is to 
be particularly avoided, and the greatest caution is therefore 
requisite. The objectives used should be as weak as possible 
with long foci, and, when much of this kind of work is to be 
done, the stage is to be covered with a glass plate, which latter 
may be fastened with clamps, when there are any on the 
stage. Broad slides for the specimens also afford some protec- 
tion. 
Notwithstanding every precaution, the optical portions of 
the instrument require cleaning, after a time, in consequence of 
a fatty coating which settles on the objective and eye-piece, 
and renders the image quite dim. Instruments which have 
been used for years almost always show this coating. One 
should not be too anxious about such a cleaning process, as by 
using a good brush and fine linen the glasses of the microscope 
do not suffer in the least. 
The microscopist’s work-table should be large and massive, 
so that it may stand sufficiently firm. A hard-wood board, at 
one or both sides of which small slabs of slate may be inserted 
for objects which require preparatory manipulation to rest 
upon, is most to be recommended as a table-top. 
A series of drawers is a valuable addition to the table. A 
number of smaller accessory apparatuses which are necessary 
to the microscopist may be kept in these, and are best pre- USE OF THE MICROSCOPE. 
93 
served in tins way from dust and other contaminating in- 
fluences. 
In these are kept the slides, the various sorts of glass cov- 
ers, glass vessels, drawing arrangements, accessory apparatus 
for the microscope, the linen rags for cleaning, etc. 
A few bell-glasses and glass cases are necessary on the work- 
table to protect things which have been temporarily set aside 
from dust. 
Reagents are to be removed from the table after being used, 
and kept in another place. 
The question as to what corporeal and psychical qualities 
the microscopist should possess, is discussed with great pro- 
foundness in many works. We think that it may be here 
omitted. Acute mental organs, calmness, love of truth, and 
talent for combination are qualities which the physician and 
the naturalist should always possess. He who has not these, 
whose perceptive faculties are clouded and the impartiality of 
whose observations are constantly disturbed by a lively, ex- 
cited imagination, should keep away from the microscope as 
well as from the profession of medicine. 
For microscopical observation and work it is necessary to 
have visual organs capable of moderate endurance. Somewhat 
short-sighted, light eyes are generally the best adapted. He 
who is so fortunate as to possess two equally good eyes, should 
accustom himself to employ them alternately. Every micro- 
scopist who uses one eye for a long time continuously in look- 
ing into the microscope while the other eye, though remaining 
oj3en, is unemployed, knows how much the acuteness of the 
one has increased, while the passive eye has acquired a certain 
irritability, so that when the latter is used in order to relieve 
the other, the field of vision appears much brighter and weari- 
ness soon makes its appearance. Where one eye is evidently 
weaker than the other, the microscopical work naturally falls 
to the latter. One should accustom one’s self from the begin- 
ning, while looking with one eye into the instrument, to keep 
the other open also. The attention is concentrated so predom- 
inantly in the active organ that the observer is no longer con- 
scious of the impressions made on that which is unemployed. 
For the protection of the visual powers, one should not 
work too continuously, avoiding the earlier morning hours, as 
well as the time immediately after dinner. Leave ofl; as soon 94 
SECTION FIFTH. 
as fatigue commences. For beginners especially, whose eyes 
often become rapidly tired from the unusual nature of the 
visual act, this is advisable, until later when long practice has 
accustomed them to more continuous labor. 
Whether to stand or sit while working, is to be determined 
by one’s previous habits. Bending the head down over verti- 
cal microscopes usually causes but little inconvenience. Eng- 
lish microscopists, however, as a rule lay great weight on the 
oblique or horizontal position of the tube and of the whole in- 
strument, to prevent the neck from becoming tired, or a How of 
blood to the head, so that not only their large, but also quite 
simple microscopes have such an arrangement. But, accord- 
ing to our Continental notions, the inconvenience of an oblique 
or vertical position of the stage is too great, when more than 
the examination of tests is concerned; this arrangement has 
not, therefore, become very generally adopted. 
Very important for the protection of the eyes is the pre- 
viously mentioned judicious shading of the held, and the skil- 
ful application of the diaphragm (hg. 22, page 22). 
The gift of seeing and observing with the microscope is, like 
all human abilities, unequal, greater with one person, less with 
another; but with a little perseverance it may be acquired to 
a suflicient degree by most persons. 
The peculiar nature of the microscopic images causes some 
difficulties for every commencing observer. The compound 
microscope shows us only that stratum of the object which lies 
directly in the focus, and everything else, which lies in other 
planes, either not at all or only indistinctly. At the same time, 
in the usual manner of examination, the whole specimen is 
transparent, illuminated from beneath and not from above, as 
in ordinary vision. Things which lie in other planes, higher or 
lower, only appear after altering the focus, and this condition 
is much more appreciable with strong objectives of a high 
angle of aperture than with weaker objectives of a lower angle 
of aperture. Hence it follows, that we are able to recognize 
immediately the outline of an object, and the relation of length 
and breadth, but not its thickness or its entire form. We are 
able to obtain these only by a combination of the various mi- 
croscopic images received by varying the focal adjustment. 
Here the beginner frequently meets with considerable difficul- 
ties, and errors may arise from combining the images. USE OF THE MICEOSCOPE. 
95 
In this kind of vision we are deprived of the aid which enables 
us, in ordinary vision, to judge rapidly of the shape of the 
object. The form of a microscopic object, regarded with inci- 
dent light, is, for this reason, generally more readily compre- 
hended. The appreciation of the form of a blood-cell is not 
difficult for those who are somewhat practised, but the contrary 
is the case in ascertaining the polyangular shape of many 
diatom acese, or the form of a cavity in an organic part. The 
comparison of a number of sections made in horizontal, ver- 
tical, and oblique directions, a means resorted to by botanists 
especially, is here, when practicable, of great value. 
The estimation of the form is difficult in still another man- 
ner, namely, in consequence of the extraordinary diminutive- 
ness of an object. With a little practice it is not difficult ta 
recognize the relations of relief in a microscopic object, for ex- 
ample, to distinguish a somewhat larger concave surface from 
a convex one, if only by means of a combination of various 
images. When such surfaces are extremely small, as is the 
case, for example, with the delicate areolations of the so fre- 
quently employed test object, the Pleurosigma angulatum, the 
discrimination is very difficult. Thus, as has been previously 
remarked, these last-mentioned areolae have been declared by 
some excellent observers to be convex, by others to be exca- 
vated, and the matter has not yet been definitely decided. 
Welckerhas given us a good means for discriminating be- 
tween convex and concave bodies. The former act as convex 
lenses, the latter as concave. When we start with the tube in 
a medium position, a convex body will appear lighter by rais- 
ing the microscope tube, a concave by lowering the tube; a 
globular structure and a hollow sphere, a ridge and a furrow, 
may thus be discriminated. 
It is much easier to recognize the shape of microscopic ob- 
jects by means of weaker objectives than by the employment 
of very strong combinations with large angles of aperture, so 
that herein also lies a weighty argument in favor of the former. 
Although the practised microscopist may accomplish his pur- 
pose with very strong objectives, still it is frequently desirable 
to have a well-constructed medium power, with the smaller 
angle of former days, added to one’s instrument. The English 
opticians have sought relief in this direction by adding a dia- 
phragm to the lenses with large angles of aperture. 96 
SECTION FIFTH. 
One soon learns to appreciate the foreign substances which 
contaminate the microscopic image, much of which may be 
avoided by neatness and carefulness in making the preparation. 
One should make one’s self familiar, and as soon as possible, 
with the appearance of air bubbles, oil globules, starch gran- 
ules, fibres of linen and cotton, etc. 
It is also important to compare the image which an object 
presents by transmitted light with that which it affords by in- 
cident light. Among other things, the appearance of one and 
the same object in media of various refracting powers is also to 
be studied. 
The optical portion of microscopic work is much more diffi- 
cult to acquire than the manual, such as the cautious use of 
the adjusting screws and the mirror, and the steady and not 
jerking movement of the object through the field. In this place 
the important principle should be impressed, that movements 
which can be securely accomplished by the human hand are to 
be left to it, and are not to be executed by screws and other 
mechanical contrivances. Every experienced microscopist will 
regard the massive accessory apparatus of the large English 
microscopes as being somewhat superfluous and inconvenient. 
The inversion of the image by the compound microscope 
causes some difficulty for the beginner. One soon becomes 
accustomed to this, however, and finally to such a degree that 
it is no longer noticed, and one is only reminded of it when 
using an erector (where the inverted image is again inverted by 
means of a lens placed within the tube of the microscope, or by 
a prism on the eye-piece). As this inversion is 
attended with optical disadvantages, such instru- 
ments have not been extensively adopted, and 
are only convenient for microscopic dissections 
when furnished with weak lenses. 
Hartnack has recently obtained a very con- 
siderable improvement by means of his image-in- 
verting eye-piece (fig. 73). This has above the 
ocular lens, that is, above the lower ring-shaped 
projection, a complicated prism, which produces 
a complete inversion of the image with a very 
Pig. 73. Hart- 
nack’s image-invert- 
ing eye-piece. 
bright though somewhat small field. It costs a little more 
than thirty francs. 
Finally, one word more is necessary concerning the phe- USE OF THE MICROSCOPE. 
97 
nomena of movement visible under the microscope. Not every- 
thing which is here seen in motion is, for that reason, to be 
pronounced vital. 
Currents sometimes occur in water, with which one should 
become familiar in order to guard against error in other cases. 
For instance, if alcohol is mixed with water, the small bodies 
suspended in it acquire a rapid motion, which continues until 
both fluids are equalized, that is, have become thoroughly 
blended. 
Then very small particles of substances which are insoluble 
in water present an uninterrupted dancing motion, the cause 
of which is still unexplained, but is, at all events, a purely 
physical phenomenon. This movement is called the “Bruno- 
nian molecular motion.” 
Finely powdered charcoal, small crystals, the granules of a 
coloring material exhibit the same peculiar dancing movement 
as the molecules of fat and melanine taken from the animal 
body. In certain cases we can observe the same motion in the 
fluid contents of cells as are taking place in the surrounding 
fluids. 
On the vertebral column of the frog, at the points of exit of 
the spinal nerves, lie small white collections of columnar- 
shaped crystals of the carbonate of lime. These, deposited in 
a drop of water, present one of the finest examples for the study 
of the molecular movement. Larger crystals, of about yj-g- to 
lie perfectly quiet, so long as there is no current in the 
fluid. Those of half this size are seldom found to have the 
dancing motion. The smaller the columns are, the more gen- 
erally the movement is to be met with, and the smallest, of 
ToVo//r and smaller, on which we are no longer able to recognize 
the columnar form, are engaged in a continual, restless motion. 
The examination of the molecular movement is instructive 
for the beginner in still another regard. One readily forgets 
how much the excursions of a moving object are enlarged by 
the optical apparatus of the microscope. The dancing of a 
small molecule will appear slight to the eye with 200-fold en- 
largement, but very energetic, on the contrary, with an enlarge- 
ment of 1000-1500 diameters. 
This is repeated in the vital movements which are seen with 
the instrument. An animalcule which we examine with very 
strong lenses shoots quickly through the held, while with the 98 
SECTION FIFTH. 
lowest powers it does not swim with any considerable degree 
of rapidity through the water. When the circulation in the 
web of the frog’s foot or in the tail of its larva is examined with 
high powers, the blood-corpuscles hasten through the capillary 
passages, while in reality the current in the capillary vessels is 
quite slow. 
There is still another consideration which is not to be disre- 
garded in observing the phenomenon of microscopic motion. 
When a series of movements follow each other with great 
rapidity, we may readily recognize the total movement, but not 
the single motions ; these are separately appreciable to the eye 
only when the entire phenomenon is retarded. We shall be- 
come acquainted with an example of this, the ciliary movement, 
in a later section. 
Finally, we have to mention still another series of movement 
phenomena which has recently attracted the attention of investi- 
gators more and more,—we refer to the changes in shape of the 
living animal cell. 
Isolated examples of this marvellous change of shape, espe- 
cially in the bodies of the lower animals, were known long ago. 
At present it is known that the young animal cell, so long as 
the cell body still consists of the original substance, the so-called 
protoplasma, is endowed in the highest organisms also with a 
capacity for independent vital contraction. Numerous cells of 
the normal superstructure, likewise pathological new formations 
—so long as they possess the character of youthfulness— 
present the changes mentioned. Such cells have been seen to 
pass out (after the manner of the amoebae) through the walls of 
the capillaries (A. Waller, Cohnheim), to wander through the 
lining tissue, and to take up into their contractile cell-like 
bodies small particles, such as molecules of indigo, anilin, cin- 
nabar, and carmine, the finest milk globules, and even extrava- 
sated colored blood-corpuscles ; so that the view here opens into 
a new world of minute actions, and it has already furnished 
extremely important information, to which we shall again refer. 
If in any microscopic investigations the most conservative 
preparation is requisite, it is just here. 
In order not to kill the cell prematurely, one must employ 
a truly indifferent fluid medium. Whoever proceeds to make 
such investigations with the old idea of possessing such indiffer- 
ent fluids in solutions of sugar and salt, albumen and water, or USE OF THE MICROSCOPE. 
99 
humor vitreus, will soon become convinced of the contrary. In 
general only those fluids which surround the cell in the body 
can be called truly indifferent. In many cases the indication 
may be fulfilled with iodine-serum (see below), or a similar com- 
position. The greatest caution 
is necessary to prevent pressure 
and evaporation. The very thin 
covering glass is to be support- 
ed by placing beneath it the frag- 
ments of one of its predecessors, 
which are usually not very rare 
with the microscopist, or—what 
is for many cases still better—the 
covering glass is entirely omitted. 
Fig. 74. Recklinghausen's moist chamber. 
Recklinghausen has invented a very efficient little apparatus 
for preventing the evaporation of the fluids. This, the “moist 
chamber,” the reader will readily comprehend by glancing at 
fig. 74. The object is placed on the somewhat broad ground 
slide ((d) in the usual manner. The glass ring (u), with its under 
surface likewise ground off, rests on the slide at some distance 
from the object. This ring may, in certain cases, be made 
higher. A tube (6) of thin rubber is fastened as firmly as 
possible about the ring. The upper end (c) of the tube is 
fastened round the neck or tube of the microscope with a small 
rubber band. In order to keep the space thus enclosed satu- 
rated with moisture, two strips of elder pith or bibulous paper, 
saturated with fluid, are to be placed at the inner surface of the 
glass ring, and the external surface of the lower border of the 
Fig. 75. A more simplified moist chamber. 
ring is to be surrounded with several little pads of moist blot- 
ting-paper. 
A moist chamber may be made in still another, more simpli- 100 
SECTION FIFTH. 
fied manner (fig. 75). A glass ring (5), a few millimetres in 
height, is to be cemented on to an object slide {a). A few drops 
of water are to be cautiously placed at the inner edge of the 
former with a brush. The object is to be placed on a circular 
covering glass (c) and the latter then turned over and placed on 
the ring ; in this way all pressure is necessarily avoided. 
One may thus—with the aid of an immersion objective—fol- 
low the movement of these cells for hours, and even days. 
The last-mentioned simple apparatus may be readily convert- 
ed into a gas-chamber (fig. 76). The thick glass plate shows a 
Fig. 76. Strieker’s gas-chamber. 
ring ground out at the bottom of the chamber. Two glass tubes 
are cemented into the two half canals. One of these tubes (a), 
connected with the caoutchouc tube a~ serves for the entrance 
of the gas, the other (a1) for its exit. The covering glass may 
be more securely adapted to the glass ring with a cement. 
Although we can in this manner, at the ordinary temperature 
of the room, study the cell life of a cold-blooded vertebrate ani- 
mal, for example, in the connective tissue, cornea, blood, and 
lymph of a frog, we cannot, with the same success, study those 
from the body of a wmrm-blooded animal. The movement is 
too rapidly retarded by the surrounding coldness. A condition 
as to temperature resembling that of the living organism must 
be attained for the success of the observation. The older mi- 
croscopists helped themselves in this dilemma, so far as it was 
possible to do so, by using warmed slides. Beale afterwards 
constructed a warmable stage, but of rather crude form. Quite 
recently a celebrated investigator, M. Schultze, has rendered a 
great service by producing an apparatus of this kind which ful- 
fils the indications more completely. USE OF THE MICROSCOPE. 
101 
Sclmltze’s apparatus* is represented by our fig. 77. A brass 
plate A, wliicli is notched (c) posteriorly, so as to fit on to the sup- 
port of the microscope, is to be fastened on to the microscope 
stage with clamps. It is perforated at a for the illumination, 
and at its front part, in the middle, the thermometer (d) is placed 
slantingly ;at the corners are the two arms b. Two small spirit 
lamps under the latter supply the heat. The lower extremity 
of the thermometer is enclosed in the brass case Ba, which has 
Pig. 77. Schultze’s warmable stage. 
two somewhat thicker wooden ledges at its sides. The ther- 
mometer winds round the aperture in the stage, passes uncovered 
and horizontally, for a short distance, on its under surface, and 
then bends to pass through the opening b to arrive at the face of 
the graduated metal plate. It has been ascertained by experi- 
ment that the actual temperature of the object is indicated by 
the thermometer. 
It is scarcely necessary to remark, that it is most advantageous 
to use immersion lenses and the moist chamber with the hot 
stage. 
Unfortunately, this apparatus has an unpleasant defect, as 
Engelmann has shown. The temperature of the object is occa- 
sionally reduced very considerably by the metallic setting of the 
lens and the microscope tube, so that, in this case, the focal 
distance of the objective exerts a marked influence. The inser- 
* It may be obtainde of the mechanician G-iessler, in Bonn, for 27 marks. 102 
SECTION FIFTH. 
tion of a bad conductor of heat between the lens and the micro- 
scope tube has been proposed. An ivory tube, 80 mm. in heigh t, 
applied in this manner, lessens this defect very materially. 
Quite recently Strieker and Sanderson, Panum and E. A. 
Schaefer have invented complicated apparatus serving the same 
purpose. 
Various arrangements have been contrived for the purpose of 
conducting electrical currents through an object under the 
microscope. We introduce, as an example, the simple one of 
Parting (fig. 78). 
Fig 78. Harting’s electrical apparatus. 
Two somewhat narrow strips of tin-foil A B are fastened with 
starch paste on to a glass slide abed; a portion of the tin-foil 
projects beyond the ends of the slide, so as to connect with the 
conducting wires of the galvanic apparatus. The central portion 
of the slide remains free. The,two glass plates de f g and 
h i 7c I are to be cemented over these strips of tin-foil with 
marine glue or a mixture of pitch and rosin, for the stage clamps 
to rest on. The two polar wires p and p (for which platinum 
is the best material) are not fastened; they receive the curve 
shown in the figure at C. The part mr s rests on the tin-foil, 
the other curved portion m t v (to which may be given any curve 
desired) dips its point into the examining fluid, which in our 
drawing is surrounded by a cell D. Harting’s apparatus may 
be readily modified. Section Surtl). 
THE PREPARATION OF MICROSCOPIC OBJECTS. 
With the exception of the finished preparations of a collec- 
tion, in most cases the objects to be examined require prepara- 
tion, which, as we have already remarked, should be as careful 
and cleanly as possible. It is only when the blood, mucus, 
pathological fluids, etc., are examined, that the mere spreading 
out of a drop of the same is sufficient. 
The object slides, which are simply strips of glass, serve for 
the reception of the object to be examined. Several dozen of 
them should be kept on hand in a clean condition, protected 
from dust in an accurately closing box. Glood slides should be 
made of pure glass, preferably without any color, and the edges 
should be ground, for the protection of the instrument. Too 
great thickness of the glass renders the use of the stronger objec- 
tives and the cylindrical diaphragms, which then become neces- 
sary, inconvenient. Therefore, the thickness of the slides should 
not exceed The most convenient form is that of a long 
square (3 inches by 1 inch), but when the stage is narrow they 
should be of a corresponding width. Square slides are less 
suitable. One should also accustom one’s self to place the object 
to be examined in the centre of the slide. It is rarely examined 
in the dry condition, but, as a rule, with the addition of some 
fluid ; as, water, glycerine, etc. This is to be added at the com- 
mencement of the preparation. One soon learns to judge of the 
quantity which is necessary. 
The object to be examined, if it is large, and especially if it is 
thick,—as for example, when one desires to examine a small 
embryo or an injected specimen of considerable size,—is to be 
placed with some fluid in a watch-glass under the microscope. 
Small quadratic glass boxes, about an inch or an inch and a half 104 
SECTION SIXTH. 
in size and two or three lines in depth, are more convenient for 
this purpose (fig. 79). 
Small glass boxes with covers, as represented in our fig. 80, 
of nearly natural size, are still better. They may be purchased 
quite cheap of E. Seybold’s suc- 
cessors, in Cologne. 
Glass cells, as made by the Eng- 
lish (see further on, at the prepara- 
tion of microscopic objects), may 
also be employed with advantage. 
Thick slides with an excavation in 
the centre are less suitable. 
The preparation is seldom ex- 
amined uncovered ; such a method 
of examination is confined almost entirely to the cases last 
mentioned. The covering glasses or covering scales, which 
have been so frequently alluded to, serve for a covering. Pieces 
of pretty thick glass were formerly used with low powers ; at 
Fig. T9. Glass box. 
Fig. 80. Glass box with its cover. 
present these have gone out of use, since thin and even very 
thin glass may be obtained from England at slight cost. 
As we have seen in an earlier section, the thickness of 
the covering glass exerts considerable influence on the opti- 
cal performance of the stronger objectives. It is well, there- 
fore, to have these glasses arranged in a series of various thick- 
nesses, which are kept in separately designated boxes. It is 
necessary to have them from to those of in 
thickness, according to the objectives with which they are to 
be used. Even the pressure of this thin glass is occasionally 
too great for very delicate objects, if one desires to avoid 
crushing or splitting them. In such cases it is necessary to 
insert a harder substance between the slide and the cover, a pre- 
cautionary measure which has already been alluded to on a pre- 
ceding page. Thicker covers may be cut from thin plate glass. THE PREPARATION OF MICROSCOPIC OBJECTS. 
105 
A few special instruments are requisite for making prepara- 
tions. But one should not think that they are indispensable. 
In practised hands the same and even more may be accom- 
plished, in a shorter time, with simple tools than with compli- 
cated ones. A number of microscopic knives, small forceps, 
and scissors have been invented, it is true, but they are gener- 
ally used by their inventors only, and are, as a rule, quite 
worthless trash. 
First of all, one should have several line forceps terminating 
in thin points for seizing objects. Such should be selected as 
have light springs, and not the stiff ones which many anato- 
mists are accustomed to use. The points should be either 
quite smooth or only slightly grooved. A hooked point is un- 
suitable. Many objects, especially those of a delicate nature, 
are more conveniently moved with a camel’s hair-brush. 
The scissors are most frequently used for dissecting, A 
line pair of so-called eye scissors is indispensable. A small 
pair with curved blades is very convenient for many purposes ; 
here and there, a pair of line elbow scissors also renders good 
service. 
A few small knives, though useful, are of relatively inferior 
value. Several very line scalpels with narrow-pointed blades, 
when possible, of somewhat strongly hardened steel, are more 
serviceable. The ordinary anatomical scalpels are much too 
clumsy, and, as a rule, are made from too soft steel to be use- 
ful for the microscopist. 
When a still liner cutting instrument is necessary, the ordi- 
nary cataract needle is to be used. It is also extremely useful 
for moving small objects. 
The tearing of microscopic objects is frequently necessary 
in histological investigations. This may be accomplished with 
very finely pointed steel needles, of medium length, let into 
wooden handles. When this picking process is necessary it 
should, in consequence of the minuteness of the elements of 
the human body, always be performed with accuracy ; devo- 
ting the few minutes required, as one will be rewarded for the 
little pains, by a good preparation. Beginners very frequent- 
ly fail in this. They stop picking too soon on a preparation 
which was too large at the commencement. 
Not unfrequently, in such cases, the work is so fine that 
one must have recourse to magnifying glasses, to the ioup or 106 
SECTION SIXTH. 
the simple microscope. A very great inconvenience is con- 
nected with the latter when used with stronger lenses; the 
shortness of the focus soon renders needle-work impossible. 
Zeiss deserves credit, therefore, for having produced the use- 
ful microscope represented in fig. 81. It has, on a short tube, 
an objective consisting of three lenses, and has a concave lens 
as an eye-piece. It permits the use of needles, even with 160- 
200 fold enlargement. 
The image inverting eye-piece of our fig. 78, p. 96, permits 
a similar use of a compound microscope. 
Fig. SI. Zeiss’ new dissecting microscope. 
[A very economical and efficient substitute for the simple 
microscope has been devised by Dr. Curtis. It consists simply 
of a binocular ophthalmoscope, the mirror of which is replaced 
by a biconvex lens of one or two inches focus. The whole 
rests over a small aperture in a little wooden box, the front 
and part of the sides of which are removed for convenience of 
manipulation with the preparation which is placed on a sup- 
port in the box. As will be readily appreciated, this gives an THE PEEP A RATION OF MICROSCOPIC OBJECTS. 
107 
upright, stereoscopic image, and a considerable magnifying 
power,] 
It is often found necessary to make very thin sections from 
fresh, and especially from artificially hardened tissues. Knives 
with double blades running parallel, and close to each other, 
have been used for this purpose. The double knife invented 
by Professor Valentin has become the best known. It is not 
Fig. 82. Double knives. 1, that of Valentin; 2, the improved English instrument. 
easy to produce a good instrument, such as is represented by 
our fig. 82, at 1, and when not well made it is entirely unser- 
viceable. This instrument has received a judicious improve- 
ment in the hands of English cutlers. We see such an im- 
proved form of the double knife represented in the same cut, 
at fig. 2. 
Even with this improved instrument, unfortunately, not 
much can be accomplished, as I know from experience. 
It is much more desirable to make thin sections, with the 
free hand, by means of a good razor. Any one who has such 
an one at his command, and has acquired the necessary dex- 
terity, will discard the double knife. Good English razors, of 
light construction, with small blades, are the most suitable. 
For many purposes, it is well to have them ground fiat; but it 
is preferable to have the blade ground hollow for very thin and 
fine sections. To preserve it in a proper condition, it is neces- 
sary that it should be well sharpened, and the strap should be 
frequently used. The blade, as well as the preparation to be 
cut, must be well moistened, for when they are dry a good sec- 
tion can never be made. The fine section is best removed from 
the wet blade by means of a brush ; it is then to be carefully 
and cautiously spread out on the slide. For making very large 
sections with sufficient delicacy, however, the razor is unser- 
viceable, in consequence of the thickness of the back of its 108 
SECTION SIXTH. 
blade. In such cases, according to Thiersch, another instru- 
ment may be advantageously employed ; it consists of a knife- 
blade of the thickness of paper (about 1 cm. in breadth by 20 
cm. in length), which is to be stretched in a watchmaker’s or- 
dinary saw-bow. 
[The best razors which I have seen for anatomical work are 
those made by Le Coultre, in Switzerland. The blades are as 
thin as paper, and are made of good material. The price 
varies according to the width and number of the blades. Those 
with one wide blade cost $1.75, gold; with two wide blades, 
$2.50.] 
The so-called microtomes are used for making sections of 
uniform thickness, or a whole series of sections. Many of these 
instruments have been invented, and some of them are quite 
expensive. 
have found Schiefferdecker’s, a modification of the instru- 
ment invented by J. Smith, very good (fig. 88). It permits of 
the use of any razor, either dry or moist. The 
razor is moved with the free hand, and the 
preparation is held firmly and moved forward 
by means of a micrometer screw. 
The microtome consists of two brass rings, 
with the greater portions soldered, and placed 
one above the other. A space is left between 
them above. They are here provided with 
screw courses, and receive a short tube which 
also has screw courses. This has above a 
Pig. 83. ScMeffer- 
decker’s microtome, 
about half the actual 
size. 
broad brass flange, the outer margin (6) of which is divided 
into 100 parts, and is bent downwards at an obtuse angle for 
the protection of the knife. A complete turn of the screw 
elevates the preparation 1 mm.; a turn of one division is 0.01 
mm. An indicator (c) is attached for reading oif. 
The preparation is inserted into a larger piece of firmer ani- 
mal tissue, such as hardened liver or spinal cord, or into elder 
pith, or imbedded in any other manner and then fixed in the 
half tube (a) which is adjusted by the horizontal screws (d). 
[A very efficient “ section cutter” has been contrived by Dr. 
Edward Curtis, of this city, to whom I am indebted for the 
accompanying wood-cut. 
The following description of the apparatus, and the manner 
of using it, is condensed from an article presented by Dr. C. at THE PREPARATION OP MICROSCOPIC OBJECTS. 
109 
the annual meeting of the American Ophthalmological Society, 
held at Newport, July, 1871. 
The apparatus is shown in tig. 83*. “It consists of the part 
A (fig. I.), for holding the object to be cut, modelled after a 
form of section cutter in common use ; and of the cutting part 
B, after my own device, composed of a long straight knife held 
FIS. I 
FIGH 
FIG 111 
FIGIV 
Fig. 83*. Curtis’ “ section cutter.” 
in a frame. The holder, A, consists of a heavy brass plate, 
faced with glass, six inches long by three and three-quarters 
wide, from the centre of which is sunk a hollow cylindrical 
barrel, one inch and three-quarters in depth, and one inch and 
one-quarter in diameter, inside measurement. Through the 
bottom piece of this barrel (which unscrews for convenience) 
works a screw shaft, furnished with a large milled head. The 
threads of the screw are fifty to the inch, and the circumference 
of the milled head is marked off into eighths, so that, if desired, 
the thickness of the sections cut can be measured. Attached to 
the under surface of the face plate, near one end, is a screw 
clamp for fastening the apparatus to the edge of a table, so as 
to leave both hands of the operator at liberty to work the cutter. 
“The principle of this ‘holder,’ as it might be called, is very 
simple. The object to be cut is first embedded in a cast of wax 
and oil, or paraffine, made to exactly fit the bore of the barrel; 
this mass is then pressed into the barrel, pushed upward by 
turning the milled head of the screw-shaft until it projects 
slightly above the level of the face-plate, when the projecting 110 
SECTION SIXTH. 
part is cut off by a sweep of the knife. Another turn, or a 
fraction of a turn, of the milled head is then made, and again 
the projecting portion is cut off, this time as a smooth, even sec- 
tion of microscopic thinness. For a cutter I had a straight 
knife made, with a blade eight inches long, one and a quarter 
inch wide, and three-twentieths of an inch thick at the back, 
and with the sides concave like a razor. This lat first used by 
itself, sweeping it over the surface of the holder in cutting the 
sections, but I found that, from the length and thinness of the 
blade, it was apt to bend under pressure, and so fail to cut an 
even section, and also that the edge soon got dull from friction 
upon the face-plate. To obviate these difficulties, I conceived 
the idea of having the knife fixed in a frame which should 
answer the double purpose of holding the blade stiff, and carry- 
ing it with the edge raised slightly above the level of the sur- 
face of the holder, so that the under surface of the arms of the 
frame should be the bearing surface upon the holder, and the 
edge of the knife be allowed to touch nothing but the tissue to 
be cut. The design of the frame will be seen at once from the 
figure ; it is made of brass, and the knife is pushed into place 
from behind, under a couple of springs, which hold the blade 
down, and, when pressed home, the knife is kept from slipping 
back by a little fastening, which is pushed against the back of 
the blade and then fixed by a turn of a quick screw. Besides 
the advantages of the frame in holding the knife stiff, and keep- 
ing its edges from scraping over the surface of the holder, its 
weight and broad tread make it sweep much more steady and 
true than that of a light knife used by itself.” 
This apparatus is so efficient that Br. C. has often cut with it 
sections of an entire human eye, thin enough for microscopical 
examination. 
In preparing the tissue and cutting the sections, however, 
there are one or two points which it is necessary to observe in 
order to get the best results. The tissues are to be hardened in 
the usual manner, with bichromate of potash and alcohol. 
When the consistence is suitable for cutting, the piece is to be 
transferred to oil of cloves, where it is allowed to stay until 
thoroughly impregnated with the oil; this takes from half an 
hour to several hours, according to the size and solidity of the 
specimen. The piece is now to be embedded for cutting. 
‘£ In order to get a mould for the paraffine which shall yield THE PREPARATION OF MICROSCOPIC OBJECTS. 
a cast of the right size to go into the barrel of the section-cut- 
ter, a solid brass plug (fig. IY. of the woodcut), one inch high, 
and made to exactly fit the bore of the barrel, forms part of the 
apparatus. In one end of it an oval excavation is countersunk, 
to let the cast of paraffine take a firm hold of its surface, and 
to keep the same from turning round under the pressure of the 
knife. A strip of letter-paper, about two inches and a half 
wide, is now wrapped tightly around this plug, the plug being 
in the middle of the strip, so that the paper projects at both 
ends. The part projecting beyond the flat end of the plug is 
folded down over it, and the opposite projecting cylinder of 
paper then forms a cup, with the excavated face of the plug 
for a bottom, of the exact calibre of the barrel of the section- 
cutter. Into this the melted paraffine is to be poured. A cap- 
sule containing paraffine, or wax and oil, in considerable excess 
of the amount required for the embedding, is held over a lamp 
till the mass is just melted, when it is taken off and the piece of 
tissue dropped into it and stirred about for a few minutes to 
rinse off the excess of oil of cloves. Then some of the melted 
material is poured into the paper mould, the piece of tissue 
immediately transferred to the same, arranged in proper posi- 
tion, and the whole set aside to cool. When perfectly cold and 
hard, the paper is unwrapped, care being taken not to loosen 
the paraffine cast from the brass plug, and cast and plug toge- 
ther are then pushed into the barrel and holder, and each sec- 
tion is cut by a sidelong sweep of the cutter. It is usual in 
cutting sections to flood the surface of the tissue and the blade 
of the knife with alcohol, so that the section, in cutting, floats 
freely over the blade. 
“ In this apparatus, however, from the great length of the 
knife, and from the fact that its edge is raised off the surface 
of the holder, this procedure is impracticable ; but I find that 
I get even more perfect sections by the plan of cutting dry— 
that is, without flushing the surface of the tissue with any fluid. 
It will be seen in the figure that the knife is set at a slight angle 
in the frame ; and this obliquity seems to give the section a 
tendency to curl away from the knife-blade in the cutting, so 
that in this dry process there is not only no more, but there is 
actual!}7 less danger than by the wet method of the section 
clinging to the blade, and so getting torn. But here the pre- 
liminary impregnation of the tissue with oil of cloves is essen- 112 
SECTION SIXTH. 
tial; for, were it in alcohol, the microscopically thin section 
wonld instantly become ruinously dry as soon as cut. The oil 
of cloves, however, from its very slight volatility, keeps the 
tissue of the section moist until it can be transferred to a fluid. 
But it will not do so long, and hence the moment a section is 
cut it should be promptly seized and dropped into fluid ; and 
if, from imperfect impregnation before embedding, the surface 
of the cut tissue looks dry, it should be moistened only by 
a touch of a camel’s hair brush dipped in oil of cloves. If the 
sections are not to be stained, they are dropped into turpentine 
as soon as cut ; this dissolves the adhering wax or paraffine 
very promptly if slightly warmed, and the sections are then 
ready for examination or mounting. If they are to be stained, 
they are put into alcohol instead of turpentine. This in a few 
minutes dissolves out the oil of cloves, and the sections are then 
put at once into the carmine staining fluid. 
“The woodcut represents two accessory pieces of apparatus 
that have not been alluded to. Fig. 111. represents a secondary 
barrel with a half-inch bore, which can be screwed into the 
bottom-piece of the main barrel to diminish its size when any 
small pieces of tissue are to be imbedded. It has a plug made 
to fit it similar to the large plug of the main barrel. Fig. 11. is 
a simple and ingenious contrivance, devised by Mr. Wale, the 
maker of the instrument, for holding hard substances which 
will bear squeezing, and which, therefore, it is not necessary or 
desirable to imbed, such as cartilage, horn, wood, etc. It con- 
sists simply of a brass plug, made to fit the barrel of the sec- 
tion-cutter, hollow, but with the bore slightly conical, and with 
a screw-thread cut on its face. A few wedge-shaped pieces of 
soft wood of different sizes, roughly whittled out, complete the 
apparatus. Supposing a stick of wood is to be operated on, it 
is grasped between two of the wedges of the right size, being 
allowed to project somewhat above their tops, the whole pressed 
firmly into the conical bore of the plug, and with a turn or two 
the soft wood of the wedges is tightly grasped by the screw- 
thread of the plug, and the object to be cut, tightly Jammed 
between the wedges, is immovably fixed. Sections can be cut 
from the projecting portion in the usual way. It may be re- 
marked, in passing, that the cutter for anatomical tissues must 
not be used for hard substances. For these a strong, heavy 
knife or chisel of less brittle temper is to be employed. THE PREPARATION OF MICROSCOPIC OBJECTS. 
113 
“In conclusion, it may not be amiss to state that the sec- 
tion-cntter and accessories can be obtained (to order) of Messrs. 
Hawkins & Wale, physical instrument makers, Stevens’ Insti- 
tute of Technology, Hoboken, Hew Jersey. Price $3O, or, 
without the knife-frame, $2O. The knife is a simple affair and 
can be made by any first-class manufacturing cutler from the 
dimensions given above. Mine was made by Mr. A. Eickhoff, 
381 Broome Street, Hew York, price $3.” 
In most mechanical microtomes the knife or cutting instru- 
ment is carried through the tissue like a chisel, that is to say, 
the cutting edge is pressed through the tissue. 
Hr. Seiler, of Philadelphia, has devised a section-cutter 
which combines the advantages of hand cutting and the me- 
chanical microtome. It consists of two rigid, parallel arms of 
metal, which at one end revolve on pivots attached either to the 
microtome itself, or to the table to which the microtome is to be 
clamped. On the other end of these arms are fastened revolv- 
ing clamps which hold the knife, the edge of which, when in 
position, rests upon the glass plate of the microtome. The 
handle of the knife is removed, so as to prevent a slipping and 
a hinderance to the motion of the knife, but can be easily at- 
tached by means of a screw, for the purpose of stropping. When 
in position, and ready for cutting, the knife is pressed upon the 
glass plate, and a slight side motion is given to it by the hands, 
which causes it to pass through tl;e tissue and cut a thin, even 
section without any difficulty. In order to cut well and evenly, 
the knife must be carried through the substance to be cut, es- 
pecially if it is soft, in a slanting direction, so that each point 
of the edge describes a curve which is equal to a part of a circle. 
This is exactly what takes place with this apparatus when the 
knife is used, the radius of the curve being the length of the 
arms from the centre of the clamps to the centre of the pivots.] 
Let us now pass to these embedding methods. They serve 
to enclose very small objects which can no longer be held, like 
coarser substances, in the fingers of the left hand while making 
the sections. Small objects may be advantageously placed in 
a thick solution of gum-arabic, or embedded in a mixture of 
wax and oil (Strieker), in paraffine, or in a mixture of glycerine 
and gelatine (Klebs). We give several recipes which may be 
readily modified as may be necessary. 
1. Embedding in gum. A paper cone or box is to be filled 
8 114 
SECTION SIXTH. 
with a very concentrated solution of gum-arabic ; in this mass 
is placed the object, from which the water has been drawn out 
by means of alcohol. The whole is then to be placed in alcohol 
for two or three days, and is then in a condition proper for cut- 
ting. The sections are to be washed out with water. 
2. Embedding in a mixture of wax and oil. Equal parts 
of each are to be warmed in a porcelain dish till they become 
fluid, and the mixture is then poured into a paper box. The 
preparation is to be deprived of its water with alcohol, and 
rendered transparent by means of an ethereal oil; it is then 
placed in the mixture, and is ready for cutting as soon as the 
latter has become cold. The sections are to be washed out in 
oil of turpentine. 
3, Embedding in paraffine. A cavity, made in a piece of 
paraffine, is partially filled with melted paraffine. In the latter 
is placed the object, which has been hardened in chromic acid 
and alcohol. Paraffine is again poured in, and the whole may 
afterwards be placed in alcohol. In many cases it is sufficient 
to drop a little melted paraffine on to a slip of gutta-percha, 
place the object on it, and cover the latter by dropping on a 
little more paraffine (His). 
Embedding in a mixture of five parts paraffine, two of 
spermaceti, and one of lard, has recently been recommended 
(Rutherford, Pritchard). 
4. Embedding in a mixture of glycerine and gelatine. 
Alcohol or chromic acid preparations may be placed in a mix- 
ture composed of about one volume of a very concentrated so- 
lution of isinglass and half a volume of pure glycerine. The 
whole, when cooled, is to be replaced in chromic acid or alco- 
hol, where the preparation and the gelatine become sufficiently 
hard. 
5. Embedding in transparent soap. Flemming dissolves it 
in one-third to one-half its volume of alcohol. The alcohol pre- 
parations are enclosed in the warmed mass and set aside for a 
day or two so that the latter may dry. 
The embedding medium is completely transparent (a great 
advantage), and the object can now be cut with a dry blade. 
The soap may be dissolved with distilled water, and the pre- 
paration mounted in glycerine. THE PREPARATION OP MICROSCOPIC OBJECTS. 
115 
6. Embedding in Albumen and Tallow. 
Bunge invented the following mixture: Take fresh white 
of egg, after removing the chalazse, 24 com., which is to be 
combined with 2\ com. of a ten per cent, solution of soda by 
shaking them together in a wide test tube. Then melt 9 ccm. 
of tallow in a similar glass, and add the other solution. The 
preparation is placed in a paper box and the mixture poured 
in. It hardens in a few minutes and is placed in absolute 
alcohol (Bresgen). [A very efficient embedding mixture con- 
sists of one part of mutton tallow and two parts of paraffine.] 
For very hard substances, such as bones and teeth, the 
knife is no longer serviceable for making thin sections. In 
such cases a small saw with a watch-spring blade is to be used, 
and the section is to be ground down on a whetstone. This 
can be best and most rapidly accomplished with a rotary stone. 
The ordinary camel’s-hair pencil is an indispensable imple- 
ment for the histologist. In addition to its usefulness for re- 
moving dust from the lenses of the microscope, it is also very 
extensively used in preparing specimens. It is the best thing 
to use for removing foreign bodies and fragments of tissue from 
the surface of preparations, and for spreading out thin and 
delicate sections on the slide. When it is necessary to remove 
from an object the cellular elements, which often occur in such 
great profusion as to conceal the entire arrangement of its su- 
perstructure, this may be much better accomplished by the 
pencilling method, originated by His, than with the stream 
Fig. 84. Pencilling microscopic objects. 
from a wash-bottle. The specimen is to be thoroughly moist- 
ened and covered with fluid (generally glycerine and water), 
and then brushed with a camel’s hair pencil of medium size, 
the perpendicular strokes rapidly following each other (fig. 84). 116 
SECTION SIXTH. 
The fluid gradually thickens and the tissue becomes transpar- 
ent. After a few minutes the preparation is to be turned over, 
and the process repeated on its other surface. In this manner, 
and occasionally removing the old fluid and replacing 
it with new, the isolated frame-work gradually makes 
its appearance. It is also very serviceable to pencil an 
object while it is floating in a larger quantity of fluid 
—for example, in one of the above-mentioned glass 
boxes. A considerable amount of patience is necessary 
to make good preparations in this way, and still more 
to obtain the proper consistence of the object to be 
prepared. When it is not sufficiently hardened, it 
becomes filled with, rents, even when the brush is care- 
fully used. Such tissues generally become quite ser- 
viceable after hardening for a day or two longer. It 
is much, worse when an over-hardened tissue is to be 
prepared in this manner. In such cases one can obtain 
only an imperfect preparation or none at all; it is no 
longer possible to remove the cells. As a rule, the 
thing is then to be entirely abandoned, for a subse- 
quent softening rarely leads to success. Billroth has 
also given some particular directions on the pencilling 
method. 
The'pipette 
The brushing may also be replaced by a carefully 
practised shaking out of the preparation. 
A strip of bibulous paper may be used for removing super- 
fluous fluids from the slides. It is more convenient to use a 
small pipette (fig. 85), an instrument which can hardly be dis- 
pensed with in making permanent specimens. Section Scocntt). 
FLUID MEDIA AND CHEMICAL REAGENTS. TITRITION. 
Animal tissues are comparatively seldom examined in a 
simple dry condition, but, as a rule, a fluid is added. This 
fluid may act indifferently, although this is more rarely the case 
than is generally imagined; it may act chemically on the ob- 
ject ; it may withdraw fluid from it, or allow fluid to pass into 
it, so that shrinking or swelling results ; finally, it may produce 
changes in the refractive conditions of the tissue. 
Let us first investigate the latter. The greater the contrast 
between the refractive power of the object and that of the sur- 
rounding medium, the sharper will the former appear. Thus 
many delicate structures may be most distinctly recognized 
when dry and surrounded by atmospheric air, while the addi- 
tion of water, by changing the refraction of the light, perhaps 
entirely prevents the details from appearing, or renders them 
very indistinct. Many textural relations of animal tissues are 
exceedingly difficult to recognize, in consequence of the slight 
difference between their refractive power and that of the sur- 
rounding water. We must, therefore, coincide with Harting. 
who says, the discovery of a fluid medium of less refractive 
power than water would afford very valuable assistance in many 
investigations. Other methods of rendering many things 
darker and more distinct, such as tinging the tissues, the appli- 
cation of reagents which coagulate and therefore darken them, 
are discussed further on. Certain reagents, acetic acid for ex- 
ample, act very advantageously by rendering a constituent 
part, as for instance the nucleus of a cell, darker, while the re- 
fractive power of the surrounding substance is diminished. 
The action of acetic acid on connective tissue affords us an in- 
structive example of how little one is justified in assuming, 
from a single method of investigation, that there is nothing in 118 
SECTION SEVENTH. 
the field because there is nothing to be seen there. By causing 
the finest fibres into which the intercellular substance of con- 
nective tissue is split up to swell, their refractive power and 
that of the surrounding fluid is rendered similar, so that one 
might think that the fibrillse had been dissolved by the reagent, 
were it not for other methods which cause the reappearance of 
the fibres which had been rendered invisible by the acid. 
On the other side, the necessity often makes itself felt of 
rendering objects which are too dark, and therefore no longer 
recognizable, as transparent as possible by means of a fluid 
which refracts the light strongly. Hence strong solutions of 
sugar, gum, or albumen may be used, when it is necessary to 
clear up tissues which are saturated with water. In modern 
times we have learned to recognize in glycerine an invaluable 
accessory of this nature ; creasote also deserves recommenda- 
tion. Tissues which are free from water are more permanently 
cleared up by means of turpentine oil, Canada balsam, or anis 
oil. While the index of refraction of water is 1.836, glacial 
acetic acid has that of 1.38, pure glycerine 1.475, equal parts of 
glycerine and water 1.40, oil of turpentine 1.476, Canada balsam 
1.632-1.549, and that of anis oil is even 1.811. 
How much the appearance of a microscopic object is deter- 
mined by the refractive power of the fluid medium is self-evi- 
dent. A small glass rod lying in water can be readily recog- 
nized with exactness, in consequence of the difference of the 
exponents of refraction. When it is placed in Canada balsam, 
whereby they become nearly similar, the glass rod ceases to 
glisten and can only with great attention be distinguished from 
a flat band. If anis oil be selected as a medium, an image is 
received as though there was a cavity in the oil (Welcker.) 
The necessity for the discovery of an actually indifferent 
fluid medium, that is, one which does not change the tissue, 
cannot be impressed with sufficient force on the hearts of micro- 
scopists. We have fallen into the beaten track of ascribing, 
with generous credulity, to water such a role, but which, in fact, 
it does not play. It is conceded that a small fraction, at the 
most, of the animal tissues make an exception, and the energetic 
action of water on the colored blood corpuscles and the elements 
of the retina cannot be denied. That the number of tissues 
affected by water is much greater, and that very few can re- 
main indifferent to it, is very clear to a few persons, but is by FLUID MEDIA AND CHEMICAL REAGENTS. 
no means generally known. While so many have recently oc- 
cupied themselves with the endosmotic processes of physical 
physiology, in the particular domain of microscopy, no investi- 
gation of this process has yet been commenced. 
Theory requires that each constituent of the body should 
be examined in a fluid medium which resembles, in respect to 
quality and quantity, the fluid which saturates the living tis- 
sue. Naturally, this requirement cannot be completely ful- 
filled in practice ; our aim should be to approach it as nearly 
as possible. 
Saliva, vitreous humor, amniotic liquor, serum, and diluted 
albumen are generally recommended as suitable media for the 
investigation of delicate changeable tissues, and in certain 
cases, they accomplish their object in a satisfactory manner. 
But do not expect them to suffice for every case. Not unfre- 
quently one and the same tissue of different species of animals 
reacts differently with the same fluid medium, as may be seen 
with the blood corpuscles. 
An important and readily proved observation is the fact 
that the addition of the slightest quantity of carbolic acid to 
such animal fluids prevents decomposition. This is more ser- 
viceable than the previously recommended camphor. 
A physical examination made by Graham presents us with 
a key to the nature of these indifferent fluids. 
In an exceedingly interesting work {Annalen dev CTiemie 
und Pharmazie, Bd. 121, S. 1), this scholar some time ago 
called attention to the fact, that two groups of substances, 
which he has designated by the names of Crystalloids and 
Colloids, are to be distinguished according to their power of 
diffusion. The former, belonging to the crystalline bodies, dif- 
fuse rapidly and remind one in this regard of more volatile 
substances ; the latter, characterized by their inability to as- 
sume the crystalline condition, show a very slight diffusibility. 
Among the organic bodies may be numbered, for example, gum, 
starch, dextrine, mucus, albumen, and gluten. 
When a column of water is placed over a solution which 
contains both these varieties of substances, chloride of sodium 
and albumen, for instance, the salt will penetrate to the upper- 
most stratum of the fluid, while the albumen, in consequence 
of its slight diffusibility, will not pass anything like so far up- 
wards, so that the upper strata remain free from it. Gelati- 120 
SECTION SEVENTH. 
nous matters from the colloid series, such as mucus, for in- 
stance, permit a very easy passage to readily diffusible mat- 
ters, but resist very energetically that of less diffusible ones, 
and do not let other colloid matters pass through. By means 
of suitable membranes of this kind, crystallized matters may 
be separated from colloid substances, and the' latter may be 
thoroughly purified in this way. According to Graham’s ob- 
servations, readily diffusible substances, such as chloride of so- 
dium, even spread themselves through a stiff jelly with almost 
the same facility as in pure water. 
It is self-evident that these investigations are of great signi- 
ficance in connection with the processes of diffusion in the tis- 
sues composed of colloid substances. 
The above-mentioned indifferent fluids now appear to us in 
a new light. They always contain colloid and crystalloid sub- 
stances. Vitreous humor contains 987 parts of water to about 
4.6 parts of colloid matter, 7.8 of crystalloid substance (that 
is, chloride of sodium). In amniotic liquor about the same 
proportions are met with. In 1000 parts occur about 3.8 of 
colloid substance (albumen), 5.8 of salts, together with 8.4 of 
urea. In serum we have about 8.5 per cent, of colloid and lof 
crystalloid substances. 
After what has been said it is unnecessary to remark that 
fluids which contain only crystalloid or only colloid matters 
can make no claim to the character of truly indifferent media, 
although they may not perceptibly alter the contours and forms 
of the tissue elements for a long time. 
Accordingly, it has very properly been suggested that the 
microscopist should always have such indifferent fluids in rea- 
diness, the more so as solutions of albumen or liquor amnii 
may readily be preserved from decomposition for months by 
placing a piece of camphor in them (M. Schultze). A solution 
of albumen, of known quantitative composition, purified by 
means of Graham’s dialyser, and to which a certain quantity 
of chloride of sodium is to be added, may be preserved with the 
aid of a piece of camphor, and will be very serviceable if diluted 
with water each time that it is used. It is useless, however, 
for the preservation of large pieces of tissue. 
It is obvious that the addition of colloid substances to solu- 
tions of the salts ordinarily used by microscopists also deserves 
a trial. FLUID MEDIA AND CHEMICAL KEAGENTS. 
121 
Sclmltze lias more recently recommended, in tlie warmest 
manner, an albuminous fluid tempered with iodine—and in fact, 
according to my own experience it is exceedingly serviceable. 
“ Jod-serum,” as he calls it, consists of the amniotic fluid of 
the embryo of the ruminantia, to which a concentrated tincture 
of iodine or a strong solution of iodine in hydriodic acid is 
added. About six drops are to be added to the ounce while 
shaking the mixture. The color of the solution is at first wine 
yellow, but after a few hours it becomes paler; this paleness 
afterwards increases, and the subsequent addition of a few 
drops of the iodine solution becomes necessary. Our mixture 
forms an excellent fluid for the examination of delicate fresh 
tissues, and is also a very good and very preservative macerat- 
ing medium, acting in this way even for hours or days. We 
must here give a piece of advice which is of great importance 
in the numerous macerations of this kind which are necessary, 
namely, to have the piece which is to be placed in them very 
small, and the quantity of the fluid as large as possible. An 
artificial mixture, composed of 1 ounce of the white of an egg, 
9 ounces of water, 2 scruples of chloride of sodium, with the 
corresponding quantity of tincture of iodine, appears to form a 
substitute. 
In the use of water, in which case distilled water should be 
employed, the swelling of the delicate tissues is, possibly, very 
considerable ; not unfrequently they may even be more perma- 
nently altered; so that it is advisable for any one who would 
protect himself from deception to try other fluid media also, 
in order to decide what has remained unaltered in his micro- 
scopic image, and what has been acted upon by the water. 
Glycerine has already been mentioned several times in these 
pages. Together with its property of rendering tissues trans- 
parent, which is of inestimable value for such as have been 
hardened and rendered opaque by reagents, it forms a preser- 
vative, though not indifferent medium for many tissues, and 
even for the prolonged preservation of larger pieces. Its power 
of rendering tissues transparent may be restrained by the addi- 
tion of water. A mixture recommended by Schweigger Seidel, 
composed of 1 part of pure glycerine to 9 parts of distilled 
water, is useful for the examination of numerous objects. 
Many delicate structures shrink in glycerine, it is true, but 
after longer action they again become filled out and clear. A 122 
SECTION SEVENTH. 
number of really chemical reagents—for example, acetic acid, 
formic acid, iodine, tannin, and chromate of potash—may be 
advantageously combined with it, and it also forms an ingre- 
dient of cold injection masses (see below). Finally, it presents 
the best fluid for mounting moist tissues. 
Nowadays chemical reagents are very frequently employed 
in microscopic investigations, and the number of these which 
are necessary for various histological and medical purposes is 
by no means small. They are the same as are generally used 
for zoochemical investigations. 
They are chiefly employed in microscopical investigations 
when we wish to ascertain the nature of amorphous and crys- 
talline deposits, the disposition of elementary granules, or the 
constitution of tissue elements. The ordinary solutions, natu- 
rally from a reliable source, are used for these processes. 
Their application, however, requires great foresight with re- 
gard to the microscope, if one would protect it from injury. 
We therefore repeat certain precepts which have already been 
given. The lenses should never be wetted with the fluids. 
Only the weaker objectives, with long foci, are to be used, and 
the covering glasses should be as large and broad as possible. 
In order to prevent the fluids from running on to the stage, 
the slides should not be too narrow. I generally cover the 
stage completely with a glass plate of the same size with 
ground edges, a precautionary measure worthy of recommen- 
dation to those who have the protection of their instruments at 
heart. When the stage consists of a plate of ground black 
glass, as is the case with some of the older microscopes, it is 
very convenient for chemical examinations. 
The reagent is either simply added to the microscopic pre- 
paration by means of a pointed glass rod, the covering glass 
being previously removed, or the fluid is allowed to flow under 
the edge of the cover to the object; it may also be allowed to 
enter gradually, in order to observe the successive changes 
which occur during its action. A thread of lint, one end of 
which is placed under the cover, may be used as a conductor, 
or two very narrow strips of bibulous paper may be placed at 
opposite borders of the cover, one of which serves to remove 
the old fluid while the new is being introduced by the other, 
whereby, however, the entrance of the reagent is more rapid 
and its effects are more energetic. FLUID MEDIA AMD CHEMICAL EE AGENTS. 
123 
More important than this momentary nse of chemical re- 
agents is the continuous application of the same for a longer 
period as hardening, preservative, or macerating fluids. Ani- 
mal tissues are frequently allowed to remain in the solutions 
for hours or even days consecutively. This method has been 
frequently used in modern times, and to it is due most of the 
knowledge that has been obtained in latter years concerning 
the tissues, etc., of the human body. Its perfection should, 
therefore, be of great interest to every investigator. Its appli- 
cation, however, requires an exact procedure. Above all things, 
one should avoid all such old delusions as when putting a tis- 
sue in acetic or sulphuric acid, or in solutions of 
potash or soda, to disregard the strength of the 
solutions, or the relative volume of the tissue to 
that of the fluid. Hence it is the duty of every 
one who employs any of these chemical methods, 
or recommends a new one, to describe his process 
accurately. 
A watch-glass, or a small shallow glass box 
may be used when the process is to continue but 
a few moments. For more continued action, small 
bottles with wide mouths and ground glass stop- 
pers are to be used, or, still better, small gradu- 
ated cylinder glasses (fig. 86). The vessels should 
always be labelled, to avoid confusion, to remem- 
ber the date, etc. 
We will now proceed to the consideration of the 
reagents which are at present most frequently used. 
Fig. 86. Gradua- 
ted cylinder glass. 
1. Among the strong mineral acids, sulphuric, muriatic, and 
nitric acids, in a concentrated form, act destructively on most 
histogenetic substances. Nevertheless, they afford an impor- 
tant means of isolating certain tissues, inasmuch as they dis- 
solve their connecting or cementing substance, and also, in 
part, the connective tissue which occurs in «them. In a more 
diluted condition they form useful hardening solutions for 
various tissues, while with a still higher degree of dilution we 
obtain the action of weak acids on various tissue elements, 
causing them to become transparent, to dissolve, or to swell 
up. In this way these acids may constitute very important 
macerating mediums. 
Sulphuric Acid.—The purified concentrated English sul- 124 
SECTION SEVENTH. 
phuric acid, non-fuming, with a specific gravity of 1.85-1.83, 
is to be used. 
The concentrated acid is but rarely used. Still it is an ex- 
cellent auxiliary in the investigation of the horny structures 
(the cornified epithelium, the nails, the hair), for isolating the 
cells of these tissues. It also forms alone, or combined with 
iodine, a good reagent for cholesterin ; the latter combination 
is also useful for cellulose or amyloid substances. Sugar and 
sulphuric acid redden many organic substances, such as albu- 
minous and amyloid bodies, oleic acid, etc. 
Strongly diluted sulphuric acid hardens albuminous tissues, 
acting similarly to chromic acid (see this). It has the advan- 
tage over the latter of rendering gelatinous and connective tis- 
sues transparent, and, at the same time, so consolidated that 
thin sections of them may be made. Moreover, less depends 
on the accurate concentration of sulphuric acid than on that of 
chromic acid.* 
When connective tissue is treated for twenty-four hours 
with highly diluted sulphuric acid, 0.1 grm. to 1000 grammes 
of water, and warmed to a temperature of from 35° to 40° C., it 
is resolved into gelatine ; so that in this way other elements are 
spared as much as possible, and may be isolated from connec- 
tive tissue. Kfihne has employed this method with good suc- 
cess for muscular fibres. 
Sulphurous Acid.—It has been recommended by Klebs to 
add a small quantity of sulphurous acid to a solution of cane- 
sugar of 5 per cent, (one drop of a pretty concentrated solution 
of the former to one ccm, of the latter fluid) for loosening epi- 
thelium, and for rendering connective tissue transparent with- 
out causing infiltration. 
Nitric Acid— The pure concentrated nitric acid of the 
chemical laboratories of 1.5 specific weight may be used, or 
acids containing more water, with a specific weight of 1.4 to 1.2 
(the latter is the officinal nitric acid). 
The former (1.5), mixed with chlorate of potash, destroys 
* M. Schultze, who has presented us with these statements, employs an acid of 
1.889 specific weight, of which about 18 drops make 1 gramme and 23 a scruple. He 
recommends, as a mean, 3 to 4 drops to 1 ounce of water (with extremes of 1 to 10), 
and praises its effects for hardening the supporting substances of the central organs 
of the nervous system, of the retina, and also the reticulated tissues of the lymph 
glands and kindred organs. FLUID MEDIA AND CHEMICAL REAGENTS. 
125 
connective tissue in a short time, and is therefore a good medi- 
um for isolating muscular fibres (Klihne). This may also be 
accomplished, though more slowly, with weaker acids. This 
reagent, recommended by Schultze, is frequently used by bota- 
nists ; it deserves further trial for animal tissues. Caution in 
its application is always advisable. 
The property of nitric acid of coloring albuminous matters 
yellow is, in general, rarely made use of in microscopical inves- 
tigations. 
Strong nitric acid serves to isolate connective-tissue cor- 
puscles, bone corpuscles and their processes, as also the denti- 
nal canals. 
Nitric acid of 20 per cent, was recommended many years 
ago by Reichert and Paulsen as a medium for the isolation 
and recognition of the elements of the smooth muscles. 
Diluted nitric acid (5 to 10 per cent.) is also used for the 
extraction of the so-called bone earths (a mixture of lime and 
magnesia salts) from calcified cartilages and bones; although 
hydrochloric acid and, still better, chromic, lactic, picric, or 
pyroacetic acids may be employed for this purpose. 
In a condition of extreme dilution (0.1 per cent.), nitric acid 
has recently been tried by Kolliker for rendering muscles 
transparent. It does not present any special advantages. 
Muriatic Acid.—Pure muriatic acid, thoroughly saturated 
with chlorine, of 1.19 specific weight, is not at all, or only 
rarely, used undiluted for histological investigations. Strong 
muriatic acid is frequently used for dissolving the intercellular 
substance of connective-tissue organs, and for isolating the 
connective tissue corpuscles and their radiating tubular sys- 
tems, as in the cornea, the teeth, and bones. This action gen- 
erally requires some time, occasionally a number of days. By 
this means the intercellular substance of the muscles (Aeby) 
and of the urinary tubes (Henle) has been dissolved. An acid 
which has been diluted with water till it ceases to smoke, is 
frequently used for this purpose. The time required is gen- 
erally 12-14 hours ; weaker acids act more slowly. The object 
is then to be washed out and macerated, for a day at least, in 
distilled water. When this process succeeds, the whole may 
be rapidly and beautifully isolated by the careful use of the 
needles. An important modification of the above-mentioned 
process consists in boiling pieces of the kidney for 6-8 hours 126 
SECTION SEVENTH. 
in alcoliol of 90 per cent., to which i to | per cent, by volume 
of purified muriatic acid of the greatest possible strength has 
been added. The operation is to be conducted on the water- 
bath, in an alembic provided with a cooling apparatus (Ludwig 
and Za wary kin). This process is also useful for other glands, 
Tomsa has recommended boiling for one or two days, and sub- 
sequent washing in water for isolating the cutaneous nerves. 
Size injections with Prussian blue retain their color and the 
consistence of the vessels with both methods. Muriatic acid, 
of the same dilution as the nitric acid, may be used for ex- 
tracting the bone earths. In a high degree of dilution (0,1 per 
cent.) it forms a medium for macerating connective tissue and 
rendering it transparent, the cells and elastic tissue of which 
then appear very beautifully. Our acid also dissolves the 
fleshy substance of muscular fibres, and may thus be ad- 
vantageously employed in the examination of muscular tis- 
sues. 
Phosphoric Acid.—Strelzoif recommends this for removing 
the lime from embryonic bones, especially at an advanced 
stage. 
Boric Acid.—This has thus far been used but slightly, as 
for example, by Bmecke, in the examination of blood-cells. 
He uses a solution which contains 2 per cent, of the pure 
melted salt. According to Kollmann this is an energetic re- 
agent. 
Chromic Acid.—Since Hannover, in the year 1840, recom- 
mended chromic acid to microscopists as a medium for harden- 
ing animal tissues, its reputation has been constantly increas- 
ing, especially since the inaccurate method of estimating the 
strength of its solutions from their color has been abandoned 
for that by means of the scales. 
It is extremely useful for hardening the brain and medulla 
oblongata, as well as the peripheral nervous apparatus. ISTot 
unfrequently it is more serviceable than alcohol, which exerts 
too great a change on these tissues, while the latter is either 
equal or preferable to the former for other organs, such as most 
glandular structures, the intestinal canal, etc. 
Well-crystallized chromic acid, as free as possible from sul- 
phuric acid, should always be used. It should be kept in a 
well-closed vessel, in a dry place, and the portion to be used 
should be dried over sulphuric acid previous to its employment. FLUID MEDIA AND CHEMICAL REAGENTS. 
127 
To economize time, a considerable quantity of a strong solution 
may be kept on band, which may be rapidly diluted to any de- 
gree desired by means of a graduated measure, I dissolve 2 
grammes in 98 grammes (or cubic centimetres) of distilled 
water, so that a 2 per cent, solution stands ready. 
For hardening purposes a chromic acid solution of from 0.5 
to 1, or, at most 2 per cent, is necessary. In no case should a 
higher degree of concentration be used, and generally the weaker 
ones work better. Very fresh tissues usually require weaker, 
older pieces somewhat stronger solutions. Very fine results 
may be obtained, especially when the pieces are not very volu- 
minous, by commencing with a weak solution (about 0.2 per 
cent.), and then, after a few days, changing the fluid for one of 
stronger concentration (0.5 to 1 per cent.), in which the object 
is to remain for days and weeks, until it has obtained the de- 
sired consistence. Then—in consequence of the readiness with 
which fungi are formed in chromic acid solutions—the hardened 
preparation should be kept in diluted alcohol. 
When a voluminous organ is to be hardened it is advisable, 
before placing it in the chromic acid, to drive the same solution 
through the blood-vessels. 
However, with all chromic acid operations, very much de- 
pends on the proper degree of concentration, and this is not 
always hit upon even by the most experienced ; this is all the 
more so, as the contamination with sulphuric acid is quite vari- 
able. Very voluminous organs may present a hardened peri- 
phery, while the interior is decomposed. Portions which are 
over-hardened have their tissue elements very much shrunken, 
and are often found to be so hard and brittle that it is no 
longer possible to make thin sections from them. An improve- 
ment may sometimes be obtained by laying the piece of organ 
in glycerine for several days. It is preferable to add some of 
this to the chromic acid at the very beginning. 
So much for these concentrated hardening solutions of chro- 
mic acid. This reagent has, however, when highly diluted, 
still another and more important property, namely, of preserv- 
ing the finest textural relations while exerting a somewhat ma- 
cerative action on them. So that in this way very delicate or- 
ganizations, especially in nervous tissues, may be made visible 
which remained completely hidden in the examination of the 
fresh tissue. For this very reason it has exerted a very endur- 128 
SECTION SEVENTH. 
ing influence in the histology of the higher nerves of sense, to 
which fact the works of M. Schultze especially testify. It has 
since been used with success for the investigation of the central 
organ of the nervous system, the ganglia, and also for glandu- 
lar structures. 
In general, according to present experience, only a concen- 
tration of from i to £ of a grain to the ounce of water, that is, 
a solution of from 0.025 to 0.05 per cent., is applicable for this 
purpose, and in fortunate cases the desired effect is accom- 
plished in from one to three days. Others (Deiters, J. Arnold, 
Kiilme) have even descended to solutions of from 0.02 to 0.01 
per cent, and less—and even to these an effect cannot be de- 
nied. 
The volume of the fluid and that of the portion of tissue 
placed in it are here of greater importance than for simple 
hardening. Generally, when the latter is small and the fluid 
plentiful, the action is naturally more energetic and rapid, so 
that in this case the limits may easily be exceeded. It is 
proper, therefore, not to select too small a piece, and not to add 
too large a quantity of fluid. When the object is too small, 
the same effect takes place as with stronger solutions ; they re- 
ceive a lively yellow color and become opaque; when of the 
proper proportions they become paler and semi-transparent. 
We have already mentioned above the interesting and, in 
their consequences for practical microscopy, very important 
observations of Graham on the colloid and crystalloid sub- 
stances. Schultze (who was the first among German histolo- 
gists to comprehend the full significance of Graham’s observa- 
tions) has properly called attention to the fact that the action 
of chromic acid is not alone concerned in this case, but to this 
is also added, when the piece is large and the quantity of fluid 
moderate, the preponderating effect of the colloid substances of 
the tissue ; such as blood, mucus, and albumen. Hence a fluid 
results which consists conjointly of crystalloid and colloid sub- 
stances ; while a small piece of tissue placed in a larger quan- 
tity of chromic acid solution is subjected, almost entirely, to 
the action of this crystalloid substance alone. 
At present microscopic technology is only in its youth, not 
to say childhood. In a riper period such combinations will 
certainly play an important role. Schultze informed us that 
he made investigations relative to this subject, and that a FLUID MEDIA AND CHEMICAL EEAGENTS. 
129 
watery solution of gum-arabic appeared to be suitable as a col- 
loid substance. 
Similar, but much weaker and more slowly commencing ef- 
fects are also produced by bichromate of potash, which will be 
spoken of further below. 
Finally, still another very advantageous use has been made 
of chromic acid ; namely, for extracting the earthy salts from 
so-called ossified cartilage, and also from bones. It is especi- 
ally commendable for foetal tissues. Generally it is necessary 
to have a higher degree of concentration (about 2 per cent., 
Thiersch), and, during an exposure of several weeks, the fluid 
should be frequently changed. It is well to add a little glyce- 
rine. The effect may be increased by a little hydrochloric acid, 
without injury to delicate textures. The decalcified specimen, 
after being washed, is to be placed in absolute or strong alco- 
hol for further hardening. 
Lactic Acid has been recommended by Strelzoff for remov- 
ing the lime from embryonic bones—and rightly so. 
Oxalic Acid.—Oxalic acid was formerly but little or not at 
all used by histologists. Some time since M. Schultze insti- 
tuted a series of experiments with it which assign it a not un- 
important rank among the microscopist’s reagents. A cold 
saturated solution of oxalic acid (one part of pure crystalline 
hydrated acid requires for its solution 15 parts of water) causes 
connective tissue structures to swell and become transparent, 
while the tissue elements which are formed of albuminous sub- 
stances retain their sharp contours, become somewhat hardened 
and permit of convenient isolation. Extremely delicate ele- 
ments of the body, such as the rods of the retina and the olfac- 
tory cells, are preserved in it excellently. The length of time 
is of relatively slight importance, so that the examination may 
be commenced after a few hours or several days. 
According to Schultze’s experience, an alcoholic solution of 
oxalic acid acts more strongly than the watery, and appears to 
present certain advantages for many purposes. 
Finally, oxalic acid is used in carmine tingeing in the same 
manner as acetic acid, although more circumscribed in its ap- 
plication, of which mention will be made later. 
Acetic Acid.—The hydrated acetic acid, thoroughly pure 
acetic acid, acidum aceticum glaciate, should always be used 
when an accurate estimation is necessary (since the so popular 130 
SECTION SEVENTH. 
specification of the specific weight affords no definite conclusion 
as to the amount of water present), and combined drop by 
drop, or in greater quantity, with water. 
Acetic acid, which is so rapid in its action, is one of the old- 
est and most frequently employed reagents in animal histology. 
Its property of rendering nuclei within the cells visible, or of 
causing them to appear isolated after the destruction of the 
envelope and cell body; and further, of giving to connective 
tissue a crystalline transqarency, and disclosing its admixture 
in the cells, elastic fibres, vessels, nerves, etc., has especially 
led to its general employment. 
Only at a later period were quantitatively defined solutions 
of acetic acid, as well as combinations of the same with other 
fluids, especially alcohol, employed for more prolonged action 
on animal tissues. Even a few drops of the acid to the ounce 
of water is sufficient to induce considerable transparency of the 
connective tissue in a few days. In this way, for example, the 
intestinal ganglia lying in the submucosa ; furthermore, the 
marvellous ganglionic plexuses, discovered years ago by Auer- 
bach, between the muscular layers ; also muscle cells in the 
mucous membranes, on vessels, etc., are made to appear dis- 
tinctly. For the recognition of smooth muscles, Moleschott 
used a 1 or li per cent, solution of acetic acid for a few min- 
utes. One part by measure of strong acid, of 1.070 specific 
weight, is to be mixed with 99 of water, that is, li to 98£. 
More recently, Kblliker has used very dilute acetic acid for 
rendering the muscles of the frog transparent, in order to dis- 
cern the nerve terminations, and the reagent accomplishes this 
exceedingly well. He recommends the addition of 8, 12, or 16 
drops of the acidum aceticum concentratum of the Bavarian 
pharmacopoeia, of 1.045 specific weight, to 100 cubic centimetres 
of water. I have substituted Ito 2 drops of hydrated acetic 
acid to 50 cubic centimetres of water. Acetic acid of from 0.8 
to 0,2 per cent, has been employed by others for many purposes. 
Auerbach recently studied the action of varied degrees of 
concentration on animal cells. Solutions of 1-0.08 per cent, 
(in the mean from 0.2-0.1) are very suitable for obtaining a 
nearly correct image ; as is also a mixture of 7 per cent, cane 
sugar and 0.06 per cent, acetic acid. 
Acetic acid, diluted to an extreme degree, is also to be recom- 
mended for softening thin sections from parts which have been FLUID MEDIA AND CHEMICAL REAGENTS. 
dried in the air ; also for washing out specimens after they have 
been tinged in carmine, in order to fix the red in the nucleus. 
This will be again alluded to further below. 
Maceration in acetic acid presents a certain difficulty in the 
recognition of delicate structural relations, in so far as that the 
part should be examined at the right time. Before this period, 
the swelling and transparency are still too little developed; 
later, however, the changes induced in the tissue by the acid 
have become too considerable. 
Beale has recommended the combination of acetic acid with 
glycerine. 
Vinegar.—The employment of ordinary cooking vinegar 
offers no kind of advantage. In it connective tissue becomes 
transparent like glass, after 6, 8, or 12 hours. If the tissue be- 
comes too soft to permit of sections being made, this may often 
be remedied by placing it, supplementarily, in a solution of 
chromic acid. It will frequently be found useful to boil in 
vinegar animal tissues which are to be dried. 
Pyroligneous Acid.—Pyroligneous acid (none but the puri- 
fied, or acidum pyrolignosum rectificatum, should ever be em- 
ployed) has frequently been used for rendering connective 
tissue structures transparent, and especially with a certain pre- 
dilection for pathological tissues. It exerts a similar, though 
not entirely the same effect as diluted acetic acid, inasmuch as 
it possesses, together with the macerating action, a hardening 
effect (from admixture of products of the dry distillation of the 
wood). Diluted pyroligneous acid should always be used for 
macerating, if it be desired to avoid marked textural changes of 
the elements which then become visible through the connective 
tissue. Pyroligneous acid, diluted according to circumstances 
with an equal, double, or quadruple volume of water, is a good 
accessory for many structural conditions ; for example, in the 
recognition of the corneal cells and their contents, the course 
of the nerves in the sub-mucous connective tissue, etc., and es- 
pecially structures which are embedded in connective tissue, 
such as glandular elements, vessels, pathological new forma- 
tions, etc. The desired effects generally take place after one 
or more days, often enough again disappearing, as a result of 
continued maceration. Consequently, without regarding the 
smell or its injurious effects on the blades of the knives, there 
is an inconvenience in the employment of our reagent. Besides, 132 
SECTION SEVENTH. 
pyroligneous acid preparations do not usually keep well when 
put up in glycerine. We have, therefore, discontinued the 
use of this fluid for many investigations. Still, it is useful for 
extracting the bone earths from calcified cartilage and from 
normal and pathological bone-tissues. 
Formic Acid has been proposed in the place of acetic acid 
(Ranvier). 
Tartaric Acid has recently been recommended simply for 
the reduction of gold preparations. 
Osmic Acid (hyperosmic acid).—Within a few years this has 
come into frequent use through M. Schultze and others ; it is 
readily reduced by several tissues and substances. It shares 
this property with several similarly applicable salts of the 
nobler metals, which will also be mentioned hereafter. 
Picric Acid.—Recommended in part as a means of tingeing, 
by Schwarz, in part for hardening tissues. According to Ran- 
vier’s experience, a concentrated solution produces an excellent 
consistence, even in 24 hours. Neither shrinking nor coagula- 
tion of albumen occurs, and lime salts are extracted at the same 
time. I can only coincide in these statements. A further use 
is made of this acid in the preparation of Ranvier’s picro-car- 
mine. 
lodine.—A solution of iodine, about 1 part iodine (it is well 
to combine with it 3 parts of iodide of potassium) to 500 of 
water, maybe used for tingeing animal cells. Nevertheless, we 
have better and newer methods of tingeing. A solution of 
iodine serves the microscopist for the recognition of amylum, 
and, in combination with sulphuric acid, of amyloid and cellu- 
lose. For this purpose a watery solution, which should not be 
too strong, is allowed to act energetically, and then a drop of 
concentrated sulphuric acid is added. 
lodine vapor is recommended by Rollett for the examina- 
tion of connective tissue structures, such as the cornea. A so- 
lution is prepared by shaking metallic iodine with water, the 
iodine is allowed to settle, and a small quantity of the slightly 
colored solution is placed in a moist chamber containing the 
object to be examined. Waldeyer states, however, that this 
reagent produces alterations. 
It has already been remarked above (page 121) that iodine 
forms a constituent of an important mixture, the so-called 
“ jod-serum,” recently invented by Schultze. FLUID MEDIA AND CHEMICAL REAGENTS. 
133 
2. Among the alkalies, solutions of potash, soda, and am- 
monia are frequently used. They are of quite inestimable 
value for the investigation of animal tissues ; this is especially 
true of the first two substances. There is one disadvantage, 
however, connected with the use of alkalies, namely, that ob- 
jects which have been macerated in them can hardly be pre- 
served permanently. 
Caustic Potash (hydrate of potassa).—The melted form, the 
kali causticum in baculis, is used. As this attracts water and 
carbonic acid from the air with great eagerness, it and its solu- 
tions must be kept in well-stoppered bottles. 
The kali causticum in baculis of commerce contains, in 
addition to carbonic acid, a variable and not inconsiderable 
quantity of water, which constitutes an inconvenience in its 
application. 
The strong solution of potash softens the substance of many 
elements, and induces in them a condition which is very favor- 
able to the imbibition of water, which afterwards penetrates 
very rapidly, so that the cells swell up, burst, etc. 
Manifold use has been made, in the investigation of tissues, 
of the resolving and destructive properties of potash solutions. 
The manner in which potash solutions act varies entirely ac- 
cording to their strength ; a subject to which Donders first 
drew attention many years ago. A saturated, or at least very 
strong solution softens many elements, without dissolving or 
attacking them very strongly. Although diluted solutions 
produce this effect more or less rapidly, they also frequently 
dissolve the intermediate connecting substance, the tissue 
cement, and thus become an extremely important, in many 
cases invaluable accessory. Credit is due to Moleschott for 
having more recently recommended 30 to 35 per cent, solutions 
of potash as excellent reagents. To make a 32.5 per cent, so- 
lution of potash he uses 32.5 parts by weight of kali causticum 
m baculis, which is to be dissolved in 67.5 parts by weight of 
distilled water. An exposure of ito an hour or more is an 
extremely useful means of isolating muscular and nerve ele- 
ments, glandular passages, and even ordinary ciliated and ol- 
factory cells. Schultze, who, together with other histologists, 
has likewise made use of potash solutions, employed for the 
last-mentioned delicate cell formations solutions of the strength 
of 28, 30, 32, 35, and 40 per cent. For other purposes, weaker 134 
SECTION SEVENTH. 
solutions of 5 to 10 per cent, are necessary, as will be indicated 
in speaking of tke individual tissues. Naturally, in the his- 
tological examination, the same solutions should be employed 
as a fluid medium, and the use of water avoided, as otherwise 
the rapidly dissolving effect of diluted solutions would take 
place. 
Caustic Soda (hydrate of soda),—The white melted mass is 
used for making the solution. Although solutions of soda 
have been used experimentally, they present no superiority, 
when concentrated, to those of potash. Weaker solutions are 
generally necessary, about two-thirds of the potash quantity 
(corresponding to the atomic weight) being used. 
Liquor Ammonia.—The action of ammonia on animal tis- 
sues is similar to that of potash and soda. Ammonia is useful 
for neutralizing acids which have been applied to a tissue ; also 
as a means of dissolving carmine. 
Lime-water.—Rollett has recently made us familiar with 
lime-water, which was previously but little noticed, as an im- 
portant accessory for the investigation of connective-tissue 
structures, and especially tendons. After remaining in it for 
six or eight days, a piece of connective tissue may be readily 
divided into its fibrillse by the use of the needle. It is there- 
fore one of the animal cement substances which is here dis- 
solved. 
Baryta-water.—The same result may be obtained with con- 
nective tissue by means of the much more energetically acting 
baryta-water, in from four to six hours, as is afforded by lime- 
water after several days’ action. At the same time, the swell- 
ing is rather greater, and the transparency somewhat more 
considerable. In both cases, before the application, the tissue 
is to be washed with distilled water, or still better, with dis- 
tilled water to which a minimum of acetic acid (just enough to 
neutralize it) has been added. 
8, Salts. 
Chloride of Sodium.—Formerly, weak solutions of common 
salt were commonly regarded as indifferent media. According 
to Graham’s observations, a colloid substance (albumen or gum- 
arabic) should always be added. 
A ten per cent, solution has frequently been used of late 
(Schweigger-Seidel and others). It has also been frequently 
used as a macerating medium, even for long-continued action. FLUID MEDIA AMD CHEMICAL EEAGEMTS. 
According to Auerbach’s experience, solutions of from 0.5 to 
1.5 per cent, are tolerably neutral to fresh animal nuclei. Other 
degrees of concentration produce entirely different effects; those 
of from 8 to 14 per cent, distend, so that the nucleus is trans- 
formed into a completely homogeneous body. Concentrated 
solutions of 35 per cent, have a hardening action. Solutions 
of chloride of sodium containing hydrochloric acid are recom- 
mended by Yon Ebner for decalcifying bone tissue. 
A special application of the chloride of sodium is also made 
in the impregnation of tissues with nitrate of silver, which will 
be alluded to hereafter. It is likewise an ingredient of various 
preservative fluids. 
Chloride of Calcium.—Chloride of calcium in solutions of 
medium strength (one part of dry chloride of calcium to two 
or three parts of water) has been recommended as a fluid me- 
dium for microscopic preparations, in consequence of its well- 
known property of attracting water. It has also been recom- 
mended for rendering sections of the spinal cord, etc,, trans- 
parent, for which purpose it is not very serviceable. It has a 
peculiar effect on muscles. 
Acetate of Potash, in a nearly concentrated watery solu- 
tion, has recently been recommended by M. Schultze as an ex- 
cellent preserving medium. 
Chlorate of Potash.—This is only used in combination with 
nitric acid (see this), as Schultze’s reagent. Extremely vary- 
ing degrees of concentration of this mixture have been made 
use of in animal histology, and the desired effect has naturally 
been obtained in very unequal spaces of time. 
Hypochlorate of Soda.—Eau de Javelle, which is used for 
bleaching, has recently been recommended by A. Budge and 
Arndt for the examination of nervous structures. It destroys 
the connective tissue. 
Cyanide of Potash.—This has been used quite recently to 
clear up gold preparations which have been too deeply stained, 
or those which have subsequently become too dark. A watery 
solution of 5 per cent, is less suitable; a mixture obtained 
by adding 5 ccm. of a ten per cent, solution of cyanide of 
potash in water to 35 ccm. of glycerine is better. The pre- 
paration may remain in the latter for hours and even days. 
The former solution acts too energetically and rapidly (L. 
Grerlach), 136 
SECTION SEVENTH. 
Nitrate of Soda.—A ten per cent, solution acts similarly to 
a chloride of sodium solution; but it permits of subsequent 
staining with silver (Lott). 
Phosphate of Soda.—Solutions of phosphate of soda of 5 to 
10 per cent, have been considerably used by microscopists. 
According to my experience thus far, they do not present any 
advantages. 
Bichromate of Potash (Red Chromate of Potash).—The 
purest possible crystallized material should be used. The ac- 
tion of this salt, which may be very suitably combined with 
glycerine, is similar to that of chromic acid, but weaker, and 
not so rapid in its appearance. For hardening many tissues it 
is extremely serviceable ; and perhaps it is better than the free 
adulterated acid ; it also exerts a much less coagulating effect 
on albumen. Besides this, the solutions of this salt have the 
advantage of not readily developing mould, which is a great 
fault of chromic acid solutions. It has also been recommended 
to commence the hardening process with our salt, and then to 
continue it with the free acid (Deiters). 
Where one jiart of chromic acid would be sufficient, it is re- 
quisite to have several parts of chromate of jmtash. Thus, 
where a given effect might be obtained with a fluid containing 
from ito of a grain of free chromic acid, to accomplish the 
same without the acid, the fluid would require from 1 to 4 
grains of the salt. However, for delicate investigations, much 
less depends on the accurate concentration of the solutions of 
chromate of potash than of the chromic acid. 
A mixture of the salt in question with sulphate of soda has 
been recommended by H. Muller for hardening the retina. 
The tissue should be exposed to its action for at least two 
weeks. 
Bichromate of potash, 2—2 d grammes. 
Sulphate of soda, 1 grammes. 
Distilled water, 100 grammes. 
This mixture, the “Muller’s eye-fluid,” is also very useful 
for preserving many other tissues, such as mucous membranes, 
glands, and even ciliated cells. It preserves delicate embryos 
exquisitely, and may naturally be modified according to ne- 
cessity. 
A combination of Muller’s fluid with an equal quantity of FLUID MEDIA AND CHEMICAL REAGENTS. 
137 
saliva forms an excellent macerating medium, to be continued 
for several days. Czerney, and subsequently Langerhans have 
very rightly recommended this mixture. It renders excellent 
service, for example with the epithelium of the conjunctiva 
and the aural cavity. 
Monochromate of Potash.—Recently made known by Robin. 
Stronger facts are necessary. 
Bichromate of Ammonia.—This has been recommended in 
the place of the bichromate of potash in solutions of 1 or 2 per 
cent., for hardening the central organs of the nervous system 
by Gerlach, and of the latter strength for sudoriparous glands by 
Reynold. 
Monochromate of Ammonia.—More recently used in a 5 per 
cent, solution for the examination of the kidney (Heidenhain) 
and in a 1 per cent, for ganglia (Arndt). 
Molybdate of Ammonia.— This was recently recommended 
by Krause as an indifferent medium for tingeing. 
Chloride of Iron.—This iron salt was formerly used by 
Fuhrer and Billroth for hardening the spleen, which becomes 
sufficiently hardened in from 1 to 2 hours in a solution of the 
color of Madeira or Malaga wine. Chloride of iron is at present 
supplanted by superior hardening media. 
Chloride of Mercury.—The chemical effects of the sublimate 
are well known. Macerating for several days in a solution of 
this salt may be advantageously used for hardening and isolating 
the axis cylinders. Although this reagent has found but little 
application, still it forms an element of several very serviceable 
preservative fluids. 
Nitrate of Silver.—This has recently come into use for a pe- 
culiar tingeing process of the tissues, especially through His and 
Recklinghausen (see below). 
Chloride of Gold.—This was advantageously employed for a 
similar purpose by Cohnheim, Kdlliker, Eberth, Gerlach, and 
many others. 
Chloride of Gold and Calamine. —This has been employed 
by Gerlach. 
Chloride of Gold and Soda is used by Waldeyer. 
Chloride of Palladium was first used by F. E. Schulze. 
Chloride of Platinum.—As Merkel informs us, this salt 
hardens tissues and gives them, at the same time, a diffuse yel- 
low tinge, especially those of flattened organs. Equal portions 138 
SECTION SEVENTH. 
of solutions of chromic acid and chloride of platinum (each 
1 : 400) are recommended for the connective-tissue frame-work 
of the retina. 
4. Alcohol.—Alcohol, the most common of the preservative 
fluids for animal tissues, is of inestimable value for histological 
investigations. The use of alcohol has come more ill to the 
foreground chiefly within a few years, since we have learned to 
recognize in glycerine an incomparable means of rendering 
transparent animal tissues which have been hardened and hence 
become cloudy. It is only for certain purposes that chromic 
acid deserves the preference. Either small pieces of the en- 
tirely fresh organ are placed in a relatively considerable quan- 
tity of alcohol free from water, or several sorts of alcohol are 
employed. Weak alcohol is used for the first few days ; this is 
then replaced by stronger, and perhaps, later, a still stronger 
one is employed. I know of no better reagent for hardening 
glandular organs, the digestive canal, or injected preparations, 
and for rendering them fit for sections and brushing. Lat- 
terly, entire series of investigations have thus been made almost 
exclusively with alcoholic preparations. The circumstance that 
the specimens do not spoil in well-closed vessels constitutes an 
advantage over chromic acid, which so readily develops the 
formation of fungi. The latter is, on the contrary, preferable 
to alcohol for the recognition of many of the finest structural 
conditions, for the central organs of the nervous system, and for 
the organs of sense. 
Alcohol is also frequently applicable in other ways. First 
of all, for microscopic objects which are to be deprived of their 
water with the utmost possible sparing of the texture, for the 
purpose of being afterwards mounted in Canada balsam or 
similar resinous masses. In such cases the thin sections are to 
be placed for one or two days in absolute alcohol. From this 
they go into oil of turpentine. 
We learned above that stronger solutions of chromic acid 
harden, and weaker ones macerate. The same is repeated by 
this fluid. A very watery alcohol is an excellent protective 
macerating medium. Ranvier uses one part alcohol of 36° Car- 
tier (this contains 84.46 per cent, by weight of absolute alcohol) 
and two parts of distilled water, and allows it to act for twenty- 
four hours. He recommends this mixture highly, a recommen- 
dation in which I concur most completely. FLUID MEDIA AND CHEMICAL REAGENTS. 
139 
Furthermore, alcohol forms an ingredient of Beale’s cold 
injecting fluid, which will also be alluded to further on. 
Finally, alcohol is also an ingredient of several recently re- 
commended mixtures, the description of which follows : 
L. Clarke and Beale’s Mixtures. 
These serve to make delicate parts hard and at the same time 
clear. The fundamental idea consists in employing two sorts 
of substances, one of which hardens the albuminous elements 
of the tissues, while the other renders them transparent. Beale, 
who has occupied himself considerably with the action of these 
solutions, remarks that they must be varied according to ne- 
cessity, also that by the addition of glycerine to the mixture its 
refractive power may be increased according to circumstances. 
He recommends in general alcohol, glycerine, acetic acid, hydro- 
chloric acid, potash, and soda. The last two acids as well as 
alcohol coagulate albuminous matters ; acetic acid, potash, and 
soda render them transparent; alcohol dissolves fat. When 
several of these materials are combined in a solution, the above 
mentioned effects are obtained. 
{a.) Alcohol and Acetic Acid.—L. Clarke used in his inves- 
tigations a mixture of acetic acid and alcohol, which, as I have 
also convinced myself, renders sections of the spinal cord mar- 
vellously clear, even in a few hours, and permits many things 
to be better recognized than by other methods customary for 
this purpose. Lenhossek also appears to have made use of this 
process in his investigations on the spinal cord. 
Clarke’s recipe, naturally to be modified according to ne- 
cessity, is to combine three parts of alcohol with one part of 
acetic acid. 
(A) Moles chotf s mixture of Acetic Acid and Alcohol.— 
Moleschott recommends the following modification of Clarke’s 
method: 
Strong acetic acid (1.070 sp. wt.) 1 volume. 
Alcohol (0.815 sp. wt.) 1 “ 
Distilled water 2 u 
He calls this his strong acetic acid mixture. This fluid is very 
serviceable for hardening many organs, causes the connective- 140 
SECTION SEVENTH. 
tissue portions to become transparent, and renders those 
formed of albuminous matters distinctly prominent. Delicate 
textures do not, as a rule, tolerate it so well. Another weaker 
acetic acid mixture was afterwards recommended, consisting 
of 
Acetic acid (same as above) 1 volume. 
Alcohol 25 “ 
Distilled water 60 “ 
(c.) Alcohol, Acetic Acid, and Nitric Acid.—Beale recom- 
mends the addition of a little nitric acid to the mixture of alco- 
hol and acetic acid for the examination of epithelial structures. 
This is also to be varied as necessity may require. A recipe 
given by the author runs as follows : 
Water 1 ounce. 
Glycerine 1 “ 
Spirit ... 2 14 
Acetic acid 2 drachms. 
Hydrochloric acid % drachm. 
Alcohol and Soda.—Beale obtained excellent results, in 
many investigations, from the use of a fluid composed of alco- 
hol and a solution of caustic soda, in the proportion of from 
eight to ten drops to each ounce of alcohol. Many tissues are, 
at the same time, rendered very hard and transparent in such 
a mixture, and it is particularly adapted, according to his ex- 
perience, for investigations upon the character of calcareous 
matter deposited in tissues in various morbid processes, also in 
tracing the stages of ossification in the early embryo. It ren- 
ders all the soft tissues perfectly transparent, but exerts no 
action on the earthy matter of bone. The most minute ossific 
points can therefore be very readily discovered. A foetus, for 
example, prepared by being soaked for a few days in this 
fluid, and preserved in weak spirit, forms a very beautiful pre- 
paration. This fluid will also be found very useful in investi- 
gations upon soft granular organs. Beale found it of special 
service when working at the anatomy of the liver. 
Methyl Alcohol. —ln England, where the high spirit duty 
imposes an obstacle to the employment of the ordinary (ethyl) FLUID MEDIA AND CHEMICAL REAGENTS. 
141 
alcohol, methyl alcohol (pyro-acetic spirit) is frequently used 
as a substitute ; this is however unnecessary on the Continent. 
Methyl alcohol has found special application as an addition to 
Beale’s cold injection fluid (see below), and also in mounting 
ipicroscopic specimens in Canada balsam. 
Sections which have been deprived of their water by means 
of absolute alcohol are placed for a short time in strong methyl 
alcohol, then taken out of this and, just as they are commenc- 
ing to dry, thrown into oil of turpentine. The latter penetrates 
sections which have been in methyl alcohol, as I have learned 
by experience, somewhat more readily than those which are 
brought from the absolute alcohol directly into this oil. Never- 
theless, methyl alcohol may be readily dispensed with for this 
purpose. 
Chloroform.—Thus far it has been very little used for his- 
tological investigations, but forms the best medium for dissolv- 
ing and thinning the Canada balsam, which is so important for 
practical microscopy. 
Chloral Hydrate.—Diluted with water this has quite recent- 
ly been used in the examination of the central nervous system 
and the retina (Butzke). 
Hither.—This serves to dissolve fat in microscopic work. It 
also dissolves Canada balsam. 
Gollodium.—So far, this has only been used for recogniz- 
ing the axis cylinder of nerve fibres. According to the state- 
ments of Pfluger and my own observations, it acts instantane- 
ously. 
Oil of Turpentine.—This comes next to chloroform as a 
medium for thinning Canada balsam. It also forms the most 
important medium for rendering transparent dried sections, or 
those which have been deprived of their water by absolute 
alcohol. We will return to this subject more in detail further 
below. 
Creosote.—Creosote forms an element of preservative mount- 
ing fluids (Hartiug). 
It has recently been recommended by Stieda, after the ex- 
ample of Kutschin, as a very rapidly acting medium for ren- 
dering microscopic sections transparent. The property which 
creosote has of rapidly making preparations which still contain 
water transparent, is of great importance. By this means, ob- 
jects which have lain in ordinary spirits, and even chromic acid, 142 
SECTION SEVENTH. 
can be used after a few minutes. But when a preparation is 
to be arranged for mounting in Canada balsam, good oil of 
turpentine deserves the preference, decidedly, according to our 
experience. 
Oil of Cloves.—This was first made known by Rindfleisch, 
as a medium for rendering tissues transparent, in the place of 
the oil of turpentine; it has also been warmly recommended 
by others. It renders tissues which contain water transparent 
in the same manner as creosote, but more slowly. A series of 
other ethereal oils, such as cinnamon, anise, bergamot, and 
rosmarine oils, act similarly to it, while others, like oil of tur- 
pentine, render only objects which have been deprived of their 
water transparent; as orange, juniper, mentha crispa, citron, 
and cajeput oils (Stieda). 
Benzine.—This has been proposed for dissolving and thin- 
ning Canada balsam in the place of chloroform and oil of tur- 
pentine (Bastian). Toldt recently recommended pure benzine 
as an excellent medium for making fat tissue transparent, after 
the previous momentary action of alcohol. 
Carbolic Acid.—For the purpose of resisting the decompo- 
sition of bodies, it has recently been recommended to add car- 
bolic acid to wet mountings. It will probably have a future 
in histology. 
Thy7nol acts very much better. It is to be tried in watery 
solutions of 1: 200-1000. 
In what has been mentioned above, we have been obliged to 
adhere to the methods which are still generally used by micro- 
scopists for determining the proportions of their reagents. 
Titrition is a far more certain and a much more convenient 
method for ascertaining the strength of a solution, and for pro- 
ducing them of definite proportions. 
In order to estimate the acid and alkaline contents of such 
fluids the following is necessary : 
The apparatus (fig. 87), which is quite indispensable for the 
investigation, consists of :—{a) two Mohr’s burettes (1) of about 
60 ccm. capacity divided into | of a ccm. ; (5) a pipette (2) 
which will allow from 10 to 15 ccm. to run out, and is divided 
into tV of a ccm., and finally (c) a cylindrical measure (8) of 
100 or several hundred ccm. capacity. The divisions of the 
latter are from 6-5, or 10-10 ccm., and must retain the desig- 
nated quantity of fluid, and not allow it to flow out; while the FLUID MEDIA AND CHEMICAL EEAGEXTS. 
burette and pipette are so divided as only to designate the 
number of com. which they allow to flow or drop out. (Such 
burettes, pipettes, and cylindrical measures may now be pur- 
chased everywhere). 
The use of the pipette is self-evident. As to the burette, it 
is filled to the zero division at its upper part with the reagent 
(the test acid or the test alkali), 
and, by making slight pressure 
on the clamp, the fluid is allow- 
ed to flow out either in a stream 
or by single drops, as may be 
necessary. 
The normal acid and normal 
alkali solutions are used for the 
construction of the test fluids, 
so far as determining the ordi- 
nary reagents (acids and alka- 
lies) is concerned. Under these 
are understood solutions which 
contain an equivalent weight of 
the active substance of the re- 
agent, expressed in grammes, 
dissolved in 1000 ccm. (1 litre) 
of fluid. 
The Normal Oxalic Acid 
Solution.—ln its formation 6.4 
grammes of pure crystallized, 
unefiloresced oxalic acid is to 
be dissolved in water, and this 
solution diluted sufficiently to 
make 100 ccm. of fluid. (The 
volume is always to be meas- 
ured at the same temperature at 
which the solution is to be used, 
therefore at 14 to 16 R.) This 
Fro. 87. Apparatus for titrition. 1, a Mohr’s 
burette, with the clamp at a, which is opened by 
pressing on the two metallic buttons at b, allow- 
ing the fluid to escape from the tube c; 2, a pi- 
pette ; 3, a cylindrical measure. 
normal oxalic acid solution is, however, only indirectly em- 
ployed, that is, in the preparation of other normal acid and 
normal alkali solutions. For this reason the greatest accu- 
racy and care should be employed in the preparation of this 
first and most important solution. 
One ccm, of this oxalic acid solution contains, as we are 144 
SECTION SEVENTH. 
already aware, 0.064 grm. of oxalic acid. For its saturation the 
corresponding equivalent of bases is necessary, therefore of— 
a. Soda 0.031 grm. NaO. 
h. Potash 0.0472 “ KO. 
c. Ammonia 0.017 “ NH3. . 
d. Lime 0.028 “ CaO. 
e. Baryta 0.0765 “ BaO. 
2. Normal Potash Solution.—From a freshly prepared so- 
lution of potash, free from carbonic acid, take, with a pipette, 
6 ccm., color it to a weak blue with a few drops of tincture of 
lacmus, and, while stirring, allow the normal oxalic acid solu- 
tion to flow into it from the burette till the color begins to turn 
red. Given, we bad used 8 ccm. of normal acid solution; we 
then add to each 5 ccm. of our potash solution, 3 ccm. of water. 
In this case we have a normal potash solution; 1 ccm. of the 
same is Just sufficient to saturate 1 ccm. of the oxalic acid solu- 
tion ; it therefore contains the above-mentioned quantity of 
potash, or 0.0472 grm. 
It is clear that with the aid of this potash solution the quan- 
tity of acid present in any fluid may be determined at pleasure. 
By the neutralization of 1 ccm. of our normal potash solution 
is indicated the presence of— 
a. Sulphuric acid = 0.04 grm. S03. 
h. Nitric “ = 0.054 At05. 
c. Muriatic “ = 0.0365 “ HCI. 
d. Acetic “ =0.06 “ C 4H404. 
We limit ourselves in this citation to the investigation of 
the most important acids. 
8. As actually pure oxalic acid belongs to the more expen- 
sive reagents, it is unnecessary to use just this acid in the esti- 
mation of alkalies. Sulphuric acid is generally used. Nothing 
is easier than the preparation of the normal sulphuric acid so- 
lution. Sulphuric acid, diluted at pleasure, is allowed to flow 
from a burette into 5 ccm. of normal potash solution, to which 
several drops of tincture of litmus has been added, till it be- 
comes red. The acid and alkali solutions are then to be di- 
luted corresponding to what was mentioned above concerning 
potash, until an equal number of ccm. of each exactly neutral- FLUID MEDIA AND CHEMICAL EE AGENTS. 
145 
ize each other. Accordingly, 1 ccm. of this normal suphuric 
acid contains 0.04 grm. of S08, and for its neutralization exactly 
the same quantities of the bases are necessary as were previous- 
ly given for oxalic acid. 
Finally, we add two other test fluids, namely ;—l. The nor- 
mal silver solution for the quantitative estimation of common 
salt. One ccm. of the XV normal solution contains 0.0108 Ag., 
or 0.0170 AgON05. It corresponds to 0.00585 NaCl. 2. The 
normal chloride of sodium solution, used for the quantitative 
estimation of nitrate of silver. One ccm. of the TV normal so- 
lution contains 0.00585 NaCl, and corresponds to 0,0170 
AgON06. In both cases a precipitate of chloride of silver 
takes place, which collects in lumps by strong shaking ; the 
operation is completed when a drop of the test fluid no longer 
induces precipitation. To make the recognition more certain 
in the first of the two processes, several drops of simple chro- 
mate of potash solution may be added to the common salt solu- 
tion, in which case the complete precipitation of the chloride 
of silver will be indicated by the red color of the chromate of 
silver which is formed. 
A few examples may serve to make the method of employ- 
ment clear. 
1. We have 10 ccm. of a solution of soda, which required 
22.2 ccm. of normal sulphuric acid for its neutralization. Now 
1 ccm. of the normal sulphuric acid corresponds to 0.031 grm. 
NaO. By multiplication with 22.2 the quantity of soda con- 
tained in 10 ccm. of the titrated fluid will be found to be 0.6882, 
consequently 6.882 per cent, (disregarding the specific weight). 
2. A solution of ammonia requires for 10 ccm. 12.6 ccm. 
normal sulphuric acid. One ccm. normal sulphuric acid cor- 
responds to 0.017 TIN3. The quantity of ammonia is, therefore, 
2.142 per cent. 
3. 5 com. of acetic acid solution requires 41.7 ccm. of the 
normal potash solution, 10 would therefore require double this 
quantity, or 88.4. But the cubic centimetre of normal potash 
solution corresponds to 0.06 of acetic acid, and hence the pro- 
portion of acetic acid is 50.04 per cent. 
4. 10 ccm. of a solution of common salt requires, for ex- 
ample, 12 ccm. of the TV normal silver solution. Now as 1 ccm. 
of the TV normal silver solution corresponds to 0.00585 Nad, 
the common salt solution contains 0.702 per cent, of Nad. 146 
SECTION SEVENTH. 
5. 10 ccm. of a solution of nitrate of silver requires 15.5 ccm. 
of the TV normal chloride of sodium solution. But 1 ccm. of 
the TV common salt solution corresponds to 0.017 AgONO„ and 
the silver solution contains 2.635 per cent, of AgON06. 
6. Supposing we desire to construct a 40 per cent, solution 
of acetic acid from the diluted acetic acid mentioned in No. 3. 
We learn from the proportion 40 :100=50.04 : x, that we have 
to dilute 100 ccm. of the acetic acid solution, which has been 
estimated by titrition, to 125.1 ccm. 
7. Let us suppose the case, that we wish to prepare a soda 
solution of 20 per cent., and that a solution which we have ti- 
trated showed a proportion of 37.5 per cent, of NaO. We find 
by calculation that 100 ccm. of the latter solution is to be di- 
luted to 187.5 ccm. 
8. We wish to make a 1 per cent, solution of nitrate of sil- 
ver, For this purpose we use the 2.635 per cent, solution of 
nitrate of silver of No. 5. It requires diluting with water to 
263.5 ccm. Section (£igl)tl). 
METHODS OF STAINING—IMPREGNATION WITH METALS—THE 
DRYING AND FREEZING PROCESSES. 
I. Methods of Staining. 
Delicate animal tissues frequently gain an extraordinary dis- 
tinctness when impregnated with indifferent coloring materials, 
and complicated structures are frequently essentially cleared 
up in the same way. The non-reception of the color by other 
tissue elements is also of great value for assisting our discrimi- 
nation in certain cases. These staining processes, therefore, 
form a very important accessory for histological investigations, 
and science is greatly indebted to Professor Gerlach, the in- 
ventor of carmine tingeing. 
The subsequently discovered hsematoxyline tingeing is of 
equal value and, in part, even superior. All other coloring 
materials are of a second or third rank, as I have learned from 
the experience of many years. 
1. GerlacKs Method of Tingeing with Carmine. 
Grerlach first gave us this process in a small work (“ Mikro- 
skopische Studien aus dem Gebiete der menschlichen Morpho- 
logic.” Erlangen), which appeared in the year 1858. In his 
carmine injections he had already noticed the eagerness with 
which the nuclear structures of the blood-vessels absorbed the 
carminate of ammonia, and how differently they behaved in this 
respect to the cells and intercellular substance. The cells also 
absorb coloring matter, but much more slowly and with greater 
difficulty, and always in lesser quantity than the nuclear form- 
ations. Intercellular substances act nearly indifferently. 
# Grerlach’s first experiments were made on the brain and 
spinal cord. Pine sections of organs previously hardened in 148 
SECTION EIGHTH. 
chromate of potash were placed in a moderately concentrated 
solution of the carminate of ammonia and left in it for 10 or 15 
minutes. He then soaked them for several hours in water, 
which was frequently renewed, then treated them with acetic 
acid and placed them in absolute alcohol to remove the water. 
The carmine solution tinges even when it is still more diluted. 
Gerlach observed this at the very first, having one night left a 
section of a convolution of the cerebellum lying in some water 
slightly contaminated with carmine. In this case things 
showed themselves which were not to be recognized by the 
first method of staining. Thereupon Gerlach employed 2or 3 
drops of a concentrated solution of ammonia carmine to the 
ounce of water, leaving his sections in it from 2 to 4 days. 
This is the purport of the first statement of the inventor. 
Since that time carmine tingeing has come into the most 
frequent use. Several years ago one observer w-ent so far as to 
assume the presence in the central organs of several kinds of 
nerve cells, to which he assigned different functions according 
to their capacity for absorbing carmine.* 
The directions for its use have been more or less fortunate. 
From what my own experience has taught, two evils are to be 
especially avoided in carmine staining; one is an excessive 
tingeing, ultimately inducing a very deep and diffuse red, which 
does not permit of further recognition of the preparation ; the 
other is an infiltration of the elements of the tissue in con- 
sequence of the action of the ammonia. 
Solutions as free as possible from ammonia should therefore 
be used. For this purpose take several grains of carmine, com- 
bine it with an ounce of distilled water and a few drops of am- 
monia. The fluid, in which a portion of the carmine has 
become dissolved, is to be filtered. Another portion of the 
carmine, which remains on the filter, may be kept for future 
use. When the filtrate has any appreciable smell of ammonia, 
the latter should be allowed to escape by leaving it in an open 
vessel under a bell-glass for a half or a whole day. If, after a 
time, granules of carmine are deposited, a drop of liquor am- 
monia serves to redissolve them. However, all solutions of 
* As carmine acid on boiling- with dilute sulphuric acid is divided as a glycoside 
into pure sugar and carmine red. Rollett has recently used the latter substance in a. 
watery solution as a tingeing medium. METHODS OF STAINING. 
149 
carmine are very decomposable and their coloring power, un- 
fortunately, very unequal—an inconvenience which cannot be 
entirely obviated. 
The fluid thus obtained is, when used for tingeing, to be 
added, drop by drop, to water, in order to obtain at pleasure 
a lighter or more intensive red. For very delicate objects a 
combination of the coloring water with an equal quantity of 
glycerine is advantageous. 
I recommend for this purpose three to six grains of carmine 
dissolved in exactly the necessary quantity of ammonia and 
mixed with one ounce of distilled water. To the filtered fluid, 
one ounce of good glycerine and two or three drachms of 
strong alcohol are to be added. The solution is to be used 
either as it is or with a further addition of glycerine. 
For many purposes, as for example, the double tingeing 
with hsematoxyline and carmine, to be described below, a con- 
centrated solution of the latter coloring material, containing as 
little ammonia as possible, is to be recommended. 
The length of time which it is necessary for a portion of tis- 
sue to remain in the fluid is determined by the intensity of the 
color of the latter. Strong solutions tinge sufficiently in a few 
minutes, weaker ones require several hours. The preparations 
may be left without disadvantage for twenty-four hours in 
very weak solutions. 
The addition of 0.5—1 per cent, of common salt has recent- 
ly been advised for limiting the swelling of the preparation 
(Leptschinsky). 
The stained pieces, when taken out, are first washed with 
pure water. They are then exposed for several minutes to a 
solution of acetic acid. I employ, as a rule, an ounce of dis- 
tilled water with two or three drops of glacial acid ; although 
a much stronger acid may be used for a much longer time 
without harm. The process may be readily modified where it 
is desirable to avoid the further infiltration of the tissue with 
water. The stained object may be deprived of its water with 
absolute alcohol, and then exposed to the glacial acid from one 
to twenty-four hours (Thiersch), or an acidulated alcohol may 
be directly applied. This may also be accomplished, as Beale 
correctly remarks, with glycerine containing glacial acetic acid 
(five drops to the ounce). Only with tissues of very unequal 
capacity for swelling, a saturated watery solution of oxalic acid 150 
SECTION EIGHTH. 
deserves the preference to acetic acid (Thiersch). Nevertheless, 
it finally extracts the red from the nucleus, and the color is less 
intensive. Fresh tissues, or those hardened in alcohol, color 
best; not so good, and somewhat more slowly, those which 
have been hardened in chromic acid or chromate of potash. 
Good carmine preparations show the nuclei intensively red- 
dened, likewise the axis cylinder of the nerve fibres. The col- 
oring of the protoplasma is usually less lively ; the connective 
tissue interstitial substance appears colorless, etc. 
One soon learns to properly estimate the intensity of the 
color of the tissue. In general, the preparations destined for 
wet mounting (in weakly acidulated glycerine) are to be less 
deeply tinged than those for resinous mounting. The latter 
(best mounted cold in Canada balsam dissolved in chloroform) 
often furnish charming preparations for review. 
Injected specimens are very susceptible of tingeing with 
many colors, such as chrome yellow and sulphate of baryta. 
The best kinds of soluble Prussian blue are also useful for 
staining; although a somewhat more strongly acidulated wash- 
ing-water is necessary to retain the lively blue. It is more ap- 
propriate for objects injected with carmine to stain them blue 
or violet; nevertheless very handsome appearances may also 
be obtained with a very light red carmine. 
The employment of ordinary red ink, of which use has here 
and there been made, is to be little recommended. 
2. Thiersch's Carmine Fluid. 
Professor Thiersch employs several methods of staining. 
a. Red Fluid. 
Carmine - • 1 part. 
Caustic ammonia 1 “ 
Distilled water 3 parts. 
This solution is to be filtered. 
A second solution is to be prepared of— 
Oxalic acid 1 part. 
Distilled water 22 parts. 
One part of the carmine solution is to be mixed with 8 parts 
of the oxalic acid solution, and 12 parts of absolute alcohol are 
to be added, and filtered. METHODS OF STAINING. 
151 
If the filtrate is orange-colored instead of dark-red, more 
ammonia is added to compensate for the preponderance of ox- 
alic acid, and the orange becomes red. The orange color may 
also be used for staining. If crystals of oxalate of ammonia 
are afterwards formed in the solution, which may take place 
from the addition of liquor ammonia or alcohol, it must be fil- 
tered a second time. 
According to Thiersch’s experience, this solution stains tis- 
sues very uniformly in the short space of from 1 to 3 minutes, 
without causing them to swell and without loosening shreds of 
epithelium. After the staining, the coloring material adhering 
to the surface of the preparation is to be washed off with alco- 
hol of about 80 per cent. When the color has become too dark 
or diffuse, the preparation is to be washed out with an alcoholic 
solution of oxalic acid. 
5. Lilac Carmine Fluid. 
Borax 4 parts. 
Distilled water 56 u 
Dissolve and add, of carmine 1 part. 
The red solution is to be mixed with twice its volume of ab- 
solute alcohol, and filtered. Carmine and borax remain on the 
filter ; this precipitate, dissolved in water, may be again used. 
Thiersch found that this solution colored more slowly than 
the simple red one, and that it was especially attracted by car- 
tilage and by bones which have been decalcified by chromic 
acid. Alcoholic solutions of oxalic and boracic acids serve for 
washing. Preparations may be very beautifully stained by 
tingeing them in the lilac solution and then placing them for 
an instant in the red fluid. 
3. BeaV s Carmine Fluid. 
This meritorious investigator has recommended the follow- 
ing mixture : 
Carmine 10 grains. 
Strong liquor ammonia % draclim. 
Cood glycerine 2 ounces. 
Distilled water 2 u 
Alcohol \ ounce. 152 
SECTION EIGHTH. 
The pulverized carmine is to be placed in a test tube and 
the ammonia added to it. By agitation, and with the aid of 
heat, the carmine is soon dissolved. The ammoniacal solution 
is to be boiled for a few seconds and then allowed to cool. 
After the lapse of an hour, much of the excess of ammonia will 
have escaped. The glycerine, water, and alcohol may then be 
added, and the whole passed through a filter or allowed to stand 
for some time, and the perfectly clear supernatant fluid poured 
off and kept for use. Various tissues require very unequal 
time for staining. 
Heidenhain’s process (first used for the mucous membrane 
of the stomach) is a modification of Beal’s method. The solu- 
tion is to be prepared without the alcohol, and the superfluous 
ammonia almost entirely removed by warming on the water- 
bath, or the addition of acetic acid. (The proportion of ammo- 
nia is proper when, after 24 hours, all the carmine of a solution 
remaining in a small open dish has become deposited in gran- 
ules.) The specimen is to be placed in a watch-glass with this 
nearly free from ammonia solution. This watch-glass, and 
another containing water and a trace of ammonia, are to be 
placed in a flat glass vessel which can be accurately closed and 
left for 24 hours. Afterwards washed in glycerine, and then 
placed in pure glycerine, the preparations are to be exposed in 
the same manner to the vapor of a small quantity of acetic 
acid. Such a protective method of staining certainly presents 
manifold advantages. Modifications of the same may also be 
readily made. 
4. Acid Carmine Fluid. 
Schweigger-Seidel recommends the following method for 
tingeing objects previously treated with acids:—An ordinary 
ammoniacal solution of carmine is to be mixed with acetic acid 
in excess and filtered. The red solution thus obtained stains 
diffusely ; but after the addition of glycerine, tempered with 
a little muriatic acid (1: 200), to the microscopic preparation, 
the cell body is seen to gradually lose its color, and the car- 
mine is only retained by the nucleus. For mounting in gly- 
cerine, the preparation is to be washed with water containing 
acetic acid. 
I have dissolved carmine in acetic acid, then filtered and METHODS OF STAINING. 
153 
subsequently diluted with water at pleasure, A fluid is thus 
obtained which tinges sufficiently in from a few hours to a half 
or a whole day. This tingeing method is highly recommend- 
able for injection preparations made with Prussian blue.* 
6. Piero-Carmine Tingeing. 
Ranvier, a meritorious investigator, is the discoverer of 
this method of tingeing. I accomplished nothing with the 
picro-carmine prepared according to his earlier recipe. We 
now have the following method: The ammoniacal solution of 
carmine is added to saturation to a saturated watery solution 
of picric acid. The original volume is evaporated one-fifth. 
The cooled solution deposits a slight sediment of carmine. 
After filtration, the filtered solution is evaporated to dryness, 
whereby a reddish ochre yellow powder is obtained. This is 
used to make a one per cent, solution with distilled water, 
which requires, when kept, an occasional filtration. This is 
serviceable. 
The recipe communicated by C. Baber, according to the 
experience of Malassez, is still more accurate : 
Carmine 1 grm. 
Liquor ammonia 4 ccm. 
Water 200 grins. 
Mix, and add picric acid 5 “ 
Shake and decant, so that the undissolved excess of picric 
acid remains behind. The fluid, after having stood for several 
days, with occasional shaking, is exposed to the air in a saucer 
for several weeks until dried. The red powder is dissolved in 
water in the proportion of two parts to one hundred, and after 
several days filtered through a double thickness of filter paper. 
The fluid should now be yellowish red, with no smell of am- 
monia. A drop on white filter paper, when dried, makes a yel- 
low-red bordered spot. A few drops of carbolic acid prevents 
decomposition of the fluid. 
ashing in distilled water draws the picric acid out of the 
preparation; glycerine, on the contrary, does not. 
* Pure carmine red (see note p. 148), dissolved in water acidulated with acetic 
acid, also forms a serviceable tingeing medium, according to Rollett. 154 
SECTION EIGHTH. 
For mounting, Baber recommends a mixture of ten drops of 
glycerine with an equal quantity of water, to which one drop 
of the picro-carmine solution has been added. 
The tihgeing is rapid, and occurs in various shades in the 
several tissues. 
6. Staining with Anilin Red (.Fuchsin). 
The idea of employing the anilin colors, so much used at 
present, for tingeing animal tissues was very natural. A se- 
ries of experiments which I had undertaken for this purpose 
showed the pre-eminent usefulness of this coloring material. 
Fuchsin (crystallized) 1 centigramme. 
Absolute alcohol 20-25 drops. 
Distilled water 15 cubic centimetres. 
A beautiful moderately intense red color results. It colors 
many of the animal tissues almost instantly, and without alter- 
ing them. It is especially adapted for the study of epithelium, 
hyaloid membranes, the lens and corpus vitreum. Diluted 
with a little water, this solution tinges the vibrating cilia of the 
ciliated epithelium of the frog, without causing the motion to 
cease. The colored blood cells also become stained, although 
slowly. The same solution of fuchsin is also useful for color- 
ing the ganglion cells and the cellular elements of lymphatic 
glands ; but it appears to me to be not so well adapted for car- 
tilage and bones. The nerve tubes, after an immersion of sev- 
eral hours, become slightly red, and their axis cylinders be- 
come sensibly darker. 
The above examples show that the solution produces effects 
which are superior in many respects to those obtained with 
carmine. The promptitude and uniformity of the coloration 
are qualities which render the fuchsin solution especially valu- 
able as a staining medium for instantaneous demonstrations, 
and for coloring pale delicate cells, which thus become more 
distinct without suffering alteration. It is very unfortunate 
that alcohol soon extracts the color, so that it is impossible to 
preserve the preparations in Canada balsam.* 
* The nitrate of rosanilin (Magenta red) in watery solution has been recom- 
mended by Roberts and Abbey; tannic acid in an alcoholic solution by Jackson. METHODS OF STAINING. 
155 
7. Purpurine Tingeing. 
Ranvier recommends this coloring matter, which is prepared 
from madder. A small quantity of purpurine, to which a little 
water has been added, is poured into a boiling watery solution 
of alumen (1: 200). The purpurine is dissolved in a few min- 
utes, though the quantity must be such that some purpurine 
remains undissolved. The hot fluid is to be filtered into a ves- 
sel which contains a quarter of the volume of alcohol of 36° ac- 
cording to Cartier’s scale. A fiuorescical fluid is obtained, 
which is of a beautiful orange red by transmitted light. It 
may be preserved for about a month in a vessel with a glass 
stopper, but so soon as deposits commence in it it should be 
rejected. 24-48 hours are requisite for its action. 
The advantages of this method consist, according to the in- 
vestigator mentioned, in the fact that it produces an excellent 
tingeing of the nucleus, while the cell protoplasma remains 
nearly colorless. It also leaves the nervous elements colorless, 
while the connective tissue frame-work is tinged. 
I acknowledge that this coloring matter has remained be- 
hind my expectations. 
8. Eosine Tingeing. 
This newly discovered body (the potash salt of the tetrabro- 
mofluoresceine) has recently been made known as a tingeing 
medium by E. Fischer. It may be used dissolved in water 
(1:10-20); or the coloring matter may be precipitated from 
this solution by the addition of an acid, and subsequently 
redissolving it in alcohol, preferably in absolute alcohol in the 
proportion of 1; 20-30. According to my experience, the 
eosine tingeing is infinitely behind carmine and hsematoxyline 
tingeing. 
9. Tingeing with Aniline-iodine Violet. 
This body, obtained from iodine methyl and aniline (of 
doubtful iodine contents) forms, as Jurgens found, an excel- 
lent accessory for the recognition of the amyloid substance. It 
is used in solution in water, 1 :100 and more, and allowed to 
act for a short time. It assumes a lively red color, while the 156 
SECTION EIGHTH. 
remaining tissue takes on a dull violet tone. Fresh tissues are 
used, as well as such as have been hardened in chromic acid or 
Mueller’s fluid. Alcoholic preparations, washed out in water, 
are also very suitable. 
10. Blue Colors for Staining. 
It is desirable in many cases to make use of a blue fluid, es- 
pecially for staining specimens injected with carmine. Other 
preparations also appear very beautiful when stained with this 
fluid, so that for many purposes I am inclined to give it the 
preference to carmine. Several of these methods are now prac- 
tised, as with the sulph-indigate of potash (so-called indigo car- 
mine), with anilin blue, and soluble parme, hsematoxyline, and 
chinoline blue. 
a. Blue Staining with Indigo Carmine. 
The following solution has been recommended by Professor 
Thiersch: 
Oxalic acid 1 part. 
Distilled water 22—30 parts. 
Indigo carmine, as much as the solution will take up. 
The soda salt also affords an excellent blue fluid. If the 
blue color is in excess it may be removed with a solution of ox- 
alic acid in alcohol. 
This blue fluid (which may also be diluted at pleasure with 
alcohol), when concentrated, tinges very rapidly and uniformly. 
According to the observation of its inventor, it is very suitable 
for coloring the axis cylinders and nerve cells of the brain and 
spinal cord, previously hardened in chromic acid. 
Canada balsam preparations, which I obtained from Thiersch 
many years since, have preserved their blue color unchanged 
to the present time. 
b. Anilin Blue Fluid. 
Ordinary anilin blue* is insoluble in water. By treating it 
with sulphuric acid, the soluble blue may be obtained. This 
* It may also be used in alcoholic solution for coloring objects which have been 
hardened in absolute alcohol. Glycerine serves for mounting. METHODS OF STAINING. 
157 
may be simply dissolved in water until it assumes a deep cobalt 
color, or the following solution may be prepared : 
Soluble anilin blue 2 centigrammes. 
Distilled water 25 cubic centimetres. 
Alcohol 20—25 drops. 
This fluid stains tissues preserved in alcohol of a lively blue, 
and in a few minutes, but those preserved in chromic acid are 
not colored so rapidly. This color may be preserved in water, 
alcohol, and glycerine, and is not altered by the addition of 
acids. The lymphatic glands, spleen, walls of the intestines, 
and more particularly sections of the brain and spinal cord, as- 
sume, under its influence, a fine appearance. I have made very 
extended use of it for years and can recommend it thoroughly, 
although it furnishes only perishable preparations. 
This method of staining has recently been improved by 
Heidenhain and E-ollett. The former employs the neutral re- 
acting aqueous solution in still higher dilution, so that, when 
poured into a watch-glass, it shows on a light ground a forget- 
me-not blue color. The sections (from alcoholic preparations) 
remain for a day in 4 ccm. of this fluid in a moist place, and are 
then to be immediately mounted in glycerine and cemented. 
The color and coloring power of the solution are considerably 
increased by the addition of a little acetic acid, or even its 
vapor ; the vapor of ammonia, on the contrary, deprives it of 
its color entirely. Rollett dissolves 1 grm. of the coloring 
matter in 400 ccm. water. The objects, when very dark blue, are 
placed in distilled water, and here, with occasional shaking, 
lose the excess of the coloring medium. 
c. Soluble Panne Fluid. 
This substance, which is obtained by treating diphenylate 
of rosanilin with sulphuric acid, when dissolved in water in 
about the proportion of 1: 1000, gives a gorgeous blue, running 
into violet, and colors the various tissues in a few minutes. 
They are then to be washed in water, and either examined in 
glycerine, or, after being deprived of their water by absolute 
alcohol, are to be mounted in Canada balsam. The latter ob- 
jects are, unfortunately, of a somewhat perishable nature. 158 
SECTION EIGHTH. 
d. Tingeing with Chinolin Blue {Cyanine) 
Dissolved in alcohol of 36° (Cartier) and cautiously diluted 
with water, this has been recommended by Ranvier for fresh 
tissues as well as for those which have been hardened, in alco- 
hol or picric acid. Fat assumes the deepest blue color. 
11. Violet Tingeing with Hcematoxylin. 
Boehmer has brought to our knowledge, in hsematoxylin, 
an extremely valuable coloring medium of variable permanence. 
The presence of an acid or of an alkali in small quantities 
causes, however, a subsequent fading or discoloration. After 
numerous trials I recommend dissolving about 1 grm. of the 
coloring material in 30 grms. of absolute alcohol. Then pre- 
pare an alum solution which contains 0.5—1 grm. of the salt 
in 30 ccm. of distilled water. The alcoholic solution of hsema- 
toxylin is to be added to this, drop by drop, till a deep violet 
blue color is obtained. The fluid must then stand for several 
days exposed to the air and then be Altered. Subsequent fil- 
tration s from time to time are unavoidable. A beautiful violet 
blue tingeing is obtained after 5, 10, 20 or 30 minutes. I have 
also operated with stronger solutions, and made solutions of 
hsematoxylin which colored excellently in from a half to a 
whole minute. Nevertheless—do not forget it—the tingeing 
power of such a solution may have changed considerably after 
a few days. A new trial must then be made. 
Distilled water is used to wash out the preparation. I be- 
lieve, from previous experience, that the subsequent action of 
a weak alum solution renders the tingeing more permanent. If 
the color is too deep, by laying the preparation from 4-12 hours 
in an alum solution, a brighter and very pretty though bluer 
color may be obtained. 
Elndtieisch recommends another process. A concentrated 
watery solution of the coloring matter, and a similar solution of 
alum are prepared. To use them add to a small quantity of the 
former as much of the latter as to cause the brown red color to 
become violet red. When this is diluted with about five times 
as much water, a blue violet tingeing fluid is obtained, in which 
the preparations become stained in from one to three minutes. 159 
METHODS OF STAIN TNG. 
For rapid staining, as in demonstrations in lectures, I pre- 
fer hsematoxylin to carmine decidedly ; also, in accordance 
with Waldeyer, Eberth, and others, for tingeing preparations 
which have been stained with nitrate of silver (see below). As 
has been said above, chromic acid preparations, when tinged in 
this manner, do not permit of permanent mounting, though 
objects which have been hardened in alcohol keep well. Alco- 
holic preparations, previously injected with carmine, when 
properly treated with our coloring matter make beautiful ob- 
jects, which permit of permanent mounting in resinous sub- 
stances. A watery solution of logwood, with a little alum, 
also produces a similar tingeing which is less sensitive to 
acids. 
12. Blue Tingeing with Molybdate of Ammonia. 
Krause has recommended this salt in a neutral solution of 
5 per cent, as an indifferent medium for giving a marine blue 
color to various tissues, as those of the nervous apparatus, 
lymphatic glands, and ciliated epithelial cells. The staining 
is completed in 24 hours, at an ordinary temperature and under 
the action of light. The preparations become brown, and 
assume a consistence suitable for making sections by supple- 
mentary exposure to the action of tannic acid (1 : 1.5) or pyro- 
gallic acid (20 per cent.). 
13. Double Staining with Carmine and Picric Acid. 
To the methods of staining previously known, a new one 
has been added, by E. Schwarz, for double tingeing. He com- 
bines staining with carmine with that by picric acid. 
That author places the tissues in a mixture consisting of 1 
part creosote, 10 parts acetic acid, and 20 parts water. The 
preparations are to be immersed in this mixture, while it is 
boiling, for about a minute, and are then to be dried (for two 
or three days). Thin sections are to be made and immersed 
for an hour in water slightly acidulated with acetic acid, and 
than washed out in distilled water, Next they are to be put 
in an extremely dilute watery solution of ammoniacal carmine, 
and, after being again washed in water, are exposed for two 
hours to a solution of picric acid (0.066 grm. to 400 ccm. water). 160 
SECTION EIGHTH. 
The sections are then placed on a slide, the superfluous acid is 
allowed to flow away, and a mixture of 4 parts of creosote to 
1 part of turpentine, which has become resinous from age, 
is dropped on to it. In about half an hour the specimen, 
which has become transparent, is to be mounted in Canada 
balsam. 
If it is undesirable to use the creosote mixture, the sections 
are to be removed from the watery picric acid solution to an 
alcoholic mixture of corresponding strength, in order to deprive 
them of their water. 
A peculiar effect is thus obtained. Epithelial and glandu- 
lar cells, muscles, and the walls of vessels show a yellowish 
color with reddened nuclei, while the connective tissue is not 
colored by the picric acid, and only presents the carmine color. 
These preparations are very handsome, and the method pro- 
mises to be of importance, especially for the demonstration of 
muscular elements. 
14. Tingeing with Carmine and Indigo-carmine. 
According to Merkel’s directions, add to the solution of in- 
digo-carmine mentioned atp. 156 an ammoniacal solution of car- 
mine until a violet color is obtained. Precipitated carmine 
requires the addition of ammonia. This fluid, which keeps 
for some time, colors the nerve medulla of brain preparations 
blue, the blood-corpuscles green, everything else red. Ossifica- 
tion preparations, previously decalcified in Mueller’s fluid and 
hydrochloric acid, become blue in the bone substance, in all the 
remaining parts red. The preparation is afterwards mounted 
in Canada balsam. 
15. Tingeing with Indigo-carmine and Picric Acid. 
Jullien mixes both fluids. A double tingeing, which be- 
comes pale in glycerine, is thus obtained. The connective tis- 
sue is blue, and the epithelium yellow. 
16. Tingeing with Hcematoxylin and Carmine. 
Strelzoff, a Russian physician, is the inventor of this pro- 
cess, which, for developing, previously decalcified bones, pro- 
duces exquisite objects, though according to numerous trials METHODS OF STAIXHSTG. 
161 
of my own, it is hardly applicable to other organs. The sec- 
tions are stained with a hsematoxylin solution, and then after 
washing out in distilled water, are placed in a solution of car- 
mine as free as possible from ammonia. After washing out a 
second time they may be again exposed to the action of a 
weaker solution of alum. The remains of cartilage appear 
blue, the bone substance red. These preparations cannot, 
however, be mounted in resinous substances, and can only be 
kept temporarily in glycerine. Hsematoxylin, unfortunately, 
does not become permanently attached to tissues previously 
exposed to acids, and, sooner or later disappears in both kinds 
of preserving fluids. * 
17. Double tingeing with Solution of Logwood and Picric 
Acid. 
Kutschin recommends that developing bones which have 
been lying in Mueller’s fluid (p. 136) should be washed out and 
exposed to the action of a watery solution of the first mentioned 
coloring matter in alum, and then place them in a saturated so- 
lution of the picric acid in alcohol. The cartilage remains and 
the cell nuclei become blue, the protoplasma of the medullary 
cells and the bone lamellae assume the yellow color of the pic- 
ric acid. Such images are not always pretty, as I can certify. 
Thus far, I have made no further investigations by this 
method. 
18. GerlacK s Complicated Tingeing. 
The meritorious investigator uses for transverse sections of 
dried vessels a weak solution of logwood containing a minimal 
quantity of alum, for one day. Then follows, for several min- 
utes, the action of a “pure” acetic acid, and then, for an 
equal period, that of a “ tolerably dilute” picric acid. After 
washing out, there is a triple coloration of the muscular, elas- 
tic, and connective-tissue elements. Such objects permit of 
mounting in glycerine or Canada balsam. 
* One may also proceed inversely, staining the objects first in a solution of car- 
mine free from ammonia, and then exposing it to the action of hasmatoxylin or a so- 
lution of logwood (Rollett). I also succeeded in obtaining beautiful double tingeing 
of embryonic bones (but only such) with aniline blue, or parme soluble and car- 
mine. 162 
SECTION EIGHTH. 
11. Metallic Impregnations. 
Within a few years histological investigation has gained 
important accessories in several readily reducible combinations 
of the noble metals. Aqueous solutions of nitrate of silver, 
osmic acid, chloride of gold and of palladium, have thus far 
come into use. Their effects are essentially different, so that 
we shall have to discuss each solution by itself. 
a. Nitrate of Silver. 
Lapis infernalis, in solution or in substance, has been used 
for a number of years for obtaining precipitates of silver in the 
cornea. This method was first extensively used by Reckling- 
hausen (“ Die Lymphgefasse,” Berlin, 1862) on animal tissues. 
His then endeavored to ascertain the nature and conditions of 
the precipitates. 
Touching the lining cornea with the surgeon’s crayon of 
nitrate of silver has, however, yielded far better results. The 
thicker corneas of larger animals can only, in this manner, be 
effectively mastered (Eberth). We shall return to this at the 
eye. 
The most extended use, good and bad, has been made in 
histological work of the nitrate of silver solution mentioned. 
Only fresh (or but slightly altered) tissues, which are still 
saturated with the albuminous organic fluids, are suitable for 
impregnation with silver. As the action of nitrate of silver is, 
for the most part, confined to the surface, they should be chiefly 
thin, membranous structures. Artificial surfaces, made by the 
knife, generally produce only very unsatisfactory results. 
It is preferable to employ only very weak solutions, those 
of 0.5, 0.25, and 0.2 per cent., or still weaker, according to cir- 
cumstances. Frequently the immersion lasts for only the frac- 
tion of a minute, till the fragment of tissue is seen to assume a 
whitish color. It is then to be washed in water and exposed 
to the light until a brownish color is noticed. The examina- 
tion may be made in acidulated water or glycerine. Tingeing, 
especially with hsematoxylin, may also be advantageously 
combined with this process. 
To increase its durability, Legros recommends the immersion METALLIC IMPREGNATIONS. 
163 
of the colored object in a solution of hyposulphite of soda for 
an instant; it is then to be washed in distilled water. Silver 
preparations which have become too dark may be brightened 
rip again by a prolonged action of this salt. 
Although the silver method produces excellent specimens 
in many cases, there are a number of defects connected with it 
besides those which have been mentioned. One of these is that 
the nuclear structures very soon become indistinct, and later 
disappear entirely. Then, with every precaution, the desired 
result is not always obtained, and the appearances which the 
strongly acting nitrate of silver produces are frequently very 
dissimilar, and are often so heterogeneous that the observer 
remains completely confused by them. The greatest foresight 
in the interpretation of such artificial productions is therefore 
necessary—and this, unfortunately, has been frequently neg- 
lected. 
The silver treatment gives decidedly the best results with 
epithelium, especially with unstratified pavement cells, and the 
membranes and tubes covered by them. Here we have pro- 
duced a mosaic, consisting of sometimes finer, sometimes 
broader, dark lines of demarcation, which enables us to recog- 
nize the contours of the cells most distinctly. This results 
either from blackening of the cement substance, or from the 
formation of the dark precipitate of silver in the narrow fur- 
rows between the cells. Such appearances are in no wise liable 
to misinterpretation so soon as the nuclei can be recognized or 
the scales isolated. We shall afterwards see to what beautiful 
discoveries in the structure of the finest blood and lymph pas- 
sages this method has led. 
Recently injections have been made into the living frog of 
solutions as low as 1: 2000, and even 8000. 
However, even in this case, instead of the bright field sur- 
rounded by dark lines, we sometimes have a diffuse, brownish 
darkening of the scales, without the black lines of demarca- 
tion. 
The outlines of smooth muscle cells are also made visible in 
a beautiful manner by this reagent. How far it may serve for 
demonstrating the finer structural relations of nerve tissue, 
future investigations will have to decide. 
Opinions have thus far agreed quite as little with regard to 
the importance of the nitrate of silver solution for connective 164 
SECTION EIGHTH. 
tissue and relative structures; on the contrary, the views of 
observers are very widely separated on this point. 
According to Recklinghausen’s statements, a diffuse colora- 
tion of the basis substance takes place, from which the cavities 
and cells glimmer forth in the form of bright spaces. Exactly 
the reverse may also take place, a dark, granular precipitate of 
silver being formed in them, while the interstitial substance 
remains bright. It has been recommended to use a solution of 
common salt to obtain the latter appearance (His). 
We are inclined not to advise the silver method for connec- 
ive tissue. 
Thiersch, an unsurpassed technist, has shown that thin sec- 
tions of alcoholic preparations may also be suitably treated 
with this silver salt. 
Such objects are placed for about five minutes in an alco- 
holic solution of nitrate of silver (1; 6000), and at the same time 
shaken. They are then placed for several seconds in an alco- 
holic solution of common salt, continuing the shaking. Sub- 
sequently, exposed more or less to the light, these objects be- 
come slightly stained, but sufficiently so to show the various 
tissue elements satisfactorily. Carmine injections, treated in 
this way, mounted in resinous substances, afford excellent, ex- 
tremely durable specimens, as I have learned from experience. 
b. Other Silver Salts. 
Alferow recommends the picric, acetic, citric, and lactic ox- 
ide of silver in solutions of 1:800, to which are added 10-12 
drops of a similar free acid. 
The same old method is used; the contours are clearer, and 
the pernicious effects are less than with the nitrate of silver. 
c. Osmic Acid (Hyperosmic Acid). 
“ The treatment of animal tissues with solutions of osmic 
acid (Os 04), introduced by M. Schultze,* permits of a very 
manifold application. Organic substances reduce the acids 
from their solutions, and hence a combination of the former 
with a lower grade of oxidation, or perhaps with metallic os- 
*I am indebted for this notice to the discoverer of this reagent. Let it there- 
fore remain here unchanged as a memento of the highly meritorious deceased ! 165 
METALLIC IMPREGNATIONS. 
mium results, which combination, sooner or later, and indepen- 
dent of light, assumes a dark bluish black color, and resists 
decomposition. The reduction does not follow in the tissue as 
a granular precipitate ; on the contrary, the elementary struc- 
tures, if fresh when immersed in it, retain the same transparency 
and texture which they have in life, and are only altered so 
far as color is concerned. These changes of color take place in 
different tissues with very different degrees of rapidity, and on 
this is based an important advantage of the method. Evidently 
this condition is due to a difference in the reducing power, or 
to the relation of the organic substances to the reduced lower 
grade of oxidation. Through this peculiarity, osmic acid may 
render structural relations visible, which could in ho other way 
be so summarily demonstrated. This is the case with the ter- 
minal tracheal cells in the luminous organ of the Lampyris. 
All kinds of fat cells and fat drops, and the medullary matter 
of central and peripheral nerves become rapidly colored black ; 
more slowly, the substance of the ganglion cells and of the axis 
cylinders, the muscular fibres, and all highly albuminous ele- 
ments, such as cells rich in protoplasma, red blood-corpuscles, 
and the fibres of the lens. The intercellular substance of con- 
nective tissues which afford gelatine and mucus, cellulose, amy- 
Inm, the watery intercellular fluid of many vegetable cells, 
which only contain traces of dissolved organic substances, color 
most slowly of all (M. Schultze and Rudneff). The chief value 
°f the method depends on the property of osmic acid of pre- 
serving the most delicate, perishable tissues, which are most 
sensitive to reagents, in a condition apparently the same as in 
fife ; as for example, embryonic tissues, the cells of connective 
tissue, the central organs and peripheral portions of the nervous 
system, the retina, etc. In this respect osmic acid excels ail 
previously known reagents, as, properly applied, it prevents all 
granular coagulation, and does not allow even the structural 
changes which result from spontaneous post-mortem coagula- 
tion to take place. It is preferable to make use of pretty 
strong, that is, from one to fwo per cent., watery solutions. It 
is best to allow the tissues to remain in this solution but a short 
time, from a quarter of an hour to twenty-four hours. If al- 
lowed to act for several hours or days, the piece becomes quite 
hard and of a very dark color. As the solution does not pene- 
trate very deeply, very small pieces should be selected for im- 166 
SECTION EIGHTH. 
mersion. Weaker, TV per cent, solutions, which, do not harden 
the tissues so much, may also be advantageously used. The 
exhalations from osmic acid are injurious to the respiratory 
organs and the conjunctiva, and are therefore to be carefully 
avoided.” 
Osmic acid has become generally naturalized in a few years 
as an excellent accessory. It belongs to the most important 
acquisitions of microscopic technique. It is necessary, in con- 
sequence of its volatility, to use small bottles with ground 
glass stoppers, in which the pieces of tissue are to remain. A 
subsequent instructive tingeing may occasionally be obtained 
with carmine, and also with hsematoxylin. 
It should not be forgotten, however, that our reagent is not 
infallible. Many modern investigators have also gone too far 
in this direction in their blind reliance. 
d. Osmiamide. 
Owsjannikow recommends Fremy’s osmiamide (1 : 1000), 
that is, the amide combination of osmious acid OsOa, which is 
0s02H2N, as a substitute for the disagreeable volatile acid. 
e. Chloride of Gold. 
The action of the chloride of gold, which Cohnheim intro- 
duced into histology, is much slower and less energetic than 
that of a solution of nitrate of silver, so that a prolonged im- 
mersion of the (freshest possible) tissue is necessary, whereby 
the quantity of the fluid appears to make comparatively little 
difference. A 0.5 per cent, solution of the gold salt is to be 
used ; it is preferable to temper it with a minimal quantity of 
acetic acid. Leave the specimen in the solution from 15 or 20 
minutes to an hour or more, till the former assumes a distinct 
straw color, which here, in contradistinction to nitrate of silver, 
penetrates deeply. After washing the preparation in ordinary 
or distilled water, place it for 24 to 48 hours or more in acidu- 
lated water, leaving the vessel exposed to the light. If the 
reduction has taken place, the color varies ; in the best cases it 
is a beautiful intense red, sometimes violet blue or a deep gray. 
They afterwards grow darker, assuming even a black tone of 
color. 167 
METALLIC IMPREGNATIONS. 
According to Cohnheim’s experience, the chloride of gold 
does not act on cornified cells and those having no protoplasma, 
like simple flattened epithelium and the scales of epidermis 
(nor on their so-called cementing substance) ; furthermore, it 
does not act on the interstitial substance of connective tissue 
and cartilage. Finally, it exerts no effect on the cell nucleus ; 
still this is well preserved, the action of the gold impregnation 
being in general much milder and much less alterative than 
that of the silver impregnation. Others (Waldeyer, Loewe), 
say the nucleus swells. On the contrary, the chloride of gold 
is energetically and with relative rapidity reduced by the pro- 
toplasma of the cell, such as that of the lymphoid and glandu- 
lar cells and the cellular elements of the connective tissue and 
cartilage ; further, by the capillary vessels and the muscles. 
The chloride of gold reduces most energetically—and herein 
the chief value of this new method appears to lie—the elements 
of the nervous system, the ganglia, the medullary sheaths of 
the nerves, which assume a dark, almost blue red color, and the 
axis cylinder, which assumes a brighter, more lively red color. 
According to what has just been mentioned, the impregna- 
tion with gold promised to be of the greatest importance for 
the finer anatomy of the nervous system, the originator of the 
method having also succeeded in making a beautiful discovery 
in the corneal nerves. Unfortunately, the method soon proved 
to be almost capriciously uncertain, in many cases leaving one 
entirely in the lurch, while other observers again obtained 
favorable results. Many have made use of solutions as weak 
as 0.005 per cent. Immersion in a solution of sulphate of 
oxide of iron is said to induce rapid reduction (Nathusius). 
The reduction occurs still more rapidly, however, according 
to Henocque, when the gilded object is taken out of the water 
and placed in a bottle with a ground glass stopper, and which 
is filled with a concentrated solution of tartaric acid, and ex- 
posed to the action of nearly boiling water. Complete reduction 
takes place in 20, 15 or less minutes. Boettcher recommends, 
as an improvement of a process given by Bastian, placing the 
cornea for 15-20 minutes in a 0.2 per cent, solution of chloride 
of gold, and then in a little bottle, with a tightly closing glass 
stopper, which contains formic acid 1 part, amylalcohol 1, and 
water 100 parts. The reduction is said to be completed in 
twenty-four hours. 168 
SECTION EIGHTH. 
Chloride of gold objects, after being carefully washed out, 
permit of staining with hsematoxylin (Eberth). Those which 
are immoderately dark may be bleached by means of a cyanide 
of potash solution, mentioned at p. 135. Nerves which have 
not yet become visible may be rendered distinct by adding to 
the washing water of the gold preparation, for a quarter to 
half an hour, one or two drops of a photographic bringing-out 
fluid which contains pyrogallic acid (Hoyer). 
Gold preparations are, unfortunately, incapable of perma- 
nent mounting. 
f Chloride of Gold and Potassium, and g. Chloride of Gold 
and Sodium. 
The first salt was used by Gerlach in very weak solutions 
for sections of the spinal cord which had been hardened in the 
bichromate of ammonia; subsequently for the examination of 
the nerve terminations in transversely striated muscle, as well 
as by L. Gerlach for the nerves of the heart. For the cornea, 
Hoyer prefers this salt to the chloride of gold, as a cleaner 
preparation. Arnold has made use of this salt, also highly 
diluted, for the fresh sympathetic nerve of the frog. Further 
below we shall return in greater detail to this method. Chlo- 
ride of gold and sodium has thus far been used only for the 
examination of the cornea (Waldeyer). 
h. Protochloride of Palladium (Chloride of Palladium). 
A few years ago, F. E. Schulze made us acquainted with 
the action of this salt. In order to dissolve the dry salt in 
distilled water, it is necessary to add a slight quantity of mu- 
riatic acid. He employs a solution of 0.1 per cent. (1 : 800— 
1:1500). From a half to a whole ounce of this fluid (of a wine- 
yellow appearance) hardens a piece of tissue of the size of a 
bean, in the course of two or three days, to a consistence 
proper for cutting, and at the same time colors it. According 
to the experience of the discoverers, chloride of palladium is 
especially adapted for the recognition of striated and smooth 
muscles, which thereby become brownish and straw-colored. 
Cells rich in protoplasma (epidermis and glands) likewise assume 
a yellow color. Cornified, fat, and connective tissues do not THE DRYING METHOD, 
169 
become colored. Furthermore, the medullary matter of the 
nerves assumes a black color, by direct action. Schulze also 
praises this reagent for the retina and crystalline lenses ; like 
the chloride of gold, it causes the nuclear formations to appear 
sharply, and by subsequently tingeing the connective tissue 
with carmine, very instructive preparations are afforded. It is 
an unpleasant circumstance that with many tissues, as the 
brain and epidermis, the action remains quite superficial. 
The preparations are to be carefully washed and mounted in 
glycerine. 
i. Prussian Blue. 
Leber recommends a peculiar method of impregnation, more 
especially, however, for the cornea of the frog. The fresh or- 
gan is to be immersed for several minutes in a 0.5-1 per cent, 
solution of a protoxide salt of iron. It is then to be taken out 
for the removal of its epithelium, after which it is to be re- 
placed in the fluid for a short time, so that the total action 
amounts to about five minutes. After washing the cornea with 
water, it is to be seized with the forceps and moved to and fro 
for a few moments in a 1 per cent, solution of ferrocyanide of 
potassium till the preparation assumes an intense and uniform 
blue color. Finally, after again washing the specimen in 
water, it shows a colored basis substance, while the corneal 
cells and canals have remained transparent. The color pene- 
trates very deeply, and subsequent tingeing with iodine, car- 
mine, and fuchsine readily succeeds. This method promises to 
be useful. 
111. The Drying Method. 
We also add to the methods above mentioned, that of drying 
animal tissues. The object of this process is to give the parts 
such a degree of hardness and firmness, by depriving them of 
their water, that the thinnest sections may be obtained by the 
aid of a sharp knife, which again swell up by the addition of 
water, and thus resume their natural appearance. We have 
already, in a previous section, become acquainted with a series 
of chemical reagents, such as chromic acid, chromate of potash, 
and alcohol, which are used for the same purpose. 
The drying process is decidedly better adapted for many 
tissues and parts of the body, as it does not render them 170 
SECTION EIGHTH. 
opaque. Especially compact structures, organs rich in con- 
nective tissue, as the skin, the tendons, and the walls of vessels, 
also the lungs (even injected preparations of the same), mus- 
cles, epidermis, crystalline lens, and the umbilical cord, may be 
treated in this manner with the greatest advantage. The dry- 
ing process is less suitable for glands, lymphatic, glands, and 
delicate mucous membranes. It is unserviceable for the brain, 
spinal cord, the nerves, and their terminal expansions in the 
higher organs of sense, in consequence of their extreme soft- 
ness and instability. 
The management of the parts is very simple. They may be 
dried on a board or a piece of cork, to which in certain cases 
a convex surface may be given. To avoid wrinkling, many 
textures may be advantageously stretched out and fastened to 
the board or cork with pins. The temperature should not be 
too low, as decomposition might take place ; but considerable 
elevation of temperature is to be avoided on account of the co- 
agulation of the albumen. A temperature of 80 or 40° C. is 
most suitable.. The sun of a warm day may also be very well 
employed for this purpose. If it be desired to avoid warmth, 
the sulphuric acid or the chloride of calcium apparatus of the 
chemical laboratories may be used. 
The pieces selected for drying should not be too large, and 
the drying should not be overdone, as they may become so 
brittle as to prevent one from obtaining fine sections, in conse- 
quence of the cracks and flaws which occur. How and then it 
will be found most suitable to have a piece not entirely dried, 
having the consistency of wax. Naturally the blade of the 
knife should be dry. If the preparation is on cork, this may 
be used as a support in cutting, hard wood being injurious to 
the knife. 
The thin sections which are made are to be softened in pure 
water, or in water to which a little acetic acid has been added. 
If they are to be stained, they may be placed directly into the 
ammoniacal solution of carmine. It is less convenient to soften 
the sections on the slide than in a watch-glass or a glass box. 
This process requires a few minutes’ time, in order to allow the 
air vesicles to escape from the spaces of the tissue. 
Dried pieces kept in a box, with the addition of a piece of 
camphor, constitute excellent material for many histological 
demonstrations. THE FREEZING METHOD. 
171 
IY. The Freezing Method. 
This process, which has been made use of more recently, 
also affords good results, and in a mnch more conservative 
manner than that of drying. The preparation is allowed to 
freeze at a temperature of 6, 8, 10, or 15° C., according to ne- 
cessity, until it assumes a consistency which will permit fine 
sections to be made with a cooled razor. The object is more 
convenient to handle if it is allowed to freeze on a strip of cork ; 
it is also judicious to make use of an artificial freezing mixture. 
Serves and muscles have been treated in this manner with 
good results (Chrzonszczewskjq Cohnheim). Glands, such as 
salivary glands, livers, kidneys, spleens, the lungs, the skin, 
and the bodies of embryos also afford excellent appearances 
(Kblliker); likewise ganglia (Arnold). Indifferent media, such 
as iodine serum, are to be used in examining the sections. 
The freezing method is, however, by no means neutral. 
Numerous rents and clefts are formed at the same time, which 
may readily pass unnoticed on subsequent thawing. Corrobo- 
ration by other methods is, therefore, quite necessary (Key and 
Retzius). Section Mntl). 
METHOD OF INJECTING. 
Of the greatest value for histological studies is the artificial 
filling of the vascular systems of the part to be examined with 
colored masses ; a procedure which, unfortunately, is still too 
much neglected by many, inasmuch as, without having obtained 
the necessary practice, it may here and there appear as though 
such a procedure were somewhat superfluous—a luxurious ad- 
junct. And yet this important accessory should never be neg- 
lected in any investigation which is at all accurate of normal 
or pathological textural relations ; for much in the construction 
of an organ at once assumes the greatest clearness and intelli- 
gibility after its capillary system has been tilled, and the de- 
sired disclosures with regard to the vascular abundance or pov- 
erty of a part are at once obtained. The art of injecting can 
only be learned, and its execution is by no means easy. Much, 
indeed the greater part, depends on apparently unimportant 
expedients, on little artifices, as well as on a skill only to be 
obtained by practice. Nevertheless, with the necessary perse- 
verance, and by not being discouraged by the almost unexcep- 
tional y unsuccessful first attempts, one soon attains the de- 
sired skill, especially if one renounces the idea of obtaining 
perfectly beautiful injections at the beginning. Success is 
gradually more and more readily obtained, and the satisfaction 
derived from the little work of art which is finally produced, 
has already been for many the incentive to further investiga- 
tions. 
In the following pages we shall attempt to bring before the 
reader the most important of the technicalities of injecting, and 
to render especially prominent that which we have learned from 
our own experience in regard to this subject. At the same 
time we are quite willing to admit that others might have re- METHOD OF INJECTING. 
173 
placed many things that are here noticed with much that would 
perhaps have been better. Although all such directions are 
not capable of thoroughly supplying that which may be ob- 
tained much more rapidly from the practical instruction of an 
experienced teacher, they will, nevertheless, present serviceable 
hints to many autodidacts. 
It will not be without interest, however, to previously give 
a cursory glance at the history of the origin of this art. 
The art of injecting, filling the canal systems of the body 
with colored or other readily recognizable masses, is, in its first 
crude commencement, relatively an old one. Hyrtl, in his im- 
portant “ Handbuch der praktischen Zergliederungskunst,” 
Wien, 1860, has given us an accurate and interesting history 
of this process. As early as the seventeenth century, wax and 
also mercury were used for this purpose. Gelatine was first 
employed for injections in the beginning of the eighteenth cen- 
tury. 
Among the older anatomists, the Hollander, Huysch (1638- 
1731), through his methods of injecting, obtained great renown 
—undeservedly, as we are at present, after accurate historical 
investigations, obliged to say, like so many of the celebrities of 
older and newer times. Tallow (tempered, in part, with-wax), 
colored with cinnabar, formed the mass used by him. IST. 
Lieberkuhn (1711-1746), on the contrary, accomplished consid- 
erable for his time, as early as the first half of the eighteenth 
century. Even at the present time his preparations deserve to 
be called excellent, as we are assured by Hyrtl, the most com- 
petent investigator in this department. He made use of a mix- 
ture of wax, colophony, and turpentine, and, as a coloring 
medium, cinnabar. At a more recent period, Sommering, I)ol- 
linger, and Berres accomplished considerable in this depart- 
ment. Among those more recently engaged in this direction, 
the name of Hyrtl shines above all others. Others may be 
honorably associated with him, as, for example, Quekett, Ger- 
lach, Thiersch, Beale, etc. 
Naturally, the method of injecting interests us here only in 
so far as it is adapted for microscopico-histological studies, so 
that we shall pass over with entire silence the technicology of 
coarser injections. 
Among the numerous methods, two kinds may be distin- 
guished : 174 
SECTION NINTH. 
1. Mixtures which are fluid when warmed, and again become 
solid when cooled. 
2. Mixtures which flow when cold. 
Among the materials of the first kind, resinous and gelati- 
nous substances have, as was above remarked, come into use. 
Hyrtl, who, among the living, has had the greatest experience 
in this department, informs us that the former renders excel- 
lent service in the injection of glandular organs and all capil- 
lary vessels of larger diameter ; but, on the contrary, in other 
parts of the body—for example, in filling the subserous blood- 
vessels or those of the mucous membranes of the air-passages, 
the oesophagus, the stomach, the perichondrium, the medulla 
of bones and of the testicle—they are unserviceable. It is alto- 
gether an error to believe that a certain injection mixture is 
equally useful for all organs. 
The Vienna anatomist prepares a resinous mixture in the fol- 
lowing manner : He evaporates the purest copal or mastic var- 
nish to the consistence of syrup, and then mixes with it about 
one-eighth as much cinnabar, which is to be carefully rubbed 
with the varnish on a grinding-slab. A very slight addition of 
virgin wax is also made, to give the mixture more consistence. 
Some time ago I made use of such a mixture, by way of 
experiment, and saw how, with a little practice, very handsome 
objects might be obtained, if the preparations were not required 
for finer histological studies, but rather for use with weaker 
magnifying powers. 
Those who desire to investigate the finer structure of the 
organ to be injected should, therefore, have recourse to gela- 
tine. The low degree of temperature at which a gelatine injec- 
tion is possible, although not sufficient for the resinous injec- 
tion, is an advantage which cannot be too highly prized. Yery 
properly, therefore, histologists have preferred the use of gela- 
tinous mixtures for their injections, Sommering and Dollinger 
having even in olden times accomplished excellent results with 
the same. The subsequent drying which ensues with the ordi- 
nary older methods of preservation is accompanied by a certain 
shrinking of the tubes which have been filled, an evil which is 
induced by the loss of water ; so that such objects frequently 
do not exhibit the full, firm appearance presented by the resi- 
nous preparations. Nevertheless, the much greater readiness 
with which the watery solution of gelatine passes through the METHOD OF INJECTING. 
175 
vessels whose walls are moistened with water is an advantage 
which can be obtained with no other mixture which solidifies, 
especially for organs with narrow capillaries. Moreover, this 
shrinking may be considerably limited by careful mounting. 
Disregarding the coloring materials at present, in order to 
prepare such a solution of gelatine and afterwards make use 
of it, several precautionary measures are necessary. 
Isinglass, as a relatively pure gelatine, has been frequently 
used. It is in no wise necessary, and its high price and the 
slowness with which it hardens in cooling are to be designated 
as disadvantages. More recently I have frequently used the 
thin, transparent gelatine tablets which are met with in com- 
merce as “ Gelatine de Paris,” and which constitute, it is true, 
a mixture which is also not to be numbered among the cheapest. 
The latter may be formed, however, from the better sorts of or- 
dinary Cologne gelatine. 
For dissolving gelatine the process most to be recommended 
is the following; 
The gelatine is to be broken to pieces and then soaked in 
distilled or rain water for several hours. The water is to be 
poured off and renewed, the gelatine is then to be dissolved in 
a water bath, never immediately over the fire, and the solution 
filtered through flannel into a porcelain dish. The coloring 
material, the necessary directions for which follow further 
below, is to be added to the solution while it is still warm. The 
consistence which is to be given to the gelatine mixture should 
be dependent on the individual circumstances. A thin gelatine 
ffnid is sufficient, if a pulverized granular coloring matter is 
added in the form of a thick pulp. If the coloring material is 
directly precipitated in the injection fluid by pouring together 
solutions of two kinds of substances, a saturated gelatine fluid 
should be employed. With a little practice one soon learns to 
flit upon the proper proportions.* 
In using such an injection fluid it is to be warmed in the 
same manner, for which purpose the same dish may be used 
several times in rapid succession. Such a fluid cannot be kept 
for a long time, however (even in a camphorated atmosphere), 
without moulding, or even without losing its former homoge- 
neous constitution, which is so important; so that one is often 
* The addition of glycerine is often useful. 176 
SECTION NINTH. 
put to tlie unpleasant, time-consuming necessity of preparing 
the gelatine lluid anew.* 
For the further treatment of specimens injected with gela- 
tine, see the end of this section. 
Quite a variety of coloring materials may be advantageously 
added to the gelatine fluid; they will be mentioned further below. 
The use of injection mixtures which solidify on cooling al- 
ways consumes time, as was remarked, and requires a variety 
of arrangements. The discovery of a material which is fluid 
when cold, and which may be used at any time, must therefore 
appear to be of great value. A number of such mixtures have 
been invented and recommended in the course of time. 
We will first mention a process practised by Bowman, the 
English histologist, which, although it may be momentarily 
employed, is less serviceable for producing a good injection than 
for coloring the blood-vessels of an organ and rendering them 
visible for microscopic examination. This method consists in 
forcing two solutions of salts after each other through the same 
vascular system, in which a lively colored precipitate is thus 
produced. Bowman used for this purpose the acetate of lead 
and the chromate of potash. A few experiments which I once 
made with this method gave a satisfactory view of the course of 
the vessels. But such a preparation is by no means beautiful. 
For his cold injections, as he informs us in his “Zergliede- 
rungskunst,” Hyrtl also employs the previously mentioned re- 
sinous mixture, to which he gives the consistence of an ordinary 
coarse injection fluid by the addition of a little wax and red 
lead. He rubs a portion of the same in a dish, with the addi- 
tion of ether, to the consistence of syrup. He then adds the 
coloring material, in about the proportion of 1:8, and again 
rubs the whole with ether until the mixture becomes completely 
fluid. Hyrtl commends the facility and convenience of manip- 
ulation of this method. In consequence of the evaporation of 
the ether, the injected organ is ready for examination in a 
quarter of an hour. 
I have of late made the most extended use of a mixture re- 
commended by Beale (“The Microscope in its Application to 
Practical Medicine.” London, 1858, p. 67), which is composed 
of glycerine, water, and alcohol, for filling the smaller vascular 
* More recent recipes of Thiersch and others follow below (p. 185). 177 
METHOD OF INJECTING. 
systems. This mixture excels all others with which lam ac- 
quainted for its facility of penetration, besides which it affects 
tile tissues less than any of the mixtures in use. As the mix- 
ture does not become decomposed or altered in any way, it may 
be preserved for any desirable length of time. It is par excel- 
lence the histologist’s injecting fluid, and when the preparations 
are mounted moist they present a most exquisite appearance. 
It has also afforded me very passable results when mounted 
dry by means of Canada balsam prepared in a special manner. 
Still the gelatine fluids are preferable for the latter preparations, 
and, in consequence of their consistence, they are indispensable 
for injecting the larger organs. 
Having discussed the injecting fluids which are at present 
generally made use of, let us now pass to the consideration of 
the coloring materials which may be employed with the same. 
These coloring substances may be divided into granular, per- 
mitting of examination only with incident light, and transpar- 
suitable for ordinary histological investigations. Those of 
the first series are very numerous and were alone employed for 
the older injections. The number of the latter is, on the con- 
trary, much smaller, consisting at the present time of only a 
few coloring materials. 
If resinous mixtures are used, it is most convenient to em- 
ploy the finest oil colors for artists, which are to be purchased 
m thin leaden tubes—a procedure made use of by Hyrtl. 
Among these “colors in tubes,” the Vienna naturalist recom- 
mends for red, Chinese vermilion ; for yellow, orange chrome 
yellow ; for green, emerald green and verdigris ; for white, 
Nottingham white and Cremnitz white; for blue, a mixture 
which he prepares from the last white color and Prussian blue. 
These colors are expensive, it is true, but are of a fineness 
such as no one can prepare for one’s self. They are therefore 
to be designated as of the first rank for opaque injections. 
If gelatine is used as the solidifying substance, it is custom- 
ary to employ red, yellow, or white fluids. 
a. Red Mixture (Cinnabar). 
Cinnabar is most commonly employed for this purpose. 
Commencing with a small quantity of a fine quality, it is to be 
rubbed up as carefully as possible in a mortar, with the grad- 178 
SECTION NINTH. 
ual addition of water, and the process continned in this man- 
ner. A little carmine may be rubbed np with it, to heighten 
the color. The coloring matter is then to be gradually added 
to the warm gelatine solution, which is, at the same time, to be 
carefully stirred. It is a common fault of beginners that they 
use too little cinnabar, and hence they obtain an injection fluid 
with which separated scattered granules of coloring matter 
afterwards appear in the vessels. A good cinnabar injection 
should, on the contrary, yield a coherent coralline red color. 
In consequence of its considerable weight, cinnabar has the un- 
pleasant peculiarity of collecting at the bottom of the gelatine 
solution, so that it is necessary to stir the mass before its use. 
None of the other opaque coloring materials should be used 
in the form of the commercial preparations, unless they can be 
given to a professional color-rubber for pulverization, as it is 
otherwise impossible to reduce the granules to the necessary 
fineness. It is much preferable to procure them by careful 
precipitation from diluted solutions. 
b. Yellow Color (Chrome yellow). 
I regard this as the best and most readily manageable of all 
the opaque coloring materials. In order to obtain a good 
chrome yellow, 36 parts by weight of sugar of lead may be 
dissolved in 2 ounces of water, and likewise, in the same quan- 
tity of water, 15 parts of red chromate of potash. By care- 
fully mixing these fluids, preferably in a high glass cylinder, a 
very finely granulated chromate of lead is produced, which is 
gradually deposited at the bottom of the vessel. This is to be 
washed with distilled water and then added, in the form of a 
thick slime, to the gelatine solution. 
Harting (in his work on the Microscope, Yol. 11., p. 123) 
gives the following recipe (which I have also found to be ser- 
viceable) : 
4 ounces 1|- drachm of acetate of lead, or sugar of lead, is 
to be dissolved in a quantity of water sufficient to make the 
whole volume 16 ounces. 
2 ounces 1 drachm 28 grains of bichromate of potash are to 
be dissolved in a quantity of water sufficient to make the 
whole volume 32 ounces. In preparing the injecting fluid, 
take one part by measure of the solution of sugar of lead, 2 METHOD OF INJECTING. 
179 
parts by measure of the solution of chromate of potash, and 
likewise 2 parts by volume of a saturated solution of gelatine. 
The chrome-yellow is to be first precipitated in a special ves- 
sel, and afterwards added to the gelatine. The precipitated 
chrome-yellow should not be allowed to stand too long, as it 
assumes a coarse granular form, in consequence of the con- 
glomeration of the colored molecules. 
c. White Color. Carbonate of Lead. Zinc White. Sulphate 
of Baryta. 
A serviceable white fluid can only be obtained with diffi- 
culty, as in most of them the granules are usually too coarse. 
Harting, who instituted a series of experiments on this sub- 
ject, gives the following recipe for producing a useful carbon- 
ate of lead : 
4 ounces drachm of the acetate of lead are to be dissolved 
in water, so that the whole corresponds to a volume of 16 
ounces. 
3 ounces drachm of carbonate of soda are to be dissolved 
m water, and the whole likewise made up to 16 ounces. 
For the injection fluid, take one part by measure of the 
Hist solution, the same quantity of the second, and combine 
them with two parts of gelatine solution. Harting remarks 
concerning this fluid, that it passes through the vessels better 
than white lead combined with gelatine. 
I formerly obtained tolerable injections with finely-pulver- 
ized zinc white. I have not used this coloring material, how- 
ler, for years. 
As a very fine white, although the color does not assume 
such complete uniformity, I recommend the sulphate of 
baryta. I made the most extended use of this material years 
ago, and am inclined to prefer it to the chrome-yellow, when it 
is necessary to have a finely-granulated and therefore readily 
penetrating fluid, though the preparations are less beautiful. 
I employ the following process :—The salt in question is to 
be precipitated from about 4 to 6 ounces of a cold saturated 
solution of chloride of barium, in a glass cylinder, by the care- 
ul addition of sulphuric acid. After standing for some time, 
nearly the whole of the fluid, which has again become clear, is 
to be poured off, and the remainder, with the sulphate of ba- 180 
SECTION NINTH. 
ryta, which is deposited at the bottom of the vessel, is to be 
added, in the form of a thick slime, to about an equal volume 
of a concentrated solution of gelatine. 
d. Chloride of Silver. 
Teichmann, in his excellent work, mentions a new, very effi- 
cient, although expensive injecting mixture of chloride of sil- 
ver. He commends the same as rendering excellent service in 
certain cases, and says that its molecules possess a very con- 
siderable fineness, occasionally similar to those of chyle. It 
is an unpleasant circumstance that the mixture becomes black 
from the action of the light and sulphuretted hydrogen. But, 
like sulphate of baryta, the combination is so fixed that decom- 
position does not take place with the employment of reagents, 
and the specimens may be preserved in chromic acid, etc. 
Three parts of nitrate of silver in solution are to be com- 
bined with the solution of gelatine, and then one part of com- 
mon salt is to be added. 
Considerably superior to these granular substances are the 
transparent coloring materials, that is, those whose particles 
are so fine that even with high magnifying powers the injected 
vessels still show a homogeneous color. Such injections are 
particularly to be recommended for histological investigations, 
as it is by their use only that it is possible to recognize the re- 
maining structural conditions, while a complete injection with 
opaque mixtures conceals, more or less, the finer structure of 
the organ. They will be substituted for the granular coloring 
materials by any one who has used them a few times when 
well prepared. The reproach which has here and there been 
made concerning these colors that they transude, refers only to 
those which are badly made, but is not applicable to good 
transparent materials. Unfortunately, the number of these 
is, as yet, but very small. Until recently, besides the soluble 
Prussian blue, there was only a red coloring material, carmine, 
known. Professor Thiersch, who has earned so much credit by 
his methods of injecting, has recently enriched us with a solu- 
ble yellow and green, and was so friendly as to communicate 
to me their composition. 
We shall first speak of such of these coloring materials as 
are adapted for gelatine injections. METHOD OF INJECTING. 
181 
A number of different mixtures are at present known un- 
der the name of transparent Prussian blue. Of these, the 
second receipt deserves but little recommendation, as the blue 
color gradually fades, especially when the preparation is pre- 
served in glycerine. The first coloring material is, on the con- 
trary, excellent, and the last is also very much extolled. 
Nevertheless, I know of no Prussian blue which lasts longer 
than ten years in injection preparations. In this regard the 
excellent coloring matter stands infinitely behind carmine. I 
have lost hundreds of the most splendid injection preparations 
in this manner to my greatest sorrow. 
1. Thiersch's Prussian Blue with Oxalic Acid. 
The best receipt with which I have become acquainted runs 
as follows : 
Prepare a cold saturated solution of the sulphate of the 
protoxide of iron (A), a similar one of ferrocyanide of potas- 
sium, that is, prussiate of potash (B), and thirdly, a saturated 
solution of oxalic acid (C). Finally, a warm concentrated solu- 
tion (2 :1) of fine gelatine is necessary. About half an ounce 
of the gelatine solution is to be mixed in a porcelain dish with 
6 ccm. of the solution A. In a second larger dish, one ounce 
of the gelatine solution is to be combined with 12 ccm. of the 
solution B, to which 13 ccm. of the oxalic acid solution C is 
afterwards added. 
When the mixtures in both dishes have cooled to about 25 
or 32° C., the contents of the first dish are to be added drop- 
wise, and with constant stirring, to the mixture in the latter. 
After complete precipitation, the deep blue mixture which is 
formed is to be heated to 70 or 100° C. for a time and constantly 
stirred ; finally, it is to be filtered through flannel. 
The injecting fluid thus obtained keeps excellently in Can- 
ada balsam. The depth of its color may be readily modified 
to any desired degree by adding a larger quantity of the gela- 
tine solution. 
2. Prussian Blue dissolved in Oxalic Acid. 
A pure Prussian blue, preferably one that has been obtained 
by precipitation, is to be dissolved with the necessary quantity 
of oxalic acid. The color is certainly very intense, so that a 182 
SECTION NINTH. 
moderate quantity is sufficient to give a lively blue color to a 
dish of gelatine solution. This mixture, like all transparent 
coloring matters, in consequence of the infinite fineness of its 
granules, readily passes through the fine capillaries. 
Harting recommends the following method (in which the 
quantity of oxalic acid appears too great):— 
Take 1 part of Prussian blue, 1 part oxalic acid, 12 parts 
water, and 12 parts concentrated solution of gelatine. First, 
rub the oxalic acid in a mortar, and then add the Prussian 
blue. Thereupon the water is to be gradually added while con- 
stantly rubbing, and finally this blue fluid is to be added to 
the gelatine. 
8. Prussian Blue from Sulphate of Peroxide of Iron and 
Ferrocyanide of Iron. 
This color, which was first employed by Schroder van der 
Kolk and afterwards recommended by Harting, is a good one, 
although it requires somewhat more time for its preparation. 
Its granules are extremely fine, and hence it flows very readily. 
Nevertheless, the older preparations of my collection have 
lately become considerably faded, so that I rather prefer 
Thiersch’s blue. 
I have used the blue made exactly according to Harting’s 
receipt, so that I can only recommend that. 
8i ounces of sulphate of iron is to be dissolved in from 20 to 
25 ounces of water and slightly warmed. Then, by the addi- 
tion of 4f drachms of sulphuric acid, of 1.85 sp. wt,, and the 
necessary quantity of nitric acid, the iron is changed to an 
oxy-salt. A sufficient quantity of water is then added to make 
the whole volume of fluid 40 ounces. 
8 ounces 6f drachms of ferrocyanide of potassium (yellow 
prussiate of potash) is to be dissolved in water, and the whole 
volume of fluid increased to 80 ounces. 
1 part by measure of the solution of oxide of iron, 2 parts 
by measure of the solution of yellow prussiate of potash, and 
likewise 2 parts of the gelatine solution are to be employed. 
In order to prevent the gelatine from collecting in lumps 
and becoming ropy, I recommend the following method. The 
solution of ferrocyanide of potassium should be warmed and 
combined with the heated solution of gelatine. The solution METHOD OF INJECTING. 
of sulphate of protoxide of iron is then to be added by drops, 
and while constantly stirring the mixture, which is finally to 
be filtered through flannel. 
4. Soluble Prussian Blue. 
This is obtained by adding to a solution of ferrocyanide of 
potassium in excess, a solution of perchloride of iron, or of 
another oxy-salt. The precipitate is to be collected on a filter, 
and after the fluid has filtered away, again washed with dis- 
tilled water till (after the removal of the salts which were in 
the solution) a blue color begins to appear in the filtrate. The 
blue mass which is thus obtained becomes so finely divided in 
water, that the impression of a solution arises. 
Several years ago Briicke recommended the following re- 
ceipt for preparing such a soluble Prussian blue : 
Ferrocyanide of potassium 217 grammes, dissolved in 1 litre 
of distilled water. 
Percliloride of iron 10 grammes, in 1 litre of distilled water. 
Sulphate of soda, a cold saturated solution. 
One volume of each of the two first solutions is to be mixed 
with one volume of the soda solution. The iron and soda solu- 
tion is then to be gradually mixed with the ferrocyanide and 
soda solution with constant stirring. 
Sections of organs injected in this manner often appear col- 
orless, but subsequently assume the blue color in oil of turpen- 
tine. They fade subsequently, however. 
5. GerlacJi- s Carmine Fluid. 
A good carmine mixture remains unexcelled as a transpar- 
ent red. This substance requires careful preparation, it is true, 
and when not properly prepared it is completely useless, as it 
transudes in all directions. Well prepared, it is of the first 
rank and of the greatest durability. 
Professor Grerlach, the inventor of the method of injecting 
with carmine, has had the kindness to communicate to me the 
composition of the fluids used by him, and to permit me to 
make them public. 
Dissolve 5 grammes of the finest possible carmine in 4 
grammes of water and i- grm. of liquor ammonia. The mix- 184 
SECTION NINTH. 
tnre should be allowed to stand for several days in a vessel not 
closed air-tight, and then mixed with a solution containing 6 
grammes of fine white French gelatine to 8 grm. of water. A 
few drops of acetic acid are then to be added, and the mixture 
injected at a temperature of 40-45° C. 
I have made the most extended use of carmine fluids for a 
long time, and recommend, after many trials, the following 
method : 
Have ready a solution of ammonia and one of acetic acid, of 
which the number of drops necessary to neutralize each other 
has been previously determined. 
Take 30-40 grains of the finest carmine, a determined num- 
ber of drops of the solution of ammonia (the quantity may be 
greater or smaller as may be desired), and about half an ounce 
of distilled water; all of these are to be put in a mortar, and 
the carmine dissolved by rubbing. The solution is then to be 
filtered, which requires several hours, and a considerable loss 
of ammonia ensues in consequence of evaporation. 
The ammoniacal solution of carmine is to be mixed with a 
filtered, moderately-heated concentrated solution of fine gela- 
tine while stirring. The whole is then to be slightly heated on 
the water-bath, and the number of drops of the acetic acid so- 
lution necessary to neutralize the original solution of ammonia 
is to be slowly added, still constantly stirring the mixture. 
By this procedure a precipitation of the carmine in an acid 
solution of gelatine is obtained. If it be intended to inject 
organs of strongly alkaline reaction (for instance, those of 
human bodies which have been dead for some time), the acid- 
ity of the fluid may be increased by the further addition of 
several drops of acetic acid. The proportion of gelatine is to 
be increased or diminished according as a deeper or brighter 
red is desired. 
This simple procedure never fails, if the carmine used be of 
a good sort (which is of great importance), and an increase of 
temperature beyond about 45° C. be avoided during the injec- 
tion. 
A more rapid process is to thoroughly dissolve carmine in 
ammonia, add the coloring matter to the hot gelatine, precipi- 
tate with acetic acid, and filter the whole through flannel. The 
latter process suffices completely for the expert. 
For the preservation of such a fluid—and, we might add, of METHOD OF INJECTING. 
185 
other injection fluids containing gelatine—add a small quantity 
of carbolic acid dissolved in distilled water. 
Thiersch proceeds otherwise. He adds sulphate of quinine 
to the water used for dissolving the gelatine, in the propor- 
tion of 0.25 grms. to 80 grms. of dry gelatine, and, in addition, 
boils pieces of camphor with it. 
6. Thiersch's Transparent Yellow. 
This beautiful yellow, which requires some care, however, 
to prepare it well, is to be obtained in the following manner : 
Prepare a watery solution of chromate of potash, in the 
proportion of 1:11 (A), and a second solution, equally strong, 
of the nitrate of lead (B). 
Combine one part of the solution A with four parts of a 
concentrated solution of gelatine (about 20 ccm. to 80) in a 
dish. In a second dish, two parts of the solution of lead 
CB) is to be mixed with four parts of gelatine (about 40 ccm. 
to 80). 
The contents of both dishes are then to be slowly and care- 
fully mixed with each other at a temperature of about 25-32° 
C., and with constant stirring. This mixture is to be heated 
to about 70 or 100° C., on the water-bath, for a considerable 
time (half an hour or more), and finally filtered through flan- 
nel. 
When a dish of this yellow mixture has stood for some time, 
it is generally necessary to heat it for a considerable time and 
filter it again, in order to render it serviceable, I have used a 
double quantity of the solutions A and B for many purposes 
with advantage. 
7. Hoyef s Transparent Yellow. 
Hoyer recommends the following mixture as a yellow of the 
finest division, which also appears transparent in the smaller 
vessels and has a lively color:— 
Equal parts of a solution of gelatine, a concentrated solu- 
tion of bichromate of potash, and the same of sugar of lead (the 
neutral acetate of lead), are to be combined with each other in 
such a manner that the solution of gelatine and that of the bi- 
chromate of potash are united, and then heated nearly to the 186 
SECTION NINTH. 
boiling point. To this is carefully added the sugar of lead so- 
lution, which should also be previously warmed. 
This mass, according to my experience, stands after 
Thiersch’s yellow. 
8. Robih s Yellow Mass. 
He recommends a saturated solution of the sulphate of cad- 
miumoxyd, 40 ccm. with .60 ccm. glycerine ; then a concen- 
trated solution of the sulphate of soda, 30 ccm. with 50 ccm. 
glycerine. Both fluids are carefully united by stirring and 
added to gelatine in the proportion of 1: 3. The color is beau- 
tiful to the naked eye, but is unfortunately coarse-grained and 
bad. 
9. Thiersch! s Transparent Green. 
Equal parts of the blue gelatine solution as used by Thiersch, 
and the yellow one mentioned under 6, when carefully mixed, 
heated for some time, and then filtered, make a good and hand- 
some green. 
10, Robin! s Green. 
Take 80 ccm. of a concentrated solution of arsenite of pot- 
ash with 50 parts of glycerine. A second fluid consists of 40 
ccm. of a saturated solution of copper oxyd, combined with 50 
ccm. of glycerine. Combine them and add to one part of the 
green substance three parts of gelatine. 
Many transparent coloring materials are capable of a more 
advantageous application, however, than being combined with 
gelatine. They are combined with a peculiar mixture which 
flows when cold, and in this manner are obtained the best injec- 
tion fluids yet known for histological investigations. 
As we have made frequent use of them, the compositions 
used follow. 
1. Beale! s Ordinary Blue. 
Dissolve 15 grains of ferrocyanide of potassium with 1 ounce 
of distilled water in a flask. Dilute from a drachm to 2 
scruples of the English muriated tincture of iron with another 
ounce of water. It is well to have this tincture of sesquichlo- METHOD OP INJECTING. 
187 
ride of iron accurately prepared according to the British phar- 
macopoeia, by a good apothecary, in sufficient quantity to last 
for some time. The latter fluid is added by drops to the former, 
at the same time shaking it smartly. A mixture is then pre- 
pared of water 2 ounces, glycerine 1 ounce, ordinary (ethyl) al- 
cohol 1 ounce, and meth3d alcohol li drachm. * This mixture 
is to be carefully added to the blue colored fluid, the flask be- 
ing smartly shaken during the process, and the charming blue 
injection fluid is ready for use. 
2. Beale's Finest Blue. 
Beale has recently (“How to work with the Microscope.” 
Third edition, p. 200) given a modified formula for the prepa- 
ration of a cold flowing blue injection fluid, which, when well 
prepared, surpasses all others that I know of in fineness, so 
that after standing quietly for weeks the appearance of a solu- 
tion remains unchanged, and there is not the least sediment 
formed. I prepare it, somewhat modified, in the following 
manner:— 
Combine 10 drops of the muriated tincture of iron mentioned 
with half an ounce of good glycerine in a flask ; in another 
hask 8 grains of ferrocyanide of potassium dissolved in a little 
water, to which is to be added another half ounce of glycerine. 
Both solutions are then to be very carefully mixed together, 
shaking them smartly, and finally half an ounce of water with 
3 drops of strong muriatic acid is to be added. 
3. Bichardson's Blue. 
B. Wills Richardson (Quart. Journ. of Micr. Science, Yol. 
8> p. 271) recommends another composition. 
10 grains of pure sulphate of iron is to be dissolved in 1 
ounce of distilled water, and 32 grains of ferridcyanide of po- 
tassium in another ounce of water. As with Beale’s blue, 
these two solutions are then gradually mixed together in a 
bottle, the iron solution being added to that of the ferridcyan- 
ide, and mixture insured by frequent agitation. This makes a 
* The methyl alcohol in this and the third formula is a superfluous addition, and 
in consequence to be omitted. 188 
SECTION NINTH. 
beautiful greenish blue, in which there is as little appearance 
of granules to be recognized with the naked eye as in Beale’s 
mixture. Then the mixture mentioned under No. 1, consisting 
of water, glycerine, and the two alcohols, is to be carefully 
added and considerably shaken. 
4. Muller* s Blue. 
W. Muller prepares in a simple way a cold flowing blue 
mixture by the precipitation of soluble Prussian blue from a 
concentrated solution by means of 90 per cent, alcohol. The 
coloring matter is thus precipitated in a state of most extreme 
fineness, and a completely neutral fluid is obtained. 
5. Beale* s Carmine. 
Mix 5 grains of carmine with a few drops of water, and 
when well incorporated add from five to six drops of liquor 
ammonia. To this solution about half an ounce of glycerine is 
to be added, and the -whole well shaken. Another half-ounce 
of glycerine, containing eight or ten drops of concentrated ace- 
tic or hydrochloric acid, is to be slowly and gradually added to 
the carmine solution, frequently shaking during the mixture. 
The carmine thus becomes very finely granular, and the whole 
assumes a bright arterial red color. For its dilution a mixture 
is used consisting of half an ounce of glycerine, 2 drachms of 
ordinary alcohol, and 6 drachms of water. 
6. White Fluids. 
As I have not, as yet, been able to find a third transparent 
coloring material for cold flowing injections, I have used an 
opaque mass, the sulphate of baryta. The mass is, as was re- 
marked, very finely granular, and is capable of being combined 
with a blue, if it be desired to inject the arteries and veins sep- 
arately. I employ the following process : 
The salt is reprecipitated from a cold saturated solution of 
4 ounces of chloride of barium by adding, drop-wise, sulphuric 
acid. After standing for some time {l2 to 24 hours) in a tall 
cylindrical glass vessel, it is deposited at the bottom. About 
half the fluid, which has again become clear, is now to be METHOD OF INJECTING. 
189 
poured off, and the remainder, well shaken np, is to be com- 
bined with a mixture of one ounce each of alcohol and glyce- 
rine. 
These masses'*—we repeat it—are distinguished by their 
great permeability, so that we prefer them to all gelatinous sub- 
stances for the injection of lymph passages and glandular 
canals. They also have the extraordinary advantage of being 
capable of preservation for mouths without alteration, so that 
they are instantly at hand. They are kept in small bottles 
with well-fitted glass stoppers. The requisite quantity for an 
injection is poured into a porcelain dish, and it is then ready 
for use.f 
7. Solution of Nitrate of Silver. 
Within a few years a solution of nitrate of silver has been 
nsed for injections, in order to render the cells of vessels visi- 
ble. The animal is bled to death, a solution of nitrate of sil- 
ver (0.25, 0.5-1 per cent.) is then injected, which is to be fol- 
lowed after a few minutes by a stream of water ; or, a mixture 
°f gelatine and a solution of nitrate of silver is used, in order 
to gain a more permanent distention. Sections of the organ 
are made and exposed to the light, and then hardened in 
*W. Miiller, in his excellent monograph on the spleen, also mentions a cold 
flowing, brownish red mass, which is obtained by precipitation from a solution of 
the chromate of copper with ferrocyanide of potassium. Chromate of copper is 
obtained by digesting equivalent portions of sulphate of copper with chromate of 
potash, and washing out the brown precipitate. The latter readily dissolves in 
chromic acid in excess, and may be precipitated from the diluted solution, by means 
°f ferrocyanide of potassium, in the form of an extremely fine brownish-red sedi- 
ment of ferrocyanide of copper. It may be at once injected, without further addi- 
tion than the solution of bichromate of potash which has been formed, and thus, at 
the same time, serve as a medium for hardening the tissue. 
f I have recently employed with advantage soluble Prussian blue simply dissolved 
m Wa-ter for the injection of the ducts of glands, urinary canals, and biliary plexuses, 
also for lymphatic canals. 10 grains of sulphate of iron dissolved in 1 ounce of 
water, 32 grains of red prussiate of potash in another ounce of water, and both care- 
fully combined (see above), make a good fluid. If the canals to be filled are very 
fine, double the quantity of each salt is to be added to each ounce of water. Gly- 
cerine may be added if desirable. The red mixture recommended by Kollmann is 
serviceable. 1 gramme of carmine is to be dissolved in a little water with 15-20 
drops of concentrated ammonia, and diluted with 20 ccm. glycerine. An additional 
-0 ccm. of glycerine is to be tempered with 18-20 drops of strong muriatic acid and 
carefully added to the carmine solution, at the same time shaking the latter strongly. 
It may be subsequently diluted by the addition of about 40 ccm. of water. 190 
SECTION NINTH. 
alcohol. By this simple method the entire vascular arrange- 
ment may also be recognized with the same distinctness as by 
the ordinary injections with colored masses. 
After having become acquainted with the fluids used for in- 
jecting, and the manner of preparing them, we now pass to the 
consideration of the apparatus and the act itself of injecting. 
All who have frequently practised this operation will agree 
with us that a very simple apparatus is all that is required. 
Before discussing the method of injecting which is most 
important and most frequently used, namely, that by means 
of the syringe, it is necessary to mention several other modern 
processes which, according to our own experience and that of 
others, may be practised with facility and success, and will, 
without doubt, lead to the extension of our knowledge in 
many directions—we mean the self-injection of the living ani- 
mal and the injection by means of constant pressure. 
The idea was sufficiently obvious of permitting the escape 
of a definite quantity of blood from the body of the living 
animal by opening a vein, and replacing what was lost by an 
innocuous colored fluid, so that the contractions of the heart 
would fill certain vascular districts with it in a much less 
injurious manner than can be accomplished by the human 
hand. 
Chrzonszczewsky made us acquainted with these methods 
some time since. They consist in the introduction of the wa- 
tery solution of the carminate of ammonia. 
10 ccm. of blood may be removed from the jugular of a 
medium-sized rabbit, and replaced by the same quantity of a 
solution of carmine, by means of the syringe to be mentioned 
below, without injury to the blood with which it becomes 
mixed. An adult animal bears 15 ccm., a dog of medium size, 
25. Even during the injection, the reddening may be recog- 
nized on certain portions of the surface. If the larger vessels 
are then rapidly ligated, first the vein and then the artery, a 
physiological injection of the blood passages is obtained. The 
kidneys, spleen, etc., may be advantageously treated in this 
manner. At the same time, this carmine injection may be 
accomplished not only from the vascular system, but also from 
the stomach, rectum, and abdominal cavity, and in amphibia 
from the lymph cavities. 
The inventor recommends the solution of 2 drachms of car- METHOD OF INJECTING. 
191 
raine in 1 drachm of liquor ammonia, the same to be diluted 
with one ounce of water. Naturally, this solution is to be fil- 
tered before using. The organ is to be placed in acidulated 
alcohol to cause the granular fixation of the carmine. 
Such injections obtain a high value in still another manner 
Not only this carmine solution, but also a cold concentrated 
solution of sulph-indilate of soda is rapidly excreted by the 
kidneys, and the latter substance also into the biliary passages 
after large quantities have been injected. If the ureter be 
ligated immediately after injecting the rabbit, and the animal 
killed after three-quarters of an hour to one hour, the entire 
system of urinary canals will be found filled with carmine. 
In injecting the biliary passages with the blue fluid, it is un- 
necessary to apply the ligature. In both cases, however, it is 
necessary to wash the blood-vessels subsequently, and to re- 
place the original coloring-matter which remains in them with 
another. The organs injected with blue are next placed in a 
concentrated solution of chloride of calcium, and then in abso- 
lute alcohol, where the coloring matter becomes fixed in fine 
granules. 
Heidenhain has recently given more accurate directions for 
Ike use of indigo-carmine in the study of the kidneys. 
The ordinary commercial indigo-sulphate of soda is an im- 
pure product, a variable mixture of various substances, gener- 
ally three in number : a, the indigo blue-sulphate ; b, the in- 
digo blue-hyposulphate ; and c, the phoenizine-sulphate of 
soda. The chemically pure soda (or potash) combinations act 
ln an entirely different manner for our purpose. 
The former salt is readily soluble in water, nearly insoluble 
ln absolute alcohol, but more readily soluble in alcohol con- 
taining water. It is completely precipitated from its solutions 
ky concentrated solutions of salt. 
ITie second salt, on the contrary, is soluble in water as well 
as in absolute alcohol, and is not precipitated by neutral salts. 
The third combination, the phoenizine sulphate salt, is of 
niuch more difficult solution in water than a, is precipitated by 
a slight addition of salt, and is readily dissolved in alcohol. 
For the following purpose, Heidenhain found only the 
combinations a and c useful, and the salt b was quite unsuit- 
able and pernicious. 
A rabbit of medium size requires about 25-50 ccm., a me- 192 
SECTION NINTH. 
dinm sized dog 50-75 ccm. of a cold saturated solution of the 
indigo blue sulphate of soda. Since we have gone so far, we 
will also give the remainder of Heidenhain’s method. When 
the animals have passed blue urine for a time, they are to be 
killed by bleeding and the kidneys examined in part immedi- 
ately, fresh in thin sections, in part after fixation of the coloring 
matter and subsequent hardening in absolute alcohol. For the 
former purpose it is best to inject the renal vessels instantane- 
ously with absolute alcohol. 
Heidenhain also discovered an excellent method for the self- 
injection of the biliary passages of the frog. A piece of indigo 
carmine, about the size of a pea, is placed in the lymph sac of 
the thigh, the wound of the skin is then closed as firmly as 
possible with a string. The biliary passages of the animal are 
found to be splendidly injected after twenty-four hours. 
We have recently, through Thoma and Arnold, become ac- 
quainted with a remarkable and astonishing action of indigo 
carmine. Brought in a proper manner, through a vein, into the 
blood passages of a living frog, it stains the homogeneous sub- 
stance which cements the epithelial cells, the so-called “ cement 
substance.” We shall return to this subsequently. 
Injecting by means of constant pressure also has great ad- 
vantages for many purposes. First, we may learn by this 
means to estimate the pressure which is necessary to fill certain 
portions of the blood and lymph passages, or of the glandular 
canals; then, besides a very high pressure we can also use a 
very low one, and finally it permits of making the injection 
with extreme slowness, which the human hand refuses to do, 
in consequence of fatigue. 
Beautiful results have been obtained by this method for the 
lymphatic passages and also for the glandular canals (kidney 
and liver). 
A simple way of making such injections is by means of a 
graduated glass tube (fig. 88 5), which should not be too small, 
held by a support (a). To the lower end of this is firmly 
secured an india-rubber tube (c), the lower extremity of which 
terminates in a metallic tube which can be closed by means of 
a cock (fig. 88 d, 89); this tube should fit into the aperture of 
the canules of the ordinary injecting apparatus. The canule 
should be tied into the vessel of the organ to be injected, in 
the manner hereafter indicated, and placed in a convenient 193 
METHOD OF INJECTING. 
position near the glass tube, which is secured in a perpendicu- 
lar position, having been previously tilled to a certain height and 
the stop-cock turned off. The end of the tube is to be cau- 
tiously but securely inserted into the aperture of the canule 
and the cock opened. The original pressure may be maintained 
Fig. 89. Tube with, 
stop-cock. 
Pig. 88. Simple injecting apparatus, 
with a glass tube. 
Fig. 90. Injecting apparatus, with a column of mercury. 
or increased, as necessity may require, by pouring in more 
fluid. Sucli an arrangement may be left to itself for a number 
°f flours or even days. 
If it be desired to use the pressure of a column of mercury, 
the readily constructed apparatus, represented in less than half 
size by fig. 90, is to be recommended. A glass bottle (<2) is to be 
closed by an accurately fitting cork (preferably of gutta-perefla) 
perforated by two holes. Through these holes pass two glass 194 
SECTION NINTH. 
tubes perpendicularly ; one of them (e), which is graduated, 
and slightly funnel-shaped at the top, extends nearly to the 
bottom of the bottle. A second one (/), which is bent on itself, 
terminates Just beneath the cork. The continuation of the ex- 
ternal portion of the latter tube is formed by a caoutchouc tube 
(g) firmly secured to it, at the termination of which the above- 
mentioned metallic tube with a stop-cock (7i) is inserted and 
receives the canule (i). At the upper funnel-shaped opening 
((e) of the first tube is placed a small glass funnel (I), supported 
by a stand (Jc); the funnel is prolonged by means of a caout- 
chouc tube (m), into the lower end of which is secured a finely 
pointed glass tube {n). It is used for pouring in the mercury, 
and has on the caoutchouc tube a clamp (o), or preferably a 
screw-clamp. 
In preparing the apparatus for use, the lower part of the 
glass vessel is filled with mercury (d), the cock of the delivery- 
tube is then opened and the vessel filled to the upper edge with 
the injecting fluid. The cork with the two tubes is now to be 
firmly pressed into position, the funnel-shaped opening of the 
perpendicular tube being at the same time securely closed by 
the pressure of the thumb, care being also taken that the lower 
end of the tube dips beneath the mirrored surface of the mer- 
cury. If mercury be now poured into the funnel-shaped open- 
ing, the knee-shaped tube will become filled with the injection 
fluid, which soon issues without air-bubbles from the aperture 
of the metallic tube. The stop-cock is then to be closed and 
the end of the metallic tube carefully but firmly inserted into 
the mouth of the canule. The stop-cock should then be opened 
a second time, when the colored fluid will flow into the organ, 
and the column of mercury in the vertical glass tube will 
rapidly sink. This may be raised, by a subsequent addition 
of the metal, to an elevation of 20, 30, or 40 mm. (in many or- 
gans to double this or more), as may be desired. The flowing 
of the mercury may easily be so regulated, by means of the 
clamp, that the amount of pressure is constantly maintained A 
If the column finally ceases to sink, the injection may be dis- 
* When it is necessary to employ a very slight pressure of known degree, it is 
advantageous to bend the tube which is connected with the funnel four times at 
right angles, so that it runs downwards and again upwards, outside the bottle and 
beneath the prolongation of the level of the mercury, somewhat in the form of a 
manometer (Mac-Gillavry). METHOD OF INJECTING. 
195 
continued or the pressure cautiously increased, according to 
circumstances. 
The apparatus described serves its purpose in practical 
hands, as I know from experience. But it is defective. The 
quicksilver comes in immediate contact with the injection mass, 
and must be subsequently purified. Then and the defect 
is appreciable with a very low pressure—unpleasant momen- 
taneons increase of tlie pres- 
sure occurs from tlie pour- 
ing in of tlie quicksilver. 
An arrangement after 
the manner represented in 
fig. 91, where the inclosed 
compressed air performs 
the expulsion of the injec- 
tion mass, appears more 
suitable. The bottle A re- 
ceives the injection mass, 
which flows out through 
the rubber tube i and the 
canule 7c. This bottle is 
connected with the bottle 
which is partially filled 
with quicksilver and re- 
ceives the tube e, by means 
°f two knee-shaped glass 
tubes, the latter being join- 
ed through a rubber tube. 
The latter bottle may have 
at its bottom an exit cock. 
This arrangement is not ne- 
cessary, though it is very 
convenient. 
It is unnecessary to re- 
mark that cold fluids are here in place. It is preferable to 
use a watery solution of Prussian blue or the Richardson mix- 
ture. The apparatus Just described may also be readily used 
for injecting with gelatine (Ludwig). The bottle is to be 
placed in a tin chest of considerable size, which rests on feet 
and contains a table for the support of the organ which is 
to k6 injected. This chest is to be filled with warm water and 
Fig. 91. Apparatus for injection with mercury and 
compressed air (after Toldt). A, injection bottle; B, air 
chamber; b, c, glass tubes with connecting rubber tube ; 
d, glass tube for the column of mercury; g, and fi, appara- 
tus for securing the tubes; i, rubber tube; k, canule fast- 
ened in. 196 
SECTION NINTH. 
the temperature maintained by means of an alcohol or gas 
flame. 
A well-adapted arrangement for this purpose, designed by 
Harting, will be at once made intelligible to the reader by our 
fig. 92. We are indebted to Professor Hering, of Vienna, for 
an excellent apparatus for such injections. By it the pressure 
on the fluid may be accurately measured and uniformly main- 
Pig. 92. Karting’s injection chest, a, chest; c, false bottom for the injection bottle ;/, thermometer; 
6. compartment lor the reception ol the preparation; d, perforated plate, the position of which may be 
altered by means of the chains e. 
tained. The arrangement is by no means simple, so that we 
must refer to a description given of it by Toldt. 
We now pass to the consideration of the method most exten- 
sively used, that of the syringe. 
The small German-silver injection syringes (fig, 98, 1), which 
may be bought of Charriere or Luer, in Paris, for a few tha- 
lers, with a half-dozen or a dozen different canules (2, 8), are 
sufficient for all purposes, and will render equally good service 
for a number of years if used with some care. It is only neces- 
sary to carefully smear the piston from time to time with tal- 
low, in order to preserve the smooth, easy movement which is METHOD OF INJECTING. 
197 
so extremely necessary. It is also necessary to clean the syringe 
after being used for resinous injections with turpentine, and 
after gelatine with hot or cold water; it is then hung up by the 
ring of the piston-rod to permit the water to drain away. If, after 
a long interval of time, the caontchonc of the piston no longer 
fits closely, the syringe is to be unscrewed and the piston placed 
for a half or a whole day in cold, or 
several minutes in hot water. It 
has then become sufficiently swollen 
again, and, when rubbed with tal- 
low, the piston performs its duty 
anew. Resinous masses always have 
the inconvenience of requiring a 
time-consuming cleansing of the syr- 
inge. The canules should also be 
cleaned with water after having been 
used, and should be stood upon a 
warm plate to dry. Nothing fur- 
ther is necessary to keep the larg- 
er tubes open. A thin silver wire 
should always be introduced into 
the, finer and finest ones after clean- 
ing them, as, without this precau- 
tionary measure, the narrow passage 
is found to be closed, that is, rusted, 
and frequently it causes all subse- 
quent experiments to remain with- 
out results. 
Those who inject much require 
several of these syringes. It is also 
very convenient to have a large syr- 
inge, of about double the capacity 
of the small instruments, for filling 
extended systems of vessels, as the 
Pig. 93.—Syringe for Injections. 1. 
a, the tube, with the projecting edges 6, 
and c, (for convenience in holding), and 
the cap/, which is to be screwed on; d, 
piston-rod with the ring e; g, the aper- 
ture (mouth-piece) of the syringe, with a 
silk thread wound round it. 2 and 3. 
Canules of the finest variety. 
repeated removal for filling the syringe is always an unpleas- 
ant procedure ; and it is just in removing and in replacing the 
syringe that the beginner so readily meets with a misfortune. 
The canules themselves do not require any ring-shaped pro- 
jection, but rather a notched edge, for convenience in holding 
them. For frequent work it is necessary to have at least a dozen 
on hand; it is still better to have even a greater stock of the 198 
SECTION NINTH. 
most varying calibre, from about two mm. aperture to that of 
capillary fineness. I use those of German silver for large ves- 
sels ; the finest are of sheet-iron, and therefore unfortunately 
of a perishable nature. 
The remaining contrivances consist of strong, well-waxed silk 
thread of several sorts, several curved and straight needles, a 
pair of fine scissors, small ordinary and curved for- 
ceps, also several slide forceps (or other clamping 
apparatus, fig. 94) for possible emergencies. These, 
together with cold water, are sufficient for cold mas- 
ses. For gelatine injections it is also necessary to 
have a kettle with hot water and a double water-bath. 
The latter are ordinary deep copper basins, which 
are filled with warm water and kept at an elevated 
temperature by means of a spirit-lamp burning 
Pig. 94, 
Series fines. 
under them. They serve to receive the dishes of 
gelatine. Gelatine masses should never be warmed 
directly over a fire ! Together with plates or porcelain dishes, 
it is also convenient to have an oblong lead chest for the recep- 
tion of the organ or the body of the animal to be injected 
warm. The chest should have divergent walls and a drain- 
tube near the bottom, with a stop-cock. 
Objects for injecting are generally selected from parts as 
fresh as possible—that is, from animals which have Just been 
killed. I have frequently used small animals while they were 
still warm, directly after death, which is preferably induced by 
bleeding. In this way I have obtained the best results, except 
where muscular parts were concerned; in which case, espe- 
cially when injecting warm masses, the rigor mortis, which fre- 
quently occurs suddenly, renders the injection impossible. 
Very soft parts may be previously immersed for a in 
alcohol, in order to render them harder. By means of this 
procedure I have frequently succeeded in injecting the spleen 
after having been unsuccessful with fresh organs, notwith- 
standing every precaution. In injecting the blood-vessels of 
bodies not so fresh, the coagulation of the blood is a great dis- 
advantage, which often ruins the whole process. It has been 
frequently recommended in such cases to precede the injection 
mass with a stream of water, and in certain cases this proced- 
ure is serviceable. But generally we soon meet with numerous 
extravasations, and we are compelled to discontinue at an METHOD OF INJECTING. 
199 
early period, long before a complete injection lias been accom- 
plished. 
The blood-vessels of pathological new formations are gen- 
erally difficult to inject. The walls of the vessels are readily 
ruptured in consequence of their extreme delicacy. It is also 
frequently necessary to ligate numerous lateral branches. Cold 
transparent masses should only be used here, if anywhere. But 
with skill and perseverance much may be accomplished. Un- 
fortunately, this department has been altogether too much 
neglected by pathological anatomists, with the exception of 
Thiersch. 
In order to inject the lymphatic vessels, for which purpose 
all bodies are not equally suitable, I have frequently placed the 
dead body in water for a series of hours, so that these vessels 
might in this way become more thoroughly distended. One 
may also frequently have the pleasure of seeing the lymphatic 
vessels become well filled, after having forced a stream of water 
through the arteries of the organ for some time. Another 
method is likewise useful. I kill the animal by a blow on the 
head or by strangulation, then open the thorax, avoiding the 
blood-vessels, and ligate the ductus thoracicus high up. The 
body then remains undisturbed for 2-6 hours. The lymphatic 
vessels are now sought out, and are, for the most part, found to 
be filled and distended in a very satisfactory manner. The ex- 
periment may be made of ligating the efferent canals or the 
veins of the larger glands in the living animal, and thus causing 
the lymphatic vessels to become firm and distended. 
The freshest possible material should be selected for injec- 
tions of the glandular canals. The canule may be inserted di- 
rectly, or the passage may be made to appear more distended 
by previously forcing water through the artery, at the same 
time compressing the veins slightly, also first endeavoring to 
cause the secretion to flow out. In this case great caution is 
always necessary. 
In searching for a blood-vessel, an artery, or a vein, avoid all 
unnecessary cutting, as small branches may thus be readily in- 
jured, which afterwards makes it necessary to stop the rent with 
igatures or the application of sliding forceps, and thus cause 
an unpleasant interruption to the progress of the work. 
In opening the vessel, which is best done under water, avoid 
making the slit too large, and above all do not make a transverse 200 
SECTION NINTH. 
cut on a small artery, as in the introduction of the canule the 
vessel might readily be torn in two. By opening the vessel un- 
der water the entrance of air, which is always to be carefully 
avoided in injecting, is, for the most part, prevented. But there 
is still some air in the canule which is to be introduced. In or- 
der to remove this, the tube should be filled with water and the 
posterior opening closed with a cork before the introduction of 
the canule, a little precautionary measure which, like so many 
others, apparently unimportant, renders very great service in 
injecting. The mouthpiece of the syringe should also be passed 
beneath the surface of the water, and then introduced into the 
opening of the canule. 
The canule having been successfully introduced into the ves- 
sel, it next becomes necessary to secure it by means of a care- 
fully waxed silk thread. The necessary skill is soon acquired, 
the thread being either seized with the forceps and passed be- 
neath the vessel or brought round it threaded in a needle. 
Large vessels should be tied as firmly as possible ; with smaller 
ones more circumspection is required, and with very fine ones, 
especially embryonic branches, the greatest care is necessary. 
If the canule has a ring-shaped groove, which should always 
be the case with large ones, the ligature is to be placed at that 
part. If there is no groove, the greatest attention is to be paid 
to the application of the ligature, to prevent the tube from slip- 
ping out. In such cases the practised hand of an assistant, who 
places a finger over the opening of the canule without pressing 
the tube deeper into the vessel, renders an important service. 
The same process is to be followed in tying the canules into 
the ducts of glands. Lymphatic vessels require greater at- 
tention. That it is necessary to inject in the direction in which 
the valves open is self-evident; although, in a few cases, the re- 
sistance which they present may also be successfully overcome. 
Still it is only rarely and for special purposes that this proce- 
dure can be made use of; as, for instance, I succeeded in this 
way, several years ago, in injecting the lymphatic glands from 
the vas efferens. 
It frequently happens, however, that a well-distended lym- 
phatic vessel, which appears very inviting for injection, can 
nevertheless not be taken advantage of, especially when the 
vessel is very fine. The colorless fluid escapes on opening the 
vessel, and frequently the whole vessel becomes almost unrec- METHOD OF INJECTING. 
201 
ognizable. One is sometimes tormented for a long time in en- 
deavoring to introduce the canule within the collapsed walls ; 
attempt after attempt may fail, until after a time, in successful 
cases, the desired object is attained. Coolness and patience are 
to be recommended to those who desire to accomplish anything 
in this direction. 
When the fine lymphatic vessels in the interior of an organ 
are to be injected, Hyrtl and Teichmann’s puncturing method 
is the process chiefly employed. Hyrtl sometimes makes a 
puncture from the cavity of a blood-vessel into the surrounding 
tissue in order to open some of the lymphatic vessels which may 
be present, and thus, in fortunate cases, inject the lymphatic 
canals from and with the blood-vessel. Another way is to make 
a small opening directly into the tissue, in order to inject imme- 
diately from this into any of the lymphatic vessels which may 
bave been opened, and from these into larger systems. 
This may be accomplished in two ways. With larger can- 
ales, a needle may be passed through the tube ; after having 
inserted the canule into a small opening in the tissue, the needle 
may be pressed forward and the tube made to follow till the 
desired point is reached, when the needle is to be withdrawn. 
Where the walls were very thin, I have had better success by 
another method. A small puncture is to be made with a fine 
cataract-needle or the point of a fine scissors which has been 
dipped into the injection fluid. The tube is now to be passed 
into the small opening, recognizable by the little point of color, 
and very slowly and carefully pushed forward with an easy 
rotating movement. When one has the requisite practice and 
patience for this process, lymphatics may be injected even 
where the method of preceding the canule with the pricking 
instrument would fail. Nevertheless, it always remains a diffi- 
cult piece of work—as, for instance, in the small intestines of 
the Gruinea-pig—to guide the tube along in the submucous tis- 
sue, as the slightest awkwardness in the . movement causes a 
perforation of the mucous membrane. Many attempts will 
fail, till at length, by a lucky hit, the injection succeeds. All 
who desire to accomplish anything in this direction should 
first practise on organs which are easy to inject, of which, 
fortunately, there are many. Try, for instance, the vermiform 
process of the rabbit, in which the injection is very easy ; then 
the small intestine of the sheep, the testicle of the calf, and the 202 
SECTION NINTH. 
Beyer’s glands of the last-named animal, and proceed gradu- 
ally to more difficult organs. In many cases it is unnecessary 
to tie the canule, as compression may often be better made 
with the fingers of fine sliding forceps. If a ligature be used, 
a very fine needle should be employed, and the loop should be 
tightened with the greatest precaution, as very frequently the 
point of the canule is finally thrust through the walls of the 
vessel. Punctures which are too large permit the escape of 
the injection fluid. Teichmann, who has obtained great ex- 
perience in this direction, very properly remarks that a punc- 
ture made at random is not sufficient, but that it is to be made 
in a direction where fine lymphatic vessels are supposed to be. 
If the extravasation which forms at the commencement re- 
mains small, the injection frequently succeeds. If it is large 
at the very beginning, and increases rapidly, stop, for the proce- 
dure has failed. If a rapidly-increasing extravasation subse- 
quently takes place, it is likewise necessary to discontinue at 
once. Very cautious management of the syringe is for the 
most part necessary, especially at the commencement of the 
injection. 
But we have wandered from our subject. When the tube 
has been firmly secured in position, the syringe is to be thor- 
oughly tilled from beneath the surface of the injection fluid; 
and while the canule, which is now opened, is seized and some- 
what raised by the index and middle fingers of the left hand, 
the mouthpiece of the syringe is to be inserted as deeply as 
possible. The syringe is to be held by the middle phalanges 
of the index and middle fingers of the right hand, and the 
thumb is placed in the ring of the instrument. It is important 
that the forearm should, at the same time, rest quietly and 
conveniently on the table. 
In this manner, therefore, the injection of the mass com- 
mences : two fingers of the left hand holding the canule, three 
of the right the syringe, the piston being pressed forwards as 
slowly as possible and with the utmost steadiness. Every 
awkward, spasmodic impulse is to be avoided, especially to- 
wards the end of an injection. If the work succeeds, the col- 
ored mass is seen to move forward in the vascular system, and 
it is noticed how in some places the capillary systems become 
filled, how these latter places constantly become more numer- 
ous, and at the same time increase at the periphery until they METHOD OF INJECTING. 
203 
flow together. During this, the finger feels a gradually increas- 
ing pressure, and one soon learns to accommodate the motion of 
the piston to it. If two or three additional syringefuls of the 
mass be necessary, the syringe is to be removed, preferably 
before it is entirely emptied, and the opening of the can- 
nle closed with the thumb of the left hand. The syringe is 
to be refilled either by the operator, with his right hand, or by 
an assistant. If one possesses several syringes furnished with 
similar mouthpieces, it is well, when injecting large organs with 
cold masses, to have several of them lying filled near him at 
the very commencement, so as to instantly exchange the emp- 
tied syringe for one that is filled. 
When the injection is completed, whereby it is often well to 
ligate the opposite vessel in order to prevent an escape of the 
fluid, the canule is to be closed by means of a stopper of cork, 
or better of metal, fitted into its opening, or by means of the 
above-mentioned (p. 192) short tube with a stop-cock. The in- 
jected vessel is now tied further below, and the other ligature 
which holds the canule is finally removed, so that the tube 
may be taken out. 
Although the above-mentioned manipulations are soon 
learned with a little aptness, it is difficult to properly estimate 
the moment when the injection must be discontinued. Here 
file beginner very readily errs, and even the most practised 
aow and then has his unlucky day. Too little may be done ; 
the injection is then insufficient, only small places are filled, 
°r fine capillary systems even not at all. Inversely, an injec- 
tion pushed too far leads to extravasations, and finally to an 
nnserviceable preparation. If it be noticed that numerous 
though at first small extravasations form, desist, or they will be 
seen to increase in a frightful measure. That a considerable 
escape of the injection fluid requires an instant cessation in 
order to rescue what is possible, is self-evident. If Beale’s 
cold mixture be employed, towards the end of the injection 
the colorless fluid is seen to be pressed through the walls of 
the urinary canals and the envelope of the organ, appearing 
on the surface as a fatty, glistening moisture. Then is the 
time to leave off ; it would be too soon in most cases before this 
exudation takes place. 
The double injection is naturally much more difficult than 
the single ; firstly, on account of the entire procedure, and SECTION NINTH. 
then while too much should not be sent through one system, 
that of the vein, for instance, in order that the possibility may 
remain for the one injection to meet that from the second sys- 
tem in the capillaries. For injecting arteries and veins, such 
masses should always be used, if possible, which give a pleas- 
ant blending of colors when they meet; for example, Prussian 
blue and carmine, Prussian bine and white, while yellow and 
green appear less handsome to the eye. Masses which flow 
when warm and harden when cooled generally deserve the 
preference for these cases, and with gelatine masses I usually 
allow some time to elapse between the first and second in- 
jection, so that the former may at least acquire some firm- 
ness. For most cases, the vein may be first injected and then 
tied in the usual way. Afterwards, if there be considerable 
resistance, the artery with its ramifications are to be injected. 
For many organs, as for instance the eye, or the spleen, it 
is well to drive the injection mixture intended for the venous 
system through the artery first, and then, through the same 
vessel, the second mass which is to serve for the arterial sys- 
tem. Not nnfrequently the injection may be essentially regu- 
lated by keeping open or closing the terminal vein. 
If, together with the blood-vessels, it be also intended to 
inject the lymphatics, or, in a glandular organ, its system of 
canals, the blood-vessel may either be injected first and then 
the latter, or inversely. If the lymphatics are to be injected 
by the puncturing method, avoid injuring the injected blood- 
vessels as far as possible. 
For all injections of the glandular passages and the lym- 
phatics, transparent cold mixtures deserve the preference, as 
was already remarked, on account of their ready permeability, 
as well as in consequence of the less degree of injury which 
their employment exerts on the tissues. 
Although the directions given are in no wise to be regarded 
as complete, and require special modifications for special or- 
gans, which are only to be obtained by experiment, they will, 
nevertheless, considerably facilitate the labors of the begin- 
ner. 
A successful injection having been made, the further ques- 
tion now arises : what is to be done with the specimen in order 
to prepare it for examination % 
As was above remarked, warm injections require, beyond METHOD OF INJECTING. 
205 
all things, the necessary time for the mass to harden. Kesi- 
nous substances require a longer time than gelatine. With 
Beale’s cold mixture, the objects may be used at once ; with 
Hyrtl’s ether injection, the injected organ may be used after a 
quarter of an hour. 
When a specimen has been injected with a gelatine mass, it 
should without delay, or at most only sufficient to wash off 
its surface, be placed in ice-water (in winter, snow), and left 
till the mass has become hardened. This may be readily 
recognized when the contents of the larger vessels no longer 
yield when felt with the points of the fingers. The injected 
organ is placed, for further hardening and preservation, in 
weak, and then in stronger alcohol. It is well to let it lie 
quietly in this for several days before proceeding further. It 
is better to place very sensitive objects, directly after the in- 
jection, in alcohol which has been previously placed in ice, or 
which has been cooled by putting pieces of ice in it (Thiersch). 
A few drops of acetic acid are to be added to the alcohol for 
injections with Prussian blue. 
Naturally, even here, numerous modifications are necessary 
in certain cases. Thus smaller organs may be left in the alco- 
hol without cutting them, as also groups of organs and the 
entire bodies of the smaller mammalia, which may be prepared 
after a few days. It is preferable to open an intestinal canal, 
which has been injected with gelatine, after the injection fluid 
fias hardened. This should be done in water, and the canal 
washed out carefully. Portions of intestine with the lym- 
phatics injected I cut open, and run a stream of water through 
the canal to wash out its contents, and then place the prepara- 
tion for a day or more in alcohol. Large organs after being 
immersed in alcohol, for example, the kidney of one of our 
ruminata, should be cut open on the following day at furthest, 
lest the cortex should harden while the internal portion decom- 
poses. Immersion in chromic acid solutions is also applicable 
to such purposes, Prussian blue being well preserved in them ; 
but it is rare that alcohol can be altogether dispensed with. I 
also place organs injected with Beale’s mixture, almost without 
exception, in alcohol, in order to obtain the necessary harden- 
ing of the tissue. 
After a few days, when the preparation has acquired the 
necessary firmness, it may be examined by the ordinary meth- 206 
SECTION NINTH. 
ods already given. Tliin horizontal and vertical sections, for 
example, are to be freed from particles of coloring matter 
which have escaped by washing, or, still better, by means of a 
camel’s-hair pencil. They are then to be reviewed with the 
microscope, and, if it be desired to preserve them permanently, 
they are to receive such further treatment as may be neces- 
sary. 
The old method of mounting dry is to be recommended 
when the preparation is to be used as an opaque object. It is 
still better to mount it carefully in Canada balsam, which will 
be treated of in the following section. 
Glycerine is being more and more employed for mounting 
histological preparations, and, as may be readily conceived, it 
reproduces the natural relations, although connected with the 
very great disadvantage of being much less durable. 
For the preservation of injected organs for a considerable 
length of time, alcohol, weak or strong, according to circum- 
stances, is used. Section ®cntt). 
THE MOUNTING AND ARRANGEMENT OF MICROSCOPIC OBJECTS. 
The reader will have perceived from the preceding sections 
that it is by no means one of the simplest and easiest things to 
obtain useful microscopic specimens, even if, at the same time, 
we also disregard the rareness of many, as, for instance, those 
of embryonic and pathological occurrences. The desire to pre- 
serve for the longest possible time such objects as are only 
obtained with trouble or the concurrence of fortunate circum- 
stances is also sufficiently obvious; and, in fact, the effort to 
obtain such preparations is as old as microscopy itself. The 
value of such collections is quite as great for the study of this 
branch of natural science as for that of others. 
Commencing with crude attempts in the preservation of 
hard structures, dried preparations of injections, etc., the in- 
dustry of the investigators has gradually brought better and 
better methods to light, so that this now constitutes an impor- 
tant section of microscopic technology. At the same time, 
although much has been accomplished in this department, still 
more remains to be attained and explored; most of those 
branches relating to preserving being at the present day still in 
an incipient condition. 
Many portions of the body may be sufficiently well pre- 
served in ordinary alcohol for the purpose of having at hand 
material from which, in case of necessity, a serviceable prep- 
aration may be made with rapidity and little trouble. Hard- 
ened glands, intestines, the central portions of the nervous sys- 
tem, tumors, injections with gelatine and cold masses, such as 
have been described in the previous section, and embryos, may 
be preserved in the most convenient manner in well-closing 
glass bottles, and constitute, especially for a teacher, invalu- 
able material for instruction. 208 
SECTION TENTH. 
But, in most cases, the matter is not so simple when a defi- 
nite microscopic preparation is to be preserved. For this pur- 
pose certain methods are necessary. 
Hard structures of many kinds, especially those of a trans- 
parent nature, scales of diatomes, thin sections of bone and 
teeth, and crystals, may be permanently preserved in a very 
simple way if they are placed on a slide and covered with a 
thin covering glass, and the latter fastened to the former. 
Various substances may be used for this purpose; as, thick 
gum-arabic (a solution of gum with powdered starch is good), 
wax, resinous substances of thick consistence, and Canada bal- 
sam. For the protection of the fragile covering glass, the whole 
may afterwards be covered with colored paper, through which 
an aperture has been made with a punch. It is well for those 
who work much with such objects to have lithographed covers 
prepared, the posterior surfaces of which are gummed for the 
sake of economizing time. On one surface of the slide the 
paper should project beyond its edges in such a manner that 
they may be covered by it, while the other surface of the glass 
plate requires a smaller covering. One soon acquires the little 
dexterity necessary to apply these covers. The gummed sur- 
face should only be slightly moistened, so that when pressed 
on to the slide the gum will not exude and flow over the visible 
portion of the preparation. Very many such preparations, 
which are in circulation and to be purchased, may be recom- 
mended as models; as, for instance, those of Bourgogne, in 
Paris; Moller, in Wedel (Holstein); and Rodig, in Hamburg. 
But, as we have already remarked, only a small number of 
objects, which are transparent per se, permit of this most sim- 
ple method of treatment. The greater portion of those which 
are to be preserved dry require, in order to render them trans- 
parent, to be mounted in a substance which refracts the light 
strongly, in a gradually hardening resinous material. 
For this purpose there is none more important or more 
generally used than the Canada balsam, and, indeed, it suffices 
for all cases. Other resinous substances, such as copal lack, 
damar varnish, and mastic are really superfluous, and are, at 
most, only to be used here and there by wTay of experiment. 
Several sorts of Canada balsam occur in commerce. To be 
good it should be of thick consistence, nearly colorless, and 
thoroughly transparent. It is to be kept in wide-mouthed ves- THE MOUNTING, ETC. 
209 
sels closed with glass stoppers, in order to limit as much as 
possible its tendency to harden in the air. If, in consequence 
of the prolonged action of the air, it has become much hardened 
it may be thinned, after being moderately warmed, with oil of 
turpentine, or, which is less preferable, with a little chloro- 
form. 
The preparation to be mounted must be thoroughly dry. 
Hence, in many cases a preparatory drying process will be ne- 
cessary. For this purpose the preparation may be placed over 
a water-bath, or over sulphuric acid or chloride of calcium. 
Many preparations may be advantageously placed in oil of tur- 
pentine, in which they are to be left for at least a few minutes. 
If the specimen to be mounted contains air, a longer immersion 
hi turpentine, occasionally in that which is warmed, will be ne- 
cessary. 
The preparation should be mounted in the following man- 
ner. The dry, cleanly-washed slide is to be moderately warmed 
ever the spirit-lamp, but never to an extreme degree. A drop 
of the balsam is then to be taken from the bottle by means of a 
pointed glass rod and placed on the slide. It will then spread 
out into a layer which, in fortunate cases, will be quite homo- 
geneous and contain no air-bubbles. But if any of the latter 
I‘emain in the stratum of balsam (if the slide be too warm they 
are developed by the boiling of the balsam), they are made to 
burst by touching them with the point of a heated needle, or 
are brought to the edge of the layer of balsam with the point 
°f a cold needle. The object to be mounted is now placed in 
position, and a second drop of balsam is placed over it by 
uieans of the glass rod. The two layers of balsam will soon 
flow together if the procedure be rapid or the slide be again 
slightly warmed. The clean and moderately warmed covering 
glass is now to be seized with the forceps and placed in an in- 
clined position, with the side opposite the forceps lowest, over 
the layer of balsam, and then allowed to gradually assume a 
horizontal position till it completely covers the object. If 
there be any air-bubbles still remaining, they may be driven 
to the margin of the covering glass by careful pressure on its 
other edge, provided the mounted object be of a nature 
which permits of the necessary pressure. The preparation is 
uow to be reviewed with the aid of a low power. If several 
air-bubbles are still to be discovered, it is preferable to place 
14 210 
SECTION TENTH. 
the slide on a warm body (in winter it is best to place it on the 
cover of an earthenware stove) covered with a bell-glass, and 
left for several honrs, whereby, at the same time, the balsam 
hardens more rapidly, and on this account it is an advantageous 
procedure, even where there are no air-bubbles. 
If too much Canada balsam has been used, a quantity of it 
usually spreads beyond the edge of the covering glass, or even 
on to its surface. In such cases it is necessary to wait till the 
balsam hardens, after which it may be scratched off with a 
knife-blade, and the surface of the glass cleaned with a rag 
freshly moistened with oil of turpentine or benzine. 
The hardening of the balsam at the interior of the prepara- 
tion proceeds very slowly, so that it still remains fluid for days, 
and even weeks, while the edges have become hard. By an 
awkward manipulation the covering glass may be displaced 
and the preparation ruined. 
Subsequent warming is here of service. 
Hard structures may be thus treated for several days. 
Soft animal parts require a more conservative treatment. An 
immoderate, too long continued heating gives the resinous 
mounting material an unpleasant yellow. 
Occasionally a Canada balsam is met with which is at first 
of a somewhat more fluid consistence. In this case the mount- 
ing may be done on a cold slide, which always economizes a 
certain amount of time. Such preparations should always be 
placed for a time on a slightly warmed support, so as to dry 
more rapidly. Although it is quite necessary to accomplish 
the expulsion of the air-bubbles from most specimens mounted 
in Canada balsam, there are other objects in which the air con- 
tained in the finest canals is of importance for the recognition 
of certain structural peculiarities, and the air must therefore 
be retained. If, for example, we place a section of bone directly, 
or after having been in turpentine, into Canada balsam which 
is very fluid, the canaliculi and the cavities of the bone become 
filled with this medium, which gradually penetrates in all direc- 
tions and forces out the air. But the processes of the bone 
corpuscles and the canaliculi appear distinct only when they 
contain air, and it is only in this way that the bone presents a 
characteristically elegant appearance. 
Such preparations must be mounted warm with the thickest 
possible Canada balsam. For this purpose the balsam may be THE MOUNTING, ETC. 
211 
placed in an open vessel in a warm place, and covered with a 
bell-glass until it becomes quite hard and firm. It is unneces- 
sary to remark that previous immersion of the object in oil of 
turpentine is here to be avoided, and that in mounting it is ne- 
cessary to expose the Canada balsam, slide, and cover to a con- 
siderably elevated temperature. 
Frequently—especially with histological work—when it is 
desired to mount a very thin and delicate specimen, as the 
object is warmed, it will be seen, to one’s great vexation, to 
shrink, become curved, and finally break. Here a solution of 
Canada balsam in ether, or, still better, in chloroform, filtered 
through ordinary filtering paper, is in place ; it may be diluted 
according to circumstances. By means of a brush or a glass 
rod it is placed cold on the slide, the object is placed in this, 
then more fluid is added, and finally the covering glass is laid 
on. As the dissolving medium evaporates, the air generally 
enters on one side between the plates of glass. In such cases 
the preparation is to be held in a slanting position, and a few 
drops more of the solution added until the process of mounting 
is finally completed. The whole procedure, which may also be 
employed for more substantial objects, is very convenient and 
cleanly. 
A solution of Canada balsam in benzine has also been 
recently recommended (Bastian). Walmsley dissolves thick- 
ened Canada balsam in pure benzine to the consistence of 
cream. 
But how should one proceed when one of the soft watery 
tissues, such as the greater portion of our body presents, is to 
be placed in Canada balsam ?' How are injected preparations 
to be treated ? 
That this can only be accomplished by intermediate pro- 
cesses is self-evident. That is, the water must be expelled by 
a fluid which mixes with it; this is to be replaced by another, 
etc., until at last the Canada balsam may be used for the final 
saturation. 
Suppose we have a thin section of the spinal cord, kidney, 
°r spleen, which has been tinged with carmine or some other 
coloring material, or the section of an intestine, brain, or 
lymphatic gland, with the blood-vessels and lymphatics in- 
jected, and we desire to mount the same as a dry preparation, 
but at the same time to avoid the shrinking occasioned by sim- 212 
SECTION TENTH. 
pie drying, which would change the preparation, in fortunate 
cases, to a caricature, or, in less fortunate ones, to hiero- 
glyphics. The object is to be placed for a day in very strong, 
or better, in absolute alcohol; from this it is transferred to 
strong methylated alcohol for half an hour, although this in- 
termediate step may also be dispensed with. By this means 
the water has been removed and the alcohol has taken its place. 
The preparation is now to be removed from the alcohol, pref- 
erably by means of a filter, and just as it begins to dry it is 
placed in oil of turpentine. The previously mentioned small, 
flat glass boxes are very suitable for this purpose. Sometimes 
the process of becoming transparent can be very conveniently 
followed under the microscope. Then, by placing a thick 
plate of glass which just covers the preparation over it, it will 
be pressed against the flat bottom of the vessel, and all curv- 
Fig. 95. Frey’s compression apparatus. 
ing of the object will be prevented, and the shrinking will be 
limited to a considerable degree, even though the specimen re- 
mains in the oil of turpentine for several days. After several 
hours, all the alcohol is expelled by the turpentine, and the 
object is ready for mounting in the chloroform solution of Can- 
ada balsam. 
If it be desired to use a still stronger pressure on tougher 
structures (and this may also be necessaiy, subsequently, for 
preparations mounted in resinous substances), it is advisable to 
employ the simple apparatus of fig. 95 with its lead tubes, 
under which is placed either the glass box or the Canada bal- 
sam preparation with its covering glass. 
Excellent preparations may thus be obtained when one has 
once mastered this method. All injected specimens (those with 
nitrate of silver also) should be mounted dry in this way only. THE MOUNTING, ETC. 
213 
In the same manner many histological details, even cylindrical 
epithelium and other delicate cells, may be preserved so as to 
be visible, and if carefully tinged with carmine or blue, they 
may be rendered still more distinct. All the transparent colors 
which were mentioned as suitable for combination with gelatine 
are well preserved in this way. At the same time we would 
also add, as a precautionary rule, to add a drop of glacial 
acetic acid to the alcohol used for drawing the water out of 
preparations injected with Prussian blue. 
We would here add still another little precautionary meas- 
ure. It is best to allow very thin and delicate sections to be- 
come sufficiently dry on the filter, then to cut out the portion 
of paper on which the object rests and immerse it in oil of tur- 
pentine. By a slight movement the preparation may then be 
floated off from the paper. 
We have placed this procedure, with all its minutiao, before 
the reader, because of its great importance. 
Here, as everywhere, the greatest cleanliness, the use of 
filtered fluids, etc., is necessary. 
The employment of other resinous bodies in the place of 
Canada balsam has been suggested and, in fact, a number have 
been recommended, such as damar, copal, mastic, etc. Several 
years ago I made extended experiments with them, and now 
recommend: 
'■Damar Resin in Turpentine. 
The preparation is very simple. The powdered material is 
placed in a bottle and pure oil of turpentine poured on it; the 
bottle is to be lightly corked and exposed for 24-48 hours to a 
moderate heat. Then filter and evaporate the excess of tur- 
pentine by letting it stand for some time in an open vessel un- 
der a bell glass. 
This mass is more colorless than Canada balsam. The con- 
tours of the objects remain more distinct. The drying of the 
preparation is much slower, however, than with the former 
resinous mounting. 
Mastic in GTdoroform. 
The powder is dissolved in a similar manner in the fluid and 
filtered. The contours of the preparation are tolerably sharp, 214 
SECTION TENTH. 
better than in objects mounted in Canada balsam. The mass 
is somewhat yellow, and permits of only moderate warming in 
the artificial drying of the preparations. 
The intermediate stage of the oil of turpentine and its 
shrinking effect may be avoided by means of solutions of resi- 
nous matters in absolute alcohol which permit of mounting 
cold without any clouding of the objects, but they do not per- 
mit of a highly increased temperature for rapid drying. 
Colophonium. 
Thiersch has quite recently made use of colophony for mount- 
ing such preparations. He prepares it in the following man- 
ner :—lt is best for the microscopist to prepare the colophony 
himself, and a solution of it in absolute alcohol of syrupy con- 
sistence should be used. The advantage which this material 
presents is, that the preparation may be placed in it directly 
from the absolute alcohol, without becoming cloudy and with- 
out prejudice to the durability of the specimen. Venetian tur- 
pentine is to be dissolved in an equal volume of sulphuric 
ether, and the solution filtered through paper. The ether and 
oil of turpentine are then to be expelled by the heat of a mod- 
erate fire, till the residuum shows a shell-like fracture when 
cold. 
I have worked considerably with this mass, which, when 
well prepared, has the color of Canada balsam. The contours 
are sharper and prettier than with any resinous material with 
which lam acquainted. The drying is, unfortunately, ex- 
tremely slow. Nevertheless, I can recommend this substance in 
the highest degree. I have had specimens for four years, which 
are still well preserved. 
Bandar ac. 
Powdered and treated with absolute alcohol, and digested 
for a day at a moderate temperature, this resin yields a filtrate 
which is but slightly yellow. When concentrated we have an 
excellent, very rapidly solidifying material for mounting. The 
contours of the objects become very indistinct, however, after 
a series of months. Many tingeing materials, such as hsema- THE MOUNTING, ETC. 
215 
toxylin commence, to fade. After tliis unpleasant experience 
of latter years, I no longer recommend the sandarac resin. 
But the natural condition of the tissues is completely repre- 
sented only when mounted in a moist condition. This method 
permits of the most accurate recognition of delicate textural 
relations, pale cells and fibres, etc., and should not be omitted 
with any tissue in the production of histological collections, 
as, even in cases where good dry preparations can be obtained, 
it affords an instructive comparison. 
Among all the preservative fluids for animal soft parts there 
is none which stands higher, at the present time, than gtycerine. 
Its strong refractive power, its property of combining with water 
and of attracting the same from the atmosphere, render it an 
invaluable medium for mounting animal tissues containing 
water. It may be truly said, that what Canada balsam is to 
dry tissues, glycerine is to moist ones. 
The ordinary impure glycerine may be used in the prepara- 
tion of a temporary specimen, for brushing, etc., but not, how- 
ever, for permanent preparations. Here the purified glycerine, 
containing no lead and as little water as possible, is always to be 
used. Undiluted, it renders the preparation very transparent; 
occasionally, after a time, too much so. For many objects it 
niust, therefore, be diluted with distilled or camphor water in 
about equal proportions, more or less, according to circum- 
stances. It is very useful, indeed almost indispensable, to 
wash the preparations which are to be permanently mounted 
for several days in pure glycerine, or a mixture of glycerine 
and water, in a small vessel, whereby the degree of transpar- 
ency which they will assume may be ascertained at the same 
time. 
The preparation is then to be mounted in the ordinary man- 
ner by means of one of the cements hereafter mentioned. The 
superfluous glycerine, which spreads beyond the covering glass, 
may be removed with a fine pipette and dried with a cloth 
moistened in alcohol. The nature of glycerine is such as to 
render it unnecessary to be in haste in the application of the 
cement, so that a number of specimens may be allowed to ac- 
cumulate before it is laid on to the borders. 
For many purposes I have found it well to add two drops of 
strong muriatic acid to the ounce of glycerine. Objects injected 
with carmine or Prussian blue always require this addition, 216 
SECTION TENTH. 
otherwise the color will fade and disappear after a time. Ace- 
tic acid accomplishes the same purpose, and possibly better. 
Ranvier has recently proposed the combination with formic 
acid (1:100). 
As glycerine is a constituent of many mixtures, so also may 
many other materials be added to it, and thus produce more 
complicated mounting fluids. Thus, for example, gelatine, 
gum-arabic, etc., may be combined with the glycerine. 
Deane recommends a mixture of glycerine 4 ounces, distilled 
water 2 ounces, and gelatine 1 ounce. The latter is to be first 
dissolved in the water and the glycerine then added. I have 
had no experience with tannin and glycerine. 
Beale also recommends one of these combinations of glyce- 
rine with gelatine. A certain quantity of pure gelatine is al- 
lowed to soak in water until it swTells up and becomes soft. It 
is then placed in a glass vessel and melted by the heat of boil- 
ing water (that is, on a water-bath). To this fluid an equal 
quantity of strong glycerine is added and filtered through flan- 
nel. The mixture may be kept for any length of time, and 
only requires to be slightly warmed before being used. Klebs 
employs 2 parts of a concentrated solution of isinglass and 1 
part of pure glycerine slightly warmed. 
Bastian recommends a mixture of 15 parts of glycerine and 
1 part of carbolic acid for mounting tissues not tinged. 
Farrants employs a still more complicated mixture, consist- 
ing of equal parts of gum-arabic, glycerine, and a saturated so- 
lution of arsenious acid. The mixture is to be used in the 
same way as the Canada balsam. 
Although glycerine is the most important preservative fluid 
now known, answering all the requirements for many animal 
tissues, nevertheless one should not believe that everything can 
be preserved in it with success. Delicate, fresh watery tissues, 
for example, blood-corpuscles or ganglion cells, soon lose a 
portion of their water and become distorted. The strong re- 
fractive power of glycerine is, therefore, a disadvantage for 
transparent tissues, however excellent it may appear to be for 
those which are hardened. Besides glycerine, a whole series of 
preservative fluids have been tried and recommended, of which 
one is sometimes here, another sometimes there to be used with 
success. It is always well in mounting objects not to place im- 
plicit trust in such recommendations, but rather to make a THE MOUNTING, ETC. 
series of experiments with various preservative fluids, of which 
only the best are to be retained after a subsequent examination. 
The deceased M. Schultze recommended, as a medium for 
mounting, a substance used by botanists, a nearly saturated 
solution of the acetate of potash in water, especially for osmic 
acid preparations which do not bear glycerine. Without re- 
moving the covering glass, a drop of this strong solution of 
potash is added to the microscopic preparation as it lies in 
water or an indifferent solution. A day later, the water having 
been in the mean time removed by evaporation, the cement is 
to be applied; although one may wait still longer. This method 
has been used for several years. 
Goadby’s solution, the conserving liquor of the English, has 
obtained a certain renown. It consists of : 
Bay salt 4 ounces. 
Alum 2 ounces. 
Corrosive sublimate 4 grains. 
Boiling water 4 pints. 
This composition, which brought the discoverer a consider- 
able sum, does not prove suitable for mounting transparent 
preparations, as they gradually become opaque and are finally 
rendered unserviceable. On the contrary, I have seen opaque 
preparations of injections mounted in this fluid, which were 
made in England, and which left nothing to be desired. Val- 
entine afterwards remarked that the tissues of sea animalcula 
are very well preserved in this fluid. The beautiful prepara- 
tions of vitreous-like medusae, salpidae, etc., in the naturalist’s 
collections also harmonize with this observation. 
Pacini lias recommended certain preservative fluids, as 
modifications of this mixture, which contain sublimate, com- 
mon salt or acetic acid, but no alum, including glycerine, how- 
ever, as a useful addition, and intended for preserving various 
tissues. They are incomparably more serviceable and deserve 
accurate consideration. They are represented by the following 
two formulae:— 
Corrosive sublimate 1 part. 
Pure chloride of sodium 2 parts. 
Glycerine (25° Beaume) IB parts. 
Distilled water 118 parts. SECTION TENTH. 
This mixture is allowed to stand for at least two months. 
After that time it is prepared for use by mixing one part of it 
with three parts of distilled water and filtering it through fil- 
tering-paper. 
Blood-corpuscles are preserved in it exceedingly well, as 
my own observations liave proved. According to Pacini, it is 
equally well adapted for nerves and ganglia, the retina, cancer 
cells, and especially delicate proteinous tissues. 
A second mixture consists of ; 
Corrosive sublimate 1 part. 
Acetic acid 2 parts. 
Glycerine (25° Baume) 48 parts. 
Distilled water 215 parts. 
This mixture is prepared for use in the same manner as the 
preceding. It is said to destroy the colored blood-corpuscles, 
but preserves the lymph-corpuscles of the blood intact. 
Further modifications of these mixtures, as they are em- 
ployed in the Pathological Institute of Berlin, are represented, 
according to Cornil, by the following : 
1. 
3. 
Corrosive sublimate 1 
Chloride of sodium 2 
Water 100 
Sublimate 1 
Chloride of sodium 8 
Water 300 
3. 
4. 
Sublimate 1 
Chloride of sodium 3 
Water 300 
Sublimate 1 
Water 300 
Sublimate 1 
Acetic acid 1 
Water 300 
5. 
Sublimate \ 
Acetic acid 3 
Water 300 
6. 
Sublimate 1 
Acetic acid 5 
Water 300 
7. 
Sublimate 1 
Phosphoric acid 1 
Water 30 
8. 
]STo. 1 is used for preserving the vascular tissues of the 
warm-blooded animals. No. 2 for those of cold-blooded crea- 
tures. No. 3 for pus-corpuscles and related structures. No, 4. THE MOUNTING, ETC. 
219 
for blood-globules. No. sis intended for epithelial cells, con- 
nective tissues, and pus-cells, when the nuclei are to appear at 
the same time. No. 6is applied to the preservation of connec- 
tive-tissue structures, the muscles and nerves. No. 7 serves 
for glands, and No. 8, finally, for cartilaginous tissues. 
Very dilute solutions of corrosive sublimate are in fact very 
useful as preservative fluids, but the degree of concentration 
should be determined every time they are used, for which rea- 
son it is judicious to mount several examples of a preparation 
in solutions of different strengths. Harting recommends solu- 
tions of 1 part of corrosive sublimate to 200-500 of distilled 
water. He remarks that it is only in such solutions that he is 
able to preserve the blood-corpuscles. Those of man and the 
mammalia require of the sublimate, those of birds those 
of frogs 3-fg-. Some of these solutions which I have tested ap- 
pear to be useful. His recommendation of these solutions for 
the brain, spinal cord, and retina appears less justifiable, but, 
on the contrary, they are useful for cartilage, muscle, and crys- 
talline lens. All solutions of corrosive sublimate readily cause 
the preparations to become dark and less transparent. 
Chromic Acid and Chromate of Potash.—Dilute solutions 
of chromic acid and of the bichromate of potash, combined 
according to circumstances with glycerine, may be advanta- 
geously employed as preservative fluids. A mixture of equal 
parts of glycerine and Muller’s preservative fluid (p. 136) ap- 
pears to be very useful. The latter, undiluted, also occasion- 
ally forms a very serviceable medium for mounting very deli- 
cate textures. 
A solution of chloride of calcium is a fluid popular with 
the botanists for mounting. It appears to be less serviceable 
for animal specimens. Harting praises the saturated solution 
of the pure salt, or one diluted with the 4-8 fold volume of 
water. Preparations of teeth and bones and sections of hairs 
are said to keep well in it. I acknowledge that thus far my 
experiments, not very numerous, it is true, with the solution 
of chloride of calcium have afforded me only very moderate 
results. 
Harting recommends solutions of the carbonate of potash in 
200-500 parts of water as the best medium for mounting nerve 
fibres. I have had no experience with this solution. Accord- 
ing to the same authority, arsenate of potash in solution SECTION TENTH. 
with 160 parts of water also exerts the same effect on nerve 
fibres. 
Watery Solution of Creosote. —According to Harting’s ex- 
perience, a solution obtained by the distillation of creosote 
with water, or the saturated and filtered solution of creosote 
in a mixture of 1 part alcohol of 32° and 20 parts of water is a 
good preservative medium for many tissues, such as muscle, 
connective tissue, tendon, decalcified bones and teeth, and 
likewise the crystalline lens. 
Arsenious Acid.—This is to be boiled with water in excess, 
and, after cooling, filtered and diluted with three times its vol- 
ume of water. It is used for the same purposes as the solution 
of creosote, and is also suitable for the preservation of fat cells 
(Harting). 
Methyl alcohol, considerably diluted with water, in the 
proportion of one to ten, has been recommended by Quekett. 
If, after several days, the fluid becomes cloudy, it should be 
filtered. Like the acetic acid solution, it causes most prepara- 
tions to assume a granulated condition after a time. 
Methyl alcohol and creosote are also elements of a compli- 
cated fluid mentioned by Beale. 
Creosote 3 drachms. 
Wood naphtha 6 ounces. 
Distilled water 64 “ 
Chalk, as much as may be necessary. 
It is prepared in the following manner:—Mix first the 
naphtha and creosote, then add as much prepared chalk as 
may be sufficient to form a thick, smooth paste ; afterwards 
add, very gradually, a small quantity of the water, which 
must be well mixed with the other ingredients in a mortar. 
Add two or three small lumps of camphor and allow the mix- 
ture to stand in a lightly covered vessel for a fortnight or three 
weeks, with occasional stirring. The almost clear superna- 
tant fluid may then be poured off and filtered if necessary. It 
should be kept in well-corked or stoppered bottles. This mix- 
ture forms a modification of Th waite’s fluid for preserving 
desmidise. 
Topping’s Fluids.—He recommends the employment of one 
part of absolute alcohol to five parts of water ; and where the 
preservation of delicate colors is necessary, he dissolves one THE MOUNTING, ETC. 
221 
part of acetate of alumina in four parts of distilled water. 
The latter mixture, diluted with an equal volume of glycerine, 
lias preserved carmine injections for me very well over three 
years. 
Deane1 s Fluid.—lie praises a mixture of six ounces of 
pure glycerine, nine ounces of honey, a little alcohol, and a 
few drops of creosote, for the preservation of animal and vege- 
table structures. The mixture is to be filtered while warm. 
Plain slides and covering glasses may be used for mounting 
very thin objects. A larger or smaller drop, as may be neces- 
sary, of the preserving fluid may be placed immediately on to 
the former by means of a brush or a glass rod, and the speci- 
men, seized with delicate forceps or a cataract needle, is placed 
in this, care being taken that it is covered by the fluid. The 
covering glass, the under surface of which has been breathed 
on, is then placed over the specimen in the manner indicated 
for mounting in Canada balsam. One should avoid employing 
too large a quantity of the preservative fluid, as it is then lia- 
ble to escape at the sides, or to flow over the edges of the cov- 
ering glass. In such cases the excess should be removed by 
means of a very finely pointed pipette, or by the application of 
narrow strips of bibulous paper. In both cases the edges are also 
to be dried with a linen rag, care being at the same time taken 
not to displace the cover. Sometimes air-bubbles remain and 
can only be removed by slight pressure. It is well to cut a 
piece of fine writing-paper about an inch long in such a man- 
ner as that it will form a long, narrow triangle, measuring 
about 2"' at its base. The point of this is now to be passed 
between the slide and covering glass ; frequently the air-bub- 
ble can be conveniently shoved out with it. 
Although with Canada balsam as soon as the covering glass 
is successfully placed in position the whole process is essen- 
tially terminated, a further enclosure of the edges not being in 
reality necessary, although even here the specimen receives 
greater protection and a more attractive appearance by means 
of a finishing touch ; it is otherwise with objects mounted 
moist ; they must be cemented ;—a procedure which will re- 
ceive more especial mention further below. 
If, however—and this will generally be the case—a some- 
what thicker object is to be mounted, or if it be feared that the 
cement as it hardens will subsequently press the covering glass 222 
SECTION TENTH. 
too much against the preparation and thus injure it, a firm 
substance should be interposed between the two glasses. Sil- 
ver wires or narrow strips of paper are to be recommended as 
simple contrivances ; various thicknesses of them may be pre- 
pared and placed under two opposite borders of the covering 
glass, or a narrow paper frame may be substituted. But then 
the insinuation of an air-bubble is quite possible, and the first 
layer of cement should not consist of a substance which is very 
fluid or which hardens very slowly, as it would then either 
penetrate into the preserving fluid immediately, or the exter- 
nal coating would afterward in contracting press in the inter- 
nal layers. 
This procedure, in its further development, leads to the 
construction of a framework which is sometimes shallow, 
sometimes deep, and which is fastened to the slide. The flat 
case thus obtained is called a cell. 
Yery manifold directions have been given concerning the 
construction of such cells. The more simple ones will be pre- 
ferred unless greater cheapness renders another procedure de- 
sirable. 
Cells may be made of gutta-percha, caoutchouc, and glass. 
The latter are the best, but also the most expensive. 
Gutta-percha Cells.—Gutta-percha occurs in commerce in 
sheets of varying thickness. A good sheet should be even, 
Fig. 96. Gutta-percha cell. 
homogeneous, and flexible. If crooked or cracked, it may be 
made to assume the former condition by dipping it in boiling 
water. With a ruler and knife quadratic or oblong square 
pieces may be cut out in the same way as from pasteboard; 
they should, however, be narrower than the slide. In these a 
round, oval, or oblate square aperture is to be cut with a 
punch and hammer, to contain the preparation and the con- 
serving medium (fig. 96). THE MOUNTING, ETC. 
Caoutchouc Cells.—These are also made from the commer- 
cial sheets, which may be placed one over the other and readily 
made to stick together by heating them, when it is necessary 
to construct cells with high walls. 
Class Cells.—These deserve the preference, but if bought 
ready made from the glass-cutter they are rather more expen- 
sive. Glass rings of different diameters and varying depths 
are used, but they have the inconvenience of requiring circular 
covering glasses. Quadratic or oblong square plates, resem- 
bling those of gutta-percha, and provided with circular open- 
nings, are useful. Those of half a line in depth and with a 
round aperture of about four lines in diameter will be found to 
suffice for most histological purposes. 
Excellent glass cells, made in England, have lately been 
brought to my knowledge through Thiersch, They are made 
of glass slides several lines in thickness, perforated by a circular 
aperture of considerable size, with covering glasses cemented 
to both surfaces. The perfectly injected eyes of white rabbits, 
divided in halves and thus mounted with their natural curva- 
ture in Canada balsam, constitute one of the handsomest prep- 
arations which Thiersch has produced. 
Any one to whom economy of time is of less importance, can 
himself prepare glass cells in still another way (fig. 97). He 
Fig. 97. Glass cell with cover. 
should have strips a line or so in breadth, cut from plate-glass 
(or, if able to use the diamond, he may cut them himself); these 
should be of two sorts, one of 6-7"' in length, another form 
only 3-4"' in length. With these the walls of the cell are to 
be constructed. 
Beale, who, as is customary with Englishmen, explains the 
matter accurately, gives several additional practical directions. 
A thin glass cover may be used for the construction of very 
shallow cells. The thin glass may be cemented while warm 224 
SECTION TENTH. 
to a glass ring, or over a hole in a plate of glass, by means of 
the marine glue which is soon to be described. A hole is then 
to be forced through it with the point of a three-cornered file, 
and this is to be enlarged to the margin; the cracks do not 
extend across that part of the glass which is cemented. The 
perforated glass may be readily removed when again heated. 
A blunt-cornered, square cell may be made by bending a sin- 
gle strip of glass in the blow-pipe flame and melting the ends 
together. Beale recommends flint-glass for this purpose. In 
practised hands, this is certainly a very good way of making 
deep and large cells. 
All these cells must be cemented to the slide. But gutta- 
percha may be warmed in hot water, and its under surface then 
carefully dried and secured to the heated slide. This method 
has not proved to be durable. 
Marine glue may be used, after the manner of the English, 
for cementing the glass cells. 
This substance is prepared by dissolving, separately, equal 
parts of shellac and india-rubber in naphtha, and afterwards 
mixing the solutions thoroughly, with the application of heat. 
It may be rendered thinner by the addition of more naphtha. 
Marine glue is also readily dissolved by ether or a solution of 
potash. According to Quekett, the variety known in commerce 
as Gr. K. 4 is best adapted for microscopic purposes. 
The following process is necessary for cementing with marine 
glue : The slide is to be warmed on a heated plate of metal (the 
English use a table of sheet-iron supported by four feet, with a 
spirit-lamp burning under it). A narrow strip of the cement is 
then melted on the heated slide and made to extend overall the 
places on which the walls of the cell are to rest. Firm pressure 
is then to be made over the cell, and the whole placed aside to 
cool. The excess of glue may afterwards be removed with the 
blade of a knife. A weak solution of potash may be used for 
cleaning the cell. 
According to Harting, the following mixture serves for ce- 
menting the india-rubber cell: One part of very finely divided 
gutta-percha is to be mixed with fifteen parts of oil of turpen- 
tine, and dissolved at a gentle heat with constant stirring. It 
is then to be filtered through cloth, and one part of shellac 
added to the filtrate ; this is also to be dissolved at a moderate 
temperature and with constant stirring. The heating is to be THE MOUNTING, ETC. 
225 
continued until a drop of the mixture, when allowed to fall on 
a cool surface, becomes tolerably hard. In this condition, the 
cement is ready for use. When afterwards used, a little oil of 
turpentine is to be added. 
In order to fasten a caoutchouc cell, it is first to be held 
under the centre of the slide ; and exactly over it, on the upper 
surface of the slide, a thin layer of the warm cement is to be 
laid on with a brush. The cell is now to be pressed into posi- 
tion on the upper surface of the heated slide, which is then 
turned over and allowed to lie on. a flat surface till the cement 
has cooled. 
Harting’s gutta-percha cement may also be used in the same 
manner for fastening glass cells, and for building them out of 
four strips of glass. 
The latteT may also be accomplished with still another ce- 
ment. 
1 part of india-rubber is to be dissolved in 64 parts of chlo- 
roform, and then 16 parts of dried powdered mastic added. 
A thin layer of the cold mixture is to be placed on the slide 
with a brush ; the cell is then to be warmed and pressed into 
position. 
This cementing of the cell may also be accomplished in a 
very simple manner by means of a concentrated solution of 
shellac in alcohol. 
Whichever method is employed, it is well to fasten the cell 
as carefully as possible, in order that no leak or entrance of air 
into the cell may afterwards occur. A glass cell should always 
have a roughened surface for the cement. The surfaces may 
readily be roughened by rubbing on a flat stone with emery 
powder. 
Cells of tin-foil have also been recommended, but I have had 
no personal experience with them. 
Cells may also be made with certain cements; these are 
entirely sufficient for many thin objects. Bourgogne’s asphalt 
cement may be used for this purpose ; 1 prefer it to the white 
cement made by Ziegler, in Frankfort-on-the-Main (Friedberger 
Grasse, 23), formerly recommended but now found to be liable 
to crack. An oblong square, a quadrate, or a circle may be 
made with it on a slide, and left to harden. 
The cell having been filled with the preservative fluid, and 
the object immersed in it, and care having been taken that 
15 226 
SECTION TENTH. 
there are no air-bubbles present, the covering glass is breathed 
on and placed in position in the usual manner (fig. 98). The 
latter should always be somewhat smaller than the cell, so as 
not to completely cover its outer margin. The superfluous 
fluid is to be removed with caution, however, as otherwise 
air-bubbles may again 
enter, 
Now commences 
the cementing of the 
covering glass. This 
must be done at once, 
unless the preserva- 
Fig. 98. Placing the covering-glass in position. 
tive fluids be glycerine or a solution of chloride of calcium, in 
which case the process may be delayed. 
Four-cornered covering glasses regularly cause greater 
trouble in cementing than the circular ones. The latter may 
now be obtained, at a moderate price, from England, in Germany 
through glazier Yogel, in Giessen, and in Hamburg through the 
microscopical institute of Rodig. By the aid of the turn-table* 
represented in fig. 100, the cementing is a small matter. The 
round brass plate of the simple apparatus has a bow, which 
exerts pressure from a spring, and which may be elevated by 
the counter-pressure of the finger. Concentric circles engraved 
in the brass, according to the size of the covering glasses, show 
the place where the brush, which is held perpendicularly, is to 
draw the ring either on the slide or, when the covering glass is 
in position, over both. For this purpose the turn-table must 
be made to rotate slowly by the motion of the finger on the 
small notched disk beneath the table. Dip the smallest possi- 
ble brush in the cement, and press it at first very lightly on the 
glass, and afterwards turning the table more slowly, more 
firmly, but always perpendicularly. One soon learns to form 
even rings. The cement should, however, be of a more fluid 
consistence than that which is used for four-cornered covering 
glasses. 
In order to prevent a cemented preparation from Curving, it 
is advisable to use the simple, cheap compression apparatus 
already mentioned at p. 212, fig. 95. 
* This, as well as the compression apparatus, fig. 95, may be obtained from Th. 
Ernst, the optician, in Zurich. THE MOUNTING, ETC. 
227 
A considerable number of cements liave come into use, and 
preparations may be mounted with several of them with equal 
perfection and security. 
At present a solution of asphalt (Brunswick black) is most 
frequently used. Various sorts occur in commerce; it consists 
of a solution of asphalt in linseed oil and turpentine. 
G-ood Brunswick black should have a transparent, homo- 
geneous black appearance. As in the application of other ce- 
ments, a camel’s-hair brush is 
used, the stroke passing along 
the edge of the cover, whereby 
the latter as well as the slide re- 
ceives a stripe of cement (fig. 99). 
With a little practice, one soon 
learns to judge of the proper 
quantity to use, and to draw a 
handsome border. If, in the 
course of time, the Brunswick 
black becomes too thick, it may 
Fig. 99. Making a border with Brunswick black. 
be diluted with turpentine. Besides being dirty to handle, it 
also has the disadvantage of having a tendency to become 
cracked and fissured, and, after weeks and months, in conse- 
quence of its further contraction, to press the fluid out from 
the cell. It has therefore been recommended to strengthen the 
margins about every six months with a new layer of cement. 
This cement may also be considerably improved by the addi- 
tion of a small quantity of a solution of caoutchouc in benzine. 
In consequence of its great tendency to the above-mentioned 
defects, I have, of late, either entirely ceased to use the ordi- 
nary Brunswick black, or only use it for the first coating, es- 
pecially when strips of paper are placed between the slide and 
cover, and then, after several days, an external layer of cement 
is to be placed over this. 
I have recently become acquainted with the Brunswick 
black used by Bourgogne, of Paris, and can only speak of it in 
the highest terms. Unfortunately, its composition is unknown 
to me. It dries with comparative rapidity, and a single coating 
is quite sufficient. 
[A very good and durable substitute for Brunswick black 
may be found in the “Liquid Stove Polish,” prepared in Eng- 
land and sold in this country.] 228 
SECTION TENTH. 
A fluid mixture, coming from England under the name of 
gold-size, is excellent for cementing preparations of thin objects 
mounted in glycerine, and is also to be recommended as being 
clean to handle. It is a complicated mixture. Beale gives the 
following directions for its composition :—25 parts of linseed 
oil are to be boiled with one part of red lead, and a third part 
as much umber, for three hours. The clear fluid is to be poured 
off and mixed with equal parts of white lead and yellow ochre, 
which have been previously well pounded. This is to be added 
in small successive portions, and well mixed ; the whole is then 
again to be well boiled, and the clear fluid poured off and kept 
in a bottle for use. 
It is applied with a brush; a second layer may be added 
after half a day. It is better to leave specimens thus prepared 
for a considerable time before making the final application of 
cement. 
The turn-table and round covering glasses permit of a much 
more simple procedure. A cement ring is made on the slide 
Fig. 100. English turn-table, with Prey’s improvement. 
with Bourgogne’s mass, with the margin of the ring of cement 
extending beyond that of the covering glass. This makes a 
flat cell. The object is placed in this with a carefully measured 
drop of fluid. A minimal covering of cement goes over the ring, 
the covering glass is placed in position and pressed on the 
sticky substance. One or more layers of cement are subse- 
quently added to the borders. Dry mounted preparations are 
also treated in this manner occasionally. 
At the commencement period of microscopical technique 
various cements were used for the moist mounting of animal 
preparations. In the earlier editions of this book I recom- 
mended Ziegler’s white cement; now, after many years’ ex- 
perience, I must acknowledge very wrongly. All such speci- 
mens of my collection of preparations have, without exception, THE MOUNTING, ETC. 
229 
been ruined by rents and cracks in this cement (often, it is true, 
only after a long period). 
Schacht recommended the so-called mask lac, which dries 
very rapidly, as a cement for wet preparations, and also as a 
coating for specimens mounted in Canada balsam or copal. 
The variety of lac used by him is designated as No. 8, at Bese- 
ler’s lac manufactory in Berlin (Schiitzen Strasse, No. 66). I 
made considerable use of this lac several years ago, and do not 
hesitate to recommend it as being the next best to Bourgogne’s 
cement. When concentrated it forms an excellent enclosure 
for four-cornered covering glasses ; when diluted with absolute 
alcohol it is also serviceable for round covers, with the use of 
the turn-table. It is of a deeper, purer black than Bourgogne’s 
cement, which has a more brownish black appearance. 
We also mention a cement which is to be used in the man- 
ner already indicated as a final coating for Canada balsam prep- 
arations. We are indebted for a knowledge of this to a 
friendly communication from Thiersch. 
When the specimens have been mounted for several days, 
weeks, or even months in pure Canada balsam, or a solution 
of the same in chloroform, they are surrounded with a border * 
of Canada balsam dissolved in chloroform, in the manner indi- 
cated above (fig. 99 and 100) for asphalt. Later—but never 
before the second or third day, still better after weeks or 
months—a final coating is to be applied. This consists of a 
colored and thick varnish of shellac. It is found ready pre- 
pared with alcohol at the wholesale druggists. It is to be 
carefully evaporated to the consistence of thin mucilage and 
colored with a filtered, concentrated solution of anilin blue or 
gamboge in absolute alcohol. Finally, about a scruple of cas- 
tor oil is to be added to each ounce of the mixture, and after 
some further evaporation it is to be preserved in a well-closed 
vessel. If, after a time, it should become too concentrated, 
this may be remedied by the addition of a few drops of abso- 
lute alcohol. 
This varnish is to be applied with a brush to the borders of 
the Canada balsam. It becomes hard in a few hours, and then 
* With alcoholic resinous solutions I also frequently use a preliminary enclosure 
of Canada balsam in chloroform, and then, after several days, use the above-men- 
tioned Bourgogne’s black cement. 230 
SECTION TENTH. 
forms an elegant and hermetic covering for objects mounted in 
resinous substances. 
The aniline blue has entirely faded, however, after a few 
years. 
Finally, the form and size of the slides are not unimportant 
for the elegant appearance of a collection of preparations. 
Similarity of form, so far as it is possible, is desirable for 
greater convenience of keeping or of occasional transporta- 
tion. 
The art of grinding the edges of the slides may soon be 
learned by employing a very thick plate of glass and a fine 
sort of emery powder, which is to be made into a paste with 
water. 
The slide should not be too small, so that sufficient space 
may be left at the ends of the preparation to affix two labels, 
one of which is to contain the general designation, while on the 
other especial remarks, the number of the collection, etc., may 
be placed. In certain cases there should also be room left for 
the indicator.* Such slides will frequently afford room for 
larger objects, and thus render it unnecessary to select a differ- 
ent form for special objects; as, for example, when an exten- 
sive section of bone or a voluminous injected preparation is to 
be mounted. 
I prefer a glass slide like those of the English collections, 
three British inches long by one inch wide (72 mm. by 24 mm.), 
above all others (fig. 101). The preparations of Bourgogne of 
Paris also have this convenient and handsome form. Slides of 
a larger size are unnecessary and appear too unwieldy. But 
* Various indicators or object-finders have been proposed for enabling one to 
find any particular place in a preparation. Fine divisions, like those of a rule, may 
be photographed on narrow strips of paper, and one of these strips pasted at one of 
the broad, and one at one of the narrow margins of the cover; for example, at the 
right and the lower side of fig. 101. A rectangular plate of metal, or, better still, a 
small square, consisting of two narrow strips of brass meeting each other under an 
angle of 90°, is used for ascertaining the particular portion of the object; this is to 
be noted on the preparation, and may be again readily found with the little plate or 
the square. The best—because the most simple—arrangement has been indicated 
by Hoffmann. Two crosses are to be scratched at either side of the aperture of the 
object stage of the microscope, the one standing (+), the other reclining ( x). If, now, 
the portion of the preparation to be marked is situated in the centre of the field, 
both crosses are to be drawn with ink on the slide exactly over those of the stage. 
It is only necessary to place these marks over each other again in order to at once 
find the object. THE MOUNTING, ETC. 
231 
those of a smaller size should also never be employed. A pat- 
tern, proposed in Giessen, 48 mm. in length by 28 mm. in width, 
is inelegant, and much less convenient than the English. 
If it be desired to place microscopic preparations in layers, 
for the sake of greater economy of room, either in keeping or 
in transporting them, the employment of protection-ledges 
(Schutzleisten) is to be recommended. These are narrow strips 
Pig. 101. English object slide. 
of glass which are to be cemented across the slide at either side 
of the object. They should naturally be higher than the cover 
and the cell. Although this arrangement is, of itself, quite 
practical, it nevertheless diminishes the room necessary for the 
labels to an unpleasant extent. 
For preserving and arranging specimens, boxes of wood or 
pasteboard, with grooved wooden racks at the sides, which 
hold the slides securely, are occasionally used. As, with 
these, the slides stand vertically and the preparations may in 
consequence readily sink, when mounted in resinous sub- 
stances which have not thoroughly hardened, or when other 
fluid media have been used, the upright position of such boxes 
deserves the preference. On the other hand, trays of wood or 
pasteboard with very low borders, or plain drawers, may be 
used ; they may either be arranged to slide out, like a chest of 
drawers, or they may simply rest on each other and be removed 
from the chest by means of loops. Slides of the most vary- 
ing sizes may be conveniently placed in them at the same 
time, and the sinking of the preparation is also avoided. 
This arrangement, however, is not serviceable for transporta- 
tion. 
Here, as with all collections (increasing in degree with its 
growth), regularity and occasional revision are imperatively 
necessary. 
As every assiduous microscopist of the present time pos- SECTION TENTH. 
sesses his own collection of preparations, so likewise do the 
various microscopical associations of Germany. For example, 
those of Frankfort-on-the-Main and of Giessen, as also the 
Microscopical Society of London. 
Among the private collections we enumerate the celebrated 
one (preparations of injections) of Hyrtl, in Vienna; that 
of Kolliker, in Wurzburg; Gerlach, in Erlangen ; those of 
Thiersch and Leuckart, in Leipzig; Welcker, in Halle; and 
Schultze, in Bonn. In Holland is the collection of Harting; 
in London are those of Carpenter, L. Beale, L. Clarke, and 
others, likewise that of the College of Surgeons ; in Manches- 
ter, that of Williamson. Among the Swiss collections may be 
mentioned those of His, in Basel; in Zurich, those of Goll and 
myself. 
Preparations may be purchased of Hyrtl and G. A. Lenoir, 
in Vienna; J. B. Moller, in Wedel, Holstein; C. Rodig, in 
Hamburg; Schaffer and Budenberg, in Magdeburg; Bour- 
gogne (9 Rue de Rennes), Paris; of Smith and Beck, also of 
Topping (4 ISTew Winchester Street, Pentonville), and of Pil- 
lischer (88 New Bond Street), London. Injections and other 
preparations of the author are to be obtained from the Magde- 
burg establishment already mentioned, from Lenoir, in Vienna, 
and from the optician Th, Ernst, in Zurich. Section (Elcucntl) 
BLOOD, LYMPH, CHYLE, MUCUS, AND PUS. 
The investigation of these cell-containing fluids belongs to 
the more easy and simple labors of the microscopist, inasmuch 
as a drop of the same, having been placed on the slide by 
means of a glass rod, and spread out into a thin layer by the 
covering glass, suffices for the first examination. But care is 
to be used in the selection of actually indifferent media, espe- 
cially in the examination of living cells. 
1. Among the animal fluids mentioned, the blood is the most 
delicate substance, so that circumspection is necessary for the 
recognition of its normal condition. 
In order to examine human blood, it is only necessary to 
prick the point of the finger and allow a drop to exude, which 
is then received on the slide. For more continued and pro- 
longed investigations a quantity of blood is to be obtained by 
means of venesection, and beaten to separate the fibrin. The 
blood of the smaller animals is to be obtained by opening one 
of the larger vessels of the heart; the blood 
may be received in a test tube. If allowed 
to remain in this, or in a cylindrical vessel, 
the cells gradually sink and the serum which 
remains above them becomes colorless. This 
Hold is the best medium for use in the inves- 
tigation. 
In consequence of the extraordinarily large 
number in which the colored cells (fig. 102, a, 
Fig. 103. Human blood- 
cells. a, a, seen from 
above ; 6, half ; c, c, en- 
tirely from the side ; d, a 
lymph corpuscle. 
c) occur in the blood, it should be spread out in a very 
thin layer, so as to bring these elements distinctly into view. 
Slight compression made on the covering glass with the point 
of the needle will facilitate the examination considerably. In 
human blood (fig. 102), when these cells have their broad sur- 234 
SECTION ELEVENTH. 
face turned towards the observer, they present the well-known 
form of circular disks {a, a), but when standing on their sides 
they appear biscuit-shaped (c, c). 
Dilution of the blood requires some little attention. The 
serum of the blood, if disposable, is best for this purpose. 
Solutions of salt, sugar, or crystalloid matter may also be 
used with advantage for a momentary examination, provided 
they are of the proper degree of concentration. The Pacinian 
fluid (sublimate, salt, and glycerine with water), which has 
already been mentioned (p. 217), is very suitable if it happens 
to be at hand, and I know of no other fluid which is capable 
of preserving our cells in so excellent a manner for years. 
The iodine serum is also very useful, and likewise, according 
to Rollett, a mixture resembling Muller’s eye fluid. The latter 
consists of one part of a cold saturated solution of the bichro- 
mate of potash, 5 parts of a similar solution of the sulphate of 
soda, and 10 parts of water. 
Such dilutions will also be necessary when it is desired to 
cause the colored blood-cells to roll, in order to recognize their 
form. The pressure of the point of a needle on the edge of 
the covering glass will then induce 
the desired current in the fluid. 
Upon carefully focussing, the hu- 
man colored blood-cells will appear 
to present a yellowish circumference 
and a colorless centre. If the tube 
of the microscope be depressed a 
little, the central portion becomes 
somewhat darker. 
bioFodG-10aContractilecellsfromhuman 
The colorless cells of the blood 
originate in the lymphatic glands, 
the spleen, and the marrow of bones. 
Dilution with an indifferent fluid is also necessary for their 
recognition, and, in consequence of the small number of these 
elements, they require some little search (figs. 102, d, 103). 
Even in human blood taken directly from the vein, one 
may, with a 4-600 fold enlargement, and without any further 
precautionary measures, observe the remarkable changes of 
form of the living colorless cells, which may slowly pass 
through the series of alterations which we have sketched (fig. 
103). But if the warm stage (p. 101) and a temperature of 38- BLOOD, LYMPH, CHYLE, MUCUS, AND PUS. 
235 
be used, and iodine serum added, the play of move- 
ments mentioned becomes extraordinarily lively. A portion of 
the colorless cells now creep about between the colored blood- 
corpuscles and present, with constantly changing form, the 
strangest variety of shapes. Granules of carmine, molecules 
of cinnabar and indigo, which have been added to the fluid, are 
now readily taken up into the cell-body (Schultze). An ex- 
tremely fine granulated anilin .blue, which has been precipi- 
tated from the alcoholic solution by means of water, is very ex- 
cellent.—If this apparatus is wanting, one may readily per- 
ceive the same condition in the lymph corpuscles of frog’s 
blood, with the aid of the moist chamber. Very beautiful ap- 
pearances may be obtained with the latter animal, if a drop of 
its fresh blood be allowed to coagulate on the under surface 
of the covering glass, in a moist chamber (after the manner 
of our fig. 73). One soon notices, after a zone of serum has 
formed at the borders of the coagulum, that, in consequence 
of their lively wandering from the clot, many of these amoe- 
boid cells have penetrated the ring of fluid, and that the 
surface of the coagulum is also thickly covered by them 
(Rollett). 
We will here mention still another method which has re- 
cently led to scientific results of the highest interest (Cohn- 
heim). 
A small quantity (at most, a few ccm.) of one of the above- 
mentioned finely granulated coloring materials, suspended in 
water, is to be injected, for several days after each other, into 
one of the large lymph spaces which lie under the skin of the 
frog, A Pravaz syringe, such as is used in practical medicine, 
may be used for the injection. On examining a drop of the 
blood, a considerable number of the colorless cells will now be 
seen to be stuffed (“ gef fitter t ”). We shall afterwards return 
to this matter. 
Some preparation is necessary in order to count the num- 
bers of both kinds of cells. The test blood must naturally be 
spread out into the thinnest layer, and the space to be sur- 
veyed divided. An eye-piece micrometer with a small number 
of quadratic fields fulfils this object. In consequence of the 
sparseness of lymph-cells in normal human blood (0.5 to 2-3 
per thousand), and likewise in mammalia, it is necessary to 
count a large number of blood-corpuscles in order to obtain 236 
SECTION ELEVENTH. 
even a tolerably accurate result. One should not stop under 
10,000-16,000.* 
The fluid of the blood, the so-called plasma, appears, as a 
rule, entirely clear like water, and free from all elementary 
forms, and therefore is not an object of microscopic examina- 
tion. As a result of an exuberant reception of fat in the blood, 
the unsaponified fat of the chyle (see below, at this fluid) may 
appear in it in the condition of the finest division, in the form 
of dust-like molecules. 
It was formerly hoped that the microscopist might discover 
changes in the form of the blood-cells in disease, and in this 
way be able to promote pathological physiology as well as 
diagnosis. These beautiful dreams have not, in general, been 
fulfilled. However various its composition may be, the blood 
presents the same microscopic appearance. It is also to a cer- 
tain degree the case, that even with regard to the normal life 
of the blood a considerable obscurity still prevails,—that we 
have but an extremely incomplete conception of the new for- 
mation and disappearance of the cells. 
However, although nothing of importance is to be perceived 
in the endosmatic changes in form of the colored blood-cells, 
which have been here and there described in processes of dis- 
ease, and just as little in the shreds of the loosened epithelium 
of the vessels, the microscope has nevertheless afforded us an 
interesting glimpse of two pathological processes of our fluid ; 
we mean the so-called leucsemia and melansemia. 
The former, coinciding with an increase in volume of the 
spleen and often, at the same time, of the lymphatic glands, 
although but seldom caused by enlargement of the latter 
organs alone, leads to a constant increase in the number of col- 
orless cells in the blood, so that finally the alteration of the 
blood no longer remains concealed from the naked eye. A 
drop of such blood (obtained by pricking the point of the fin- 
ger with a needle) shows, together with the colored, a consid- 
erable number of colorless blood-corpuscles. This may pro- 
* Malassez lias recently given very accurate directions for counting tlie blood-cor- 
puscles, but which cannot be understood, however, without figures showing the ap- 
paratus to be used. The author found the number of colored blood-cells in a cubic 
millimetre to vary from 18,000,000 to 3,000,000 for mammals, from 4,000,000 to 1,600,- 
000 for birds, from 2,000,000 to 700,000 for osseous fish, from 230,000 to 140,000 
for cartilaginous fish. BLOOD, LYMPH, CHYLE, MUCUS, AND PUS. 
ceed to such an extent that to three colored blood-corpuscles 
there will be one or even two colorless ones, and in certain 
cases the number of the latter variety of cells will be greater 
than that of those containing hsematin. Transition forms of 
both kinds of cells may also be met with (Klebs, Eberth). 
In malignant forms of intermittent fever the enlarged spleen 
has been seen to have a blackish appearance. The microscope 
shows, as a cause of this change of color, granulated lymphoid 
cells, often of considerable extent, and which contain within 
them granules of the black pigment. Passing out through the 
splenic vein, they become mixed with the blood and are seen in 
this fluid when it is subjected to microscopic examination. In 
consequence of their size they produce obstructions in certain 
capillary districts, especially in the brain and liver. 
Embryonic blood is to be examined in the same manner. 
The warmable stage is to be used when it is desired to follow- 
the very rapid progress of the division of the nucleated colored 
cells. The instability of these cells is, moreover, very great, so 
that one may often be misled by artificial products. 
Recklinghausen communicated a singular discovery to us a 
few years ago. After a series of days one may see the lym- 
phoid cells become transformed into red blood-corpuscles, in 
blood taken from the frog, if one understands preserving its 
vitality. 
For this purpose the blood is to be received in a glazed por- 
celain dish, which is to be placed in a large glass vessel, the air 
in which is to be daily renewed, and kept constantly moist. 
After twenty-four hours the coagulation gives place to a pro- 
cess of liquefaction ; a few days later, island-like collections of 
contractile lymphoid cells have become formed; after 11-21 
days one may recognize the first of the new-formed blood-cor- 
puscles. Frog’s blood may be preserved in this way for thirty- 
five days without decomposition taking place. 
By means of an electrical discharge the colored blood-cor- 
puscles are rendered corrugated, at first with coarse, then with 
fine indentations.* These processes afterwards disappear, and 
the blood-corpuscle becomes transformed into a smooth bor- 
dered globule, which finally undergoes discoloration (Rollett). 
* The thorn-apple form appears to occur by no means rarely in the blood of patients 
with fever. 238 
SECTION ELEVENTH. 
The living blood-cells of man and the mammalia undergo a 
very singular alteration (tig. 104) when exposed to a tempera- 
ture of 52° C. on the hot stage, represented in fig. 75. A num- 
ber of deep indentations rapidly take place, which very soon 
become constrictions, causing the formation of globules on the 
surface of the cell. These are either separated at once or con- 
tinue for a time to be connected, by means of a long, slender 
pedicle, to the remainder of the cell body (a). The strangest 
appearances are thus caused, such as bead-like rods, globules 
with projections like handles, etc. When these fragments be- 
Fig. 104. Human blood-cells 
heated to 52° C. 
Fig. 105. a, Human blood-cells under the action of water ; b, 
in evaporating blood ; c, in a dried condition ; cl, in coagulated 
blood; e, rouleaux-like arrangement. 
come separated, they commence the most lively molecular move- 
ment (Beale, M. Schultze). 
The treatment of the blood-corpuscles with chemical reagents 
is indispensable for the accurate investigation of their structure, 
and is a very good exercise for the beginner, especially if the 
large nucleated cells of the naked amphibia are used in the 
place of the small non-nucleated corpuscles of human and 
mammalial blood. 
Distilled water is used to cause them to swell (fig. 105, a). 
The bright central portion disappears at once and a uniformly 
yellowish structure is seen which rapidly loses its color, and 
which, in rolling, permits its globular form to be recognized. 
In this way the granulated nucleus may be rendered distinct 
in the blood-cells of fish, amphibia, and birds. Many watery 
solutions in a condition of extreme dilution exert a similar ef- BLOOD, LYMPH, CHYLE, MUCUS, AND PUS. 
feet. For comparison, it is useful to treat, in a similar manner, 
the large nucleated blood-cells of the first three classes of ver- 
tebrates. In order to obtain them in a shrivelled condition (tig. 
105, h), it is only necessary to leave a drop of blood uncovered 
on a slide for a few minutes, in which case the familiar corru- 
gated and indented forms make their appearance. A very 
small drop of blood, taken from the living body by pricking 
with a fine needle, not unfrequently presents this indented ap- 
pearance of the cells on the glass slide at once. We can obtain 
a similar effect by means of numerous concentrated solutions, 
such as those of salt, sugar, and gum. 
If, on the contrary, we rapidly dry the blood-corpuscles on 
a glass slide, we have the appearance represented by fig. 105, 
c, a form in which the blood-corpuscles may be very well pre- 
served as a permanent preparation. 
Other reagents dissolve its substance, and in this way de- 
stroy the cell. Diluted acids produce this effect, likewise weak 
solutions of the alkalies. Although concentrated solutions of 
the latter cause the blood-corpuscles to swell, they do not de- 
stroy them, even after acting on them for hours. A saturated 
solution of potash is, as Bonders found, an excellent medium 
for rendering the cells of dried blood again visible. 
Many materials have a coagulating effect on the cell sub- 
stance of the blood-corpuscles. Among these are to be enu- 
merated alcohol, concentrated chromic acid, sublimate, and 
other metallic salts. 
In defibrinated, but also very generally in a drop of freshly 
removed blood, one may observe the familiar Joining together 
of the colored cells with their broad surfaces, the so-called 
rouleau formation (fig. 105, e). This arrangement is missed 
only in the more distended and globular cells of the blood in 
the splenic and hepatic veins. 
In order to ascertain the appearance of coagulated blood, 
one may either allow a drop of blood to coagulate on the slide, 
or the finest possible section may be taken from a clot. The 
cells will then be seen to be embedded in a homogeneous layer 
of fibrin which has the appearance of folds or filaments (tig. 
105, d). 
Indifferent fluids are necessary in the examination of blood 
extravasations, for the proper estimation of the condition of 
the cells. 240 
SECTION ELEVENTH. 
The origin of fresh clots of blood, treated in the same man- 
ner, may be ascertained by microscopic analysis. One will be 
able, for example, to distinguish, by their form and size, the 
cells of the blood of birds from those of human blood, etc., and 
in this way to detect impostors. It is difficult, and in many 
cases impossible, to render a decision in old masses of dried 
blood. The character of a spot which is suspected to be blood 
may, on the contrary, be determined in the most certain man- 
ner by means of Teichmann’s hsemine test, a subject to which 
we shall again refer. 
The accessories mentioned under lymph and chyle are to be 
used when the further investigation of the colorless blood-cells 
is necessary. 
It is only under certain circumstances that the colored 
blood-cells can be tinged with carmine, but this may be readily 
accomplished with anilin red; still, nothing is to be gained 
thereby. 
The above-mentioned process of rapid drjdng may be very 
advantageously employed for preserving blood-cells perma- 
nently as preparations for a collection. I have in my possession 
preparations of the blood of different animals which are more 
than twenty years old, and which leave nothing to be desired. 
The first-mentioned Pacinian fluid is adapted for mounting 
the cells of human blood moist; Pacini’s second mixture (see 
p. 218) serves for the colorless cells of the blood. 
Solutions of sublimate, as formerly mentioned (p. 218), have 
also been recommended. Parting employs for the blood-cells 
of man and the mammalia, 1 part of bichloride of mercury to 
200 of water, for those of birds 1 to 300, for those of the frog 
Ito 400. Remak employed, for embryonic blood-cells, very 
weak solutions of the bichromate of potash, of chromic acid 
(0.03 per cent.), and of sublimate (0.03 per cent.). 
We should make ourselves responsible for a considerable 
deficiency were we to omit mentioning the various crystalliza- 
tions which are to be obtained from the colored blood-corpus- 
cles. This subject has in our day been zealously and persist- 
ently investigated; but, regarded from a scientific point, this 
matter leaves, even yet, much to be desired. 
From the blood of man and the various vertebrated animals, 
including birds, one may obtain the coloring substance of the 
cells in a crystalline condition ; the so-called blood-crystals be- BLOOD, LYMPH, CHYLE, MUCUS, AND PUS. 
241 
ing formed. This substance has been called haemoglobin or 
hsemato-crystalline. Many investigations have been instituted 
concerning these remarkable structures by Funke, Lehmann, 
Kunde, Teichmann, Rollett, Bojanowski, and others ; Reichert 
having previously discovered in them a crystallized, colorless, 
albuminous body. 
According to the general acceptation, the blood-crystals 
present various forms, such as prisms, tetrahedes, hexagonal 
tables and rhomboids. The 
prismatic form is regarded as 
the most common, and ap- 
pears in man and most of the 
mammalia (fig. 106 «, c), to- 
gether with which, rhomboid- 
al tables (5) may also be met 
with. Tetrahedal (but not 
regular) crystals are formed 
by the haemoglobin of the 
guinea-pig (d) and, as is gen- 
erally alleged, of the mouse ; 
rhomboidal crystals are met 
with in the hamster (e), hex- 
agonal tables (/) in the squir- 
rel (and mouse ?).* 
With regard to the man- 
ner of producing blood-crys- 
tals, we limit ourselves to the 
following examples:— 
They are to be prepared 
for microscopic examination 
according to Funke’s direc- 
tions. A drop of blood is to 
be placed on the glass slide, 
whereit is left in contact with 
Fis. 106. Blood-crystals of man and several of the 
mammalia, a, blood-crystals from human venous 
blood; 6, from the splenic vein ; c, crystals from the 
blood of the heart of the cat; d. from the jugular 
vein of the guinea-pig; e, from the hamster ; and /, 
from the jugular of the squirrel. 
the air for several minutes. A drop of water is then to be 
added, and the whole breathed on a few times. A covering 
glass is now placed over it, and evaporation allowed to take 
place slowly, whereby the crystallization is promoted by the 
action of the light. 
* In reality, nearly all blood-crystals belong to the rhomboidal system, only those 
of the squirrel to the hexagonal. 242 
SECTION ELEVENTH. 
Bojanowski recommends the following procedure : Blood, 
as it escapes from the vein, or still better, such as is taken 
from the vessels of a dead animal, is to be kept in a vessel for 
2-4 days in a cool place, whereby the coagulum begins to dis- 
solve into a thick, fluid, dark red to blackish mass. A drop 
of this fluid is to be placed on the slide, covered, and exposed 
to the light for a few hours. The crystals may then be seen. 
If the blood which is to be used for this purpose is too thick, 
the drop may be very suitably diluted with distilled water. 
Rollett, who has also produced a very valuable work on 
blood-crystals, makes use of a blood, the cells of which have 
been destroyed by freezing and remelting. The formation of 
crystals also readily takes place in electrified blood, and in that 
of the guinea-pig (which of all kinds of blood crystallizes the 
most readily) tills is often so rapid as to appear “as though 
the crystals had been struck out with the spark.” Blood 
from which the gases have been 
pumped out is also well adapted 
for obtaining hsemato - crystal- 
line. 
Chloroform with the access 
of air also causes the formation 
of our crystals (Bottcher). 
Lehmann has taught us how 
to produce crystals of the hydro- 
chlorate of hsematin (figs. 105, 
106). 
They are to be obtained by 
treating fresh blood or large 
spots of blood which are two 
Fig. 107. Crystals of hydro-chlorate of haa- 
matin. 
days old with alcohol containing oxalic acid and ether (1 
part alcohol, 4 parts ether, and TV of a part of oxalic acid). 
Preserved in well-closed bottles, the crystals are gradually 
precipitated from the fluid; the process is hastened by the 
addition of chloride of calcium which has become liquefied 
by exposure to the air. Where the separation takes place 
more rapidly the crystals are more of the acicular form, as 
represented at the lower part of fig. 107; if more slowly, 
either the hexagonal tables of fig. 107 or the crystals which 
are represented in fig. 108. They appear to have a long and 
narrow laminated shape and twisted one or two times on BLOOD, LYMPH, CHYLE, MUCUS, AND PUS. 
their long axis. They are very thin, of a brownish and brown- 
ish-green translucency, as represented at the upper half of fig. 
108. If allowed to remain for some time in the mixture of 
alcohol and ether in which they 
were precipitated, we have pro- 
duced, as another modification, 
the crystals given in the lower 
half (to the right) of the figure, 
quadratic and also rhomboidal 
black tables which, by more ac- 
curate examination, prove to be 
flat rhomboidal octahedrons. 
Teichmann has produced crys- 
tals of the same modification of 
hsematin and called them hse- 
min. The coloring matter of the 
blood, in its different conditions, 
is to be dissolved by means of 
hot concentrated acetic acid, so 
as to become separated in crys- 
talline form as it cools. A con- 
Fig. 108. Crystalline forms of the hydro- 
chlorate of hsematin. 
dition of the precipitation is the presence of alkaline chlorates. 
The hsemin crystals obtained present the appearances repre- 
sented in fig. 109, as rhomboidal tables of a blackish-brown, 
sometimes blacker, more rarely light-brown color. 
By proper treatment the crystals 
with which we are at present occupied 
may be obtained from blood which is 
either fresh or decomposed by putridity, 
from that which is dried, and even from 
the oldest blood-stains, Hsemin is there- 
fore of great importance in a forensic 
point of view, and forms the best means 
of recognizing the origin from blood of 
a suspected stain. 
If it be desired to produce a some- 
what larger number of crystals, a quan- 
fig. io9. crystals of hremin. 
tity of blood is to be boiled for about a 
minute or two in the 10-20 fold volume of glacial acetic acid and 
filtered. As the fluid cools it becomes somewhat cloudy, and a 
blackish sediment is deposited, consisting of crystals of hsemin. SECTION ELEVENTH. 
For the momentary demonstration the following process is to 
be employed :—A drop of blood is to be rapidly dried on the 
slide, over the spirit lamp, and then scraped to a powder with 
the point of a knife. About 10-20 drops of anhydrous acetic 
acid is to be added and allowed to boil a few times ; the slide 
is then to be set aside for a few moments. A drop of blood, 
diluted with 15-20 drops of glacial acetic acid and placed in 
a watch-glass on the stove, also forms the crystals in question, 
as the fluid evaporates. They are likewise deposited when 
blood is mixed with an excess of concentrated acetic acid. Af- 
ter a few days a film, consisting of these crystals, is formed on 
the surface ; after the removal of this a second is formed, and 
so on. 
In order to obtain the hsemin crystals from an old blood- 
stain, the stained substance is isolated and placed in a test- 
tube, glacial acetic acid is then poured over it and boiled for a 
few minutes ;it is then filtered into a watch-glass. This fluid, 
to which more acid is to be added, is then exposed to evapora- 
tion in a warm place. lam indebted to the kindness of Dr. A. 
Schmidt, of Frankfort, for a preparation of hsemin which was 
obtained from a pocket-handkerchief 
saturated with blood at Sand’s execu- 
tion. 
Hsemin crystals, in consequence of 
their durability, may be very readily 
preserved as microscopic preparations. 
They may be mounted dry or in gly- 
cerine. 
In old blood extravasations, for ex- 
ample, those of the brain, in hemor- 
rhagic infarctions of the spleen, in ob- 
literated veins, in the corpus luteum 
(Ordinary form.) 
of hajmatoidm. 
crystals of hsematoidin, discovered by 
Virchow, are formed (fig. 110); they differ from the biliru- 
bin which occurs in the bile. They generally occur in small 
rhomboidal prisms of a lively orange or ruby-red color, with 
dark carmine-red borders and edges. Together with these, 
amorphous precipitates of hsematoidin, in granular and globu- 
lar masses, will be frequently met with. 
Staedeler succeeded, by treating the ovaries of the cow with 
chloroform, or with sulphuret of carbon, in obtaining uncom- BLOOD, LYMPH, CHYLE, MUCUS, AND PUS. 
245 
monly large crystals (fig. Ill) of onr coloring material, some of 
them measuring even 0.2'". These make their first appearance 
under the microscope as acute-angled, three-sided tables, with 
one convex side (a), although this convex side may also be re- 
placed by two direct lines, so that deltoid tables (5) result. 
Two such tables usually become united like twins, their con- 
vex sides coming in contact with or overlapping each other, 
and melting together {h, c). In this manner are formed the 
rhomboidal tables, usually designated as hsematoidin (fig. 110). 
As a rule, there are at first indentations in the place of the ob- 
tuse angle of the rhombus, which gradually become filled out 
(d, d). Not unfrequently two other crystals also become 
united with the first two individual crystals, so that four-rayed 
Fig. 111. Very large crystals of hsematoid- 
in obtained from the ovarium of the cow by 
treating with chloroform. 
Fig. 112. The blood-current in the web of 
the frog, a, the vessel with the colored 
blood-corpuscles in the axial portion, and the 
colorless cells in that portion of the current 
near the walls; b, the epithelial cells of the 
tissue. 
stars now appear (<?). By the filling out of their re-entering 
angles four-sided tables (/', g) are formed, which, by increas- 
ing their thickness, finally assume the appearance presented 
by dice when seen somewhat from the side (Staedeler). 
Preparations of hsematoidin may be readily and well pre- 
served dry or lying in glycerine. 
We have reserved the most interesting portion of this sec- 
tion for the end; the movement of the blood in the living ani- 
mal body is still to be discussed. 
In order to see the blood flowing through the vessels of the 
living animal (fig. 112), it is necessary to select transparent 
localities. The web of the hindfoot of the frog, the transpar- 246 
SECTION ELEVENTH. 
ent tail of the larvae of the frog and salamander, the embryos 
of fish and small recently-hatched fish are exceedingly well 
adapted for the first observations. 
If the larvae of frogs are nsed, the anterior portion of the 
body is to be enveloped with a strip of moistened blotting- 
paper, and the tail, after being moistened with water, is to be 
covered with a thin covering glass. If the frog itself is to be 
nsed, a strip of wood or cork containing a glass window, 5 or 6 
lines in size, which goes over the hole in the stage, is to be em- 
ployed. The frog is to be wrapped in a moistened rag, or en- 
closed in a small linen bag, and secured to the wooden strip. 
The web is to be expanded by means of pins (but without too 
great tension), and, after being moistened with water, a thin 
covering glass is to be placed over it; it is best to have the lat- 
ter three-cornered or rhomboidal in shape. Instead of the sim- 
ple strip of wood, a small table may be very suitably arranged 
for supporting the frog. Frog-holders have been invented for 
this purpose; they are quite superfluous. If one has the re- 
markable muscle-poison, woorara, at one’s disposal, it is only 
necessary to inject a minimal quantity of the same under the 
skin to render our animal, after a few hours, immovable for a 
considerable time—one or two days—so that the simplest 
Fig. 113. Object-slide for the larvae of frogs and salamanders. 
arrangement is then all that is necessary. An object slide of 
considerable size, on which is cemented a small, thick, right- 
angled plate of glass with a cork ring surrounding it, for fast- 
ening the toes to, is then sufficient. For tadpoles, the ante- 
rior portion of the body may be simply enveloped in a strip of 
blotting-paper, and the tail, with the addition of water, covered 
with a thin glass. Object slides with long, four-sided excava- 
tions, as proposed by F. E. Schulze, and represented in section 
by our fig. 118, are very well adapted for the examination of 
the larvae of naked amphibiae and young fish. The head goes 
under the edge u, and the tail of the animal lies on the inclined 
surface h. The whole is to be covered with a thin glass. The 
apparatus may be very readily constructed by cementing four 
pieces of glass on to a slide. BLOOD, LYMPH, CHYLE, MUCUS, AHD PUS. 
247 
In examining the circulation, only very weak lenses should 
be employed at first, in order to obtain a more considerable 
view of the relations of the currents. Then proceed to the use 
of higher powers, with which the details, especially in the 
capillary vessels, are to be investigated. It is unnecessary to 
remark that the apparent rapidity of the current is in this 
way very much increased. In reality, this is by no means 
considerable in the capillary districts. A corpuscle of frog’s 
blood passes through the fifth or fourth part of a line in a 
second. 
The colored, in contradistinction to the colorless elements 
of the blood of the adult animal, are without any vital contrac- 
tibility, as may be best learned by just these observations of 
the circulation of the frog ; it is only possible to recognize 
here certain passive changes of the so flexible and elastic 
cells. 
A discovery recently made concerning an anomalous condi- 
tion of the blood-cells of the mammalia is of interest. So long 
as they remain in the circulation, they but rarely appear in the 
above-mentioned form of the passive condition, but rather pre- 
sent the greatest variety of shapes, so that that which in the 
frog formed an exception has here become the rule. Even this 
only concerns a passive condition, for as soon as they become 
quiet they again resume the familiar cup shape (Rollett). 
The mesentery of the frog is to be recommended for study- 
ing the condition of the circulation during the process of in- 
flammation (Cohnheim). Take a sufficiently large plate of 
glass, cement to this a small glass disk nearly a line in thick- 
ness and of about 12 mm. diameter, and around the latter a 
narrow (about 1 mm. broad) cork ring. An opening is to be 
made through the abdominal walls on the left side of a frog 
which has been paralyzed with woorara, the mesentery is to 
be drawn out, and the loop of intestine fastened with a few 
fine needles to the cork ring. The simple irritation of the 
air produces the inflammation, and if the mesentery be pro- 
tected from drying the process may be studied for many 
hours. 
Small mammalia, maintained in a condition of narcosis by 
means of ether or chloral, may also be used for such investiga- 
tions, although with the assistance of manifold complicated 
apparatuses (Strieker and Sanderson). 248 
SECTION ELEVENTH. 
But let us return to the mesentery (fig. 114) of our frog! 
Dilatation of the vessels (at least of the capillaries) gradually 
takes place, sluggishness of the current follows, and numerous 
lymphoid cells collect at the colorless peripheral portion of the 
veins. The lymphoid cells (a, h) begin to migrate through the 
uninjured walls of the latter (.B) and of the capillaries (A); col- 
ored corpuscles also pass through the capillaries into the neigh- 
boring tissues. After a half or a whole day, when the surface 
of the mesentery is covered by a dull grayish layer of pus-cells, 
these remarkable phenomena have commenced in full force. 
The pus-cells have therefore come from the blood-vessels (Cohn- 
heim). If a finely granular coloring material has been previ- 
Fig. 114. Blood-vessels of the irritated mesentery of the frog, with emigration of the lymphoid cells 
(after 8 hours). A, a larger capillary shows at a emigrating, and at b emigrated cells. B, a vein ; at a 
the lymphoid cells closely crowded against the walls, and pressing through, at b external to the vessel | 
c, colored blood-corpuscles. 
ously injected into one of the lymph sacs of the animal, a part 
of these cells will contain coloring matter. 
If, on the contrary, the circulation be arrested by ligating 
the crural vein, the blood-corpuscles will be seen to be pressed 
closely together in the vessels of the web of our animal. Here, 
also, there is a passive escape of colored blood-cells. It is al- 
most impossible, on the contrary, for the lymphoid corpuscles 
to manifest their vital contracting power, in consequence of the 
compression exerted by the overloaded condition of the vessel. 
Here their active emigration generally fails, or is but very 
slight. BLOOD, LYMPH, CHYLE, MUCUS, AHD PUS. 
249 
A similar emigration of tlie lymphoid cells also takes place 
in normal life. The movable cells, which wander through the 
spaces in the connective tissue, are to be reckoned among these. 
Cohnheim’s beautiful observations, which confirm the older 
views of A. Waller, possess an extraordinary range and have 
rapidly called forth an entire literature. Opinions are still un- 
defined with regard to this subject. Do all these migratory cells 
and pus-corpuscles originate in the blood, and, having mi- 
grated, are they incapable of further increase by division % May 
not pus-cells proceed from the cellular elements of the connec- 
tive tissue ? Finally, are these emigrants capable of being 
transformed into other tissue elements ? The latter is not to be 
doubted ; and very many observers have affirmed the division 
of the lymphoid cells, as well as their origin from the cells of 
the connective tissue. We shall again refer to some of these 
points. 
2 and 3. The examination of lymph or chyle is also very 
easy ; only some little preparation is necessary for obtaining 
the material. In order to obtain lymph, a mammal is to be 
killed by a blow on the head, and, after carefully opening the 
thorax, a ligature is to be applied to the ductus thoracicus. 
The lymphatic vessels will be found to be swollen even after a 
quarter of an hour, and the distention is increased by waiting 
for a longer time. If the animal has been killed several hours 
after a plentiful meal containing fat, the lacteals become filled 
with a milk-white fluid and stand out in the most beautiful 
manner. With small herbivorous animals, for instance, rab- 
bits, an elastic catheter may be introduced into the oesophagus, 
and a considerable quantity of milk injected through this into 
the stomach. After an interval of several hours the lacteals 
will be found magnificently filled. 
The lymphatic or lacteal vessels are then to be ligated in 
pieces about one inch in length, a ligature being applied at 
each end, and the vessel carefully separated from the connective 
tissue. The separated vessels are to be cleaned by washing in 
water and again dried, after which they are to be opened over 
a watch-glass or a slide. 
If the lymph-corpuscles are desired for rapid demonstration 
only, the necessary material may be obtained by pricking any 
lymphatic gland. 
In lymph and chyle we find, by 2-400 fold enlargement, the 250 
SECTION ELEVENTH. 
characteristic cells (fig. 115), the same with which we have al- 
ready become familiar in the blood as colorless blood-corpus- 
cles. When examined in their natural fluid, these structures 
do not, as a rule, show anything further than a granulated 
globule of varying size (fig. 115 1-4). If this examination is 
made with the necessary precautionary measures, the same 
change of form of the cell may here be found, as an evidence of 
a vital contractibility, which we have 
mentioned above (p. 234) concerning the 
colorless elements of the blood. 
In order to demonstrate further the 
manner of its organization (nucleus and 
cell-body), water or extremely diluted 
acetic acid may be used. (Stronger 
acids soon dissolve the envelope of the 
cell and its contents.) These changes 
Fig. 115. Lymph-cells. 
are represented in the figure from 5 to 18. The ammoniacal 
solution of carmine, fnchsine, and aniline blue may be used 
for staining. 
Innumerable fat molecules, in the condition of the finest 
division, occur in the milk-white chyle, as the cause of its color. 
These atoms require a strong (4-600 fold) enlargement. 
For their preservation, the mixture mentioned at p. 218 
(No. 3), consisting of sublimate (1), salt (2), and water (300), is 
to be recommended; Pacini’s second fluid may also be em- 
ployed. 
4, Mucus does not require any preparation. It may be 
either scraped with the blade of a knife from the surface of the 
mucous membrane, or it may be obtained from the nose or re- 
spiratory organs, etc, A moderate quantity is to be placed on 
the slide. Uncommonly tough masses of mucus are to be di- 
vided with the scissors. 
The microscopic examination (with a 2-400 fold enlarge- 
ment) shows us a somewhat irregular constitution. We meet 
with an extremely variable quantity of the same colorless gran- 
ulated cells which have just been referred to as colorless blood- 
corpuscles, and also as elements of the lymph and chyle, the 
“lymphoid cells.” The name of mucous corpuscles has been 
given them ; only in the cavity of the mouth these structures 
are called salivary corpuscles. In the latter place, coinciding 
with the thinner and more watery fluid, granular movements BLOOD, LYMPH, CHYLE, MUCUS, AHD PUS. 
251 
are observed in the interior of the cells. Conformably to this, 
a cessation of these movements may be produced by the addi- 
tion of concentrated solutions ; they may also be incited in all 
other lymphoid cells by removing them to a very watery neigh- 
borhood (C. Richardson). Together with these, is also associ- 
ated an extremely variable quantity of the desquamated cells 
of the existing epithelial formation, and likewise the separated 
cells of the various mucous glands. In consequence of its viscid 
nature, there are very generally air-bubbles imprisoned within 
the mucus. Furthermore, there are also very many extraneous 
admixtures to be seen ; as the remains of food, for example, 
of meat, grains of starch, particles of dust, threads of 
fungus, and many others. The recognition of the latter ingre- 
dients requires a certain amount of practice. 
I have tried a number of conserving fluids for preserving 
mucus, but thus far without any notable results. 
5. The same granulated cell formation—we know it already 
—occurs finally as an element of a 
pathological fluid, the pus ; it re- 
ceives the name of pus-cell, or pus- 
corpuscle. 
A fluid may be recognized as 
pus, not by its constitution, but 
rather by the number of its cells. 
Pus-cells are the extravasated 
colorless blood - corpuscles which 
have collected at the point of irrita- 
tion. The formation of these struc- 
Fig. 116. Pns-cells of man and mam- 
malia lying in the interior of epithelial 
cells. 
tures in the interior of epithelial cells (fig. 116), where, by 
the destruction of the mother cell, the contained cell was set 
free, was also formerly assumed (Remak, Buhl, Rindfleisch). 
These observations are certainly correct. If the thin, watery 
secretion of the mucous membrane in the first days of a 
catarrh be examined, one may perceive, according to the va- 
riety of the epithelium, together with free pus-corpuscles, ordi- 
nary desquamated epithelial cells, and others with contents 
such as are represented in the figure mentioned. But the ex- 
planation must be very different. These structures which lie 
before us are those vagabonds of the body, the wandering cells, 
which have penetrated from the tissue of the mucous mem- 
brane into the epithelial cells. SECTION ELEVENTH. 
We shall afterwards speak of a possible and probable for- 
mation of pus-cells from the connective-tissue cells. Naturally 
a collection of the pus-cells never takes place on the surface of 
a mucous membrane. They may afterwards be found scattered 
through the tissue of the interior of an organ (for instance, in 
the inflamed cornea) also ; they may then collect in great num- 
bers beneath the epithelium, finally force off the epithelial cov- 
ering, and thus cause an erosion and an ulcer, or, when in in- 
ternal parts, they may cause the formation of an abscess in 
consequence of the melting down of the neighboring tissues. 
Pus-corpuscles are naturally to be examined in the same 
manner as the elements of lymph and chyle. 
The vital changes of form of pus-cells have become known 
to us within a few years. If after about two days, as the re- 
suit of the application of an irri- 
tant to the cornea of a frog, its 
humor aqueus becomes cloudy, 
the latter will show a number of 
energetically contracting proteus- 
like cells (fig. 117). Thin, thread- 
like processes may give the pus- 
corpuscle a radiated appearance 
(a) which may afterwards change 
to an irregular indentated form 
(b) Not unfrequently the pro- 
cesses become further ramified, 
and, by the meeting and blending 
of neighboring branches (c), retic- 
ular processes result (c, d). Long, 
Fig. 117. Contractile pus-cells from the hu- 
mor aqueus of the frog, s-t, vital changes of 
the cell; 6, a pus corpuscle with granules of 
carmine in its interior; I, the dead cell. 
extended forms sometimes show themselves temporarily {e, i). 
A reception of neighboring small molecnles, such as carmine, 
within the interior of the cell may also be observed (I)). 
The pus-cells of man and the mammalia also possess a sim- 
ilar vital changeability of form. 
A similar alteration of shape may be recognized when these 
cells are in the spaces of a more compact tissue ; as for instance 
in the cornea. Here, it is true, the cells generally appear 
stretched out and rendered narrow, being constrained by the 
limited space. 
Such a locality also presents the best opportunity to follow 
the above-mentioned progression, or wandering of these con- BLOOD, LYMPH, CHYLE, MUCUS, AND PUS. 
253 
tractile structures through the passages alluded to. This is not 
unfrequently quite energetic. However, it is not even neces- 
sary to have an inflamed organ, lor the same lymphoid cell, 
with the same variation and the same progression, also occurs 
in the normal cornea. 
The most conservative treatment, the avoidance of positive 
fluid media, of pressure, and of evaporation are absolutely 
necessary, if one desires to witness the remarkable phenomena 
mentioned. 
The intermingling of other cells, such as epithelium and 
blood-corpuscles, is recognized without trouble. 
Many transformations take place in pus, which we cannot 
at .present discuss further. We will only mention one of these, 
the acid fermentation of pus. It precedes the alkaline de- 
composition, and brings with it 
anatomical and chemical altera- 
tions. 
When the reaction is some- 
what acid, the nuclei of the pus- 
cells become visible. The neutral 
fats are decomposed, and free 
fatty acids make their appear- 
ance in a crystalline form. Such 
are shown in our fig. 118, partly 
in the shape of needles, and 
partly in pointed, lamellated 
masses; together with these are 
the rhomboidal plates of choles- 
terin. 
Fig. 118. Acid pus from an old abscess of 
the upper part of the thigh. 
A mixture consisting of 1 part sublimate, 1 part salt, and 
300 water, is used for preserving them. Another preservative 
fluid has been recommended for causing the nuclei to ap- 
pear :—1 part sublimate, 1 part acetic acid, and 300 water (p. 
218). 
We should make ourselves responsible for a deficiency, 
if we avoid mentioning in this little book certain microscopic 
parasites of the smallest dimensions, and which have recently 
attracted a constantly increasing attention. This is the most 
suitable place for their discussion. We refer to the bacteria, 
vibriones, and kindred structures. 
Minimal structures with a filamentous, sometimes homo- 254 
SECTION ELEVENTH. 
geneous, sometimes moniliform body of varying length, and 
which are met with in unspeakable numbers in decaying sub- 
stances in the living as well as in the dead organism, have long 
been known. They were at first assumed to be animals, and 
with apparent justice, as some of them presented a very lively 
change of place. At present most investigators, and all bot- 
anists, who have busied themselves with these smallest of the 
small, regard the bacteria and their connections as vegetable 
organisms belonging to the very lowest rank in the group of 
Schizomyceta. 
By many, and probably rightly, a finely granular substance 
imbedded in a homogeneous gelatinous-like matrix has been 
drawn into the circle of development of the bacteria. It has 
been called zoogloea (Cohn), micrococcus (Hallier), microsporon 
(Klebs). Other observers went still further. They included a 
structure consisting of long, very fine filaments, the so-called 
leptothrix, which we shall again meet with as occurring in the 
human mouth. Contradictions have, nevertheless, not been 
wanting. All these assertions are dubious, however, in con- 
sequence of the extraordinary diminutiveness of these little 
parasites. 
According to our present knowledge, these bacteria are the 
producers or, at least, the bearers of putrefaction. They arrive 
in the living organism, or in portions which have died, less by 
means of the air than by water and by contact with already 
polluted bodies. Their increase is then quite incredible. The 
decomposing properties of these smallest structures prove to be 
very considerable. The firmest tissues succumb to them at 
last. 
The bacteria are not mentioned here on this account, how- 
ever. They are also the producers or, at least, the bearers of 
contagion in some, perhaps in many affections, the so-called 
infective diseases. 
A French physician, Davaine, many years ago found such 
bacteria, in innumerable quantities, motionless in the blood of 
animals with disease of the spleen. Such blood, inoculated into 
other mammals, produced the same diseased process ; gangrene 
of the spleen again resulted. 
In other diseases also, such as gangrene of the lung, in 
diphtheria, a dangerous affection of the human oral and 
pharyngeal cavities, bacteria are found in the sputa and the BLOOD, LYMPH, CHYLE, MUCUS, AND PUS. 
255 
exudated matters, and the disease may be inoculated. A simi- 
lar phenomenon also occurs in pysemic and septicsemic affec- 
tions, also in variola (Rindfleisch, Waldeyer, von Reckling- 
hausen, Klebs, Eidam and Loevinson, Eberth), perhaps, also, 
in Asiatic cholera (Klob). 
It is not to be accepted that the same variety of bacteria 
can exert such dissimilar effects ; they are rather to be consid- 
ered as an indifferent transporting medium of the contagious 
matter, conducted through the lymph and blood, and deposited 
in remote localities. 
The highest powers of our modern immersion systems, in 
addition to the most rigid precautionary measures, are neces- 
sary in the investigation of this very obscure department. 
Lostorfer’s so-called syphilis corpuscles have nothing to 
do with bacteria. These small molecules, which occur after a 
few days in the blood of patients thus diseased, and also in 
smaller numbers in the blood of other people, are granular 
precipitates of an albuminous body. Section Stoelftl). 
ENDOTHELIUM AND EPITHELIUM, NAILS, HAIR. 
The various so-called corneous tissues of the human body 
require similar methods of examination, in consequence of the 
resemblance in their chemical constitution, and may therefore 
be very appropriately discussed together. 
1. Under the name of epithelium are understood the cover- 
ings of crowded cells which are presented by the various sur- 
faces of the body, partly as simple layers, partly as stratified 
layers. According to the form of the cells, the pavement or 
flattened epithelium, consisting of flattened elements, is dis- 
tinguished from the cylindrical, in which the cells are long 
and narrow. Furthermore, we have as modifications the cili- 
ated epithelium, in which the surface of the cell is covered 
with very fine cilise which vibrate during life, and the pigment- 
ed epithelium, containing within the cell granules of black 
pigment, the so-called melanine. 
According to their genesis, all the cell layers of the upper- 
most and lowest germinal layers are regarded as true epithe- 
linm. The cellular coverings of the cavi- 
ties of the middle germinal layer are 
called endothelium / they are always 
unstratified. 
Layers are in general found only in 
flattened epithelium. The cylindrical 
forms a single layer, which, it is true, 
is also the case with many other cover- 
ings of pavement-shaped cells, that is, 
all endothelium. 
Fig. 119. Flattened epithelium 
of the mucous membrane of the 
mouth of man. 
The adjacent wood-cuts may serve to represent the various 
forms of epithelium. Fig. 119 presents the flattened epithe- 
lium of the cavity of the mouth ; fig. 120, the cylindrical ENDOTHELIUM AND EPITHELIUM, NAILS, HAIJK. 
257 
variety from the intestinal canal, while fig. 121 shows the cili- 
ated, and fig. 122 the pigmented form. 
It is scarcely necessary to remark, that only stratified 
epithelium is visible to the naked human eye, while such cellu- 
lar coverings, when they consist of but few layers or only a sin- 
Pig. 120. Cylindrical epithe- 
lium of the large intestine of 
the rabbit. 
Pig. 121. Various forms of 
the ciliated cells of mamma- 
lia. 
I'm. 122. Pigmented pavement 
epithelium (so-called polyhedral 
pigment cells) of the sheep. 
gle one, are only rendered apparent by the aid of the micro- 
scope. Thus, the densest epithelial covering, that of the ex- 
ternal skin, was known in olden times, while, for instance, a 
knowledge of the simple cell coverings of the surfaces of serous 
membranes and of the vessels is an acquisition of a more recent 
period. 
In order, therefore, to obtain the first view of the epithelial 
cells of a surface, it is sufficient to separate the cells from their 
natural connections with the clean blade of a scalpel, and to 
transfer them with a little fluid to the slide. One will then 
meet in part with isolated structures, in part with whole shreds 
of connected cells. 
That which is here artificially accomplished is in many cases 
performed by nature. The pressure and friction which many 
surfaces of the body undergo, disconnects the epithelium from 
its basis. In this manner are separated the cells of the epi- 
dermis, and those of the various mucous membranes. Old 
cells fall off spontaneously, as it is said. The mucous cover- 
ings of the various mucous membranes exhibit in varying 
abundance the desquamated epithelium of the membrane in 
question, as, by way of example, we find in the mucus of the 
mouth, the oldest and largest cells of the flattened epithelium ; 
in that of the nose and air-passages, the ciliated cells ; in that 
of the intestinal canal, the cylindrical epithelium. 
However, much of the epithelium of the body appears to be 
of a more enduring nature ; it is less rapidly renewed, and we 258 
SECTION TWELFTH. 
do not notice that spontaneous desquamation. As examples, 
we have the flattened cells which cover the posterior surface of 
the cornea, the pigmented pavement epithelium of the eye, etc. 
Moreover, the cells of which these coverings are composed 
prove to be very delicate when acted upon by reagents, and do 
not resist decomposition for any length of time. 
The cells of all unstratified epithelium are seen to be com- 
posed of soft and readily alterable albuminous matters. Hence 
the greatest freshness of the tissue is necessary for their ex- 
amination. It would be a piece of folly to look for them in a 
cadaver which is several days old. In this case they would be 
either entirely destroyed, or only fragments of them would be 
found. 
Simple pavement epithelium or endothelium, as it occurs on 
the posterior surface of the cornea, on the serous membranes, 
and the inner surfaces of the vessels, is to be obtained by 
scraping and examined with strong (400-fold) magnifying power. 
The isolated cells are frequently so pale that, even with consid- 
erable shading of the field, it is desirable to have them tinged. 
Solutions of carmine, hsematoxyline, aniline blue or aniline red 
may be used for this purpose. We would especially recommend 
the latter as coloring instantly, and not exerting any alterative 
effect. Very dilute acetic acid may be used to render the 
nuclei more distinct, although there is rarely any occasion for 
its use. It is somewhat difficult to obtain a simultaneous view 
of these simple tesselated cells and their basement membrane. 
Thin vertical sections of the previously dried tissue will rarely 
lead to the desired results, as the cells, as a rule, become sepa- 
rated by the reapplication of moisture. A characteristic view 
may be more readily obtained from parts which have been hard- 
ened in chromic acid or alcohol. In the vascular system the 
free border of a valve is a favorable locality for the recognition 
of its epithelial covering. A view of the epithelium of the 
serous membranes may be obtained by carefully separating a 
shred of the membrane from its bed and forming a fold of its 
free surface. If the posterior surface of the cornea be energeti- 
cally scraped, inverted pieces of the membrane of Descemet 
with its epithelial covering may sometimes be seen in the 
preparation. 
Recklinghausen’s method of impregnation with silver (see 
p. IG2) is also an excellent means of demonstrating the contours ENDOTHELIUM AND EPITHELIUM, NAILS, HAIR. 
of pale epithelial cells. The boundary Tines become extremely 
distinct, even after a slight action of the silver solution, as the 
precipitation takes place in the intercellular or cement sub- 
stance first, and the cell cavities remain free. If it be desired, 
the nuclei may be afterwards stained with carmine. The epithe- 
lium appears with such distinctness in the small blood and 
lymphatic vessels, that the course of these vessels may be rec- 
ognized the same as in an injected preparation. Even in the 
cavernous passages or the sinuses of the 
lymphatic system, an epithelial covering 
may in this way be made visible through- 
out (fig. 128, a, b). 
We shall afterwards learn what re- 
markable information the silver treat- 
ment has recently furnished concerning 
the structure of the capillaries. 
We must return to the cement sub- 
stance of the epithelial and endothelial 
cells. The beautiful works of Arnold 
and Thoma have shown that the injection 
of Prussian blue in the blood-passages of 
the dead frog colors this cement border 
Pig. 123. Cylindrical epithelium 
from the surface of lymphatic 
canals after Impregnation with sil- 
ver. a, elongated ; b, broader mo- 
saic. 
blue. This is also to be recognized when a solution of indigo 
sulphate of sodium is carefully injected into the blood-vessels 
of the living frog in small doses, at slowly repeated intervals, 
and the tongue, the object to be examined, is drawn out, and a 
current of a 1.5 per cent, solution of salt made to flow over it, 
and a dilatation of the blood-vessels occurs. Alternated in- 
jections of suitable solutions of cyanide of iron and potash and 
chloride of iron also produce a similar effect. A solution of 
good China ink with common salt is still better. As this color- 
ation of the epithelial cement borders has been noticed in the 
most various portions of the body of the frog, and also in the 
mammalial animal, it appears probable that the former is con- 
cerned in the nutrition of our cell tissue. For further details, 
especially the apparatus used, we must refer to the original. 
Indifferent fluids are to be recommended rather than water 
as media for the examination of this endo- and epithelium. I 
have not, as yet, been able to preserve these structures very 
well when mounted moist, but silver preparations keep very 
well, especially in Canada balsam. SECTION TWELFTH. 
The pigmented pavement epithelium (the polyhedral pig- 
ment cells of a former time), which occurs in the eye, and covers 
the choroid with a simple, the ciliary processes and the pos- 
terior surface of the iris with a stratified layer, is to be ex- 
amined in the same manner. Shreds of the same may be readily 
removed with a scalpel or a brush, and, when carefully spread 
out with the brush, they present the beautiful mosaic (fig. 122) 
to view. Such shreds, when folded, present a side view of the 
cells. Chromic acid preparations and dried eyes may also be 
used for demonstrating the epithelial formations of which we 
are at present speaking. 
If one desire to observe the molecular movement of the 
black pigment granules, it is only necessary to make pressure 
with the covering glass in order to liberate the cell contents, 
which then begin their movements in the water. In this 
case it is advantageous to use the strongest objectives, so 
as to magnify the movements of the granules as much as pos- 
sible. 
The highest modern magnifying powers appear to indicate 
a crystalline constitution of these molecules. 
They may be successfully mounted in 
glycerine, Muller’s fluid, and Canada bal- 
sam. 
The methods of investigating cylindri- 
cal and ciliated epithelium are also the 
same. 
Scraping with the blade of a knife fur- 
nishes ample views of these cells, isolated 
and hanging together in shreds (fig. 124). 
Cylindrical epithelium may be most ad- 
vantageously examined several hours after 
Pig. 124. Cylindrical epithe- 
lium from the small intestine of 
the rabbit, a, Side-view of the 
cells, with the thickened and 
somewhat elevated seam, which 
is permeated by porous canals; 
ft. view of the cells from above, 
whereby the apertures of the 
porous canals appear as small 
points. 
death, as they are then more readily separated from their 
parent tissues. Not nnfreqnently, groups of cells have their 
free surfaces turned towards us, and thus present, seen in 
bird’ s-eye perspective, the familiar, elegant mosaic {b). 
In investigating the epithelium of the mucous membranes, 
it is well to postpone the examination till a few hours after the 
death of the animal, or to place the organs of an animal which 
has just been killed, for example the trachea or the small in- 
testine of a mammal, in a refrigerator, and keep them there, in 
their mucus, for several days. The cells may then be easily ENDOTHELIUM AND EPITHELIUM, NAILS, HAIR. 
261 
isolated. lodine serum, or some otlier neutral fluid, is useful 
for the closer investigation. 
The dried mucous membrane may be used in order to obtain 
a view of the cylindrical epithelium with its attachments. Wet 
preparations, that is, such as have been hardened by means of 
chromic acid, bichromate of potash, and alcohol, are much 
more suitable. If the part was sufficiently fresh when im- 
mersed, the epithelial covering will be beautifully seen on thin 
sections, made with a sharp razor. The appearances are ren- 
dered much more distinct by tingeing with carmine or hsema- 
toxyline. 
Indifferent fluids, tingeing, and the application of dilute 
acetic acid, are generally employed for the further investigation 
of this structure. 
An animal killed during the digestion of fat may be used 
for demonstrating the passage of molecules of chyle through 
the cylindrical epithelial cells of the small intestine (with this 
point the previous section, 
Chyle, is to be compared) 
The thickened seam 
which occurs on the free 
surface of the cylindrical 
cells of the small intes- 
tines, etc., has more re- 
cently been subjected to 
an accurate investigation, 
and found to be permeated 
by fine vertical lines (com- 
pare fig. 125, also 124). 
Most investigators of the 
present time accept these 
Pig. 125. The same cells. At a, the seam is lifted up by 
the action of water and slight pressure ; at 6, appearance 
in the natural condition ; at c, a portion of the thickened 
border destroyed; at cl, e, f, it has become resolved into 
isolated rods or prismatic pieces by the prolonged action of 
water. 
lines for the optical expression of fine passages which pass 
through the seam, so-called porous canals, an opinion which is 
also entertained by the writer of these lines. Strong magnify- 
ing powers, especially immersion systems, are requisite for the 
recognition of the subtile textural relations. The animal may 
be used immediately after being killed, but it is better to expose 
the intestine to the air for several hours, which will facilitate the 
separation of the cells. Intestinal mucus, blood serum, weak 
solutions of chromic acid, solutions of salt (2 per cent.), and of 
phosphate of soda (5 per cent.), may be used as media. The 262 
SECTION TWELFTH. 
addition of water has a destructive effect on the seam. The 
individual pieces separate from each other in the direction of 
the vertical lines ; not unfrequently, the appearance is present- 
ed as if the cell had a border of cilia {d, e,f), which was also the 
opinion of the first observers (Gruby and Belafond). A similar 
effect is produced by maceration for about six hours in phos- 
phate of soda (5 per cent.), or the so-called strong acetic acid 
mixture of Moleschott (Coloman Balogh). 
All that was said concerning the cylindrical cells also holds 
good for the examination of ciliated epithelium ; only, one 
should commence as soon as possible after death, and make 
use of indifferent media, as water usually attacks the fine cilia 
and soon causes them to fall off. On the contrary, a strong 
solution of potash, from 28 to 40 per cent., preserves them 
well, as Schultze ascertained. 
Tingeing with aniline red is very useful; it may be rapidly 
done, and—in the frog at least—does not cause the ciliary 
movements to cease. 
Mounting in strongly diluted glycerine is to be recommend- 
ed for preserving cylindrical epithelium, especially that which 
has been hardened by means of alcohol. I have not as yet 
succeeded in keeping the ciliated cells, with the preservation of 
their cilia, for any length of time. 
Before proceeding to the lamellar epithelium, we will allude 
to the most remarkable vital phenomenon of the tissue, the vi- 
bratory or ciliary motion. 
Since the vibratory phenomenon outlasts the death of the 
creature and the separation of the cell from its natural con- 
nections for a very unequal length of time, in the individual 
animal groups, it is of the greatest importance to make a suita- 
ble selection. Mammalia and birds, in which the movements of 
the cilia very rapidly cease, are therefore to be avoided in the 
first examinations. The naked amphibia, salamanders and 
frogs, are best adapted ; the larger size of their cilia also con- 
stitutes a second and not unimportant advantage. Many of 
the invertebrates, such as the river muscles of the genera unio 
and anodonta, as well as the genus cyclas, which have on their 
gills a covering of ciliated cells with splendid long hairs, are 
exceedingly well qualified for this purpose. By using very 
powerful lenses one may also obtain a view of an important 
textural condition in the vibratory cells of the intestine of the ENDOTHELIUM AND EPITHELIUM, NAILS, HAIR. 
river muscle. The cilia are the continuations of fine proto- 
plasma filaments of the cell-body (Eberth, Marchi). 
The fluid media are of great importance in the study of the 
vibratory movements. It is asserted in general that everything 
which does not affect the cell substance chemically allows the 
ciliary movement to continue; everything, on the contrary, 
which alters its molecular condition terminates the movements 
once for all. 
The indifferent natural fluids should therefore be preferred 
to all others. Blood serum in the first line, also liquor amnii, 
vitreous fluid, milk, and even urine form excellent fluid media. 
lodine serum appears to be very serviceable ; bile exerts an 
unfavorable effect. The addition of pure water increases the 
activity of the vibrations for a short time, to cause them to 
cease all the sooner. An alkaline reaction of the fluid media 
is to be denoted as favorable, acid as unfavorable. Oxygen 
has an exciting, carbonic acid a paralyzing effect (Kiiline). A 
moderate increase of temperature increases the activity^; a 
higher temperature, which destroys the life of the jDrotoplasma, 
exerts the same effect on the allied ciliary movement (Both). 
In order to commence the first observations, a piece is to be 
cut from a membrane covered with ciliated cells (for example, 
the mucous membrane of the gums, or the pericardium of the 
frog), serum is to be added, and the membrane folded in such 
a manner that its cellular surface forms the free border of the 
fold. In order to avoid pressure, which might dislodge the 
slippery mucous membrane or force the folds apart, the frag- 
ment of a somewhat thick covering glass is to be laid in the 
fluid and the preparation covered ; or the specimen may be 
made to adhere to the under surface of the covering glass and 
placed in the moist chamber (fig. 75). Blood-cells which float 
in the fluid form a valuable addition (they may be replaced by 
particles of coal, granules of indigo, and carmine). 
If the examination be made with a low power, a movement, 
a vibration, as the phenomenon has been appropriately named, 
is recognized at the margin of the fold. The corpuscles will 
now be seen driven forward in a rapid current, which is always 
in a definite direction ; and if the fold shows hills and valleys, 
one may see some of the corpuscles driven forward and then 
suddenly thrown back again. The older observers were led to 
think of electrical attraction and repulsion. When the phe- 264 
SECTION TWELFTH. 
nomenon begins to be paralyzed and the magnifying power is 
somewhat increased, the movement becomes more distinct and 
appreciable. The regular and simultaneous vibration of the 
cilia now appears like an undulating border, like the flaring of 
a candle, or the rippling of a clear rivulet in the sunlight. If 
we follow the vibratory movement for a still longer time, and 
at the same time increase the magnifying power, a moment 
arrives in which the individual cilia may be distinctly seen to 
vibrate, but only one direction of the excursion can be recog- 
nized at first. Already the blood-corpuscles are driven past 
more slowly, and we are able to perceive how a cell is driven 
down into a valley and then, by means of the microscopic 
whirlpool, it undergoes the above-mentioned repulsion. If the 
examination be still further prolonged, the number of the in- 
dividual vibrations becomes less and less ; we can now see both 
of the excursions of the cilia, and a moment soon arrives when 
small bodies suspended in the water—in our example, the 
blood-cells—present only irregular fluctuating movements in 
front of the ciliated margin. Finally, the cessation, the expira- 
tion of the movements appear. Over a certain space all the 
cilia are stiff and motionless. There may still be a vibratory 
movement in the neighborhood for a short time ; finally, this 
ceases also. 
It was a beautiful discovery of Virchow’s, that the ciliary 
movement which has but just ceased may be again called to life 
for a short time. Very dilute solutions of potash and soda are 
necessary for this purpose. 
If the isolated piece of mucous membrane is not too large, 
one may watch it as it is slowty driven from its position by the 
united labor of its innumerable cilia. 
The ciliary movement may also be examined in still another 
manner—and this is to be especially recommended for more 
accurate investigations with powerful lenses. The epithelium 
is to be separated in shreds by scraping somewhat energetically 
the surface of the exposed mucous membrane. Here one may 
at first recognize a few groups of cells engaged in the most ac- 
tive rotatory movements, also isolated disconnected cells with 
vibrating cilia, etc. 
With regard to the number of vibrations which take place 
in a given space of time, the cilia move so rapidly at first that 
an estimation having any degree of accuracy is not to be ENDOTHELIUM AND EPITHELIUM, NAILS, HAIR. 
265 
thought of. It has been assumed that there were a few hun- 
dred vibrations to the minute, but this is an uncertain valua- 
tion, and is really much too low. Afterwards it becomes more 
and more easy to count them. 
The manner in which the cilia vibrate is by no means always 
the same. Purkinje and Valentin, who investigated the ciliary 
movements in the most thorough manner a number of years 
ago, distinguish four varieties of movements: the hook-like, 
the funnel-shaped, the oscillating, and the undulatory. The 
first variety is regarded as being by far the most frequent. 
According to Engelmann’s beautiful investigations, on the 
contrary, the ciliated cell, when thoroughly unimpaired, only 
exhibits the undulatory motion. All other forms of vibration 
are caused by the cilia having become stiff and motionless in 
certain places. 
The examination of the ciliary movement in mammalia and 
birds requires the rapid preparation of the tissue immediately 
after the death of the animal, the addition of its blood, iodine 
serum, and the hot stage. Sometimes, in spite of all haste, one 
is too late, in other cases the vibration continues to be lively 
for several minutes. A few cases are known, in which, long 
after death, in the bodies of mammalia which have become 
quite cold, the liveliest ciliary movements were still perceptible 
to the astonished eye. I have myself observed such a case, 
years ago. 
Human ciliated cells with well-preserved cilia can only be 
observed in a cadaver which is quite fresh ; those with moving 
cilia may be obtained under certain circumstances from the liv- 
ing. If one bores with a feather (the beard of which has been 
cut short) in the upper part of the nose, ciliated cells which 
are still living may sometimes be found in the mucus which is 
thus rubbed off. They may be more readily obtained by ex- 
amining the thin watery secretion from the nasal or respiratory 
mucous membranes at the commencement of a severe acute 
catarrh. In such cases, together with regular shaped ciliary 
cells, abnormal examples will also be found in great numbers, 
some which are swollen, others which present a more globular 
form, and within which may be recognized a granular body, a 
pus-cell (fig. 116,/, p. 251). (Rindfleisch.) 
All of the varieties of simple epithelium which have thus 
far been mentioned consist of relatively alterable soft cells. 266 
SECTION TWELFTH. 
It is different with the stratified flattened epithelium, as 
met with on many mucous membranes, and most strongly de- 
veloped as a covering to the external integument. In these 
cases it is only the deeper layers of younger cells which still 
retain a similar soft and readily alterable con- 
stitution. As it appears, these are to a great 
extent Joined together in a very peculiar 
manner (Schultze). The surfaces of these 
membraneless structures (fig. 126, a, h) are 
everywhere covered with points, prickles, and 
ridges which insinuate themselves between 
those of the neighboring cells “like the bris- 
tles of two brushes when pressed together,” 
so that the name stachel and riff cells is quite 
appropriate. 
Fig. 126. So-called stach- 
el or riff cells, a, from the 
deeper layers of human epi- 
dermis ; b, cell from a pa- 
pillary tumor of the hu- 
man tongue (observed by 
Schultze). 
The older layers of this variety of epithe- 
lium show, on the contrary, cells with smooth- 
er surfaces, which, in becoming flattened and 
spread out, are also chemically altered. They 
consist of a much more resistant modification of albumen; 
they are cornified, as it is said. The methods of examination 
are therefore to be modified. 
It is self-evident that the various layers, even to the young- 
est, may be brought to view by scraping, and at the same time 
one of the ordinary methods of 
tingeing may be advantageously 
employed, especially for the young- 
est cells. By the use of reagents, 
and especially of a weak acid, we 
may recognize a considerable power 
of resistance in the older scale-like 
epithelial cells, while those which 
are younger are soon attacked and 
only their nuclei remain. 
In order to isolate the cells, it is 
well to macerate for a day or two in 
Fig. 127. Comeal epithelium of the calf 
(maceration preparation), from Muller’s 
fluid mixed with saliva. 
iodine serum, in a 10 per cent, solution of common salt, in 
Czerney’s mixture of Muller’s fluid and saliva (p. 137), or, as 
Langerhans recommended, in concentrated nitric acid. The 
most manifold and in part strongest cell forms are then met 
with (fig. 127) in a quite unexpected manner. ENDOTHELIUM AND EPITHELIUM, NAILS, HAIR. 
267 
Drying and hardening in alcohol are employed for obtain- 
ing transverse sections through a whole stratum of epithelium. 
The first method is in general to be preferred for the external 
integument, the last for the mucous membranes. Weak tinge- 
ing with carmine and subsequent washing in water acidulated 
with acetic acid yields excellent preparations. The cell nuclei 
may be recognized even in the most superficial layers of the 
epithelium of mucous membranes, while the quite colorless 
non-nucleated scales of the cornified epidermis appear in the 
most beautiful manner above the deeper layers which are 
stained. Impregnation with silver may also be used here with 
good results. 
There is no medium which renders such good service in the 
examination of the stratified flattened epithelium as alkalies, 
especially potash and soda. By the use of these reagents the 
cells may be made to assume a sometimes lower, sometimes 
higher degree of distention ; they may be isolated, their nuclei 
destroyed while their membranes are preserved; and finally, 
they may be entirely dissolved. The use of alkaline solutions 
is, therefore, of the greatest value in the enumeration of the 
superimposed layers, as, on the other hand, they reveal the 
structural conditions of the epithelial cells better than any 
other method. 
A strong solution of potash or soda forms a combination 
with the substance of the flattened epithelium in question 
which causes the cell to swell and which eagerly mixes with 
water, and thus induces an increasing intumescence till the cell 
is finally dissolved. Concentrated solutions therefore exert a 
different effect from those which are more diluted, and the 
quantity of potash especially which a fluid medium contains is 
of the greatest importance. 
Moleschott, who has examined this subject more accurately, 
has instituted a series of experiments on this point. He made 
use of the dried tissue. 
A strong solution of potash of 85 per cent, induces only a 
moderate distention ; the cells form a very elegant mosaic and 
their nuclei are preserved. The intercellular or cement sub- 
stance which unites the cells is gradually dissolved, the cells 
become isolated and float about in the fluid. The nuclei are 
preserved even with solutions of 30 per cent., but they are 
rapidly attacked by those which are weaker, below 20 per cent. 268 
SECTION TWELFTH. 
In order to cause a considerable distention of the cells, to the 
form of elliptical vesicles, the tissue is to be placed in a solu- 
tion of potash of 30-10 per cent, for the space of about four 
hours. 
If water be added to these swollen cells, they become dis- 
tended into vesicles which are as transparent as glass, and soon 
dissolve. Before this, however, the reduction of an albuminous 
matter (their corneous 
substance) may be in- 
duced in the epithelial 
cells of the prepara- 
tion, by over-saturating 
the fluid with acetic 
acid. From what has 
been said, the corre- 
sponding illustrations 
of our flg. 128, which 
represent the pavement 
epithelium of the cav- 
ity of the mouth (1), as 
well as that of the ex- 
ternal integument (2) 
under such treatment, 
must be intelligible. 
The cells are gradu- 
ally dissolved in very 
weak solutions, from 
Fig. 128. 1. Epithelial cells: at a, an unaltered flat cell from the 
cavity of the mouth; at b-f, the same variety of cells after treat- 
ment with caustic soda, some still with nuclei (6, c, d), some already 
without nuclei (e, /); at g, after the action of soda with the ad- 
dition of acetic acid. 2. Epidermoid cells: a. unaltered; 6, at 
the commencement of the soda action ; at c, the more prolonged 
action of the reagent; d, with the addition of acetic acid. 
10-5 per cent., of potash, but weaker solutions, under 5 per 
cent., exert less effect on this tissue. 
Solutions of soda may also be employed with advantage, 
but they must be more dilute. 
A solution of chloride of gold (0.005 per cent.) and its reduc- 
tion by means of sulphate of iron (p. 167), has recently been 
recommended by Nathusius for the cornified tissues. Such 
preparations may afterwards be exposed to the alkalies with 
advantage. 
For the examination of the stratified flattened epithelium, 
fine vertical sections of the tissue which has been thoroughly 
hardened in alcohol or chromic acid are to be especially rec- 
ommended. Tingeing with carmine should also not be neg- 
lected. ENDOTHELIUM AND EPITHELIUM, NAILS, HAIR. 
269 
The cornified cells may be readily mounted in preservative 
fluids. Glycerine is to be used with stained sections. They 
often make right handsome preparations when deprived of 
their water and mounted in Canada balsam. 
2. The tissue of the nails. In consequence of their consist- 
ence, the nails permit of sections being made in the various 
directions without further preparation, but their elements are 
combined in such a manner that one can see nothing but a ho- 
mogeneous tissue which, in consequence of its brittleness, is 
permeated by numerous rents and flaws. Reagents which 
soften and dissolve the intercellular substance are, therefore, 
indispensable. Sulphuric acid and alkaline solutions have 
been used. The former, even concentrated, act but slowly 
when cold, although after a few days epithelial disks may be dis- 
tinctly recognized. By boiling they make their appearance 
very rapidly, even in half a minute.. The nuclei do not become 
sufficiently visible by this method. 
Solutions of potash and soda act very much better, as was 
indicated by Kolliker many years ago. One may often obtain 
very handsome specimens of isolated and distended cells, in 
which the nuclear formations not 
unfrequently stand out very beauti- 
fully, even without using solutions 
of known strength. A solution of 
potash of about 25-27 per cent, ap- 
pears to be suitable. Weak solu- 
tions destroy the nuclei. 
A momentary boiling in a dilute 
solution of soda (about 10 per cent.) 
also frequently affords very charac- 
teristic views. The structure of the 
nails may be demonstrated in this 
way almost instantaneously. Fig. 
129 shows us the cells of the nails 
isolated in the latter manner. 
Fig. 129. Tissue of the human nail, in 
part after the action of the solution of soda. 
a, cells of the most superficial layers in 
profile ; b, a cell seen from above ; c, half 
profile ; d, a number of cells which are ren- 
dered polyhedral by the pressure of their 
neighbors; e, a cell, the nucleus of which 
is beginning to disappear; f, cells of the 
deepest layer (stratum mucosum Malpig- 
hii); at g, one of these cells with double 
nucleus. 
As is well known, numerous epithelial new formations occur. 
Cysfcs and encysted tumors are, for the most part, lined with 
pavement cells. Hypertrophied growths of the skin, indura- 
tions, verruca and hornlike excrescences present an arrange- 
ment which is similar to the strata of the cornified epidermis 
and which require analogous methods of examination, such as 270 
SECTION TWELFTH. 
drying, vertical sections, solutions of potash, etc. The pearl- 
like tumors (among which are to be reckoned Hassal’s concen- 
tric bodies of the thymus) and the epithelial cancers or can- 
croids also have an epithelial character, the first in the form of 
benign, the latter in the form of malign neoplasms. The pre- 
paratory methods are to be adapted to their varying consistence. 
The fresh tissue may be examined in part as fine sections and 
picked preparations, in part after the use of hardening agents. 
Tingeing and the alkalies are also to be employed. Nails un- 
dergo but slight changes. 
3, Hair and its tissue. We shall as- 
sume that the complicated structure of 
the human hair has already been learned 
from the text-books on histology. 
In order to examine the hair with its 
sac and the most inferior portion of its 
bulb, a hair of strong calibre is to be pre- 
pared from the skin, or a piece of the 
skin of the head which has either been 
dried in the air or hardened by means of 
alcohol, may also be used with advan- 
tage. But in making vertical sections, it 
is necessary to keep as close as possible 
to the directions in which the hair passes 
through the skin. Transverse sections 
through the hair and all its coverings 
(fig. 130) may be obtained in a similar 
manner. Moleschott recommends the im- 
mersion in his strong acetic acid mixture 
for a few months. 
Pig. 130. Transverse section 
through a human hair and its 
follicle, a, hair; &, epidermis of 
the same ; c, inner, and a, outer 
layer of the inner root sheath ; e, 
outer root sheath ; /, its periph- 
eral layer of elongated cells; (/, 
structureless membrane of the 
hair sac; h, its middle, and i, ex- 
ternal layer. 
A hair which, has been slowly drawn 
out from the head may be used for the 
first examination. 
The root will often be found covered 
with the white substance of the so-called 
root-sheath, with the exception of its 
lowermost portion, which has remained with the terminal part 
of the bulb in the follicle. White hairs are most suitable; 
blond are better than dark. Water or glycerine may be used 
as a medium. Weak powers will then permit of the recog- 
nition of the essential structural conditions. ENDOTHELIUM AND EPITHELIUM, NAILS, HAIE. 
271 
No further preparation with the exception of strong lenses, 
and at most the use of acetic acid, is necessary for examining 
the hirer structure of the outer root-sheath (figs. 180, e, 131, c). 
The inner root-sheath (fig. 130, c, d) may be obtained either 
from sections, made parallel with the surface of the skin of 
hairy parts of the body, or from hairs which have been drawn 
out after stripping off the outer sheath and removing it from 
the shaft of the hair. It may also be seen on short transverse 
sections, made through the bulb of the moistened hair while 
lying on the slide, and then picked with needles. Although 
the first few attempts may fail, a little attention and the use of 
strong lenses will lead to the recognition of the two differently 
shaped layers of cells (figs. 130, c, d, 131, as h) of the inner sheath. 
The structure of the shaft and bulb of the hair, as well as the 
epidermoid covering, may even now be recognized to a certain 
Fig. 131. Cells of the root-sheaths; 
inner root-sheath with Henle’s (a) 
and Huxley’s (b) layer; c, cells of the 
external sheath. 
Fig. 132. a, cells of the hair- 
bulb ; b, from the commencement 
of the shaft; c, cortical mass treat- 
ed with sulphuric acid, and at d. 
separated into plates; e, f, cells 
of the cuticle of the hair. 
extent. Reagents, the application of which we will now con- 
sider, are necessary for the further penetration into their struc- 
ture. 
Let us commence with the last-mentioned covering of epi- 
dermoid cells (figs. 130, &, 132, e,f). The action of concentrated 
sulphuric acid for a few minutes, the importance of which was 
indicated many years ago by H. Meyer, is an excellent means 
of separating the cells. The same result may be accomplished 
with alkalies, though much more slowly. Moleschott praises a 272 
SECTION TWELFTH. 
potash solution of 4.6 per cent. When this has acted for about 
forty hours (in the cooler temperature of winter) the cells begin 
to separate from the shaft of the hair. After three or four days 
the cells are eveiy where isolated in the most beautiful manner. 
Solutions of soda may also be used. 
The use of concentrated sulphuric acid at a moderate tem- 
perature is the best means of demonstrating the cortical layer 
of the shaft of the hair, and for isolating the peculiar plate-like 
cells. After several minutes it will be found that the cuticle 
is commencing to separate, and that the surface of the shaft 
has become rough and felt-like. After a short interval, espe- 
cially when the hair is made to roll with a little pressure, the 
spindle-shaped cells begin to peel off. The inner layers (& d) 
afterwards become separated, until, finally, the medullary sub- 
stance is exposed. 
These plates may also be split off in groups by mechanical 
means. For this purpose, a dry hair is to be placed on the 
slide and scraped in the direction from the point towards the 
root. The scrapings are to be moistened and placed under the 
microscope (c). 
Alkalies were long since recommended for rendering visible 
the shrunken air-vesicles of the medulla (Kolliker). For the 
medullary cells of the hairs of the beard, and especially blond 
hairs, Moleschott praises the maceration, for one or two days, 
in a 3 per cent, solution of soda. Placing the hair for several 
days in a 2 per cent, solution of potash, or a longer immersion 
in one of 4.6 per cent, produces good specimens. 
The following process is most to be recommended for ob- 
taining transverse sections through the hair-shaft: A bundle of 
hairs is to be imbedded in one of the mixtures mentioned at 
page 114. Then (and even here a microtome is useful) a sharp 
razor is used, and the sections are subsequently freed from the 
embedding mixture. To obtain transverse sections of the deep- 
er portions of the hair, from the part situated beneath the skin, 
such as is represented in our fig. 130, a preliminary hardening 
with absolute alcohol is necessary, and the section should be 
tinged with hgematoxyline. With some practice, the most 
charming specimens may thus be obtained. ATo other tingeing 
material renders equal service. 
The employment of very dilute acetic acid is very useful 
for examining the cells of the outer root-sheath. Stronger ENDOTHELIUM AND EPITHELIUM, NAILS, HAIR. 
273 
solutions of potash are used for the cells of the inner root- 
sheath. 
We shall afterwards consider a few of the pathological con- 
ditions. 
The first rudiments of foetal hairs are obtained from sections 
of skin hardened in chromic acid or alcohol. Tingeing with 
carmine is very useful. The later stages of development are 
studied in a similar manner. 
Hair preparations are to be mounted dry in Canada balsam 
or in glycerine, according to circumstances. Section ®t)irteentl). 
CONNECTIVE TISSUE AND CARTILAGE. 
Modern histology designates at present with the name of 
connective substance a series of tissues which are nearly re- 
lated, although proving different enough in their terminal 
forms, and which are all, directly or indirectly, interchange- 
able, They also take their origin from very similar textures, 
and thus present substantial evidence of being members in a 
natural series of relationship. Gelatinous tissue, reticular and 
ordinary connective tissue, fat, cartilage, bone, and dentine are 
to be enumerated here. 
These members also resemble each other in still another 
physiological regard. They are tissues of low rank, which do 
not take part in the higher vital processes, but, on the con- 
trary, they form throughout the whole body, in all its parts, a 
widely expanded framework (although of varying quantity), 
in the spaces of which are embedded other tissues, such as 
muscles, nerves, vessels, glandu- 
lar cells, etc. V irchow deserves 
the credit of having, by a series 
of investigations, shown the im- 
portance of connective tissue in 
pathological new formations. 
1. As gelatinous tissue, we 
distinguish soft transparent 
masses, consisting of round or 
Fig. 133. Ti&sue of the vitreous body of a hu- 
man embryo at the fourth month. 
star-shaped cells (figs. 183,134), which have between them a con- 
siderable quantity of an ordinary homogeneous, slimy intercel- 
lular substance. Nearly all of them belong to the foetal period 
of life, and concern either transitory organs or are only devel- 
opment stages of the ordinary connective tissue. A single one 
of these, of a peculiar watery form with stunted cells, persists: CONNECTIVE TISSUE AND CARTILAGE. 
275 
the vitreous body of the eye (fig. 133). The extreme softness 
of all these tissues renders it very difficult to obtain tolerable 
preparations. At the most, the pale and delicate cells may be 
studied with a strongly shaded field with- 
out further treatment. Hardening media 
are therefore necessary, and among these 
chromic acid and bichromate of potash take 
the first rank. As a rule, a chromic acid 
solution of 0.5-2 per cent, hardens the tissue 
to such an extent that sections may be made 
from it with a sharp razor. With one of 
the organs which belongs here, the umbil- 
ical cord, the drying method may be very 
suitably employed. Neumann has given a 
peculiar but very appropriate process for 
the vitreous humor. It is to be saturated 
for 1-2 days with the albumen of an egg, 
and then hardened by a momentary immer- 
sion in hot water, after which it is to be 
placed in alcohol. In this way the organ 
is not only rendered more consistent, but 
also darker. 
In consequence of the delicacy and pale- 
ness of the cells of gelatinous tissue, tinge- 
ing is very much in place. Excellent prepa- 
rations of the vitreous fluid are obtained 
with aniline blue. 
Fig. 134. Cells of the ena- 
mel organ of a four months’ 
embryo; at a, smaller, at b, 
larger and more developed 
star-shaped cells. 
Preparations of the gelatinous tissues may be preserved, 
after tingeing, in glycerine. 
2. With the name of reticular connective tissue we desig- 
nate a reticulated framework made up of star-shaped cells, 
which no longer harbors in its sometimes wider, sometimes ex- 
tremely narrow meshes the mucous fluid of the gelatinous 
tissue ; on the contrary, its contents are different. They con- 
sist either of lymph-corpuscles—in which case the tissue has re- 
cently been called “adenoid” or “cytogenetic” (His, Kolliker) 
or of drops of fat (hibernating glands), or of nervous elements 
(spinal cord, brain and retina). Here, as in the whole connective 
substance group, we cannot speak of a sharply demarcated 
tissue. The reticulated often passes over into ordinary con- 
nective tissue, and probably also into gelatinous tissue. 276 
SECTION THIRTEENTH. 
If any tissue of the body is qualified for showing the great 
value of the more modern methods of investigation, it is Just 
this reticular connective tissue (fig. 135) which for many years 
has been frequently examined and formerly caused numerous 
controversies. All the forms in which our tissue occurs in the 
lymphatic glands, lymphoid follicles of the thymus, spleen, in- 
testinal mucous membrane, etc., are too soft to permit of an 
examination being made without previous preparation. It is, 
therefore, indispensable to employ hardening media for several 
days beforehand. Among these, chromic acid, bichromate of 
Fig. 135, Reticulated connective tissue from a Peyer’s follicle of an old rabbit, o, the capillary ves- 
sels ; 6, the reticulated connective tissue framework; c, lymph corpuscles. 
potash, and alcohol take the first rank. When these glandular 
organs or the intestinal mucous membrane have attained the 
proper degree of hardening, the finest possible sections are to 
be made from them with the sharp and moistened blade of a 
razor. These sections are to be carefully brushed, in the man- 
ner indicated by His, with a soft earner s-hair brush. Tingeing 
with carmine and hsematoxyline, and subsequent washing in 
slightly acidulated water, serve for demonstrating the nuclei at 
the nodular points of the network. They will then be readily 
seen, especially in young subjects. However, all of the innu- CONNECTIVE TISSUE AND CARTILAGE. 
277 
merable nodular points do not have a nucleus, as not only the 
simple processes of the cells, but also the ramifications of these 
processes become united with each other, so that the cell radii 
present, together with the nucleated centres, a number of non- 
nucleated nodular points. Tingeing with carmine will also 
prevent one from mistaking the stained nucleus for the trans- 
verse section of a vertically ascending colorless reticulated fibre. 
In older animals—and our drawing is taken from such a one— 
the nuclei may, indeed, be entirely wanting in a few places, and 
frequently only such as are stunted and shrivelled can be rec- 
ognized. In conditions of irritation, however, they soon re- 
sume their former distended appearance. A larger or smaller 
residue of the lymph-corpuscles (c) will be perceived in the 
meshes of the tissue, according as the brushing is continued 
for a longer or shorter period. 
In many cases it is not easy to hit upon the proper degree 
of hardening, and on it, in reality, everything depends. If the 
preparation is over-hardened, it does not permit of the sufficient 
removal of the lymph-cells; if not hardened to a sufficient 
degree, the whole frequently falls to pieces after a few strokes 
with the brush. 
For the intestinal mucous membrane and most of the 
lymphoid organs I prefer alcohol to chromic acid. The pieces, 
which should not be too large, are to be placed in a consider- 
able quantity of fluid for the first two days. This should 
consist of alcohol of about 36°, which is to be diluted with 
an equal part of water. The fluid is then to be replaced 
by the same alcohol, but without the former addition of 
water; generally, after from four or five days to a week the 
tissue is in a proper condition for brushing. Well-hardened 
pieces may in this way be preserved in weak alcohol for 
months and years. Very strong alcohol is to be entirely 
avoided. 
If it be desired to use chromic acid, commence with a solu- 
tion of about 2-5 per thousand, and proceed gradually, chang- 
ing the fluid to one of 1 per cent. Chromate of potash is to be 
used in a corresponding quantity (concerning which p. 186 is to 
be compared). 
The reticular connective tissue of the lymphatic glands, 
Peyer’s follicles, and the Malpighian bodies of the spleen, may 
be recognized with comparative facility. The thymus and the 278 
SECTION THIRTEENTH. 
tissue of the pulp of the spleen give more trouble. Its recog- 
nition is difficult in the hibernating glands, which I have 
investigated with Hirzel, and to a still higher degree in the 
nervous organs, especially in the gray substance of the spinal 
cord and the brain, likewise the retina of the eye. More dilute 
solutions of chromic acid than those above mentioned gr, 
to 1 ounce) are to be used, and allowed to act for several days. 
Very strong objectives should also be used. 
We shall return to this subject in speaking 
of the organs in question. 
Tinged preparations, mounted in dilute 
glycerine, afford the best specimens for a 
collection. 
3. The examination of fat tissue is sim- 
ple and causes no trouble, whether a sim- 
ple form of the same (fig. 136) is concerned, 
or a pathological new formation, for exam- 
ple a lipoma. The determination of the 
origin and retrogression is more difficult. 
A small piece of the tissue (a) is to be 
picked in the fluid media and then reviewed 
with a low power. The large, sometimes 
Fig. 186. a, Human fat-cells 
completely filled with fat, lying 
together in groups. 6, free glo- 
bules of fat; c, empty envelopes. 
smoother, sometimes rougher cells will be recognized pressed 
closely together, often with a polyhedral flattening. At the 
same time, a number of free globules of fat (5) will be met 
with in consequence of the laceration of the cells which has 
occurred. The optical properties of both are quite similar. 
We perceive a pellucid, sometimes slightly yellowish tinged 
substance, having sharp, dark contours with transmitted light, 
but with incident light a silver-like lustre and a whitish or yel- 
lowish periphery. While the fat-cells are of a definite size, 
that of the free drops of fat varies exceedingly. The latter flow 
together under pressure, but the cells do not. 
Osmic acid deserves recommendation for the recognition of 
small masses of fat, whether free or contained in cells. It 
stains them black, as we have already learned (p. 165). 
In order to demonstrate the cell membrane, it is necessary 
either to rupture the cell, in which case the former remains 
behind as a collapsed sac (c) after the fat has flowed out, or 
the fat is to be removed by chemical means with alcohol, ether, 
or benzine, which last was recently recommended by Toldt for CONNECTIVE TISSUE AND CARTILAGE. 
279 
this purpose. The nucleus may be demonstrated by tingeing it 
with carmine in the ordinary way. 
The treatment with picric acid and carmine, and the subse- 
quent addition of formate of glycer- 
ine, affords very handsome specimens 
(Flemming). 
Not unfrequently, a deposition oc- 
curs within the fat-cells of crystalline 
needle-shaped masses (fig. 137, c), the 
same as we have already met with in 
acid pus. A prolonged immersion in 
glycerine almost invariably produces 
such a crystallization within the cell 
cavity. 
In order to study the blood-vessels 
of fat tissue, injections are to be made 
with transparent masses, carmine, or 
Fig. 137. Human fat-cells containing 
«va fey needles; & larger 
cluster; c, the cells themselves having 
these dusters within them; a, anordi- 
nary fat-cell free from crystals. 
Prussian blue, and in making tlie microscopic examination pure 
glycerine is to be used as a medium, winch last, in consequence 
of its strong refracting power, is very well adapted for fat-cells 
in general. 
Glycerine (pure or mixed with formic or carbolic acid, p. 216) 
is to be used for mounting, or, if the fat tissue is injected, 
Canada balsam or alcoholic resinous solutions may be advan- 
tageously employed. 
4. Ordinary connective tissue is very widely diffused, and 
consists, in its developed form, of a fibrous substance which is 
divisible into bundles and fibrillse, and in which long or stel- 
late cells, the frequently mentioned connective-tissue corpuscles, 
are met with, as are also the various phases of elastic tissue. 
The whole lies embedded in an extremely variable quantity of 
homogeneous basis substance. 
If living connective tissue be selected from a suitable place, 
for instance, in the frog, the thin transparent membrane (to 
which Kiihne called attention) between the crural muscles (fig. 
188), and examined with the addition of lymph, one may recog- 
nize in the pellucid basis-substance the fibrillse (/) and bundles 
of the connective-tissue fibres (g), and also a network of very 
fine elastic fibres (h). The connective-tissue corpuscles then 
appear as flat, membraneless cells, consisting of a nucleus and 
fine granular protoplasma. Several varieties of these cells may 280 
SECTION THIRTEENTH. 
be noticed (a and &, c, d and e), and one may at the same time 
convince one’s self that the first two varieties of the connective- 
tissue corpuscles {a, b, c) have a sluggish, but unmistakable vital 
contractility, so that the 
cell a gradually changes 
to such forms as are repre- 
sented in our figure at b. 
However, as we now know, 
the shape is even yet not 
completely described. 
An uncommonly pale 
marginal portion, which 
very readily escapes no- 
tice, as well as accessory 
plates resting laterally at 
various angles on the fiat 
cell, and which are recog- 
nized with still greater dif- 
ficulty, give this thing, 
even in the higher ani- 
mals, the shape of an ir- 
regular paddle-wheel (fig. 
139, a). Such connective- 
Fig. 138. A piece of living connective tissue from the 
upper part of the thigh pf a frog (the cells are represented 
somewhat more pressed together than they usually lie), a, 
contracted cell; 6, radiated, expanded connective-tissue cor- 
puscles, one of them without a visible nucleus: c, one with 
a vesicular nucleus; d and e, immovable cells ;/, fibrillae ; 
g, simple bundle of connective tissue; h, plexus of elastic 
fibres. 
tissue cells have lately been met with very widely diffused 
(Waldeyer, Ranvier, and others). 
In addition to this cell form, the connective tissue contains, 
sometimes more rarely, sometimes more frequently, another (fig. 
Fig. 139. Cells of the human connective tissue. 
a, flat and shovel-shaped elements; b, coarse 
granule cells. 
Fig. 140. So-called plasma cells 6, 
collected around a vessel a. From 
the testicle of the rat. 
189, b), which probably has a more embryonic character. It is 
more plump, the granules are coarser ; it has not the lamellar 
and veil-like system of processes. The latter elements, which CONNECTIVE TISSUE AND CARTILAGE. 
281 
have been called “plasma, or perivascular cells” (Waldeyer), 
generally lie in the vicinity of the blood-vessels. 
Together with these, the remarkable amoeboid migratory 
cells, the emigrated lymph-corpuscles, which we mentioned at 
p. 248, are met with. Accordingly, the fixed have been dis- 
tinguished from the migratory cells of the connective tissue. 
Certain places are also found in tlie warm-blooded animals 
wliicli permit of tlie examination of living cells ; as, for example, 
the thin connective tissue which covers many of the muscles of 
the smaller mammals (Rollett). 
As the proportion of the cells, fibrillse, and elastic elements 
varies considerably, the form of the tissue is necessarily modi- 
fied in accordance with these 
several admixtures. The diver- 
sity which the twisting and in- 
terweaving of its bundles pre- 
sent is not less considerable. 
If a piece of dead connective 
tissue be prepared in a fluid 
medium with the aid of sharp 
needles, it may be very readily 
separated into the above-men- 
tioned strings or bundles (fig. 
141). The bundles themselves 
show a striation running paral- 
lel with their long axes, and 
may be separated, in accordance 
with the latter, into finer strings, 
Pig. 141. Connective-tissue bundles (at the left, 
several isolated fibrillre) with very abundant ho- 
mogeneous interstitial substance. 
and, finally, into extremely thin, homogeneous, more or less 
undulating fibres or threads, the so-called primitive fibrillse. 
While in former times the anatomists adopted a fibrillated 
condition of the connective tissue as a simple expression of this 
very easily made observation, Reichert, in the middle of the 
fifth decade of this century, pronounced these fibres to be arti- 
ficial products, and the longitudinal striations to be the optical 
expression of the folding and wrinkling of a thoroughly homo- 
geneous membrane. 
Controversies were waged for a long time concerning the 
latter acceptation. It was only at a later period, when the 
method of isolation by chemical means had been discovered, 
that the pre-existence of these fibrillse (which the reader already 282 
SECTION THIRTEENTH. 
recognizes from fig. 138), could be proved in the most indubi- 
table manner. If the connective tissue be treated alternately 
with reagents which cause it to swell and to shrink, the finest 
fibres appear in the most beautiful manner (Henle). Further 
observations were then made by Rollett. 
If a portion of human tendon be immersed for a week or 
more in lime-water, and then a bundle of it placed on the slide, 
one may readily succeed, by inserting the preparing needles 
into the middle of the same, in drawing it out into longitudinal 
fibres of greater or lesser calibre, which cross each other at 
acute angles. All attempts at spreading out the tissue as a 
homogeneous membrane in accordance with Reichert’s views 
are unsuccessful, and cause it to split up into fibrillse. Baryta- 
water produces the same effect, but in a much shorter time— 
from 4 to 6 hours. 
For the microscopical investigation it is necessary to remove 
the hydrate of lime or baryta, either by washing for a long 
time in water, or by the addition of so much acetic acid as just 
suffices to neutralize the lime or baryta. The lime or baryta 
water dissolves an albuminoid body, which is evidently the ce- 
ment substance of the fibrillse. 
Hypermanganate of potash (Rollett) and a 10 per cent, solu- 
tion of common salt (Schweigger-Seidel), also cause this disso- 
lution of the inter-fibrillary intermediate substance. 
Although one series of connective-tissue textures behave 
similarly in this regard, others present a deviation. The co- 
rium may serve as an example. This is separated by the same 
treatment into stronger, apparently entirely homogeneous fibres, 
which can only be split up into the longitudinally arranged fi- 
brillse after a long-continued maceration (from 10 to 12 days) in 
lime-water. 
According to Rollett’s observations, the fasciculi of the scle- 
rotica, the aponeuroses, the fibrous capsular ligaments, the dura 
mater, and the interosseous ligaments, are formed after the 
type of the tendons. 
The examination of connective tissue by polarized light also 
speaks for the presence of the fibrillse. They are positively 
double refracting, and the optical axis lies in the longitudinal 
direction of the fibrillse. None of the reagents which maintain 
the fibrous appearance of the connective tissue alter the optical 
nature of the same to any considerable extent. On the con- CONNECTIVE TISSUE AND CARTILAGE. 
trary, methods of treatment which render the connective tissue 
apparently homogeneous, also change the double refraction 
very much (W. Muller). 
The same arrangement as in the external skin is found in 
the conjunctiva, the subcutaneous cellular tissue, the submu- 
cous tissue of the intestinal canal, and the tunica adventitia of 
the vessels. 
The interweaving of the connective-tissue bundles, and the 
entire arrangement of a connective-tissue part, may be recog- 
nized in dried preparations by making coarse sections from 
them and simply softening these in water. Tingeing with car- 
mine may also be suitably employed. 
A finely punctated substance may be discovered in the 
transverse sections of the fasciculi, which many microscopists 
have declared to be the transverse sections of the connective- 
tissue fibrillse, as, for example, in the tendons. 
In order to demonstrate the cellular and elastic elements 
which occur between the fibrillse, reagents have been used for 
many years which cause the fibrillse to swell, and at the same 
time lower their refractive power to such an extent that it be- 
comes equal to that of the water which is added. Thus is 
caused an apparent dissolution of the fibrillse, and the remain- 
ing elements of the connective tissue are rendered prominent, 
although the cells have undergone extensive modifications and 
disfigurations. 
This manner of action has been longest known in connection 
with acetic acid, but other organic acids may also be employed. 
Pyro-acetic acid has been frequently used for this purpose, 
sometimes undiluted, sometimes diluted with an equal volume 
of water. Mineral acids, such as nitric and muriatic acids, in 
a condition of extreme dilution, exert a similar effect. 
It is only necessary to neutralize the acid with ammonia to 
cause the fibrillse to reappear. 
The connective-tissue fibres also undergo the same swelling 
in alkalies as in these acids. As was the case with epithelium, 
the supplementary addition of water produces a rapid dissolu- 
tion of the fibres. 
In still another, much more conservative manner, namely, 
by employing a fluid medium of strong refractive power, the 
embedded structures may be recognized in the unswollen con- 
nective tissue. Glycerine is of the highest value in this regard. 284 
SECTION THIRTEENTH. 
The swelling of the connective tissue from the above-men- 
tioned action of acids may give rise to peculiar appearances. 
In many portions of the body the connective-tissue bundles are 
invested like a sheath by a condensed substance. 
Now this expands to a much slighter degree, and 
consequently it is not unfrequently torn across 
and then more and more pressed together by the 
contained mass, which protrudes with a certain 
force, until finally, in consequence of the strong- 
compression, it has assumed the form of a ring. 
This ring is very similar in appearance to that of 
an elastic fibre running in a circular direction, for 
which it has also frequently been mistaken. This 
phenomenon has been considerably discussed in 
former and more recent periods, and even Flem- 
ming, the latest and very capable observer, has not, 
in my opinion, been very fortunate in this direction. 
But enough about the Abridge. Let us inquire 
into the methods of examining the cells. 
A thin strip of interstitial connective tissue may 
be cut from the living body, and, after being moist- 
ened with lymph and enclosed in the moist cham- 
ber, examined. The appearances presented are in- 
structive ; but the wrinkling of such a lamella is a 
fatal circumstance, as every observer has experi- 
enced. 
Fig. 142. A con- 
nective-tissue bun- 
dle from the base 
of the human 
brain, treated with 
acetic acid. 
We are therefore indebted to Ranvier, a French histologist, 
for the discovery of a new method. Artificial oedema is to be 
produced by injecting the tissue. lodine serum, or a weak so- 
lution of the chromate of potash, for instance, may be injected 
into the subcutaneous or intermuscular connective tissue of a 
frog. A beautiful preparation may be obtained by rapidly 
placing a fine section of this gelatinous infiltrated mass on the 
slide under the covering glass. A weak solution of nitrate of 
silver (0.1 per cent.) is in a still higher degree qualified as an 
injecting fluid, as by this means the pale borders of the connec- 
tive-tissue cells are covered with a granular precipitate and 
thus rendered more distinct. Masses which become hardened, 
such as solutions of gelatine, are much preferable. Flemming, 
imitating Ranvier’s process, made use of the glycerine-gelatine 
mentioned at page 216. That is: gelatine J, distilled water CONNECTIVE TISSUE AND CARTILAGE. 
285 
glycerine The mixture is heated to about 40° C., and about 
one-tenth of its volume of a 5 per cent, solution of nitrate of 
silver added. The parts are to be frozen by packing in ice. 
Sections are to be exposed to the light for about half an hour, 
and then tinged with picro-carmine. After about one hour the 
preparation is to be washed several times, and finally treated 
with water containing 3-4 per cent, of acetic acid. 
Formerly, the cellular elements were isolated by dissolving 
the intercellular substance. This readily succeeds, as the lat- 
ter becomes changed into gelatine. 
As is well known, connective tissue may be converted into gela- 
tine by treating it for a variable length of time with boiling water. 
This action is, however, altogether too energetic for histo- 
logical purposes. The softer connective tissue, at least, may be 
dissolved by other means in a much more conservative manner. 
After softening it for about a day in very slightly acidulated 
water, it may be dissolved in 24 hours by moderately warming 
Fig. 143. Spindle cell from the tendon 
of a hog’s embryo eight inches long, a, 
cell with protoplasma; b, connective-tis- 
sue fibrillse. 
Fig. 144. Soft connective tissue from the vicinity 
of the tendo Aohillis of a human embryo of 2 
months, a, spindle cells; b. a very elongated one; 
c, intercellular substance with fibrillm. 
the water to 35-40° C. At the muscular tissue we shall again 
have to speak of this procedure, which deserves a more ex- 
tended application. 
It would lead us too far to describe these artificially changed 
connective-tissue cells in this place. For the rest we refer to 
the two adjoining figures, 143 and 144, which were drawn from 
alcoholic preparations. 286 
SECTION THIRTEENTH. 
Colmheim lias very properly recommended the impregnation 
of connective tissue with gold. 
The great majority of the so-called elastic fibres (fig. 145) 
are undoubtedly of a sol- 
id nature, and all attempts 
to stain them with carmine 
fail. The great power of 
resistance which they pre- 
sent renders their exami- 
nation comparatively easy 
and simple. 
Parts which are very 
rich in elastic tissue re- 
quire a somewhat more 
careful preparation. In 
this way the great exten- 
sibility of the finest fibres 
(a) will be noticed ; at the 
same time it will be seen 
that these fibres may as- 
sume the strangest con- 
Pig. 145. Various forms of human elastic fibres, a, 
unbranched; b and c, ramified. 
volutions in the swollen connective tissue. Thicker elastic fila- 
ments prove to be much less extensible, and frequently present 
themselves as fragments (c). 
The fasciculi of a tendon of the external skin or of the sub- 
cutaneous cellular tissue may be employed for the first exami- 
nation of connective tissue. Do not spare the trouble of un- 
ravelling a very small piece in water or an indifferent fluid. 
For demonstrating the connective-tissue corpuscles, it is cus- 
tomary to use reagents which cause the tissue to swell, especi- 
ally acetic acid. Tingeing with carmine and hsematoxyline is 
also useful. Panvier has also made us acquainted with a use- 
ful method of examining tendinous tissues. 
The extremely thin fibres from the tails of small mammalia, 
such as young rats, mice, and moles are used. If the last 
caudal vertebrae be torn from their attachments, a considerable 
length of the tendons remains connected with the separated 
parts. Their ends are to be fastened to the slide with sealing- 
wax, carmine is then to be employed, together with the usual 
supplementary treatment with acetic acid. The preparation 
may also be first left for a day in a one per cent, solution of CONNECTIVE TISSUE AND CARTILAGE. 
287 
osmic acid and then washed out and left for 24 to 48 hours in 
picro-carmine. It is subsequently submitted to various meth- 
ods of treatment, such as picking, longitudinal and transverse 
section. In consequence of the small size of the object, it is 
well to embed it, in gum arabic, for instance. 
The preparations, after treatment with acetic acid, are to be 
mounted in glycerine, either pure or containing formic or car- 
bolic acid. 
Elastic fibres become distinct after treatment with acids and 
alkalies, as well as after the action of solutions of fuchsin (von 
Ebner). 
An opportunity of studying them is presented in the sub- 
cutaneous cellular tissue, the corium, and 
the ligamentum nuchae of the mammalia. 
A more suitable object for learning the great 
diversity in the manner of appearance of 
elastic tissue can scarcely be found than the 
wall of a large artery from one of the larger 
mammalia, the various layers of which are 
to be separated with forceps and scalpel. 
Embryonic connective tissue (and many 
of the pathological new formations of our 
tissue, at a similar stage of organization 
and consistence, are to be enumerated here) 
is to be examined partly fresh in indifferent 
fluids, partly after the production of an 
oedema, and finally, although not so good, 
in preparations hardened by chromic acid 
or chromate of potash. In order to decide 
what is here present as elastic tissue (fig. 
146), the use of alkalies, preferably boiling 
for a short time in a 10-15 per cent, solu- 
tion of potash, should not be neglected, as 
the connective-tissue corpuscles (A, d) are 
in this way made to disappear, but not the 
PS?aS““Tfht 
elastic fibres {B, c). Both elements react alike with acetic 
acid. 
At the commencement of this section we alluded to the im- 
portance, which is indeed very great, of connective tissue in 
pathological formative processes. We are prevented by the 
narrow limits of our little book from making more than a few 288 
SECTION THIRTEENTH. 
remarks on tins subject, which is now being so completely rev- 
olutionized. 
Although, until within a few years, it was generally' con- 
sidered that pathological growths consisting of lymphoid cells 
were formed by the division of the normal connective-tissue 
cells, the emigration of the former elements from the blood 
passages has become prominent, in consequence of the Weller- 
Cohnheim theory. It is certain that this plays an important 
though not exclusive role, as, according to Strieker’s experi- 
ence, a complete absence of participation cannot be ascribed to 
the neighboring connective-tissue corpuscles. At all events, in 
such difficult matters, one should avoid springing with incon- 
siderate haste from one extreme to the other, and thus entirely 
ignoring the physiological origin of the lymphoid cell. 
Such collections of cells may again disappear, the mass 
melting down and becoming “pus,” in the old sense of the 
word. They may also become organized, that is, form new con- 
nective tissue accompanied by the growth of vessels in them, 
whereby the migratory cells are transformed into connective- 
tissue corpuscles and an interstitial substance which is split up 
into bands and fibres. Parts which have been divided are 
reunited in this manner, and then one speaks of cicatricial tis- 
sue, Loss of substance, occasioned by suppuration or ulcera- 
tive destruction, undergoes essentially the same restorative 
process. Luxurious growths of this unripe tissue, which is 
overloaded with lymphoid cells, constitute the so-called granu- 
lations. 
Hypertrophic connective-tissue formations are frequently 
found as a result of a continued distention of a part with 
blood, the so-called congestive and inflammatory processes, but 
likewise without any cause, spontaneous, as it is said. Thick- 
ening of the various integuments, the corium, the fibrous and 
serous membranes, etc., are to be enumerated here; likewise 
interstitial growths between muscles, nerves, glands, etc. In 
these cases the microscopic examination shows an increase in 
the number of the cells and of the intercellular substance. 
The various tumors consist either entirely of connective tis- 
sue, or, together with other elements, have at least a connec- 
tive-tissue framework. The forms in which they appear differ 
extremely. In many we meet with an entirely undeveloped 
structure, resembling granulation tissue or that of lymphatic CONNECTIVE TISSUE AND CARTILAGE. 
289 
glands, as, for instance, in syphilitic tumors and in tubercle. 
Others, the polymorphous group of the sarcomata, constitute 
a transition to a more highly organized variety of our tissue. 
The latter belong, for the most part, to the fibroid or cellular 
tissue tumors. The lipomata are formed of connective tissue 
with collections of fat-cells, a pathological fat-tissue. New 
formations of gelatinous tissue also occur under various cir- 
cumstances and constitute the myxomata. 
The carcinomata or cancerous tumors, those enigmatical 
and most dangerous new formations of the body, are embedded, 
at least in the normal connective-tissue textures, and show, in 
conformity therewith, a framework consisting of a connective- 
tissue intercellular substance. In the sometimes larger, some- 
times smaller spaces of this framework lie embedded cells 
wdiich may, in certain cases, resemble those of pavement epi- 
thelium, but generally, however, they present a character 
which does not thoroughly correspond to that of any of the 
normal cells, although they may have taken their origin from 
glandular or epithelial cells. These u cancer cells ” are capa- 
ble of an unlimited, exuberant multiplication. It is customary 
to distinguish between certain forms of carcinoma. A tumor 
is generally called scirrhus (Faserkrebs) wdien there are only 
small collections of cells embedded in a firmly interwoven con- 
nective-tissue framework, so that the tumor possesses through- 
out the character of hardness and firmness. Inversely, one 
speaks of medullary carcinoma where large aggregations of 
cells occur in spaces of considerable size, the whole having a 
softer consistence, and the groups of cells forming masses of a 
butter-and-cream-like nature. If the cells have the appear- 
ance (but not the group-like arrangement) of pavement epithe- 
lial cells, we have one form of epithelial cancer, while the 
others have cylindrical cells, in both cases certainly descend- 
ants from the epithelial and glandular cells. If the substance 
of the framework presents a strongly marked fungous (alveo- 
lar) structure, and in the numerous spaces lie cells wdiich are 
undergoing the colloid transformation, we have the alveolar or 
colloid cancer of the pathological anatomists. It is well known 
that sharp boundaries between these various forms of carcino- 
ma do not exist, that they frequently pass into each other, and 
that in one and the same tumor, some localities may be more 
of one character, and others more of another. 290 
SECTION THIRTEENTH. 
Finally, let ns inquire into the method of examining these 
abnormal connective-tissue structures. They are substantially 
the same as those which we have mentioned for the normal 
tissues. Sometimes one procedure, sometimes another will be 
necessary, according to the exceedingly variable consistence. 
In a fresh condition, and by the employment of truly indiffer- 
ent media, we may obtain satisfactory views of the cells and 
their transformations by picking, by scraping the cut surfaces, 
etc. Hardening methods (chromic acid, chromate of potash, 
and alcohol) are generally resorted to in order to ascertain the 
further arrangement. It is very well to place small pieces of 
such tumors, and if possible while still warm, in a considerable 
quantity of absolute alcohol. One may then proceed, even 
after a few hours, to the preparation of thin sections (Wal- 
deyer). Even here, tingeing with carmine and especially hsema- 
toxyline, shows many things very handsomely; brushing leads 
to the isolation of the framework substances. Fine sections 
also constitute the most important means of ascertaining the re- 
lations of the so important region of demarcation between the 
normal and diseased connective tissue. 
It will be necessary to mount most preparations of connec- 
tive tissue in fluid, if they are to be kept as permanent speci- 
mens. The first of Pacini’s fluids (p, 217), also a solution of 
sublimate (1), salt (2), and water (100) may be employed. An- 
other mixture, consisting of sublimate (1), acetic acid (3), and 
water (300) is also well adapted for preserving, although the 
action of the acid makes itself felt. Glycerine media will be 
resorted to, as a rule. If an untinged preparation is to be 
mounted, the glycerine is to be diluted with a larger quantity 
of water, so that the former may not become too transparent. 
Stained specimens permit of the use of a more concentrated 
glycerine. The latter preparations, for example a cornea, the 
section of a tendon or of a scirrhus, deprived of their water by 
means of absolute alcohol, not unfrequently present a very 
fine appearance when mounted in Canada balsam. 
5. tThe examination of the cartilage tissue is very simple, 
as it has a degree of consistence which permits of thin sections 
being made without any further preparation. Cartilage which 
has been hardened in alcohol, chromic and picric acids also 
affords very characteristic and good specimens. 
Notwithstanding its consistence, cartilage is a tissue which CONNECTIVE TISSUE AND CARTILAGE. 
291 
requires foresight in the employment of fluid media, if one de- 
sires to have a view of the unaltered texture. Even ordinary 
water has a strongly alterative action on the cartilage cells, 
especially those of young animals. 
There are three varieties of cartilage to be distinguished: 
the hyaline, with a homogeneous inter- 
stitial substance (fig. 147); the fibrous 
or reticular, with a basis substance which 
is split up into bands (fig. 148); and fi- 
nally, the connective-tissue cartilage (fig. 
149), in which a few cartilage cells are 
found between the bundles of connec- 
tive tissue. 
For the first examination a foetal car- 
tilage may be used, the fine sections from 
which, in consequence of their trans- 
B’ig. 147. Hyaline cartilage. 
parency, require a certain shading of the field. A bone which 
is commencing to ossify may be used for studying the forma- 
tion of the daughter-cells. These cell formations may be met 
with, of an elegant appearance, close to the calcified tissue. 
The articular cartilages of adults form very suitable objects, 
Fig. 148. Reticular cartilage from 
the human concha auris. a, cells; b, 
homogeneous zone; c, elastic reticulum. 
Via. 149. Connective-tissue 
cartilage, 
and the costal cartilages of older men (fig. 150) are especially 
useful for investigating the textural changes which occur in 
cartilage which is undergoing senile degeneration. Together 
with ordinary semi-transparent places (a) in the section, others 
will be discovered which appear more opaque with transmitted 292 
SECTION THIRTEENTH. 
light, and with incident light they have a peculiar asbestos-like 
lustre. The transformation of the interstitial substance into a 
system of delicate fibres (c) running in a parallel and straight 
direction may also be seen; one may also meet with large, 
often colossal moth- 
er-cells («d, e), with 
whole generations 
of daughter-cells, to 
which Bonders call- 
ed attention many 
years ago. Such a 
costal cartilage af- 
fords an excellent 
opportunity for 
studying the vari- 
ous stages of thick- 
ening of the cap- 
sules of the carti- 
lage cells {/). 
Frequent endeav- 
ors have been made 
of late to demon- 
strate a network of 
plasmatic canals 
(juice canalicules) 
permeating the car- 
tilaginous matrix. 
For this purpose use 
has been made of os- 
mic acid (Bubnolf, 
Fig. 150. Costal cartilage of an old man. a, homogeneous; b, split 
up into bands; c, fibrous interstitial substance ; d, e, large mother- 
cells ; f, a mother-cell with considerably thickened capsule. 
Hertwig), a ten per cent, solution of chromic acid, nitrate of 
silver (Heitzmann)—and, according to our opinion, only arte- 
facts have been described. Indigo-carmine, placed in the body 
of a living frog, permeates the cartilaginous matrix after a 
number of days (4 to 7) and subsequently undergoes granular 
precipitation in and around the cell body (L. Gerlach). 
Calcified cartilage tissue requires various methods of treat- 
ment, according to the quantity of calcareous molecules em- 
bedded in it. If the latter be but scanty, an ordinary watery 
medium suffices. If the calcification be more extensive, glycer- 
ine or Beale’s mixture of alcohol and soda is to be used, in CONNECTIVE TISSUE AND CARTILAGE. 
293 
consequence of its stronger refractive power. A stage of calci- 
fication soon arrives, liowever, in which even these reagents are 
no longer capable of rendering the opaque, dark preparations 
transparent. Various methods are here advisable. A one or 
two per cent, solution of chromic acid with a few drops of 
muriatic acid may be used (EL Mueller). Pyroligneous, lactic 
(p. 129), and picric acids (p. 182) are more serviceable. After the 
solution of the lime molecules, the preparation is rendered very 
intelligible by the addition of glycerine. We shall soon see, 
when speaking of the process of ossification, how important these 
methods are for the recognition of extremely difficult relations. 
The epiglottis or the cartilage of the ear is to be selected for 
the first examination of reticulated cartilage. In consequence 
of the opacity of the basis substance the section cannot be 
made too thin. At the borders of such a preparation one not 
unfrequently meets with a few of the cartilage cells projecting 
more or less above the interstitial substance. 
In order to study the genesis of our tissue, select the auri- 
cular cartilage of mammalial embryos, which should be imbed- 
ded for the purpose of making thin sections (O. Hertwig). 
Among reagents, the action of a one per cent, solution of 
osmic acid for an hour or two has been recommended. It colors 
the elastic elements dark. It is also tinged by a very dilute 
solution of the soluble aniline blue. 
Object tinged with carmine, and then, after washing out in 
acidulated water, treated with this preparation of aniline, show 
the cellular elements red, and the elastic blue in a colorless 
matrix (Ewald). 
The examination of connective-tissue cartilage requires the 
same methods as connective-tissue. 
The intervertebral ligaments are to be selected for demon- 
strating the varieties of cartilage in a small space near each 
other. 
The polarizing microscope teaches us that cartilage likewise 
belongs to the double refracting tissues. We are not as yet 
sufficiently enlightened with regard to the direction of the op- 
tical axis. 
Recently, by means of energetic reagents, the apparently 
homogeneous substance of hyaline cartilage has been com- 
pletely reduced to a system of thick rings or areae surrounding 
the individual cells or groups of cells ; and in this manner the 294 
SECTION THIRTEENTH. 
origin of these basis substances from the cellular elements has 
been proved beyond all doubt (Heidenhain, Broder). 
In order to obtain this important appearance (fig. 151), the 
cartilage may be digested in water, at a temperature of from 
35 to 50° C. ; it may be exposed to the action 
of diluted sulphuric acid (1 : 25), or the fa- 
miliar mixture of nitric acid and chlorate of 
potash may be used. We would especially 
recommend the latter, particularly the com- 
bination of 80 ccm. of nitric acid of 1.16 sp. 
wt. with an equal of distilled water, 
and the addition, at an ordinary temperature, 
of sufficient chlorate of potash to saturate. 
After a few days the desired reduction will 
be obtained, and the appearances will be ren- 
Fig. 151. Thyroid car- 
tilage of the swine. The 
basis substance is divid- 
ed into cell-districts by 
means of chlorate of pot- 
ash and nitric acid. 
dered very beautiful by tingeing with aniline-red or carmine. 
According to Landois’ experience, these arern are even rendered 
distinct by tingeing with fuchsine sections of cartilage which 
have been deprived of their water by means of alcohol. How- 
ever, even without any artificial interference, the central por- 
tion of the cartilage of the ensiform process of the rabbit usu- 
ally presents the same appearance of the basis substance 
(Remak). It affords excellent views, the best and most in- 
structive with which I am acquainted. 
There are various means for dissolving the interstitial sub- 
stance of cartilage. This is effected by immersion for several 
hours in a concentrated solution of potash. The same object 
may be accomplished by immersion for four hours in sulphuric 
acid containing an atom of hydrate water, and the subsequent 
addition of water. The means most commonly used, however, 
is a long-continued boiling in water. While the cartilages of 
small embryos undergo this solution after several hours even at 
a moderate temperature, the older tissues require, with the ac- 
cess of air, to be boiled for 12, 18, sometimes 24 to 48 hours. 
If the cartilage which is being treated in this manner be ex- 
amined at each stage of its decomposition, one may recognize 
the obstinacy with which the cartilage cells themselves resist 
the boiling temperature, and that in none of their parts do they 
contain any gelatine-producing substance. Even when the en- 
tire basis substance is dissolved one may meet with numerous 
cells floating in the fluid. CONNECTIVE TISSUE AND CARTILAGE. 
295 
The capsules of the cartilage cells also resist the effects of 
the boiling water more energetically than the interstitial sub- 
stance, so that the chondrogenons matter of the latter is in no 
wise to be regarded as being the same as that of the capsules. 
The substance of reticular cartilage shows the extraordinary 
insolubility of the so-called elastic tissue. 
Pathological cartilage tissue is not a rare occurrence. It 
appears as an inflammatory new formation in chronic arthritis 
and in the formation of callus; but, as a rule, such cartilagi- 
nous tissue makes its appearance in the form of tumors, the so- 
called enchondromata. The textural conditions of such carti- 
laginous tumors present different appearances, the same as in 
the normal tissue. Thus the basis substance may appear 
homogeneous (and this is predominantly the case), in places it 
may form an elastic framework, or, finally, it may have a con- 
nective-tissue character ; not unfrequently one may meet with 
all three of these varieties of cartilage in the various parts of 
one and the same enchondroma. 
It would be superfluous to enter further into the considera- 
tion of the methods of examination ; they are the same as for 
the normal tissue. 
Various fluids have been recommended for preserving pre- 
parations of cartilage. Even distilled or camphor water renders 
good service. Glycerine, strongly diluted with water (2 parts 
water, 1 part glycerine), also acts advantageously, at least in 
many cases. Harting sometimes employs creosote water (p. 
220), sometimes a solution of sublimate (1 part to 2-500 water). 
I have also used the latter fluid with success. Furthermore, the 
sublimate in combination with phosphoric acid (sublimate 1, 
phosphoric acid 1, and water 80) has also been recommended 
(p. 218). According to my present experience I would here 
prefer the Tarrant’s fluid. Cartilage strongly tinged with car- 
mine or hsematoxyline, and deprived of its water by means of 
absolute alcohol may be mounted in Canada balsam with ad- 
vantage. Section iTouttceutt). 
BONES AND TEETH. 
We consider these two members of the connective-sub- 
stance group in a special chapter because they require peculiar 
methods of investigation, in consequence of their hardness and 
density. 
There are two kinds of preparatory treatment of the bones 
and teeth, according as one desires to preserve these parts with 
their inorganic elements or deprived of the same. Let us first 
speak of the latter. 
The removal of the bone earths is best effected by the meth- 
ods already mentioned in connection with calcified cartilage 
tissue (p. 293). The older process, the use of dilute muriatic 
and nitric acids, appears less suitable. 
Whether the one or the other process is adopted, changing 
the fluid and a certain patience are necessary. Always make 
use of very small pieces of tissue. 
The methods mentioned produce decalcification while the 
organic substratum becomes swollen. 
The immersed object will be seen to become gradually paler 
and more flexible, and finally to resemble cartilage in appear- 
ance and consistence. The action of the acid is now to be dis- 
continued, and the bones or teeth carefully washed out with 
water. The parts which have thus been decalcified, or—to use 
a badly-selected expression—the bone and tooth cartilages, 
then permit of the same methods of examination as cartilage 
tissue proper. These methods are most to be recommended 
for all investigations where it is necessary to obtain a large 
series of views with economy of time and labor. Dried speci- 
mens may be decalcified in this manner as well as those which 
are fresh, taken directly from the body. Bones in the latter 
condition, treated with chromic acid, show at the same time BONES AND TEETH. 
297 
the substance which fills their canals and cavities, the me- 
dulla. 
Decalcified in the same manner, the texture of the dentine 
and also of the cement may be well recognized, but not that of 
the enamel, in consequence of the considerable amount of min- 
eral elements which it contains. 
Naturally, more energetic measures are necessary if it be 
desired to isolate the walls of the canaliculi and lacunae together 
with the cell remnants, that is, the bone 
corpuscles of the bone and the dentinal 
tubes of the dentine. 
Virchow showed how to liberate the 
bone corpuscles in this way, years ago. 
A thin piece is to be removed from a fresh 
bone and either simply macerated in muri- 
atic acid or boiled, in a decalcified condi- 
tion, in distilled water, or (which is pref- 
erable) in a solution of soda, A period 
then arrives in which the tissue assumes 
a pulp-like softness. Preparations which 
are now examined (fig. 152) show us, es- 
pecially if a slight pressure be made on 
the covering glass, the bone corpuscles to- 
1?IG. 152. Remains of the bone- 
corpuscles with their boundary 
layer, from the decalcified shaft 
of the femur, after boiling in a 
solution of soda, abc, corpuscles 
containing nuclei (at 6, an adhe- 
rent residue of the basis sub- 
stance) ; d, a bone-corpuscle with 
a crumbled nucleus. 
gether with their processes and nuclei protruding from the dis- 
solved basis substance. Occasionally, some of these may be 
entirely isolated in this way (u, c, d). That they may have 
undergone considerable changes in consequence of this ener- 
getic treatment is sufficiently obvious. 
Forster has made us acquainted with another method of iso- 
lation by means of strong nitric acid. Thin pieces of the dried 
bone or tooth are to be placed in concentrated or but slightly 
diluted nitric acid, to which a little glycerine is added. The 
desired effect is obtained after a series of hours, sometimes not 
till the following day. Even bones in which all the soft parts 
are destroyed yield a similar appearance with the same treat- 
ment (Neumann). 
A maceration in strong muriatic acid, likewise a protracted 
boiling of the piece of decalcified bone in a Papin’s digester, 
also causes the destruction of the interstitial substance and 
the isolation of the bone-corpuscles with their systems of pro- 
cesses. Thin scales of bone fall to pieces after the action of 298 
SECTION FOURTEENTH. 
diluted solutions of potash or soda for half a day or several 
hours. 
A more accurate examination of our bone-corpuscle now 
shows that its form may be likened to that of a plum pit. 
To demonstrate the bone-cells proper (fig. 
158), however, very thin scales of fresh bone, 
and especially such as are carefully tinged 
with carmine or hsematoxyline, are necessary. 
These (6), surrounded by the already mention- 
ed elastic boundary of the basis substance {a), 
represent the bone-corpuscles of the foregoing 
woodcut. 
Fig. 153. Bone-cells 
from the fresh ethmoid 
bone of the mouse, tinged 
with carmine, a, limiting 
layer; b, cell. 
The impregnation with gold has also been 
recommended for the recognition of the bone- 
cells. The thin bones of the cranium of the water salamander, 
after an immersion of from one hour to an hour and a half in 
a 1 per cent, solution, and a subsequent reduction in acidulated 
water, yield good specimens in from one day to a day and a 
half. The adherent soft parts may be scraped from the bone 
while it is in the gold solution. Even fragments of large 
bones permit of this treatment (Joseph). 
The walls of the dentinal tubes of dentine may also be iso- 
lated by similar methods. In fragments of fresh teeth one 
may see these tubes occupied by a system 
of soft fibres (fig. 154, c), which latter rep- 
resent the processes of the dentinal cells 
of the tooth-pulp, or the so-called odonto- 
blasts (p) (Tomes). 
An entirely different procedure is ne- 
cessary for the examination of the calcare- 
ous tissue of the bones and teeth. Thin 
plates must be sawed from the bone and 
ground on a stone till they have become 
as tfi in as paper, and have acquired the 
Fig_. 154. Two dentinal cells, 
6, which pass with their proces- 
ses through a portion of the 
dentinal canals at a, and pro- 
trude from the fragment of den- 
tine at c ; after Beale. 
transparency necessary for their examination. The whole 
procedure requires time, is troublesome, and therefore, as a 
rule, it is shunned by microscopists. However, with a little 
perseverance, one may obtain excellent and uninjured prepara- 
tions. 
The desired object may be accomplished in various ways, 
and there are numerous methods extant for producing sections BONES AND TEETH. 
299 
of bones and teeth. We will here communicate to the reader 
a procedure which leads to the production of very beautiful 
specimens, and the outlines of which were given a few years 
ago by Reinicke. 
A fine saw, the blade of which is made from a watch-spring 
and is held by screws, is employed for sawing out the plates of 
bones or teeth. The bone or tooth is to be firmly secured in a 
vice. Brittle objects which are liable to splinter are to be pre- 
viously wrapped in paper. 
After sawing out the plate, it is to be ground on a small ro- 
tary grindstone, the handle of which is to be turned by the left 
hand while the plate is pressed by the fingers of the right hand 
on one of the flat surfaces of the stone. The stone is to be kept 
moistened by means of a trough placed under it containing 
water. If this tolerably inexpensive apparatus is not at hand, 
the first excess may also be removed with a file. 
In order to obtain a smooth surface, the thin preparation is 
now to be placed on a fine flat whetstone, such as is used for 
sharpening razors ; in this way, held by the fingers, it may be 
further ground on both surfaces. This may also be accom- 
plished between two such whetstones, and indeed more rapidly. 
Small objects are to be previously cemented on to a glass plate 
with Canada balsam ; ether serves best for loosening the bone 
and for removing the remains of the balsam. The bone may 
also be very conveniently cemented with red sealing-wax, and 
the adequate thinness of the section may finally be recognized 
by the liveliness with which the red shines through it. The 
sealing-wax is to be dissolved with strong alcohol. The prepa- 
ration is then to be cleaned in water, either with a camel’ s-hair 
brush or a soft tooth-brush, and dried. If the grain of the 
whetstone is sufficiently fine, nothing further is necessary. If 
one desires to obtain a better polish, one may employ a glass 
plate or a piece of soft leather which is nailed to a flat strip of 
wood, and which is smeared with tripoli or some other polishing 
powder. A beautiful polish may also be produced in a short 
time with fine emery paper. A preparation obtained in this 
way—for example, a transverse section (fig. 155)—presents a 
charming appearance. The various general or fundamental 
lamellae {a, d, ~ti) may be recognized passing throughout the 
entire bone, and the transverse sections of the Haversian canals, 
with their special lamellae (c) surrounding them, as well as the 300 
SECTION FOURTEENTH. 
innumerable so conspicuous lacunae with their canalicnli (e), 
may also be seen. 
To obtain these appearances, however, the latter system of 
canals must be dry and filled with 
air. A section which is sufficiently 
thin presents this appearance with- 
out any addition, and in this con- 
dition it may enter the collection as 
a permanent preparation. Very 
handsome preparations are obtain- 
ed by melting the sections into a 
resinous substance. Ordinary fresh 
Canada balsam is not adapted for 
this purpose, as, in consequence of 
the slowness with which it hardens, 
the air escapes more or less com- 
pletely from the section. In order 
to obtain a good medium for mount- 
ing, proceed in the following man- 
ner :—A quantity of fresh Canada 
balsam is to be poured into a watch- 
glass, and placed, with a bell-glass 
over it, on a warm stove for several 
days, until the Canada balsam has 
become quite hard and solid. With 
this, and by strongly heating the 
glass slide, the sections of bones and 
teeth may be mounted without dis- 
placing the air, especially if the 
preparations are exposed to the cold 
immediately afterward. 
Pig. 155. Transverse section of a human 
metacarpal bone, a, external; b, internal 
surface; d, interstitial lamellae; c, Haver- 
sian canals in transverse section with their 
lamellar systems; e, lacuna; and canalicnli 
containing air. 
There is still another, much more 
convenient and better process. The lamella of bone may be sur- 
rounded with a warm solution of filtered gelatine. When this 
has cooled and dried, any resinous mounting material suffices. 
If, on the contrary, it be desired to bring the lacunae and 
canalicnli filled with fluid into view, in the form of cavities, 
oil of turpentine is to be used in the examination ; and for 
mounting permanently, fresh fluid Canada balsam. Tingeing 
with carmine and haematoxyline may precede as a useful acces- 
sory (fig. 156). BONES AND TEETH. 
301 
In order to fill the blood-vessels, which is not very easy, the 
gelatine may be injected by a large vessel (in small animals), 
or by the nutritive artery (in larger creatures). The capillaries 
of the bones prove to be 
ensheathed by lymph 
passages (A. Budge). 
Injected bones, decal- 
cified slowly and conser- 
vatively in dilute chrom- 
ic acid, may be examined 
and preserved in Canada 
balsam or in glycerine. 
For such purposes one 
should select a durable 
coloring material. Bones 
injected with soluble 
Prussian blue have af- 
forded me very handsome 
preparations. It is ad- 
visable to brush out the 
cavities a little. 
We are indebted to 
Grerlach for a method of 
filling the cavities of the 
lacunae and canaliculi 
with coloring material, 
and thus demonstrating 
Pig. 156. Portion of a transverse section of the shaft of the 
humerus, treated with oil of turpentine, a, Haversian canals; 
b, their lamellar systems; c, newly deposited osseous sub- 
stance ; d, lacuna;. 
their hollow character in the most perceptible manner. A 
transparent coloring material, and one of the smaller long bones 
which has been sufficiently macerated and deprived of its fat, 
should be used. A hole is to be made in the epiphysis for the 
reception of the canule, and the entire surface of the bone is to 
be covered with shellac, so that the injection fluid may not 
escape from the apertures of the Haversian canals. 
In order to recognize the double refraction of the probably 
positively uniaxial bone (whereby the direction of the optical 
axis corresponds with the long diameter of the bone corpuscles), 
undecalcified sections are to be sawed out as accurately as pos- 
sible in the transverse or vertical direction. They should be 
neither too thin nor too thick, but should be rendered strongly 
transparent by means of Canada balsam or turpentine. If we 302 
SECTION FOURTEENTH. 
have a suitable transverse section, in which the diameter of the 
Haversian canals is perpendicular to the long axis of the bone, 
we may recognize, by polarized light, a regular and elegant 
cross, which is not changed by rotation. However, only a 
minority of the bone sections fulfil these requirements suffi- 
ciently. Very beautiful appearances are obtained by the in- 
tercalation of suitable films of selenite or mica. 
We have remarked above that the decalcifying methods 
previously employed were attended with a swelling of the bone 
tissue. They have not enabled us to recognize the structure of 
the basis substance. 
Yon Ebner recently found a method of avoiding this de- 
fect, and in this manner discovered the fibrillary nature of 
the matrix. 
For the first examination a relatively simple method may 
be adopted: a 10-15 per cent, solution of common salt which 
contains 1-8 per cent, of hydrochloric acid. The bone thus 
decalcified remains white. After washing out the salt it as- 
sumes a more transparent condition. To proceed with greater 
exactness, in order to obtain a neutral preparation, this able 
investigator recommends another method. 
A suitable quantity of a cold saturated solution of com- 
mon salt is to be diluted with an equal volume of distilled 
water. Muriatic acid is then gradually added in the course of 
several days until the bone has been deprived of its lime salts 
and has become quite pliable, that is, until it has become a so- 
called bone cartilage. The piece of bone is then washed in 
running water till it is semi-transparent. Reimmersion in a 
saturated solution of salt diluted with an equal volume of dis- 
tilled water then follows, during which the continuous extrac- 
tion of the acid from the bone naturally gives our fluid an acid 
reaction. In order to neutralize the bone, which is to remain 
in the solution from one to seven days, a very dilute solution 
of ammonia should be carefully and repeatedly added, A 
neutral piece of “ bone cartilage ” is thus obtained, which is to 
be examined in water or highly diluted glycerine. 
Even without further preparation in thin transverse sections 
of a tubular bone examined in water, one may recognize a very 
delicate stippling, while longitudinal sections present fine lon- 
gitudinal striations. This condition comes out beautifully, 
with a relatively simple texture, in the thigh of a frog, like- BONES AND TEETH. 
303 
wise in the phalanges and metacarpal bones of the bat, less so 
in the more complicatedly formed human bones. 
In order to isolate the extremely fine bone fibrillse, make a 
section parallel to the surface and scrape with a knife blade. 
Under water they appear united in bundles, which may pre- 
sent intercrossings. Their appearance reminds one of connec- 
tive-tissue fibres, with wdiich they share the familiar behavior 
under acetic acid. A cement substance, which unites them 
and prevents the isolation of longer fibres, is, according to von 
Ebner, the bearer of the bone earths, while the fibres remain 
soft. The lamellar structure appears the more distinct the 
greater the variety in the course of the fibrillse in the individ- 
ual lamellae. Thin strata 
of non-fibrillated cement 
substance are described 
by von Ebner as “cement 
lines.” They furnish ap- 
pearances which are impor- 
tant in connection with the 
resorption and new forma- 
tion of the tissue. 
Fig. 157. The Sharpey’s fibres, b, of a periostal lamel- 
la of the human tibia ; «, c, lacuna;. 
The decalcified bones of man and the mammalia are also to 
be used for demonstrating the so-called Sharpey’s fibres (fig. 
157), collagenous fibrillge permeating the bone tissue, which are 
frequently calcified. 
Elastic fibres partly in the strata immediately beneath the 
periosteum, partly in the inner layers of the Haversian canals, 
may also be seen in the bones of adults. Immersion for 24-48 
hours in a very dilute solution of fuchsine serves for their 
recognition (von Ebner). 
Dentine also presents a fibrillary composition similar to 
that of the bone matrix. The method of investigation is natu- 
rally the same. 
In investigating carious teeth, they may be broken to pieces 
in a vice, as recommended by Neumann, and then sections 
made from the portions which have become brown and de- 
prived of their lime salts. But if one desires to follow the 
transition from healthy to diseased tissue more closely, the 
previous decalcification is to be recommended. Tingeing with 
carmine, hsematoxyline and iodine also renders good service. 
It is much more troublesome to prepare the enamel of the 304 
SECTION FOURTEENTH. 
teeth than bones and dentine for examination. It is preferable 
to nse only young teeth in a fresh condition; much care 
should be taken in sawing, and still more in grinding. Dried 
teeth may be rendered serviceable again by soaking them for 
several days in water. Longitudinal and transverse sections 
of the enamel prisms (figs. 159, 160) may be recognized in good 
Pig. 159. Transverse 
section of human enam- 
el prisms. 
Fig. 158. Vertical 
section of a human in- 
cisor tooth. 
Pig. 160. Side view of hu- 
man enamel prisms. 
specimens. The transverse lines of the enamel may be best- 
seen by moistening the object with muriatic acid. Developing 
teeth are to be used for isolating the enamel prisms. 
The dental pulps are to be examined in fresh teeth; they 
are to be liberated by breaking the teeth ; in a vice or by the 
blow of a hammer. Teeth carefully decalcified by means of 
chromic acid and then hardened in alcohol also afford very 
good views, especially in tranverse sections. We shall speak 
of the nerves further on. 
With regard to the so difficult and complicated histological 
relations of the development of the teeth, we must refer to the 
text-books. As material for examination, may be selected em- 
bryos from the third to the sixth month of foetal life, likewise 
those of the mammalia, as for example of the hog, or, among the 
carnivora, of the dog and cat; they should be immersed in BONES AND TEETH. 
305 
chromic acid or another protective decalcifying medium. The 
new-born may also be used with advantage. It is preferable 
to immerse only the jaw. The finest specimens are obtained 
by a very gradual decalcification, occupying several weeks, by 
means of chromic acid solutions of 0.1-0.8 per cent., which 
must be frequently changed. A 5 per cent, solutidh of the 
officinal nitric acid is also very highly praised for this purpose 
by 8011. Fine sections are to be made with a razor, in various 
directions, through the jaw thus softened, and examined in 
glycerine. Canada balsam is to be recommended for mounting 
permanent preparations after tingeing with carmine. 
The examination of developing bone is not less difficult. Al- 
though twenty years ago, in consequence of the incompleteness 
of the methods of investigation at that period, the osteogenetic 
process could scarcely be found out, we have succeeded more 
recently, by the aid of improved methods, in unfolding the 
chief points, at least, of the textural conditions which here 
occur. 
The various portions of the skeleton are divided into such as 
are preformed in a cartilaginous state, and others in which such 
a cartilaginous preformation cannot be recognized. We have 
finally ascertained, through modern researches, that in the for- 
mer the cartilage does not become transformed into bone sub- 
stance, as was considered to be the case at a former period ; but 
rather that the cartilaginous tissue disappears in consequence of 
the formation of vessels and the deposition of bone salts, and 
that in the spaces formed by its dissolution the bone substance 
appears as a secondary, newly formed tissue. This is called 
the endochondral bone. 
Cartilage which is destined to give place in this manner to 
the bone substance is seen to be permeated by canals filled with 
small cells, and in which the development of blood-vessels takes 
place. This observation is in general easy to make in a few 
sections of foetal bone cartilage. If, as is at present the custom, 
the embryos of man and the mammalial animals which have 
been immersed in chromic acid are made use of, the blood-cells 
will not unfrequently be recognized in glycerine preparations 
as a reddish-brown mass filling these newly developed vessels. 
The so-called points of ossification then make their appear- 
ance ; that is, those places in the cartilaginous skeleton where 
numerous calcareous granules lie embedded in the interstitial 306 
SECTION FOURTEENTH. 
substance (fig, 161, a), and where the solution and melting down 
of the cartilage, which soon commences, begins. Chromic acid 
preparations are also exceedingly well adapted for this purpose, 
Fig. 161. The last dorsal and first lumbar vertebra of a human foetus of ten weeks, in vertical section. 
«, calcified, b, soft cartilage; c, oblong cells at the periphery of the developing symphysis; d, remains of 
the chorda dorsalis becoming transformed into the gelatinous nucleus of the vertebral symphysis. 
as, after the decalcification, the places in question still remain 
recognizable by their cloudy appearance and the irregular con- 
stitution of the interstitial substance; but it is only by the use 
of glycerine that they obtain such a degree of transparency that 
the processes in question can be investigated in all their details. 
By the aid of similar methods—and we here most urgently 
recommend tingeing with hsematoxyline and carmine—the 
later stages of the process are also to be followed (fig. 162), such 
as the more and more preponderating formation of cavities in 
the cartilaginous skeleton (a, b, d, f) in consequence of the con- 
tinued melting down of the tissue of the cartilage, the progress- 
ing calcification of the cartilage at the periphery, the formation 
of daughter-cells, etc., concerning which the text-books on 
histology are to be consulted. 
If the sections are brushed out a little, the newly-formed 
bone substance may be noticed in the form of a homogeneous 
layer (figs. 162, d, d, 164, b) covering the walls of the cavities, to- 
gether with the young bone-cells (e), which are at first thin, soft, 
and unstratified, afterwards thicker, stratified, and diffusely cal- 
cified in the outer layers. If Strelzoff’s excellent double tinge- 
ing (p. 160) be carefully employed, magnificent appearances are 
obtained. BONES AND TEETH. 
307 
The cartilaginous remains appear blue, the new-formed bone 
substance red. Unfortunately, however, such preparations are 
of a perishable nature. 
The recognition of the origin of the bone-cells requires a more 
accurate examination, and a careful analysis of the cell forma- 
Fig. 162. A phalangeal epiphysis of the calf, cut perpendicularly through its ossifying border. At the 
upper part, the cartilage with its irregular capsules containing daughter-cells, a. Smaller medullary 
spaces penetrating the cartilage, in part without visible entrance; 6, the same, containing cartilage mar- 
row-cells ;c, remains of the calcified cartilage; d, larger medullary spaces, on the walls of which the 
newly-formed, partly thin and unstratifled, partly thicker and lamellated bone-tissue is deposited ; e, a 
developing bone-cell; f, an opened cartilage capsule with an embedded bone-cell; gr, a partially filled cavity, 
covered externally with bone-substance and containing a marrow-cell; h, numerous apparently closed 
cartilage capsules with bone-cells. 
tions which occupy the cavities. Here, also, tingeing is very 
useful. 
These (figs. 162, b, h, 163, 7c, and 165, <z), formerly regarded 
as derivatives from the daughter-cells of the perishing cartilage 
tissue, are seen by the naked eye as a soft, reddish mass, and 
appear in the form of lymph-cells as roundish, small, and 308 
SECTION FOURTEENTH. 
granulated, with a simple or double nucleus. Many assume 
spindle and stellate shapes (165, c, c) to become transformed into 
connective-tissue cells, others form capillary vessels, others 
again, with a proportionate increase, probably become at a 
Fig. 163. Transverse section from the metacarpus of a sheep’s embryo, a, periosteum ; &, proliferous 
layer ; c, medullary canals, formed by the latter, and pressing at d into the endochondreal bone; e, peri- 
osteal bone; jT, boundary line of the same \ Q. persistent cartilage remains ; /i, endochondreal bone ; i- 
inner side of the same; A:, cells of the bone medulla in the axis cavity. 
later period enlarged in size and transformed into the globular 
fat-cells of the bone-marrow (d, e). If attention be directed to 
the periphery of the cellular contents, especially in thin sections 
which have been slightly and cautiously brushed, a layer of 
peculiar cells will be seen closely pressed together, which differ 
somewhat from the ordinary marrow-cells, and remind one of 
epithelium (fig. 163, d, and 166, c). From these, the “ osteoblasts ” 
of G-egenbaur, the deposition of the basis substance of the bone 
tissue takes place in an outward direction, and some of these 
cells, advancing beyond the crowded ranks, sink into this BONES AND TEETH. 
309 
tissue (166, g), to grow in a radiated manner and become bone- 
cells (/). 
Fig. 162, d, e, shows such cells commencing to assume the 
stellate form; some of them are already entirely surrounded 
by a homogenous interstitial substance, others have only a por- 
Pig. 164. Transverse section from the up- 
per portion of the femur of a human embryo 
at the 11th week, a, Kemains of cartilage; &, 
covering of osteoid tissue. 
Pig. 165. Cartilage marrow-cells, a, from 
the humerus of a 5-months human foetus; b, 
from the same bone of the new-born ; c, star- 
shaped cells of the former melting down into 
fibrous formations; d, formation of the fat- 
cells of the marrow; e, a cell filled with fat. 
Fig. 166. Transverse section from the femur of a hu- 
man embryo of about 11 weeks, a, a transverse, and b, a 
longitudinally divided medullary canal; c, osteoblast; d, 
the more transparent, younger; e, the older bone sub- 
stance ;/, lacunse with the cells; g, cell still united to 
the osteoblast. 
tion of their surface (that which is directed outwards) covered 
in this manner. 
The continued formation of new cavities in the remaining 
portions of the cartilage causes the opening of numerous car- 
tilage capsules. These spaces are also soon occupied by bone- 
cells and intercellular masses. If the entrance of a cavity filled 
in this manner with young bone substance (fig. 162, /) be recog- 
nized, the appearance is easy to comprehend. This aperture 
is, however, much more frequently not to be seen {7i, h), and 
then it makes an impression as if there were bone corpuscles 
lying in the interior of unopened cartilage capsules. Earlier 310 
SECTION FOURTEENTH. 
observers had frequently met with such appearances in their 
investigations, and were thus led to the erroneous conclusion 
that (after the manner of the formation of the porous canals in 
plants) the cell remains of the unevenly thickening cartilage 
capsule became transformed into bone corpuscles. Very in- 
structive examples of these apertures in the cartilage capsules 
may be obtained from the comparison of a series of consecutive 
transverse sections (Muller). However, the question as to 
whether the bone-cells occur in ruptured cartilage capsules 
only, and not in those which still remain closed, is one which 
is not, as yet, definitely solved. 
The later phases, the increasing deposition of new bone- 
lamellae, and the final melting down of the last remains of the 
cartilage (figs. 162, c, 164, a), may also be investigated by the 
aid of the above-mentioned methods. Tingeing with carmine 
should be invariably employed when it is necessary to distin- 
guish the already diffusely calcified older bone tissue from that 
which is quite young and still soft. The soft (osteogenous) 
bone substance readily assumes a lively red color, while the 
older, calcified (osteoid) takes up the coloring matter less rea- 
dily and much more slowly, even in cases where a considerable 
portion of the bone salts have been removed by means of chro- 
mic acid. This method is also excellent for the inverted pro- 
cess, for the normal as well as the pathological decalcification 
and melting down of bone tissue. 
To demonstrate the manner of growth of foetal or young 
bones, longitudinal and transverse sections should be made 
from those which have been decalcified. In the former we see 
the growth in length taking place at the expense of the cartila- 
ginous, articular portion, and showing the same structural 
changes which we have just mentioned in discussing the pri- 
mary formation of bone. 
Transverse sections which are to be tinged with hsematoxy- 
line and carmine deserve the preference, as a rule, for studying 
the manner in which bones increase in thickness. This takes 
place by the formation of a new osteogenetic tissue (fig. 163, e) 
from the connective tissue of the periosteum («, b), with the 
help of a similar layer of osteoblasts (c). To these is due the 
elegant and regular structure which the bone assumes after 
the melting down of the primary, irregularly deposited osteoid 
substance. BONES AND TEETH. 
311 
The bones of the second group, originating from connective- 
tissue substance, without a cartilaginous preformation, coin- 
cide very nearly with the periosteal mode of growth, and require 
the same methods for their examination. A preliminary pro- 
tective decalcification, followed by Strelzoff’s double tingeing, 
has afforded me the best preparations. 
If one fortunately succeeds in injecting the embryos des- 
tined for such examinations with transparent masses, many 
things will be better recognized in this case, as in the investiga- 
tion of all osteogenetic processes, than when the blood-vessels 
are not filled. 
For the examination of the bone-marrow, the preparatory 
hardening methods with chromic acid, bichromate of potash, 
and Muller’s fluid may be employed. The fresh tissue, with 
indifferent fluid media, is also to be recommended. Here, for 
instance, in tadpoles, the vital changes of form of the bone- 
marrow cells may be readily appreciated (Bizzozero). In this 
way numerous lymphoid cells which are undergoing transfor- 
mation into red blood-corpuscles may be seen in the red bone- 
marrow of mammalial animals. This source of the latter cells 
was not noticed till quite recently (Bizzozero, Neumann). We 
have already mentioned this circumstance, in a cursory manner, 
at p. 234. The idea that our cells pass through the thin walls 
into the vessels of the bone-marrow is obvious. 
With regard to the ossification of permanent cartilage which 
occurs in the later periods of life, such as those of the ribs and 
many of those of the larynx, this may, as a rule, be considered 
as a calcification of the cartilage, which is the same process 
that takes place on a more extensive scale in the foetal skele- 
ton, and never ceases entirely at any period of life. As in 
the embryo, so also in the aged, the calcified cartilaginous 
tissue may be absorbed, and osteogenous substance deposited 
in the cavities thus formed. 
The examination of rachitic bones constitutes an interesting 
study, completing that of the normal foetal bone formation. 
The appearances naturally vary, according to the grade of the 
disease, the attempts at restoration which have taken place, 
etc. The individual parts of a bone also present numerous va- 
riations. 
An insufficient, occasionally almost entirely wanting calci- 
fication of the cartilages, the persistence of considerable por- 312 
SECTION FOURTEENTH. 
tions of the foetal cartilage, together with peculiar transforma- 
tions of its capsules, and an osteogenous substance which is 
sometimes inadequately, sometimes not at all impregnated 
with bone earths may, in general, be regarded as the chief an- 
omalies. 
In the rachitic cartilaginous skeleton the medullary carti- 
lage cells are met with the same as in normal bones, as also a 
similar rupture of the cartilage capsules and the deposition of 
bone-cells with their interstitial substance. Even in the me- 
dullary spaces, anomalies of form and extent may be seen. 
They frequently advance beyond the calcifying border of the 
cartilage and even to a considerable distance into the unaltered 
portion of the latter. Very deceptive appearances are pre- 
sented by the capsules in that portion of the cartilage which 
remains; in consequence of the thickening of their walls, the 
residue of their contents may be recognized as star-shaped 
bodies. Appearances are caused in this manner which bear 
great resemblance to bone corpuscles, and which, in fact, can 
scarcely be distinguished from many ruptured capsules in 
which true bone corpuscles are embedded, unless the point of 
entrance happens to lie in the plane of the section. Hence we 
shall readily comprehend that until within a few years rachitic 
bones were regarded as affording the most certain proof of the 
transformation of cartilage cells into bone corpuscles, and were 
accepted as true paradigms of the process of ossification. In 
reality, however, they constitute very insidious and deceitful 
objects. 
These few remarks must suffice, in consequence of the nar- 
row limits of our little work. The investigations of Bruch, 
Kolliker, Virchow, and Muller are to be consulted for further 
details. 
Fresh bones or those preserved in alcohol may be selected 
for examination. Those which have been dried also occasion- 
ally afford very handsome specimens. Muller found the em- 
ployment of weak solutions of chromic acid, with the subse- 
quent addition of glycerine, very useful in these cases. 
The best views are here afforded, however, by Strelzoff’s 
double tingeing. The blue cartilaginous remains come out 
with marvellous sharpness. 
In consequence of the exuberant vitality of bones, new for- 
mations of osteogenous tissue, physiological as well as patho- BONES AND TEETH. 
313 
logical, are of very extensive occurrence. In both cases the 
point of origin of the new bone tissue may be from the perios- 
teum and the endosteum, that is, the connective-tissue layer 
which lines the medullary cavity. The former is, however, 
much more frequently the case, and Ollier’s interesting experi- 
ments show that the living periosteum is not deprived of its 
bone-producing power by transplantation to a remote part of 
the body. 
A beautiful, accurately-investigated example of this double 
origin is afforded by the reunion of fractured bones, the so- 
called callus formation. If the examination be made with the 
aid of the methods at present used for the normal osteogenesis, 
the newly-formed osteogenous substance which has originated 
in the periosteum may be seen surrounding the ends of the 
bones like a ring. Beneath the periosteum, which is here 
thickened and swollen, appear the various layers of osteogenous 
tissue which are formed from it. In man these strata have, as 
a rule, a connective-tissue character, much less frequently that 
of cartilage (while in mammalial animals, under similar condi- 
tions, there is a more plentiful production of cartilage). Sec- 
ondly, there is a reunion of the bone tissue beneath the endos- 
teum. The latter also swells up and produces new osteoge- 
nous tissue, which spreads through the medullary cavity and 
plugs it up. 
Where there is a greater loss of substance in a bone, the 
regeneration takes place from the periosteum. 
Other new formations of bone tissue, such as the hypertro- 
phies or hyperostoses, the inflammatory productions of the 
same and the bone tumors originate in part and chiefly from 
the periosteum, in part from the connective tissue of the 
medullary cavity. 
Hyperostosis is, in reality, exactly the same occurrence which 
is met with in the increase in thickness of young bones, and, 
in suitable transverse sections, it presents very similar appear- 
ances. The local, more or less salient new formations of bone 
substance of this kind, which are not separated from the ordi- 
nary tissue by any line of demarcation, constitute the compact 
exostoses. Next to these come the tumors which are com- 
posed of a denser bone tissue. They show, in part, the ordi- 
nary compact texture ; in many cases they are of a more 
spongy nature ; in others, finally, they have an ivory-like SECTION FOURTEENTH. 
hardness, in consequence of the slight development of medul- 
lary canals. The osteophytes have a sponge-like arrange- 
ment. 
The cases hitherto mentioned have placed before the reader 
bone tissue formed from the periosteum. In the so-called scle- 
roses of bones we meet with the new formation of osteogenous 
tissue proceeding from the medullary cavities and the medul- 
lary canals. Among the osteosarcomse, the central ones are 
developed from the large medullary cavity, the peripheral 
ones from the periosteum. They show, in the main, only iso- 
lated globular and flake-like masses of bone tissue, without 
vessels or medullary canals. 
The new formation of osteogenous substance in soft tissues, 
independent of pre-existing bone, has certainly been very much 
exaggerated in favor of the modern connective substance the- 
ory. In most cases there is only calcified connective tissue 
with indented corpuscles. However, the production of true 
bone substance in connective-tissue parts does take place, 
although rarely. The stratified arrangement of the basis sub- 
stance, and the radiated bone corpuscles, connected with each 
other by their branches in a reticular manner, secure one 
against mistaking the one for the other. 
The resorption of the previously decalcified bone tissue con- 
stitutes the opposite process. In normal life the melting 
down of the bone substance occurs very extensively in growing 
young bones. Only call to mind the formation of the larger 
medullary cavities in the foetus, and the Haversian spaces of 
later periods ! The anatomical events which take place here 
are the increase of the medullary cells and the enlargement of 
the medullary spaces, the crumbling down and fatty degenera- 
tion of the bone-cells together with the decalcification of the 
neighboring osteoid substance and the subsequent dissolu- 
tion of the same. Hereby the liquefying bone tissue fre- 
quently shows excavated borders, as if gnawed out, so-called 
Howship’s lacunae. According to Kdlliker’s observations, large 
multinuclear cells, which he calls “ osteoclasts,” occur in such 
places, and which are said to produce this dissolution. If such 
a condition occurs at a later period as an abnormal process, we 
have the so-called osteoporosis. Osteo-malacia also presents us 
with a similar increase of medullary cells and medullary 
spaces, with impoverishment of the osteoid substance in bone BONES AND TEETH. 
315 
earths, and the dissolution of the same. In reality the same 
process occurs in the formation of granulations. While, how- 
ever, in this case the interstitial substance of the granulating 
medullary cells still presents a certain firmness, similar to the 
ordinary consistence of foetal bone tissue, in other cases there 
may be a liquefaction of the interstitial mass. The cells which 
are suspended in such a fluid are then called pus corpuscles, 
and the process itself is called caries. The latter, correspond- 
ing to the two localities of the osteogenesis, may either occur 
within the bone, in its medullary cavities, or externally in the 
canals which are filled with bone-marrow by the periosteum. 
Thus the microscope here teaches in a very beautiful manner 
how normal and pathological processes may pass over into 
each other. 
Decalcified bone substance is said by many histologists to 
be capable of transformation into ordinary connective tissue. 
According to our views, this is incorrect. This substance is 
incapable of any future development; it simply undergoes 
liquefaction, sooner or later. 
Finally, if inquiry be made as to the methods of examining 
diseased bones, reference is to be made to what has already 
been remarked. They are the same as for the normal tissue. 
Dried bones are less to be recommended than moist ones, which 
may be decalcified by means of chromic acid with the addition 
of a little muriatic acid, and which may be subsequently hard- 
ened again, according to circumstances, in strong alcohol. 
Bones which are strongly impoverished in bone earths may be 
examined fresh, or as alcohol preparations, without the use of 
acids. As we have already remarked, the decalcified tissue 
distinguishes itself in a very beautiful manner from that which 
is still calcified, by the readiness with which it imbibes car- 
mine. Section ififteentl). 
MUSCLES AND NERVES. 
Muscles and nerves, in consequence of their softness, require 
very different accessories than the 
hard tissues which we have lust 
left. 
The muscular tissue of man and 
the vertebrate animals consists of 
two forms of fibres, the smooth and 
the transversely striated. 
The latter muscles show as their 
elementary formation, a generally 
undivided, more rarely branched, 
fibrilla, which is marked with fine 
and closely - arranged transverse 
lines (the so-called primitive bun- 
dle), while the smooth muscles are 
formed of spindle-shaped, linearly 
arranged cells. With this differ- 
ence in structure is also associated 
differences in their manner of ac- 
tion. The smooth muscles of man 
always act involuntarily and slow- 
ly ; the transversely striated mus- 
cles, on the contrary, are obedient 
in their rapid contraction to the im- 
pulses of the will. But the heart, 
a transversely striated muscle, also 
contracts involuntarily like the 
smooth tissue, but rapidly. 
Pig. 167. Smooth muscular tissue, a, the 
foetal developing cell from the stomach of a 
pig ;6, a somewhat more advanced cell; c-h, 
various forms of the contractile fibre-cells 
from the mature body; i, bundle of smooth 
muscle; Jc, transverse section of the latter. 
The examination of smooth 
muscles (fig. 167) is in general difficult. 
This very tissue shows how important the employment of MUSCLES AND NEEYES. 
317 
suitable reagents is for the recognition of many textural condi- 
tions. 
For a long time histologists regarded the elements of the 
smooth muscles as fiat bands (i) containing nuclei placed behind 
each other, and, in fact, the older methods of investigation 
yielded nothing further. It was not till about 1847 that the 
piercing eye of Kdlliker succeeded in resolving these bands into 
long spindle-shaped cells arranged in rows, with a columnar- 
shaped nucleus (c-7i). Since that time the elements of the 
smooth muscles bear the name of contractile fibre-cells. 
Formerly acetic acid was generally used in studying the 
smooth muscles. Boiling the tissues (Henle), or hardening 
them in alcohol, also affords serviceable preparations, especially 
with subsequent tingeing with carmine. 
More recently, however, we have become acquainted with 
more conservative methods. 
For the first examination the frog may be selected, the uri- 
nary bladder and lungs of which afford good objects ; the 
smaller arteries of the frog are also to be recom- 
mended. To isolate single fibres without re- 
agents, take the walls of the intestines. 
The more minute arrangement is to be exam- 
ined either with the addition of an indifferent 
fluid, such as blood- and iodine-serum, or by the 
application of reagents. Impregnation with gold 
(0.1 per cent.) may be used, but decidedly more 
may be accomplished by macerating for one or 
two days in a very weak chromic acid solution 
of 0.01-0.05 per cent. 
The two last-mentioned methods also show us 
the nucleolus (fig. 168), single or multiple (Frank • 
enhauser, Arnold, Schwalbe). It was formerly 
overlooked in the tissue which was altered by 
acetic acid. The nucleolus is occasionally re- 
markable, however, even in the fresh cell. 
Fig. 168. Elements 
of the smooth muscles 
of the rabbit. 
Impregnation with silver is also well adapted for the recog- 
nition of delicate strata of organic muscles ; for example, in 
the villi and the mucous membrane of the small intestine (His); 
likewise chloride of palladium (F. E. Schulze) and picric acid 
(Schwarz), which color yellow. 
Drying, and thereupon tingeing with carmine, and the ac- SECTION FIFTEENTH. 
tion of acetic acid, were formerly employed for obtaining trans- 
verse sections of bundles of smooth muscles. The preparatory 
hardening by means of alcohol, chromic acid, or bichromate of 
potash, appears to be more suitable. The most conservative 
treatment consists, however, in the freezing method, with a sub- 
sequent addition of serum (Arnold), or of a 0.5 per cent, solu- 
tion of common salt (Schwalbe). For this purpose select the 
walls of the stomach or intestines of a frog or mammalial ani- 
mal, the urinary bladder of a dog (Schwalbe), or a section may 
be made in a vertical direction through the coats of a larger ar- 
tery. The two umbilical arteries also afford handsome speci- 
mens by this method. Thus (fig. 167, k) the transverse sections 
of the fibre-cells will be seen, some more round, some more 
polyhedral in shape, and in many of them the transverse sec- 
tion of the nuclei may also be recognized, and one will be read- 
ily convinced that the contractile fibre-cells are by no means 
flattened structures, but rather spindle-shaped. 
For isolating the cells we have three especially good methods 
at present in use. 
1. The maceration in nitric acid of 20 per cent., with which 
Reichert and Paulsen have made us acquainted. The first ef- 
fect is to render the tissue darker and more yellow ; after 24 
hours the separation of the bundles into contractile fibre-cells 
commences, and after three days the latter readily fall apart, 
especially with a little shaking. At the same time a peculiar 
transversely wrinkled or folded appearance occurs in the ele- 
ments of the smooth muscles. 
Muriatic acid of 20 per cent, also exerts a similar effect. 
2. Diluted acetic acid. 
This has at all times played an important role in the exam- 
ination of the tissue with which we are at present occupied, and 
was also extensively made use of by Kolliker in his investiga- 
tions. Its value lies, firstly, as we have already remarked, in 
the rapidity with which it renders the so characteristic nuclear 
formation visible ; then, by making the connective tissue trans- 
parent, it causes the bundles of smooth muscles themselves 
to become prominent. Solutions of 2-5 per cent, are to be 
used. 
8. Treatment with 30-85 per cent, solutions of potash. 
If the demonstration of the nucleus be renounced, the solu- 
tions of potash of the strength mentioned, or one of 32.5 per MUSCLES AND NERVES. 
319 
cent., constitute the best means of isolating and demonstrating 
the contractile fibre-cells. After an action of 16, 20-30 minutes, 
numerous examples of the latter may be obtained, which are 
frequently of an undulating, serpentine form. 
4. Treatment with 10 per cent, solutions of common salt. 
The cells are but slightly changed by this reagent, though 
they are subsequently very readily detached from each other ; 
thus, in the dog’s intestine after 48 hours ; much more slowly 
in the frog (Schweigger-Seidel). 
The maceration in iodine-serum, or the already mentioned 
extremely diluted chromic acid, also leads to the isolation of 
the muscular elements. 
The destruction of smooth muscular tissue by fatty degen- 
eration of the cells is a not infrequent event, as a normal oc- 
currence (uterus) as well as a path- 
ological one ; likewise the new for- 
mation of the tissue from the pre- 
existing. The latter phenomenon, 
however, requires a more careful 
study. 
The transversely striated mus- 
cles (fig. 169) offer much more 
remunerative objects. The more 
important elements make their ap- 
pearance readily and beautifully, 
and only the resolution of certain 
very delicate textural conditions 
leads to a difficult domain lying at 
the limits of our present instru- 
ments. 
If we desire to bring the fibres 
of the transversely striated muscu- 
lar tissue to view, in as unaltered 
a form as possible, the frog is to 
be especially recommended. The 
animal is to be decapitated, and 
Fxq. 169. 1. Transversely striated muscu- 
lar fibrill®; a, so-called primitive fibres ; b, 
and c, transverse and longitudinal lines ; (/, 
nuclei. 55. A muscular fibrilla, the sarcous 
portion, &, b, of which is torn in two, and 
shows the empty primitive sheath at a. 
the well-known cutaneous thoracic muscle, or one of the flat 
muscles running from the os hyoides to the lower jaw, im- 
mediately cut out, avoiding all straining and tearing. These, 
with the addition of blood-serum or some other indifferent 
fluid, will afford us excellent views of the familiar longitu- 320 
SECTION FIFTEENTH. 
dinally and transversely striated fibrilhe (compare figs. 169, 1; 
170, 6). We obtain similar appearances in tire living creature 
by selecting the tail of the frog’s larva; young fishes Just 
hatched also afford admirable objects. If entire freshness be 
disregarded, a muscular fasciculus from the body of any verte- 
brate animal may be used several hours after death. A small 
portion of tissue, carefully picked apart with needles, always 
Fig. 170. 1, Muscular filament, with so-called primitive fib- 
rillEe and distinct transverse lines ; 2, isolated fibrillae more 
strongly magnified; 8, the sarcous portions united as a disk; 
4, the commencing separation of the disks; 5, muscular fila- 
ment after longer maceration in muriatic acid; a and b. 
nuclei; c and d, brighter and darker zones; 6, two pointed 
fibrillEe of the biceps brachii, already ending in the course of 
the muscle. 
Pig. 171. A muscular fasciculus of 
the frog by 800-fold enlargement, o, 
dark zones with sarcous elements; h\ 
bright zones; c, nuclei; ci, interstitial 
granules. (Alcohol preparation.) 
affords good specimens, and shows us the fibrillse varying in 
their diameters and markings. 
To recognize the nuclei, use a weak acid (diluted acetic acid, 
muriatic acid of 0.1 per cent., etc.). They will then be dis- 
covered in the form of oval bodies (figs. 169,1 d; 171, c). A 
remainder of original cell-substance (protoplasma) surrounds 
the nucleus and extends beyond both its poles in a spindle- 
shaped prolongation (muscle corpuscles). 
We do not see the sarcolemma, or the primitive sheath of MUSCLES AMD MEEVES. 
321 
the muscular filament in the ordinary method of examination, 
as this envelope closely surrounds the contractile contents. 
One may succeed in recognizing them in various ways. The 
muscles of the pisciform amphibise, the proteus and axolotl, 
which have been in alcohol for some time, afford, without fur- 
ther preparation, a very good view of the loose and expanded 
envelope. If the greater portion of the various albuminous 
substances are dissolved by a longer-continued maceration in 0.1 
per cent, muriatic acid, one may perceive the softened contents 
projecting from a surrounding sheath at the divided extremities 
of the muscular fibres. The sarcolemma may be completely 
isolated, as Kiilme has taught us, by means of a somewhat com- 
plicated process. For this purpose the muscular fasciculus of 
the frog is to be macerated for a day in water with 0.01 per 
cent, of sulphuric acid of 1.88 sp. wt., and then freed from its 
connective tissue by digestion in water at 85-40° C., which like- 
wise requires 24 hours. The fibre is now to be exposed for a 
day to the action of muriatic acid of 0.1 per cent. 
However, we possess still other accessories, by means of 
which we are able to bring the sarcolemma into view instan- 
taneously. If a bundle of muscular fibres be drawn with a pair 
of sharp forceps out of one of the muscles at the upper part of 
the thigh of a freshly decapitated frog, one will soon be able, by 
the addition of water, to recognize numerous separations of the 
primitive sheath from the contractile contents, as a result of 
the energetic imbibition. At first there are small, limpid 
pouches ; these soon grow larger and larger under the eye of 
the observer, neighboring ones flow together, and the vesicular, 
elevated portions of the sarcolemma are separated by annular 
constrictions from those which still remain attached. 
Other muscles may also afford us the desired results, if in 
their preparation we subject the several fibres to a strong ten- 
sion and tearing. In some of them the contractile contents are 
torn in two ; while over this place the more extensible sarco- 
lemma remains intact. Such an appearance is seen in the mus- 
cular fibre fig. 169, 2, a. 
The drying method served for a long time to show the rela- 
tion of the several muscular fibres with each other, as well as 
the formation of the bundles of muscles and of the entire mus- 
cle. Thin sections which were again softened, and especially 
such as were soaked in an ammoniacal solution of carmine, and 322 
SECTION FIFTEENTH. 
subsequently treated for a few minutes with very dilute acetic 
acid, then presented the frequently mentioned and characteris- 
tic appearance of fig. 172, a. One may recognize, at the same 
time, in the muscles of man and the mammalian animals, the 
manner in which the nuclear formation is imbedded in the peri- 
phery of the contractile substance, and lying against the inner 
surface of the primitive sheath (e). In the muscular fibres of 
the heart, on the contrary, nuclei also occur in the more cen- 
tral parts, a condition which seems to predominate in the lower 
vertebrated animals. 
Hardening in absolute alcohol affords better results. 
The freezing method presents very much better results, how- 
ever (Cohnheim). By the aid of the highest magnifying powers 
Fig. 172. Transverse section through a bun- 
dle of the biceps brachii of man. a, the mus- 
cular fibres; 6, transverse section of a vessel; 
e, a fat-cell lying in a large connective-tissue 
interstice; d, capillaries cut across; e, nuclei 
of the muscular fibres. 
Fig. 173. Transverse section through 
a frozen muscle of the frog, a, groups 
of sarcous elements; b, a nucleus; c, 
transparent transverse connecting me- 
dium (Querbindemittel). 
one may then recognize groups of sarcous elements as a mosaic 
of small, dull areolations of various forms (fig. 173, a), and sur- 
rounding these groups a lattice-work of transparent glistening 
lines (c). 
Various methods may be employed for obtaining the rami- 
fied muscular filaments, such as occur in the heart and tongue. 
Solutions of potash from 30-35 per cent, are used for the heart 
muscles. Solutions of nitrate of silver with the subsequent 
action of these potash solutions are recommended for demon- 
strating the cell boundaries. In order to isolate the fibres with 
the needles, immerse for a few days in Czerny’s mixture (p. 137) 
or in a mixture of muriatic acid (1) and glycerine (20). The iso- 
lation succeeds very finely after two or three days’ action of a MUSCLES AND NERVES. 
323 
20 per cent, nitric acid (Weismann, Scliweigger-Seidel, Langer- 
hans, L. Gerlach). 
To examine the tongue, either place the object fresh in 
pyroligneous acid, or let this reagent act on preparations pre- 
viously hardened in alcohol or chromic acid. 
The value of the pyro-acetic acid (or of a dilute acetic acid) 
naturally consists in its property of rendering the connective 
tissue transparent. 
The isolation of the muscular fibres in their entire length is 
necessary for a number of purposes of investigation. In this 
way we recognize the course of the fibres in a muscular fasci- 
culus, the divisions of the same as phenomena of growth, and 
the increase in the number of fibres in the enlargement of the 
muscle; etc. We have the choice of several methods for this 
purpose. 
1. The mixture of chlorate of potash and nitric acid may be 
employed in various degrees of concentration. We are in- 
debted to Kuhne for a suitable procedure. The bottom of a 
beaker is to be covered with crystals of the chlorate of potash, 
slightly moistened with distilled water, and four times the vol- 
ume of pure concentrated nitric acid added. After considera- 
ble stirring, the fresh muscle (of a frog) is to be placed at the 
bottom of the vessel and buried beneath the crystals of potash 
by means of a glass rod. In about half an hour the muscle is 
to be removed from the mixture and placed in water in an or- 
dinary test tube. This is to be strongly shaken, and then, in 
fortunate cases, the tissue separates completely into fibrillse. 
If this separation does not succeed the first time, the muscle is 
to be replaced in the mixture and exposed to the same pro- 
cedure at intervals of five minutes. 
By this means exquisite specimens are obtained, and the 
nuclei appear very finely in the slightly browned sarcous sub- 
stance. 
The method given by Wittich for using this mixture is also 
very judicious. That is, boiling in chlorate of potash and 
nitric acid strongly diluted with water (water 200 ccm., nitric 
acid 1 ccm., and chlorate of potash, 1 grain). 
2. The same may be accomplished by maceration for twenty- 
four hours in 0.01 per cent, sulphuric acid and the subsequent 
treatment for one day with warm water, as recommended above 
(p. 321) for the demonstration of the sarcolemma. 324 
SECTION FIFTEENTH. 
3. After the example of Rollett, the muscle may be placed, 
without any addition of water, in a small glass tube which may 
be hermetically sealed by the heat of a lamp and then warmed 
to 120°-140° C. on a sand-bath for ten minutes. The tube is 
then to be broken and the muscle agitated in warm water. 
4. A strong, but no longer fuming muriatic acid (p. 125) may 
also be employed with advantage. After an action of several 
hours the interstitial connective tissue is likewise found to be 
dissolved. 
5. Finally, a potash solution of about 36 per cent, also forms 
a very good accessory. A sometimes slighter, sometimes larger 
portion of the muscular fibres will always be 
found isolated, after an action of from fifteen 
to thirty minutes. 
The high value of reagents is not more strik- 
ing in any question with regard to the structure 
of muscular tissue than that of the relation of 
the muscular fibre to the tendon. 
Until recently it could only be stated as a 
true expression of what had been observed, 
that there was no boundary to be discovered 
between the contractile substance of the fibrillse 
(fig. 174, a) and the connective-tissue fibrous por- 
tion of the tendon (&), whether the muscle be 
inserted into the tendon in a straight line or at 
an oblique angle. It was therefore extremely 
probable that the sarcous portion, as well as 
the sarcolemma, were continued directly into 
the tissue of the tendon. This continuity of 
the contractile substance and the connective 
tissue was certainly somewhat strange, and we 
might say inconvenient. 
At the present day we must all admit the 
Fig. 174. Two muscu- 
lar fibrillm (a), with the 
apparent continuation 
into the connective-tis- 
sue bundles of the ten- 
don (6). 
error, even though we formerly defended this theory, since 
Weismann has discovered a medium in the 35 per cent, solu- 
tion of potash, which decides in a beautiful and certain man- 
ner the long-contested structural relation. 
After 10, 20-30 minutes the muscular fasciculus presents the 
appearance shown in fig. 175, a, b. The apparent continuity 
has disappeared. The former, covered by the sarcolemma, is 
separated by a sharp line of demarcation from the tendinous MUSCLES AND NEKYES. 
325 
fasciculus (c). In many specimens they are even seen discon- 
nected from their tendons {d), especially when a slight pressure 
has been made. There is therefore no longer any doubt that 
the fasciculi of the muscles and tendons are only “ cemented” 
together in the firmest manner. It is this substance, this “ tis- 
sue cement” which the potash solution has dissolved, which 
holds them together. 
While it was formerly supposed that every transversely 
striated fibre continued throughout the entire length of its 
muscle, more recently numerous exceptions to this have been 
observed; that is, muscular fibres which terminate in a point 
Pig. 175. Two muscular flbrillas (a, 6) after 
treatment with solution of potash. The one 
still in connection with the tendon (c), the 
other separated from the same (d). 
Pig. 176. Vascular net-work of a trans- 
versely striated muscle; a, artery; b, 
vein 1 c, d. the capillary net-work. 
or some other form at a greater or lesser distance from the ten- 
dinous extremity (Eollett, Weber, Herzig, and Biesiadecky). 
Such fasciculi (fig. 170, 6) have their connection with the ten- 
don, to a certain extent, in the interstitial connective tissue. 
For these investigations, which are easy to make, fresh as well 
as boiled muscles may be immersed for twenty-four hours in 326 
SECTION FIFTEENTH. 
glycerine, or the solution of potash mentioned may be em- 
ployed. 
To see the extended capillary net-work of the muscular tis- 
sue (fig. 176), they should be injected with transparent masses, 
with carmine or Prussian blue. Thin, flat muscles taken from 
a frog which has been drowned in alcohol, and placed on the 
microscopic slide, will bring to view the capillary system filled 
with blood in the most beautiful manner ; and with a little 
contraction of the muscular fibres, the delicate windings of the 
capillary vessels may be readily recognized. 
We may not yet leave the transversely striated muscular 
filaments. Ranvier recently discovered that in many crea- 
tures, especially our domestic mammals, such as the rabbit, 
but also in cartilaginous fishes, in addition to the ordinary col- 
ored muscles, others of peculiar structure also occur, which 
are distinguished by a livelier, deeper, more red color (as for 
instance, the semitendinosus of the rodent animal mentioned). 
They are characterized by a much greater number of the nuclei 
or muscular corpuscles; furthermore, they act more slowly, 
are more sluggish, and their capillary network also presents a 
difference. The longitudinal tubes of the latter are more 
strongly curved, the transverse branches of the capillaries 
follow each other more rapidly, and in places permit of the re- 
cognition of spindle-shaped dilatations. 
This beautiful discovery of the excellent Parisian investiga- 
tor may be readily demonstrated on a rabbit by the aid of the 
ordinary methods of examination. Injections are to be made 
by the abdominal aorta. 
Concerning the nerves of the muscles, reference is to be 
made to one of the following pages. 
The structural conditions which have thus far been men- 
tioned of the transversely striated muscular tissue are all, as 
we have remarked, relatively easy to examine, and with the 
requisite methods, they afford a suitable study for the begin- 
ner. It is otherwise with regard to the subtle question con- 
cerning the constitution of the contractile substance which they 
contain, the “sarcous substance.” 
We are here, unfortunately, at the optical limits of our 
microscopes, and the phenomena of incurvation of the light 
(p, 62, note) make themselves felt in an appreciable manner 
(Abbe). MUSCLES AND NEEYES. 
The muscular fibrillse (fig. 177, 1) show a double marking, 
which, however, is subject to considerable variation as to 
sharpness and distinctness. We recognize coming to the sur- 
face of the fleshy substance, sometimes over a long space, 
sometimes only for a short distance, and then disappearing in 
it, a fine longitudinal marking (c), extending throughout the 
entire thickness of the former; and secondly, a likewise very 
fine, transverse linear marking (5), which may also be followed 
through the entire substance of the muscle. In many fibrillse 
Fig. 177, 
Pig. 178. 
the latter is alone present; in other specimens the longitudinal 
lines predominate occasionally to exclusiveness, and fine bands 
and fibres (a) may project from the cut extremities. It was 
especially the latter cases which, in former times, led the micro- 
scopists to the acceptation of a further composition of the mus- 
cular fibrillse out of the finest fibres, the so-called ‘£ primitive 
fibrillse” (fig. 178, 1, 2). The transverse lines were then gener- 
ally referred to a knotty condition of these elementary fibrillse 
resembling a string of pearls. 
At the present day this theory still finds its defenders, and 
even among renowned investigators, although the so much im- 328 
SECTION FIFTEENTH. 
proved optical accessories of the period by no means decide in 
their favor. 
In other specimens the transverse markings come out sharper 
and more distinct (fig. 178, 6). If the longitudinal lines are 
wanting, one might even here imagine that the muscular fasci- 
culus was composed of disks or plates arranged over each other 
in layers. The appearances become still more deceptive where 
the transverse lines stand farther apart than is the rule, and 
where the border or periphery of the librilla has indentations 
corresponding to the striations. 
The theory originated by the English histologist Bowman, 
and further improved by some of his countrymen, finds at pre- 
sent the most adherents. According to it, the contents of the 
muscular fasciculi consist of small molecular corpuscles, the 
so-called fleshy particles or “ sarcous elements,” which are 
held together by a homogeneous connecting medium, which is 
in reality twofold, and not exactly alike chemically. Accord- 
ing, now, as the one or the other of these two connecting media 
predominates, we see the sarcous elements united either longi- 
tudinally or laterally; in the first case, the appearance of 
fibrillse (1, 2) results ; in the lat- 
ter, that of transverse lines (1) 
increasing to transverse plates 
(4, 5). 
The sarcous elements in the 
muscular fibres of man and the 
mammalia are entirely too small 
to enable us to state anything 
with certainty in regard to their 
form, although by the use of 
very strong magnifying powers 
they may be shown with satis- 
factory distinctness (fig. 179, 2, 
a, afk). The muscles of the lam- 
Fig. 179. Two muscular fibrillse, from the pro- 
teus, 1, and the hog, 2, magnified 1,000 times (the 
first from an alcohol preparation, the latter treat- 
ed with acetic acid of 0.01 per cent.), a, sarcous 
elements ; 6, bright longitudinal connecting me- 
dium. At a* the sarcous elements are further 
apart, and the transverse connecting medium is 
visible, c, nucleus. 
prey and of the pisciform amphibise, on the contrary, have 
prismatic sarcous elements of considerable size, so that in alco- 
holic specimens of the proteus (fig. 179, 1) the recognition of 
these prisms (a) 0.00075"' in size, and of the more transparent 
longitudinal connecting medium (5) becomes very easy. Fur- 
thermore, the muscles of the house-fly form very beautiful 
objects ; their prismatic sarcous elements distinctly assume an MUSCLES AND NERVES. 
329 
oblique position during contraction (Amici). Similar sarcous 
elements are frequently to be met with in insects ; their mean 
longitudinal diameter may be assumed to be about 0.0015"' 
(Schonn). The crab was also very properly recommended for 
this observation years ago (Hackel), as may be proved by any 
one who has one of Hartnack’s immersion systems, No. 10 or 11. 
Without mentioning that the various appearances of the 
muscular fibrillse may be readily explained by what has been 
stated, this theory has received still further important supports, 
partly chemical, partly optical in their nature, through the la- 
bors of German investigators. 
Firstly, we have a series of reagents which attack the longi- 
tudinal connecting medium more or less, while the transverse 
remains unaltered, or is only subsequently affected. 
Very dilute acids are here accorded the first rank. Thus 
acetic acid of from 0.5-1 per cent, causes in a short time the 
longitudinal lines to disappear, and the transverse striations to 
become distinct in the swollen muscular fibres. Other acids, 
as, for example, diluted phosphoric acid, cause similar effects. 
The finest appearances are, however, afforded by the strongly 
diluted muriatic acid of 0.5, 0,1-0.05 per cent. 
After several hours one may perceive not only the most dis- 
tinct transverse lines (fig. 178, 5), but also a regular breaking- 
up of the muscular fibrillse into transverse disks (4). The 
same effect is also produced by the gastric juice by means of 
its free acids. Vomited pieces of meat often present similar 
extremely elegant appearances. Older muriatic acid prepara- 
tions show the molecular decomposition more and more, till at 
last a mucilaginous granular mass issues from the opening in 
the sarcolemma. 
However, not only solutions of acids, but also those of many 
salts of the alkalies and alkaline earths, such as those of the 
carbonate of potash, the chloride of calcium, and the chloride 
of barium, present excellent media for rendering transverse 
plates visible in most shrinking muscular fibres. The trans- 
verse lines are gradually rendered very sharp, and there is fre- 
quently a distinct breaking-up into transverse plates, especi- 
ally from the action of the carbonate of potash. 
On the other hand, we have become acquainted with a series 
of other reagents which first attack the transverse connecting 
medium of the sarcous elements, then dissolve it, and are thus SECTION FIFTEENTH. 
capable of producing the separation of the muscular filament 
into the so-called primitive fibrillse. 
Among these may be enumerated the maceration of the 
muscle in cold water, the boiling in the same, an immersion in 
absolute alcohol, in diluted alcohol, in diluted solutions of 
chloride of mercury, chromic acid, and chromate of potash. 
The latter, after acting for about a day, may in favorable cases 
produce appearances such as are represented in fig. 180; the 
muscular filament becomes separated, like a string, into long- 
crooked threads. 
If such a fibre be examined with very strong objectives, one 
may distinctly recognize that it is composed of alternating 
Fig. 180. A muscular 
filament after treatment 
for twenty-four hours 
with chromate of potash. 
Fig. 181. Krause’s transverse discs, 
a, a. 1, a muscular fibrilla without, 2, 
one with strong longitudinal traction, 
both very much enlarged ; 3, muscular 
filament of the dog immediately after 
death. 
Fig. 182. Muscular fila- 
ment of the amphioxus. a, 
the Heusen’s middle disc ; 
6, bright transverse zone 
(alcohol preparation). 
darker and brighter zones (the sarcons elements and the longi- 
tudinal connecting medium). 
We cannot omit to mention that investigations have lately 
been made public by Krause and Hensen, which are said to 
prove a further more complicated composition of the trans- 
versely striated muscular fibre. 
Krause found a dark transverse line in the transparent lon- 
gitudinal connecting medium, fig. 181, a (which had already 
been noticed by Martyn); Hensen saw the sarcous element 
divided at half its elevation by a transverse transparent stria- 
tion, fig. 182, a. A crowd of after-comers then precipitated 331 
MUSCLES AND NERVES. 
themselves against this theme, which, according to our views, 
is inextricable. The purpose and narrow limits of this book do 
not, unfortunately, allow us to enter this dark domain. The 
strongest objectives with the use of oblique illumination, and 
the comparison of fresh objects with what is shown by reagents, 
are indispensable. According to our convictions, the defraction 
phenomena of the light impose a veto here which is difficult to 
overcome. 
The various substances of the muscular fibre are still fur- 
ther distinguished, as Briicke ascertained, by dissimilar optical 
properties. The substance of the sarcous elements consists of 
a double refracting material, while the longitudinal connecting 
medium only refracts simply. Even with crossed nicols, one 
may recognize the bright and dark zones interchanging in 
a beautiful manner; still finer appearances are produced by 
the intercalation of a selenite or mica plate. According to the 
observations of the scientist, the muscular fibre is positively 
uniaxal, and the optical axis coincides with the long axis of the 
image. The muscles of insects, deprived of their water by 
means of alcohol, and mounted in Canada balsam, may be em- 
ployed for these investigations, the correct interpretation of 
which has since been questioned by Valentin and Rouget. 
Smooth muscles consist, according to Valentin, of a doubly re- 
fracting substance. 
The changes which occur in the transversely striated muscle 
during its contraction, as well as those which take place after 
death during the rigor mortis, deserve a more accurate study 
with the aid of our improved optical accessories. A few com- 
munications have recently been made concerning the contrac- 
tion of the smooth tissue. 
The larva of frogs, or the embryos of the hen or of the mam- 
malise, may be used either fresh or hardened in alcohol or chro- 
mic acid, for the study of the foetal muscles and of their manner 
of origin. The methods of investigation consist in the prepa- 
ration of fine sections, tearing with needles, tingeing (glycerine- 
carmine, hsematoxyline), and the application of weak acids. 
Fatty degenerated muscles and those streaked with fat are to 
be examined either fresh or from chromic acid preparations. 
The latter, in which the connective tissue between the muscular 
fibres is changed into fat tissue, that is, into a series of fat-cells 
—a condition which also occurs with high degrees of obesity 332 
SECTION FIFTEENTH. 
and over-feeding—is shown in our fig. 183. Fig. 184 repre- 
sents the former condition, in which fat-molecules are formed 
within the sarcolemma at the expense of the sarcous elements, 
which undergo fatty degeneration. 
The inflammatory changes of the muscles, with their increase 
of cells and the typhous transformations so beautifully de- 
scribed by Zenker a number of years ago, also require similar 
methods of treatment. 
We should render ourselves responsible for a defect if we 
should pass over in silence a subject which has recently awak- 
Fig. 188. Human muscle streaked with 
fat-cells, a, muscular fibres ; 6, rows of fat- 
cells. 
Fig. 184. Fatty degenerated human 
muscular fibres, a, slighter; b, increas- 
ed ; c, highest degree. 
ened the greatest interest among physicians and laymen ; we 
refer to the occurrence of trichinae in the transversely striated 
muscular tissue. 
The trichina spiralis, these small forms of nematodes, are, as 
is well known, eaten with the flesh of the hog, and, after a few 
days, they arrive at a condition of sexual ripeness in the human 
intestinal canal, so that we now meet with examples of some- 
what larger females (measuring more than V") and smaller 
males (intestinal trichinae). About a week after the transplanta- 
tion they produce a multitude of very small living young ones, 
which, after perforating the walls of the intestines, find their 
way into the muscles. Here they force themselves through the 
sarcolemma into the fibres of this tissue, in which they increase 
considerably in size, so that they may obtain a longitudinal di- 
mension of from i to i'" (muscular trichinae). 
All the transversely striated muscles, with the exception of MUSCLES AND NERVES. 
333 
the heart, serve as a location for these small parasites, whose 
number may not unfrequently become extraordinarily large, 
in consequence of repeated immigrations. Nevertheless, the 
muscles of the jaw and neck and the diaphragm are distin- 
guished as favorite localities. The tendinous extremity of the 
muscles—obviously because there is here a mechanical impedi- 
ment to further emigration—usually shows the greatest abun- 
dance of the dangerous guests. 
The little worm devours a portion of the fleshy mass beneath 
the sarcolemma of the muscular fibre, where it gradually rolls 
itself up in a spiral manner. Around tins 
a capsule (fig. 185) is gradually formed, 
which requires months for its completion. 
While this is taking place, we see the 
muscular corpuscles of the neighborhood 
increasing luxuriously and forming a more 
compact internal investing layer, to which 
the thickening sarcolemma is also associ- 
ated as an external layer. The form and 
size of the capsules vary; we meet with 
oval (more rarely cask-shaped), spindle, and 
lemon-shaped forms, generally with consid- 
Fig. 185. Incapsulated tri- 
china iu man. a, muscular 
fibres; b, capsule; c, worm. 
erably thickened extremities. The length is usually 0.2, 0.3, 
0.5'". The calcification of the capsule, which commences in 
the internal portions, begins late (scarcely before the expiration 
of a year). This process, with its further development, renders 
the whole thing visible to the unaided eye as a white point, 
which was not the case with its earlier phases. The trichinae 
were first discovered many years ago, in just this latter con- 
dition, in which the parasite may preserve its extremely 
tenacious life for many years in the calcified capsule. 
The examination of muscles infected with trichinae is very 
easy. Thin sections made in the direction of the fibres, with or 
without picking apart, will show the presence of the worms 
when examined in the ordinary fluid media, with the addition 
of acetic acid or alkalies. A magnifying power of about 40 
diameters suffices for the first examination ; for more accurate 
investigation one of 150 or 200 should be used.* In invalids, 
* This object may be accomplished with ordinary and therefore cheaper micro- 
scopes, with which the several enlargements mentioned in the text may be obtained. SECTION FIFTEENTH. 
where trichiniasis is suspected, fragments of muscle may be 
removed from the body with a small harpoon-shaped instru- 
ment. For the microscopical examination of the flesh of the 
hog, a number of very thin, as large as possible, sections should 
be taken from the muscles of various parts of the body, but 
especially from the chief localities of the parasites. 
Only injected muscles, or those intended for polarized light, 
are to be mounted in Canada balsam for preservation. Suitable 
tinged preparations imbedded in Thiersch’s colophonium afford 
excellent views. Objects which are destined to show the finest 
textural relations must, naturally, be mounted in glycerine 
diluted with water. 
The elements of the nervous system are marked by exceed- 
ingly variable qualities, so that in their investigation numerous 
precautionary measures become necessary. 
We distinguish, as is taught by every hand-book, white and 
gray substance. The former consists exclusively of one of the 
two elements of tubes or fibres, called nerve-tubes, nerve-fibres, 
primitive fibres of the nervous system. In the gray substance 
we meet with the second element, together with a sometimes 
slighter, sometimes greater quantity of the nerve-fibres. This 
second element, the ganglion-body, ganglion-cell, or nerve-cell, 
is generally a large cellular structure with a vesicular-shaped 
nucleus. The other constituents consist of connective substance 
in various stages of development, and blood-vessels. 
In order to see the nerve-tubes, which consist of an albumi- 
nous central fibre, the so-called axis cylinder ; of a peculiar 
substance surrounding this, the nerve-medulla or the medullary 
sheath; and of a very fine envelope surrounding the whole 
and holding it together, the primitive sheath or the sheath of 
Schwann, in as unaltered a condition as possible, we cannot 
proceed too rapidly, and must, at the same time, avoid almost 
all preparatory manipulation. For this reason, there are but 
few parts of the bodies of vertebrated animals which afford 
suitable objects. The cornea of a small mammalial animal Just 
With this optical apparatus, the weaker power should show distinctly the larger 
scales of the lepisma saccharinum (p. 61), while the stronger combination should 
afford a satisfactory image of the smaller forms of the scales of this insect, with 
their longitudinal and oblique lines. Some of the modern “trichina microscopes ” 
fulfil these requirements in a satisfactory manner, but a quantity of the most miser- 
able trash has also been put in circulation. MUSCLES AMD NERVES. 
335 
killed, for example, that of a rabbit or of a mouse, may be ex- 
amined on the warm stage without the addition of any fluid 
medium. The cornea should be incised at its margin. A very 
line form of nerve-fibres will here be met with. The frog 
affords better preparations ; its transparent eyelid shows larger 
tubes, isolated or lying together in bundles. The tails of their 
larvae permit the observation to be made on the living creature. 
Quite fresh, unaltered nerve-fibres should present the ap- 
pearance of entirely homogeneous, opaline, cylindrical fibres, 
in which there is no trace of any further composition to be 
recognized. The addition of iodine serum is here to be recom- 
mended. 
If we take a nerve from the body of an animal recently 
killed and pick it in water with needles, notwithstanding the 
greatest rapidity of manipulation, it is no 
longer possible to obtain the natural con- 
dition ; on the contrary, its appearance is 
more or less changed ; there is an alteration 
of the medullary sheath which it has been 
agreed to call a coagulation. 
Our fig. 186 may represent the com- 
mencement of this coagulation. In the 
beginning it gives the nerve-fibre a darker 
contour. Soon, however, we see a thin 
peripheral layer coagulated and separated 
by a second, more internal and finer line 
from the central portion of the medulla, 
which is not, as yet, drawn within the 
sphere of these changes. But to present 
these “double contours” the nerve-tubes 
must have a certain thickness (a, V). If the 
transverse diameter falls below a certain 
size, the tubes then and afterwards appear 
Fig. 186. Human nerve-fi- 
bres. a, broad; b, medium 
breadth; c, d, e, fine. 
with only simple contours (c, d, e), but at the same time they 
readily assume a peculiar appearance, they become “vari- 
cose,” as it is called. 
Further changes render the coagulated peripheral layer 
broader, and frequently show an irregularity of the inner con- 
tours. The process may here become stationary; the coagu- 
lated portion protects the internal, still uncoagulated medulla 
to a certain extent. But generally this is also drawn into the SECTION FIFTEENTH. 
sphere of the changes; the previously homogeneous appear- 
ance is lost; a few lumpy formations make their appearance in 
it and increase in number and size ; not unfrequently the whole 
becomes a granular, crumbling mass. But all nerve-tubes do 
not behave in exactly the same way ; we may meet with them 
lying close beside each other, showing various phases of coagu- 
lation. 
We have not yet perceived anything of the axis-cylinder 
and the delicate envelope. 
The so-called'nerve-medulla is a mixture of peculiar sub- 
stances of cerebrine and lecithine, with a very changeable body 
belonging to the albuminous group. We shall therefore un- 
derstand why reagents, such as strong alcohol, concentrated 
chromic acid, a solution of corrosive sublimate, and many 
others which have a coagulating effect on albumen, should 
also produce the more advanced phases of coagulation almost 
instantaneously. 
For the same reason it is unnecessary to state that such a 
coagulated nerve-medulla, by the addition of alkaline solutions, 
such as those of potash or soda, again assumes a more fluid and 
homogeneous condition, and exudes from the cut ends of the 
nerve-tubes in the shape of double-contoured, fat-like drops 
and filaments. 
If strong pressure be made with the covering glass on the 
nerve-tubes, treated in this manner with alkalies, the medulla 
may be forced out of many of them, and in this way the empty, 
homogeneous, extremely delicate primitive sheath may be seen. 
If careful search be made among the nerve-tibres, which have 
been isolated by picking a nerve-trunk apart, a few will be 
met wi th in which their contents have been somewhat displaced, 
in consequence of the pulling and the pressure of the prepar- 
ing needle ; and the sheath, which is generally collapsed, may 
also be recognized for a short distance. 
It was frequently denied, at a former epoch, that the axis- 
cylinder was an integral constituent of the nerve-tubes, and 
this was quite proper, for, with the accessories then employed, 
it could only be brought to view in an isolated condition. At 
the present day it is a small matter to demonstrate these fibres 
in all nerve-tubes; and we have the choice between several 
methods. 
For the demonstration of the same, Schulze’s reagent, the MUSCLES AMD NERVES. 
337 
mixture of chlorate of potash and nitric acid, may be employed 
(Budge and Uechtritz). Chloroform renders good service (Wal- 
deyer), and collodion is very excellent (Pfluger). A fresh nerve 
is to be picked apart on the slide, without any addition of 
fluid. A large drop of collodion is then to be added, the cover- 
ing glass placed over it, and the examination made immediately. 
The nerve-tubes rapidly become more and more pale, and, 
instead of the dark medulla, only a few granules are to be seen 
enveloped by the distinct primitive sheath. 
This becomes contracted, and thus fre- 
quently shows a series of extremely char- 
acteristic invaginations. The axis-cylin- 
der appears in each tube as a pale fibre. 
During the contraction of the nerve-fibre 
it frequently appears to be too long; and 
not unfrequently, under the eye of the ob- 
server, it shoves itself through the axis to- 
wards the periphery, and protrudes as a 
fibre from the cut extremity (fig. 187, h). 
This interesting appearance may be 
followed in this manner for a short time, 
but it soon undergoes further changes, 
and often becomes entirely unserviceable 
in a quarter of an hour. 
I afterwards found in aniline red of 
the above-mentioned (p. 154) strength a 
new accessory for the demonstration of 
the axis - cylinder in fresh medullated 
tubes. Frog’s nerves, picked apart and 
placed in the solution, show in from 4 
Fig. 187. Various nerve-fibres. 
a, after treatment with absolute 
alcohol; b, with collodion; c, 
fibre of the lamprey; d. of the 
olfactory nerve of the calf; e and 
/, nerve-fibres from the human 
brain. 
to 12 hours the beautifully reddened axis-cylinders glistening 
through the fatty enveloping mass. 
Still other methods permit of the recognition of the axis- 
cylinder in a beautiful manner. Thus, after a longer treatment 
with strong alcohol or ether, it may be rendered visible in the 
tubes deprived in this way of their fat. A solution of subli- 
mate and Moleschott’s acetic acid mixture also afford good 
specimens. Chromic acid preparations (or those obtained by 
means of chromate of potash) present very beautiful appear- 
ances. Long, hardened filaments frequently project from the 
cut extremities (e). 338 
SECTION FIFTEENTH. 
Impregnation with various metals has also been used re- 
cently for demonstrating the axis-cylinder. Nitrate of silver 
(fig. 188, e) either gives it a uniform dark color, or causes it to as- 
sume a peculiar transversely striated appearance, reminding one 
of muscular fibre (Frommann, Grandry). 
The chloride of gold, recommended by Cohn- 
heim (if successfully employed), shows the 
axis-cylinder shining bright-red through 
the dark-red medullary substance ; it after- 
wards appears blackened. Osmic acid, on 
the contrary, very soon blackens the nerve- 
medulla, while the axis-cylinder remains 
colorless or only slightly browned (M. 
Schultze), so that we possess in our re- 
agent an excellent accessory for deciding 
the presence or absence of the medullary 
sheath of the peripheral ramifications of 
the nerves (b, c, d). 
We have another interesting condition 
to mention here. Years ago we were fam- 
iliar with constrictions in freely exposed 
nerve-fibres, after the manner of our fig. 
188, a. We all considered them, at that 
time, to be accidental phenomena, products 
of the preparing needle. 
Ranvier recently learned tlieir regular 
occurrence, and showed in the most certain 
manner that, between every two of these con- 
strictions, the “ constriction rings ” (,Schnur- 
ringen, as we have happily translated the 
word into German), a cell nucleus always 
Pig. 188. Nerve-fibres of 
the frog, a, after treatment 
with picro-carmine; 6, c, d, 
with osmic acid; e, with ni- 
trate of silver. 
occurs. The investing and isolating medullary sheath of the 
nerve-fibre is regularly wanting at the constriction ring; the 
axis-cylinder is here naked and freely exposed to the inter- 
change of material. Treatment with osmic acid with subse- 
quent hsematoxyline tingeing (b, c, d) is best for the demonstra- 
tion. 
We have finally to mention the recognition of the axis-cyl- 
inder in transverse sections of previously hardened nerve- 
trunks ; this is also of particular interest in still another regard. 
If a human or mammalial nerve be immersed for a short time, MUSCLES AND NERVES. 
339 
first in chromic-acid solution of 0.2, then in one of 0.5 percent., 
it will attain such a consistence as to permit the finest trans- 
verse sections to be made with a sharp razor. These, tinged 
with carmine, are to be deprived of their water by means of 
absolute alcohol, and, after soaking in turpentine, mounted in 
Canada balsam. Then, the medulla having become transpar- 
ent, the axis-cylinder may be recognized as a small reddened 
circle, surrounded by transparent medulla, which forms a sin- 
gle or multiple circle around the axis cylinder (a condition to 
which attention was called several years ago by Lister and 
Turner, and which it has not as yet been possi- 
ble to explain), and finally the whole is found 
to be surrounded by the simple contour of the 
transversely divided primitive sheath. 
Formerly, the axis-cylinder was generally 
regarded as a homogeneous structure, although 
there has never been any want of manifold 
testimony to its more complicated formation. 
Newer, more conservative methods, show that 
it is with great probability composed of the 
finest fibres, the axis fibrillse of Waldeyer or 
the primitive fibrillge of M. Schultze (fig. 189). 
The white substance of the brain and spinal 
cord serves best for their recognition in medul- 
lated nerve-fibres. The fresh object may be 
examined in blood-serum with very strong 
magnifying powers, but it is preferable to 
macerate for a day or more in iodine-serum. 
Osmic acid (£—|- per cent.) renders excellent 
service. After a short action the axis-cylinder 
becomes sufficiently hardened without any 
granular opacities, and shows the longitudinal 
markings very distinctly, especially when freed 
from the medullary sheath (Schultze). 
Fig. 189. Fibrillated 
arrangement of the axis- 
cylinder, after Schultze. 
a, a thick axis-cylinder 
from the spinal cord of 
the ox; 6, nerve-fibre 
from the brain of the 
torpedo. 
Mednllated tubes are not shown by all the nerve-trunks in 
man and the mammalia, however. The fibres of the olfactory 
nerve (fig. 187, d) all appear pale and nucleated, and by proper 
treatment may be resolved into a bundle of the finest primitive 
fibrillse. In the ramifications of the sympathetic nervous sys- 
tem of man and the higher vertebrata, there also occurs, inter- 
mingled with mednllated nerve-tubes, a system of pale, nucleated 340 
SECTION FIFTEENTH. 
fibres, which bear the name of Remak’s fibres, after their dis- 
coverer, Remak (fig. 190, 5). Considerable controversy has 
arisen as to their nature, whether nervous or of connective tis- 
sue ; but at the present time there is no further doubt as to 
their nervous constitution. Indeed, in the earlier embryonic 
periods, all nerve-tubes appear pale, non-raedullated and nu- 
cleated. Finally, in the lower vertebrata, all the nerve-tubes 
may remain through life at this stage of development, as, for 
instance, in the lamprey, of which such a nerve is represented 
by our fig. 187, c. 
For the examination of these pale, nucleated fibres, the 
fresh tissue may be employed, with picking and perhaps the 
Fig. 190. Sympathetic 
nerve-branch. Two medul- 
latedj nerve-tubes (a), sur- 
rounded by numerous fibres 
of Kemak (6). 
Fig. 191. Ganglion-cells of the mammalia. A, cells with 
connective-tissue envelopes, from which spring Eemak’s 
fibres d, d ; a, a cell without a nucleus; 6, two single nu- 
cleated ones; and c, one with two nuclei; B, a ganglion 
body without an envelope. 
addition of a weak acid. A longer immersion in very dilute 
acetic acid (about 20-50 com. water, with a few drops of hy- 
drated acetic acid) is preferable. A maceration in weak solu- 
tions of chromic acid and of chromate of potash, of the degrees 
of concentration given by Schultze (comp, above, p. 128), also 
produces very beautiful specimens. 
Osrnic acid is more suitable. Chloride of palladium has 
also been recommended by Bidder. I recommend tingeing 
with hsematoxyline or picro-carmine for demonstrating the nu- 
clei. 
The examination of the nerve-fibres in polarized light shows 
the interesting fact of a double refracting positive sheath, and MUSCLES AND NERVES. 
341 
a likewise double refracting but negative medulla. The long 
axis of the primitive fibres and the optical axis coincide. Val- 
entin, to whom we are indebted for this interesting result, re- 
marks that we may thus, with the aid of the polarizing appa- 
ratus, distinguish the me- 
dullated from the non- 
medullated nerve-tubes. 
We have now to speak 
of the examination of the 
second elementary form of 
the nervous system, the 
ganglion-cells (figs. 191, 
192). 
These appear as cells 
Fig. 192. A multipolar ganglion-cell from the gray sub- 
stance of the human brain. 
of considerable size, although subject to great variation in this 
regard, with large, round, vesicular nuclei and a rather thick, 
very finely granular, sometimes colorless, sometimes pigmented 
cell-body, which usually hardens into a thin rind at its periph- 
ery. Accessory envelopes are found covering these ganglion 
bodies in the peripheral ganglia, and are either (as is generally 
the case in the lower vertebrates) a homogeneous membrane or 
a thicker, nucleated, connective-tissue substance, which shows 
numerous nuclei imbedded in it, and not unfrequently runs 
out into thread-shaped processes presenting the appearance of 
Remak’s fibres. 
An epithelium-like lining on the inner surface of these 
envelopes is of interest. Nitrate of silver, or the method of 
impregnating with gold indicated by Gerlach (p. 168), may be 
employed for demonstrating the latter. 
The first incomplete view of the ganglion bodies maybe ob- 
tained either by selecting a small ganglion, for example, a 
spinal ganglion of a frog or a mouse, and carefully picking it 
apart with sharp-pointed needles, with the addition of an in- 
different fluid medium, or a thin section from a larger fresh 
ganglion may be subjected to the same treatment. 
Naturally, by this procedure, numerous divisions of the 
connection take place, and the absence of a sufficient insight 
into the arrangement of the whole is felt. To obtain these, 
places should be selected in small creatures where microscopic 
ganglionic swellings occur on fine nerve-branches, which may 
be viewed in their totality without preparatory manipulation. SECTION FIFTEENTH. 
For this purpose the frog stands in the first line. The small 
imbedded ganglia, frequently consisting of only a few cells, 
which may be recognized on the cardiac nerves in the septum 
of the ventricles, or on the branches of the sympathetic system, 
afford admirable specimens. Schwalbe praises the spinal gan- 
glia of the lizard. A very dilute acetic acid may here be used 
with advantage. Strongly diluted phosphoric acid has also 
been recommended for this purpose. 
The relation of the nerve-fibres to the ganglion bodies is of 
great importance. As is known, the opinions of investigators 
have undergone great changes in this regard of late years, and 
even at the present time we are far from meeting with coin- 
ciding or even similar views. 
Although it was at first considered that there was but a 
simple juxtaposition of both elementary forms in a ganglion 
(Valentin), connections of the ganglion-cells with the nerve- 
tubes were afterwards frequently observed (Wagner, Robin, 
Bidder, and others), and the doctrine of bipolar, multipolar, 
unipolar, and apolar ganglion-cells founded. This is not the 
place to test the correctness of these various opinions, and we 
must refer on this point to the text-books on histology. 
The several animal groups are of very unequal service for 
ascertaining the origins of such fibres by means of picking. 
The scanty admixture of a soft, loose connective tissue with 
the nervous elements of a ganglion facilitates the acquisition 
of this knowledge very much. A more plentiful admixture of 
a firmer, interweaved connective-tissue formation either ren- 
ders the isolation difficult to a high degree, or makes it entirely 
impossible. The cartilaginous fishes (rays), therefore, form 
extremely favorable objects in the former regard, and many 
osseous fishes are, at least, serviceable. The bodies of the 
naked amphibise are less suitable, and the ganglia of man, the 
mammalia, and birds are scarcely to be mastered with the 
preparing needles. 
Suitable ganglia, for example, those of the trigeminus, 
vagus, and the spinal nerves of the pike and the burbot (Gtadus 
lota) may be picked apart either fresh or, which may not be 
called unserviceable, a few hours, 10-15, after death. A pre- 
paratory maceration for a day in dilute chromic acid (0.1-0.5 
per cent.) may also be employed. We also recommend the 
trial of a method indicated by J. Arnold, which affords good MUSCLES AMD NERVES. 
343 
results, at least with the frog. The ganglion is to be placed 
for four or five minutes in acetic acid of 0.8-0.2 per cent., and 
then for twelve to forty-eight hours in a 0.02-0.01 per cent 
solution of chromic acid. The preparatory treatment with a 
very dilute solution of chloride of gold (0.005 per cent.) has 
also been used (Bidder). Notwithstanding every precaution, 
numerous fractures and lacerations are unavoidable. 
Hardening in chromic acid or in chromate of potash may 
also be used with the higher ver- 
tebrates. In such cases one 
should begin with weak solutions 
of the acid, of 0.2-0.5 per cent., 
change them frequently, and 
gradually increase the concen- 
tration. The chromate of potash 
is employed in corresponding 
quantity (comp. p. 136). The 
ganglia thus hardened permit of 
very thin sections being made 
with a sharp razor, which are to 
be examined in glycerine diluted 
with water. One will thus be 
able to recognize appearances, 
for instance, in a sympathetic 
ganglion of a mammalial animal, 
which come near to our fig. 193, 
which is indeed drawn somewhat 
Fig. 193. A sympathetic ganglia of a mam- 
malial animal. The meduliated nerve-tubes 
of the three trunks, a, 6, c, pass through a 
profuse, nucleated fibrous tissue (Remak’s); 
d, multipolar ganglion-cells; at d*, one with 
a dividing nerve-fibre; e. unipolar, /, apolar 
cells. 
diagrammatically. Multipolar cells {d, d) are, as it seems, of 
very frequent occurrence in the sympathetic ganglia of the 
mammalia, in contradistinction to those of the lower verte- 
brata, in which bipolar and unipolar constitute the rule. The 
ganglion-cells of the sympathetic of the rabbit and the guinea- 
pig appear to have two nuclei. 
More recently we have become acquainted with other suita- 
ble methods. These sections of chromic-acid preparations may 
be placed for 12-24 hours in a solution of osmic acid (1 per 
cent.), in which the nerves become blackened. The solution 
of the chloride of palladium (1: 500) is still better, however, 
because it hardens and colors at the same time. Even after 
24 hours (if the fluid has been changed in the meantime) the 
ganglion may show a blackish-gray color and be ready for 344 
SECTION FIFTEENTH. 
preparation. If the cut surface is still yellow, a further action 
till a following day is then sufficient, Yery instructive ap- 
pearances result, as the connective tissue is pale, the ganglion- 
cells yellow-brown, and the nerve- 
libres blackish (Schwalbe). 
These hardened ganglia may be 
examined in still another way. The 
sections are to be stained, then de- 
prived of their water by means of 
absolute alcohol, and oil of turpen- 
tine added. If the brain of a small 
mammal, a rabbit, or a guinea-pig, 
be thoroughly injected from the arch 
of the aorta with carmine gelatine, 
the Gasserian ganglion, after deli- 
cate staining with carmine, affords 
excellent specimens of this kind. 
Within a short time another in- 
teresting structural condition has 
been observed in the ganglion-cells 
of the sympathetic of the frog (fig. 
194). From the cell {a)—and from 
the central portion of its body— 
arises a straight fibre (c, e) (axis cyl- 
inder), in which a nuclear forma- 
tion is not unfrequently remarked. 
These are surrounded by one or sev- 
eral spiral fibres, which likewise pre- 
Pig. 194. Ganglion-cell from the sym: 
pathetic of the hyla or green-tree frog 
(after Beale), a, cell-body ; &, sheath; c, 
straight nerve-fibre; and d, spiral fibre; 
continuation of the former, e, and of the 
latter, /. 
sent nuclei (d). They originate from the surface of the cell 
body. 
This was the condition which Beale found in glycerine prep- 
arations tinged with carmine. Arnold, an able investigator, 
who made use of the method * mentioned at p. 342, states that 
* In a second article the author communicates new and more complicated meth- 
ods for the investigation of these ganglion-cells. To isolate the spiral fibres in the 
greatest possible length, immerse them in 5 ccm. of nitric acid of from 0.01 to 0.03 
per cent. Even after five to ten minutes the structure of the ganglion-cell becomes 
clear. After an immersion of from twelve to twenty-four hours, however, these 
fibres may be followed very far into the nerve-trunk, and be seen to become true 
nerve-fibres. Chloride of gold also colors both varieties of fibres, the straight as 
well as the spiral. Immerse the tissue in 4-5 ccm. of a 0.02-0.05 per cent, mixture MUSCLES A3STD XEEYES. 
345 
both varieties of fibres arise from the nucleolus of the ganglion- 
cell. I could not convince myself of this, and am inclined to 
regard Beale’s spiral fibre as elastic. Nevertheless, by this the 
possibility is not to be denied that, in the bipolar ganglion- 
cells, where both nerve- 
fibres arise close to each 
other, the one may sur- 
round the other with con- 
volutions. 
Remarkable ganglionic 
apparatuses of microscop- 
ical fineness have recently 
been discovered in the walls 
of the abdominal viscera. 
To these belong the gan- 
glia in the submucous con- 
nective-tissue of the diges- 
tive apparatus (fig. 195), 
discovered by Meissner, 
and then investigated by 
Remak, Manz, Kollmann, 
Billroth, and others. Like- 
Fig. 195. A ganglion from the submucous tissue of the 
intestinal canal of a child ten days old (pyroacetic acid 
preparation), a, ganglion ; &, its radiating nerve branch- 
es ; c, injected capillary net-work. 
wise the plexus myentericus, pointed out by Auerbach, a 
highly developed ganglionic net-work between the two muscu- 
lar layers of the intestinal canal. 
The examination of these submucous nerve-ganglia has for 
the most part been made with the aid of maceration in pyro- 
acetic acid. But many observers (Billroth, for example) have 
committed the fault of allowing this reagent to act in much too 
energetic a manner, and were therefore able to describe arte- 
factions only. Portions not too large, taken from the fresh 
body, are to be placed in purified pyroligneous acid diluted 
of 1 per cent, acetic acid and chloride of gold and potassa. When the first traces of 
a violet color make their appearance (after about three to four hours), the main 
trunk of the sympathetic is to be placed in 10 ccm. of acetic acid of the above- 
mentioned strength. The color has become intense in from four to five days, and 
the connective tissue remains light and loose. A microscopic preparation, to which 
acidulated glycerine has been added, is now to be placed on a white surface, and 
exposed to the action of day- or sun-light for the further reduction of the gold. After 
four to five days the straight nerve-fibre has become bright red ; the thickest of the 
spiral fibres also present the same appearance, while the finer ones only gain an in- 
tense color on the eighth or tenth day. 346 
SECTION FIFTEENTH. 
with one or several times its volume of water. After one, two, 
or three days the examination should be attempted on vertical 
sections, or the isolated submucous tissue (likewise surface sec- 
tions of the latter made with the scissors), in order to recognize 
the horizontal ramifications. 
A certain attention is always necessary in this case, because 
exactly the proper degree of maceration must be employed in 
the investigation, and 
an excessive action of 
the pyroacetic acid 
soon follows. The py- 
roacetic acid may also 
be replaced with very 
dilute acetic acid. One 
may also succeed, for 
example, in the new- 
born child, in demon- 
strating this ganglion- 
ic plexus (fig. 196, 1) 
in the fresh intestinal 
canal, with the cells 
{a) and the pale nerve- 
fibres (5, c). Fine ver- 
Pig. 196. 1, A large ganglion from the small intestine of a 
child 10 days old. a, the ganglion, 'with the ganglion cells ; 6, c, 
efferent nerve-branches, with pale nucleated fibres in a fresh con- 
dition. 2. Such a nerve-trunk from a boy 5 years old, with three 
pale primitive fibres, treated with pyroacetic acid. 
tical sections may be employed, or (which has proved to be 
more suitable) a portion of the intestine may be well stretched, 
and the muscular layer and the mucous membrane carefully 
dissected from both sides, so that the submucous connective 
tissue remains isolated. Even without any further addition, 
one may, with some pains, discover a few ganglia, but as soon 
as the connective tissue has been rendered transparent, by 
means of very dilute acetic acid, the whole arrangement may 
be readily seen. Simple chromic acid preparations also fre- 
quently afford good specimens, at least in vertical sections. 
The ganglionic plexus mentioned has been, in an almost in- 
comprehensible manner, asserted to be a capillary net-work. 
All doubt may be removed by injecting a portion of intestine 
with Prussian blue or sulphate of baryta, and immersing it in 
pyroacetic acid (fig. 195, c). 
The plexus myentericus (fig. 197) of the larger mammalia 
and of man is only to be recognized with difficulty and pains, 
in consequence of the thickness of the muscular coat. Macera- MUSCLES AND NERVES. 
tions in dilute pyroacetic acid or acetic acid, also appear to 
constitute tlie best accessories. The demonstration succeeds 
very readily, on the contrary, with smaller animals, such as 
rabbits, but especially with guinea-pigs, rats, and mice. A 
portion of the small intestine, still better of the colon of a 
guinea-pig, immersed in purified pyroacetic acid diluted with 
several times its volume of water (20 to 15 per cent.), will after 
24 hours (or even sooner) have acquired such a swollen and 
Fig. 197. Plexus myentericus, from the small intestine of the Guinea-pig. a, nervous plexus; 6, gan- 
glia ; c, lymphatics. 
macerated condition as that the mucous membrane may be 
readily removed. If the thin muscular and serous layers be 
now immersed in watery glycerine, and placed under the 
microscope with a low magnifying power, a surface view of 
the whole elegant nervous apparatus (a, 6) may be at once ob- 
tained. 
We have since become familiar with better methods. L. 
Gerlach has recently investigated this nerve-plexus more 
accurately. Those animals are best adapted in which the 
slightly developed longitudinal muscular stratum can be read- 
ily drawn with the serosa away from the transverse layer, as, 
for example, guinea-pigs, rabbits, doves. The plexus myenter- 
icus then remains adherent to this longitudinal layer. This 
result may be accomplished even in fresh objects, but better 
with such as have remained for 12-24 hours in dilute solutions SECTION FIFTEENTH. 
of bichromate of potash or in a 10 per cent, solution of com- 
mon salt. In other creatures, such as the sheep, hog, man, 
this mechanical separation succeeds imperfectly, even after the 
object has remained in these solutions for days. The prepara- 
tions are to be colored in acid carmine, and finally placed in 
acidulated glycerine. 
In order to isolate the ganglion-cells of our plexus, let a 10 
per cent, solution of common salt act on this stratum for 8-10 
days, changing the fluid daily. Objects which have been 
treated with osmic acid may also be macerated in glycerine. 
The best views are furnished by the guinea-pig. 
In addition to the coarse plexus, the plexus myentericus 
presents a finer network of nervous cords. To demonstrate the 
latter, place the detached muscular membrane for three or four 
days in solutions of bichromate of potash of about 1: 300, and 
remove them to a chloride of gold solution of 1: 10000. They 
remain in the latter till the margins of the preparation have a 
weak violet color. This should occur in 6-8 hours. The object 
is then to be washed out, deprived of its water and mounted in 
a resinous medium. 
The structure of the central organs of the nervous system, 
the spinal cord and brain, is so complicated and obscure, and 
at the same time the subject of such frequent controversy, 
that it would lead us far beyond the limits of this book if we 
were to enter at all into the details of these textural condi- 
tions. We therefore limit ourselves chiefly to the description 
of the methods of investigation generally employed at pre- 
sent. 
These may be divided into two series : first, such as are in- 
tended for isolating the elementary structures; and then the 
others, which are to harden the central organs to such a degree 
as that thin sections may be conveniently made from them, 
and thns an appreciation of the entire arrangement obtained. 
It is hardly necessary to remark that a thorough promotion of 
our knowledge requires the combination of both these methods 
of investigation. 
The older investigators frequently attempted to examine 
the ganglion-cells and nerve-fibres in picked preparations of 
portions of brains and spinal cords, which were as fresh as pos- 
sible, as well as of those which were not so fresh. The delicate 
nervous structures are too intimately united by the connective- MUSCLES AND NEKVES. 
349 
tissue framework, however, for one to hope to find more than 
their fragments. And, in fact, we have more recently discov- 
ered much better and more productive methods. The highly 
diluted solutions of chromic acid, and of the bichromate of 
potash, recommended by Schultze, as well as the process re- 
cently practised by Ranvier, the preliminary injection of a 
0.38 per cent, solution of osmic acid into the fresh gray sub- 
stance of the brain, constitute accessories of the first rank, as 
they exert a partly macerating, partly hardening effect on the 
various elements of these organs, without producing any deeper 
textural changes. 
The reader would deceive himself, however, if he were to 
regard the successful application of the solutions as a relatively 
easy affair. Even after following certain directions, selecting 
only fresh, preferably still warm organs, and especially those 
of the larger mammalia, such as the ox and calf ; furthermore, 
not to place too large pieces in a relatively small quantity of 
fluid ; there are, nevertheless, many difficulties still remaining. 
Next arises the problem of hitting upon the proper degree of 
concentration of these fluids, and this, lying within nar- 
row limits, requires careful experiment, as further differences 
present themselves according to the warmth, nature, and age 
of the animal. Solutions which, to the ounce of water, contain 
more than 0.1-0.125 gr. of the chromic acid, or more than 2 
grains of its potash salt, are absolutely objectionable. Even 
much higher degrees of dilution are frequently employed with 
advantage. 
Let us listen to Reiters, the most competent of the modern 
investigators in this department of technology. He recom- 
mends the immersion at first in a solution of chromate of pot- 
ash, which contains 0.5 gr. to the ounce, till the second day, 
whereby the desired result is not unfrequently obtained. If 
the latter has not yet taken place, or if it be desired to preserve 
the preparation for a few days longer, this solution may be 
doubled in strength for an additional day, and then increased 
to 2 grains for another twenty-four hours. Not unfrequently 
weaker than half-grain solutions are to be preferred. Thus, 
one may commence with 0.125 and 0.25 gr. and then terminate 
with 0.5 gr. ; or solutions of chromic acid may be first em- 
ployed, and then its salt, whereby greater looseness of the pre- 
paration is obtained. The strength in which the chromic acid 350 
SECTION FIFTEENTH. 
is employed is from 0.088, 0.05 to 0.1 gr. to the ounce. Two 
days are to be allowed to pass without changing the fluid ; on 
the third day it is to be renewed, Now, occasionally even 
sooner, a very good degree of maceration for many parts is ob- 
tained. For the combination of both these methods it is rec- 
ommended, after using the chromic acid for two days, to place 
the piece in a 0.5 gr. solution of chromate of potash, then on 
the following day in one of 1 gr., afterwards perhaps increasing 
the strength to 2 grs. After this, to obtain a considerably ma- 
cerated condition of the framework substance, such objects 
may be advantageously exposed to the action of extremely 
dilute solutions of the alkalies. A drop of a2B per cent, solu- 
tion of caustic potash may be added to the ounce of water; 
after having been exposed to this for an hour, the preparation 
is to be removed and washed (in dilute chromic acid, for in- 
stance), then replaced in the solution of chromate of potash, 
which should contain at first 0.6, the following day 1, after- 
wards perhaps 2 grs. to the ounce. 
The simpler of these methods, or a combination of them (it 
is better to employ several of them simultaneously), will, to- 
gether with many failures, also afford suitable objects for ex- 
amination, although they only continue to be serviceable for a 
few days. It is best to remove a small portion of the tissue 
with the point of a knife, and pick it apart as carefully as pos- 
sible. 
With such accessories Deiters succeeded in making a re- 
markable discovery concerning the multipolar ganglion-cells 
of the central organs. They (fig. 198) have two kinds of pro- 
cesses. The greater proportion of the latter are only continua- 
tions of the same protoplasma-like substance which is presented 
by the body of the ganglion-cell. These processes, the “pro- 
toplasma processes” of Deiters, divide into manifold ramifica- 
tions, until at last they disappear as the finest terminal branches 
in the supporting substance. At the first glance an exceedingly 
long process (a) may be distinguished from the protoplasma 
processes, which arises either from the cell-body itself or from 
one of the broadest of the former processes ; it never presents 
any ramifications, and is afterwards covered by a medullary 
sheath. Deiters has called it the “ axis-cylinder process.” 
Finally, one may also recognize, passing off at right angles from 
the protoplasma processes of our multipolar ganglion-cells, MUSCLES AND NERVES. 
extremely fine filaments (5, &), which the above-mentioned in- 
vestigator believes to be a second system of extremely fine 
axis-cylinders. 
Still another method has recently been recommended by 
Crerlach, an investigator who has accomplished much for micro- 
scopical technology, 
for isolating these 
ganglia and a very 
fine nervous net-work 
(that is, their proto- 
plasma processes) 
connected with them 
(of which, according 
to his views, the gray 
substance of the spi- 
nal cord consists). 
Thin longitudinal 
sections are to be 
made with a razor, 
preferably through 
the region of the an- 
terior horns of the 
quite fresh and still 
warm spinal cord of 
a mammalial animal. 
These are to be placed 
for 2-3 days in very 
weak solutions of the 
bichromate of am- 
monia (0.01-0.02 per 
cent,). They are then 
to be placed in a like- 
wise extremely dilute 
ammoniacal solution 
of carmine, which 
produces the neces- 
Fia. 198. Multipolar ganglion-cell from the anterior horn of the 
spinal cord (of the ox), with the axis-cylinder process (a), and the 
branched protoplasma processes, from which at 6 the finest fila- 
ments arise (after Deiters), 
sary tinge in about a day. Those portions which are thinnest 
and best tinged are then to be carefully picked apart. 
Still another complication of the structure of these ganglion- 
cells of the central organs has been observed. According to 
Schultze’s investigations, both varieties of the processes of the 352 
SECTION FIFTEENTH. 
central ganglion-cells (fig. 199) present a fibrillated structure ; 
this is most distinct in the axis-cylinder (a), however, while in 
the protoplasma processes (b) there is a greater quantity of 
a granular intervening substance. The “primitive fibril!m 5’ 
(p. 839) may be followed 
into the body of the 
ganglion - cell, where 
they are seen to have 
a complicated course. 
This arrangement, first 
noticed by Remak, may 
be observed without dif- 
ficulty in fresh speci- 
mens simply moistened 
with serum, or in osmic 
acid preparations. 
Frommann asserts 
that he has ascertained, 
by treatment with ni- 
trate of silver, that these 
fibrillge originate in the 
nucleoli and are sur- 
rounded like a sheath 
by tubes which proceed 
from the nuclei. Arnold 
also informs us of sim- 
ilar results. He used 
serum or chromic acid 
(0.01 per cent.) and chro- 
mate of potash (0.02-0.05 
per cent.) as fluid media. 
These points will 
have to be decided by 
future investigations. 
Fig. 199. Ganglion-cell from the anterior horn of the spinal 
cord of the ox, after Schultze. a, axis-cylinder; b, cell-pro- 
cesses. 
It was supposed, many years ago, that the nerve-fibres origin- 
ated in the nucleolus and nucleus of the ganglion-cell (Harless, 
Axmann, Lieberkuhn, GK Wagner). 
The art of giving the substance Of the brain and spinal cord 
a consistence suitable for making sections has been possessed 
for many years. 
Alcohol, the solutions of chromic acid and of the bichromate MUSCLES AND NERVES. 
of potash, and ammonia are used for hardening. Whether the 
one or the other of these fluids is used, only pieces of the brain 
and spinal cord which are quite fresh and carefully removed 
from the recently killed animal and deprived of their envelopes, 
should ever be immersed in them. The pieces should not be 
too large. If their volume be too large, the exterior may 
acquire a good consistence, but the central portions will, on the 
contrary, remain soft or even become decomposed. I would 
recommend, as a useful method, to allow such pieces to float in 
a tall glass cylinder, suspended by means of a silk thread 
to a hook in the glass stopper. Betz subsequently confirmed 
this. 
Among the reagents mentioned, alcohol takes the lowest 
place. Preference has therefore, for many years, been given to 
solutions of chromic acid and the chromate of potash. Here 
we must also censure the custom of estimating the strength of 
these solutions only by their color. Now and then the proper 
degree of concentration may be obtained in this way ; but in 
many cases one will be deceived and fail in obtaining the de- 
sired result, which might have been accomplished with less 
trouble by making an accurate solution. 
Now, what degree of concentration should be given to such 
solutions % Here it must be remembered that the fluids used 
by former observers were generally much too strong, so that 
a considerable shrinking of the tissues took place, and not unfre- 
quently the whole became entirely too brittle to permit of a 
section being made. A chromic acid solution of 1 per cent, is 
certainly too strong for commencing the hardening. I have 
obtained good results with mammalial animals as well as with 
cold-blooded vertebrates, such as Ashes and frogs, when I com- 
menced the hardening with solutions of 0.2 per cent.; then 
changed the chromic acid after a few days, replaced it by a 
stronger solution, and thus finally arriving at those of 1 per cent. 
Bichromate of potash is to be used in the corresponding strength 
of 2-6 per cent. (comp. p. 136). Deiters employed the following 
method for hardening the brain and spinal cord : He first im- 
merses the preparation for one or two weeks in a solution of 
the chromate of potash (15 grains to the ounce of water). Then 
(when a uniform saturation has taken place and the hardening 
has commenced) the preparation is placed either immediately 
or after washing out the potash salt, in a solution of chromic SECTION FIFTEENTH. 
acid which contains 2 grains to the ounce and may be increased 
to 8 grains. 
Grerlach recommends the use of a 1-2 per cent, solution of the 
bichromate of ammonia for at least fifteen or twenty days, occa- 
sionally for five weeks. 
It is impossible to state anything definite with regard to the 
time which is generally required for the hardening. Chromic 
acid salts act more slowly, the free acids more rapidly. I have 
often found that the spinal cord of small animals has become 
sufficiently firm in a week in these solutions of the free acid. 
As a rule, a space of three to four weeks, not unfrequently still 
longer—six weeks or more, is necessary. There is great varia- 
tion, however, in this regard. Reissner is therefore correct in 
asserting that the central parts, especially the spinal cord of the 
various kinds of animals, also show differences in regard to the 
time which is requisite to harden them. It is generally stated, 
it is true, that the hardening takes place more rapidly with 
small animals than with those which are larger. This is, how- 
ever, by no means universally the case, as, according to his ex- 
perience, the spinal cord of the calf becomes hard in weaker 
solutions than does that of the rabbit, the mouse, or the rat. 
To ascertain the proper degree of consistence, nothing further 
is necessary than to make a trial section with the razor from 
time to time. The hardening should have progressed in exactly 
such a manner as that with the moistened blade, a very thin 
layer may be removed conveniently and without crumbling. 
If the tissue crumbles it is already overhardened ; if the consis- 
tence is insufficient, only thick sections are possible. In the 
latter case a further immersion is necessary ; in the former, the 
procedure is a failure. 
If one has been so successful as to have obtained the proper 
consistence, the hardened object is to be placed, after having 
been washed, in weak watery alcohol. It may be preserved in 
this for a long time without undergoing any changes, to serve 
for future investigations. 
With some practice and a good razor one soon learns to 
make marvellously thin sections. In doing this, the object is 
to be held with the points of the first three fingers of the left 
hand, and care is to be taken to keep the preparation and the 
blade sufficiently moistened with alcohol. It is impossible to 
hold very small objects, such as the spinal cord of a mouse, for MUSCLES AND NERVES. 
instance, with the points of the fingers. They may be placed 
in a larger animal body, the spinal cord of a larger animal for 
instance, or in a piece of elder pith ; or an embedding method 
(p. 113) may be employed. Sections may be cut with the free 
hand, or an ordinary microtome (p. 108) may be used. 
Sections made in all directions are naturally necessary, in 
order to construe from the various preparations the structure 
of such central parts as the spinal cord, for example. Trans- 
verse sections are first made, then longitudinal ones, of which 
vertical and horizontal longitudinal as well as oblique (that is, 
such as are made, for instance, from the right posterior cornua 
towards the left anterior cornua) sections are of importance. 
Those which are made oblique to the long axis of the cord ap- 
pear to be of less importance. 
For most examinations it is advantageous to tinge the sec- 
tions thus obtained. Staining with carmine is nowadays gen- 
erally employed in these cases, and, according to our experi- 
ence, it is of the first rank for such things. 
Here, as with all delicate tissues, I employ a solution of 
carmine obtained with a minimum of ammonia, which is to be 
considerably diluted with water, and then an equal volume of 
glycerine added. The sections are to be washed out in very di- 
lute alcohol, to free them from any chromic acid which may be 
present, and then placed in the solution to acquire the desired 
redness, for which two, four, eight to twelve hours is necessary, 
according to the concentration of the coloring medium. 
The object is next to be placed for a short time in clean 
water to wash out the superfluous carmine, then in water very 
slightly acidulated with a few drops of acetic acid, or in dilute 
alcohol thus acidulated. The diffuse redness disappears, and 
the remaining carmine is then fixed to the cells, nuclei, and 
axis-cylinders. If individual differences occur with regard to 
the capability of imbibition of the tissue elements of the brain 
and spinal cord, the epithelium, ganglion bodies, axis-cylin- 
ders, and the nuclei of the connective-tissue framework are to 
be designated as those parts which become especially impreg- 
nated with the coloring matter. Hmmatoxyline also furnishes 
very excellent specimens ; unfortunately, like all objects which 
have been treated preliminarily with acids, they perish rapidly. 
Aniline blue deserves to be recommended (p. 156). 
Preparations thus treated may be examined in a moist con- 356 
SECTION FIFTEENTH. 
dition. Glycerine may then be used to increase their trans- 
parency. 
The preparation may be rendered more permanently trans- 
parent, however, by immersing it, after it has been carefully 
and cautiously deprived of its water, in oil of turpentine or 
Canada balsam. This method is the most popular at present, 
and also affords the most beautiful and most durable prepara- 
tions for a collection. We refer for it to page 212 of our book.* 
We would here earnestly recommend the alcoholic resinous 
solutions (p. 2f3). 
Metallic impregnations were then tried. I would not advise 
osmic acid, having accomplished nothing with it. Beautiful 
but, unfortunately, perishable preparations are occasionally 
obtained with chloride of gold. 
Several years ago Gerlacli praised the treatment with chlo- 
ride of gold and potash as an excellent means of rendering the 
course of the nerve-fibres in the spinal cord visible. 
Fine transverse sections are made from the spinal cord after 
it has been hardened by immersion for 3-6 weeks in a solution 
of the bichromate of ammonia. The sections are to be placed 
for 10 or 12 hours in a 0.01 per cent, solution of the gold salt 
to which a little acetic or muriatic acid has been added. Then 
(when the white substance has gained a pale lilac color, and 
the gray presents but a slight tinge), the section is to be washed 
with a to-and-fro movement, continued for several minutes in 
very dilute hydrochloric acid (1 ; 2-3000). Gerlach now places 
* We here add several other methods : 
1. Years ago Lockhart Clarke, who was afterwards imitated by Lenhossek, made 
use of the following process ; The fresh spinal cord is to be hardened in alcohol; the 
first day it is to be placed in such as is diluted with an equal volume of water, then 
left in pure alcohol until thin sections are possible, a condition which is generally 
obtained, in the cooler portion of the year, in from 5-6 days. The sections are then 
to be immersed for 1-3 hours in the mixture mentioned at page 139, consisting of 1 
part acetic acid and 3 parts alcohol. In this, not only the nerves and fibrous ele- 
ments are rendered more sharply prominent, but the gray substance is also rendered 
quite transparent. 
3. J. Dean, to whom we are indebted for a very superior work on the central or- 
gan, hardens in alcohol or chromic acid, and colors the washed sections moderately 
in glycerine-carmine, in which they remain from 4-8 hours, according to the intensity 
of color desired. Alcohol, oil of turpentine, and Canada balsam are then employed. 
According to Dean, thick copal varnish is often preferable to the balsam for the rec- 
ognition of fine details. Dean also praises Clarke’s method highly, and, we will add, 
very appropriately, if the mixture is allowed to act on tinged preparations. MUSCLES AND NERVES. 
357 
it for about 10 minutes in a mixture of 1 part muriatic acid and 
1000 parts alcohol of 60 per cent., and afterwards, finally, for a 
few minutes in absolute alcohol. Oil of cloves serves to render 
the section transparent, and it is then mounted in Canada bal- 
sam, which terminates this somewhat complicated process. To 
render the ganglion-cells visible, it is necessary, before immers- 
ing the preparation in the gold salt, to employ one of the other 
methods of metallic impregnation for several hours, such as 
that with chloride of palladium (p. 168), or, which the author 
prefers, to make use of a very dilute solution of a metallic salt 
which has not been previously employed in histology, the 
nitrate of uranium. 
Henle and Merkel stain alcohol preparations with molyb- 
danate of ammonia* (p. 137); chromic acid objects first with 
chloride of palladium and then with a stronger carmine solu- 
tion, which here acts very rapidly, coloring the medulla yellow 
and the axis cylinder red. 
Betz, finally, recommends the following method (in which 
iodine is used for the first time): The preparation is first 
placed for days in a 70-80 per cent, alcohol, which is colored 
light brown by the addition of iodine. As the tissue becomes 
impregnated with the latter material, the subsequent addition 
of drops of a strong alcoholic solution of iodine is necessary. 
The arachnoid and pia mater are to be removed during the 
first few days. 
After this merely preliminary hardening, place the object in 
a 30 per cent, solution of bichromate of potash, taking such 
precautions as may be necessary to prevent the preparation 
from rising and swimming on the surface. It is allowed to 
stand in a cool place, and the several portions of the spinal 
cord harden in unequal periods. After washing out in water 
place them in a 0.5-1 per cent, solution of this salt, where they 
may remain for months. 
The sections (of spinal cord or cerebellum) are deprived of 
their water for a few days, tinged with carmine, again deprived 
of their water in alcohol which is gradually strengthened, and 
* The authors use the following process: 1 vol. of a concentrated solution of 
the molybdanate of ammonia is diluted with 1-2 vols. of distilled water. Then add 
the point of a knife-full of iron-filings and so much officinal muriatic acid as suffices 
to produce a dark blue, almost black color (a brown color is useless). After ten 
minutes, filter. 12-15 hours are necessary for staining. 358 
SECTION FIFTEENTH. 
finally in absolute alcohol, then rendered transparent in resin- 
ous turpentine, and, finally, mounted in a solution of gum 
dammar in turpentine. 
We must refer to the original for further details. 
Schielferdecker places the spinal cord for about a month 
continuously in Mueller’s fluid, then places the preparation in 
water for a day, and again hardens it in alcohol. The sections 
are placed either in a solution of chloride of palladium (1:10- 
000) or one of chloride of gold (1-5:10000). The durability 
of these preparations is, unfortunately, limited. 
With industry and perseverance, and by the aid of the 
methods of preparation which have been given, one may suc- 
ceed in recognizing the more important textural relations of 
the spinal cord (those of the brain with greater difficulty),* 
whereby, as was remarked, the examinations should commence 
with transverse sections. At the same time one will also 
recognize the great difficulty of accurately describing the tex- 
tures of the central organs—a difficulty which is founded in 
part on the nature of the object; in part, also, on the methods 
of investigation, which still remain insufficient. Many observ- 
ers have certainly exaggerated the results of their investiga- 
tions very much, frequently drawing very false conclusions 
from fragmentary isolated appearances. Other investigators 
have, however, become infected with an excessive skepticism. 
Attempts have even been made to disprove the reticulated 
commissural communication of the large multipolar ganglionic 
bodies in the anterior cornua of the spinal cord, as also the 
continuation of some of their processes into nerve-fibres of the 
anterior motor root. In our opinion these textural conditions 
may be observed with entire certainty, although only with 
difficulty and on very rare occasions. 
To obtain injected preparations of the brain and spinal cord, 
one should proceed in the following manner. One of the 
* Betz uses a somewhat modified method for the cerebrum divided through the 
corpus callosum. It is first placed in tincture of iodine highly diluted with water to 
a light brown color. After standing in a cool place for 24-48 hours, remove the pia 
mater as carefully as possible, add to the old fluid about half its quantity of alcohol 
containing iodine, and reimmerse the brain for 24-72 hours. To complete the hard- 
ening, place it for 10-14 days in 70 per cent, tincture of iodine, and, finally, in a 4 
per cent, solution of chromate of potash. Well-hardened brains permit of making 
very large and very thin sections with the aid of special microtomic apparatus (Betz, 
Gudden, Schiefferdecker). MUSCLES AND NERVES. 
359 
smaller mammalia, a rat, a G-uinea-pig, a rabbit, or a cat may 
be selected, and the camila inserted into the commencement of 
the aorta, after this vessel has been ligated below the carotids 
and the subclavians. The injection readily succeeds on the 
fresh body (with some loss of injecting fluid, it is true) with 
cautious management of the syringe. But to judge of the cor- 
rect moment for terminating the procedure is somewhat diffi- 
cult. If a white rat or an Albino rabbit has been used, the 
complete injection of the eyeball affords a criterion. To inject 
the upper half of the spinal cord, the aorta is to be ligated as 
it passes through the diaphragm, and the procedure completed 
as above mentioned. Deep-red carmine-gelatine constitutes 
the best injection fluid. Alcohol is used for hardening, and 
hsematoxyline for staining the sections. Prussian blue is to be 
preferred, if it be desired to accomplish the former with 
chromic acid, and an acetic acid solution of carmine for subse- 
quent tingeing. 
Key and Retzius have recently investigated the serous and 
lymphatic spaces of the brain and spinal cord. They injected 
colored fluids, by a constant and low pressure, beneath the 
dura mater or the arachnoid. Further information may be 
obtained from the hand-books on histology. 
A further difficulty in the investigation of the central organ 
of the nervous system is found in distinguishing the connec- 
tive-tissue framework (neuroglia) from the nervous elements. 
Although the tacit presumption, that everything which is 
present in the brain and spinal cord must also be of a nervous 
nature, was accepted for many years, the extensive occurrence 
of a connective-tissue substance, in which the nervous tissue 
elements are imbedded, was afterwards rightly maintained by 
Bidder and his followers, although with some exaggeration. 
There is repeated in the brain and spinal cord, therefore, 
one of those undeveloped, reticular connective substances, such 
as have been frequently observed of late in the human body— 
one of those reticulations and frameworks with cell-bodies in 
some of the nodal points. 
In tlie white substance this is of a more compact structure, 
and appears in transverse sections as a net-work with isolated 
nuclei and round apertures for the reception of the nerves 
(fig. 200). 
The reticular connective tissue in the cortical la3mr of the 360 
SECTION FIFTEENTH. 
white substance passes uninterruptedly into the pia mater, 
where it is more richly developed and the reticulations become 
very much liner. 
The reticular framework of the gray substance of the spinal 
cord likewise appears to be extraordinarily del- 
icate, and frequently the meshes are extremely 
fine. This also appears extremely developed 
and with distinctly radiated connective-tissue 
cells in the interior of the so-called central 
thread of ependyma. 
Such a supporting substance certainly oc- 
curs in the brain also, although not so well 
known (fig. 201). In the gray substance of the 
Fig. 200. The con- 
nective - tissue frame- 
work from the posteri- 
or column of the hu- 
man spinal cord. 
cortex, the net-work, which has nuclei in its nodal point, as- 
sumes an infinite fineness and delicacy of its fibres and meshes, 
so that its existence has frequently been totally denied. 
Methods of maceration, such as were recommended by 
Deiters (p. 349), serve for the recognition of these framework 
substances, which are also extremely important for the pathol- 
ogists. The action of nitrate of silver on segments of the fresh 
tissue, with a subsequent addition of glycerine, has also been 
used with success (Frommaim): likewise osmic 
acid. 
For the examination of the gray substance 
of the brain, Ranvier recommends the following 
process : Inject a solution of osmic acid (1: 300) 
into the tissue, pick this apart after an hour or 
two in distilled water and stain with picro-car- 
mine. The connective-tissue elements and the 
ganglion-cells show with equal perfection. 
Glerlacli recommends the two methods of treat- 
ment with chloride of gold and potash and car- 
mine, mentioned above (p. 356), for distinguish- 
ing the neuroglia of the gray substance from 
Fig. 201. Porous 
tissue of the gray 
substance of the hu- 
man cerebellum: ob- 
tained with extreme- 
ly dilute chromic 
acid. 
the very fine net-work of nerve-fibres wThich also occurs there. 
Only the nervous elements, but not those of the connective 
tissue, become colored. For the diagnosis of nervous and con- 
nective-tissue cells in them, a suitable reagent is still wanting. 
Tumor-like new formations of the framework substance 
mentioned occur in the central organs and in the retina. They 
have been called glioma (Virchow). MUSCLES AND NERVES. 
361 
A deposit of peculiar structures, frequently discussed of 
late, the so-called amyloid bodies, corpuscula amylacea (fig. 
202), takes place in this framework substance after death, as a 
result of decomposition, and even during life 
in abnormal conditions. 
These, varying in size, occur as globular, 
ovoid, or double-loaf-shaped structures, in 
which a distinctly stratified appearance may 
frequently be recognized under the micro- 
scope, In these cases they remind one very 
much of amylon granules, for which they 
have also been mistaken. Their reaction may 
be that of amylon, taking a blue color with 
Fig. 202. Amyloid cor- 
puscles from the human 
brain. 
a solution of iodine. Others, on the contrary, assume a violet 
hue from the action of iodine and sulphuric acid (see p. 132), 
and put one in mind of cellulose. The best and finest results, 
a beautiful blue and red tingeing, are presented by the aniiine 
iodine violet recently recommended by Jurgens (p. 155), per- 
mitting of a distinction from a starch granule. 
In addition, let it be re- 
marked that similarly reacting 
masses may also make their 
appearance in many other 
parts of the body, and an 
amyloid degeneration has con- 
sequently been recently as- 
sumed. 
As we are at present re- 
ferring to chemical matters, 
let ns also at the same time 
mention the so-called myeline. 
It appears under the micro- 
scope in the form of double 
contoured drops and lump- 
like masses, and is also not 
limited to the nervous sys- 
tem. 
Fig. 203. Crystals of cholesterine and deposits 
of myeline. 
Our fig. 203, in its lower half, may afford us a representation 
of this optical peculiarity of that substance. The upper portion 
of the drawing is occupied by crystals of cholesterine, a pecu- 
liar substance, widely spread throughout the animal body 362 
SECTION FIFTEENTH. 
(which has also been more recently discovered by Beneke and 
Kolbe in plants). This cholesterine forms an element of the 
nerve-substance ; it also occurs in the blood, though in small 
quantity, more abundantly in the bile (and especially in the 
biliary calculi); likewise in most of the other animal fluids, 
with the exception of the urine. Finally, it occurs in patho- 
logical fluids and tumors, and has the signification of a product 
of decomposition. 
It occurs in very delicate, thin, rhomboidal tables (with 
acute angles of 79° 80', also of 87° 30;, and of only 67° 20;), and 
is thus for the most part readily recognizable. It likewise 
shows certain characteristic reactions. If a mixture of 6 parts 
of sulphuric acid (of 1.85 sp. wt.) and 1 part of water be added 
to the crystals of our substance under the microscope, a pecu- 
liar change of colors takes place. The borders of the tablets 
become carmine red, then, with a commencing dissolution into 
drops, violet. If iodine and sulphuric acid be applied, pure 
cholesterine assumes a blue ; impure, a violet, reddish, or vari- 
egated color. The whole affords a beautiful microscopical 
image, but is, as a rule, without any practical value, as the 
shape of the crystals is for the most part entirely sufficient for 
the recognition of cholesterine. 
We have, finally, to mention the methods of investigation 
which are nsed at present for the recognition of the termina- 
tions of the nerves. 
These vary exceedingly, according to the constitution of the 
part to be investigated, as, together with the examination of 
the freshest possible and the altered elements, there is also an 
innumerable quantity of methods employed which vary with 
the parts of the body. 
Let us commence with the manner of termination of the 
motor nerves, especially those in the transversely striated mus- 
cles. 
The tissue taken from an animal which has Just been killed 
is to be first employed, as, immediately before the rigor mortis 
takes place, the muscular filaments present a considerable de- 
gree of transparency, which soon gives place to a more cloudy 
condition. In such investigations the object is to be examined 
either without any fluid medium, and covered with a thin glass 
scale only (which may, at the most, be very carefully pressed 
upon, to give a smooth surface), or with the addition of indif- MUSCLES AMD NERVES. 
ferent fluids. Only certain, especially thin membranous mus- 
cles, are adapted for such investigations. 
The orbital muscles of small mammalia! animals, and among 
these the retractor bulbi (of the cat), also the psoas muscle of 
these animals, fur- 
thermore the flat 
muscles which 
pass from the hy- 
oid bone to the 
lower jaw of the 
frog, and the cuta- 
neous thoracic 
muscle of this ani- 
mal, the very short 
muscles in the tail 
of the lizard, etc., 
may be advanta- 
geously employed. 
One may also, 
without trouble, 
succeed in obtain- 
ing appearances 
like our fig. 204, 
with suitable pre- 
parations, from 
the frog. The di- 
vision of the dark- 
bordered primi- 
tive fibres into me- 
dullated branches, 
and their contin- 
ued splitting up 
into finer dark 
ones, may be fol- 
lowed, until at last 
Pig. 204. Radiation ol the nerves in the voluntary muscles of the frog. 
A nerve-fibre, a, without a neurilemma, with repeated subdivisions into 
several smaller branches, b. b; c, a nerve-fibre with a neurilemma of 
the simplest kind, without division. 
fine terminal branches appear to end in the muscular fila- 
ments. It was believed for many years, in fact, that we had 
thus penetrated to the ultimate terminal branches. 
A series of investigations lately undertaken shows that these 
earlier views are at all events untenable, and that the nerve-dis- 
tribution takes place beyond these alleged terminal branches. 364 
SECTION FIFTEENTH. 
The results of the observations instituted by Kiihne, Margo, 
Kolliker, Rouget, Krause, Engelmann, and others do not, how- 
ever, agree. Still, after unprejudiced examination, it can no 
longer be doubted that the nerve perforates the sarcolemma 
(whereby its neurilemma becomes continuous with the latter), 
and terminates beneath it in a nucleated, line, granular, lamel- 
lated substance. The latter, however, pass at their borders 
and inner surfaces uninterruptedly into the sarcous substance 
of the muscular filaments (Rouget, Engelmann). 
Our fig. 204 shows the terminal structures in question, which 
have been suitably designated by the name of £ ‘ terminal 
plates,” from the psoas 
of the guinea-pig, at the 
left in profile, at the right 
as seen from above. In 
mammalia, in which they 
are well developed, the 
terminal plates have a 
magnitude varying in the 
mean between 0,0177 and 
0.0267///. The number of 
their nuclei fluctuates be- 
tween 4, 6, 10, and 20. 
The terminal plates be- 
come more and more sim- 
plified in the lower verte- 
brates. 
As has been shown by 
more recent investiga- 
tions (Kiihne, Engel- 
mann), however, these ter- 
minal plates do not repre- 
sent the entire arrange- 
Via. 205. Two muscular filaments from the psoas of the 
Guinea-pig. a, 6, the primitive fibres and their continua- 
tion into the two terminal plates e, f; c, neurilemma con- 
tinuous with the sarcolemma g, g; h, muscular nuclei. 
ment. Suitable profile views show that the axis-cylinder 
becomes divided and spread out into a tree-shaped figure in 
the external portion of the terminal plate. Beneath it, “like 
a sole,” lies the granular nucleated mass. 
Most of the accessories which have thus far been employed 
are intended to render the whole muscle, or at least a part of 
it, as transparent as possible, so that the distribution of the 
nerve-fibres may be better followed than in the unaltered tis- MUSCLES AMD NERVES. 
365 
sue; and secondly, to isolate tlie transversely striated mus- 
cular filaments with as little injury as possible, and subject 
them to examination freed from their interstitial connective 
tissue. 
The alkalies are unserviceable for the former purpose, but 
various acids, highly diluted, are, on the contrary, very good. 
Kolliker recommends the dilution of 8, 12-16 drops of aci- 
dum acet. concent, of the Bavarian Pharmacopoeia, of 1.045 sp. 
wt., with water to 100 ccm. and to immerse in it the cutaneous 
thoracic muscle of the frog for hours, after which time it 
is said to become transparent like glass. I have accomplished 
the same result with 1-2 drops of hydrated acetic acid to 50 
ccm. of water. Highly diluted acetic acid also proves very 
serviceable for the muscles of other animals (Engelmann). I 
would also give this acid the first rank for such purposes. Mus- 
cles which have thus been rendered transparent may be pre- 
served for some time in 1-2 per cent, acetic acid. 
Muriatic acid of 0.1 per cent, is likewise a suitable reagent. 
It produces a similar condition of the muscle in from eight to 
twelve hours at the ordinary temperature of the room. 
The action for twenty-four hours of nitric acid, of the same 
concentration as the hydrochloric acid, is also serviceable. 
The still living muscular fibres, fortunately isolated by me- 
chanical means, often give the most characteristic appear- 
ances. 
We have received from Kiihne a good method for the fur- 
ther isolation of the muscular filaments (naturally, with as little 
injury as possible). 
He was able, by means of the mixture of nitric acid and 
chlorate of potash, mentioned above at the muscular tissue, p. 
828, to isolate the muscular filaments with the adherent nerve- 
fibres very handsomely ; but it was impossible to ascertain the 
further distribution of the latter. On the contrary, the treat- 
ment, which we have also mentioned, with extremely dilute sul- 
phuric acid, and the subsequent digestion in water, constitutes 
a very suitable process. 
Krause recommends, furthermore, the immersion of the 
muscles for several days in a 88 per cent, solution of acetic 
acid, and then the isolation of the filaments by careful picking 
from the swollen connective tissue. He also obtained good 
preparations by placing them in a 2 per cent, solution of the 366 
SECTION FIFTEENTH. 
chromate of potash, with the subsequent action of 25 per cent, 
acetic acid. He furthermore praises solutions of sublimate 
of 0.8-0.5 per cent., and the subsequent treatment with the 
same acid ; and finally, sulphuric acid of 0.1 per cent. 
The so readily decomposable structures of warm-blooded 
animals are less to be*recommended than those of the scaly am- 
phibise for seeing the arborescent distribution of the nerve- 
fibres in the terminal plates. A lizard 
or a ring-snake, killed twenty-four 
hours previously by destroying the 
central nervous system, presents with 
the addition of a 0.6 per cent, solution 
of chloride of sodium, very character- 
istic appearances (Engelmann). Others 
recommend solutions as high as one 
per cent, of this salt. 
The most recent observer of these 
relations, who has rendered great ser- 
vice to microscopic technology, Pro- 
fessor Greiiach, has come to quite dif- 
ferent results. According to his views 
(which are not entirely shared by us) 
there exists in the transversely striated 
Fig. 206. Muscular filament (a), of 
the lizard; b, nerve-fibre; c, its 
branches with the peculiar terminal 
figure d. 
filament a fine terminal nervous net-work, which finally coales 
ces with the sarcous substance. 
This author tested most accurately the silver treatment for- 
merly recommended by Cohnheim, as well as the gold method, 
and has given very careful directions for its rather useless 
employment. We omit these here, and refer to the original. 
We will mention only the gold method, which has already 
been recommended, and which afforded him by far the best 
results. 
Use a solution of chloride of gold (1: 10000 parts of water) 
and frog’s muscles, preferably 6-9 hours after death, at a 
period where possibly the acid condition of rigor mortis be- 
gins to terminate. The frog may advantageously be rendered 
tetanic by a blow on its head, and the leg, the gastrocne- 
mius of which is to be used, cut off. The muscles of mam- 
mals should be used earlier, though it is very difficult to hit 
the right period. 
The frog’s muscle is, according to G-erlach’s directions, to MUSCLES AMD MERYES. 
367 
be picked apart into bundles, placed in the gold solution, and 
kept in a dark place for 10-12 hours. It is then to be washed 
out in weakly acidulated water and proceeded with further 
in the familiar manner. Mount in glycerine with gum or a 
minimum of muriatic acid. A reddish tinge shows a successful, 
a yellowish one an unsuccessful impregnation. If the prepa- 
ration is immoderately dark, some improvement may be ef- 
fected by a solution of cyanide of potash in water (1 : 200). 
I have repeated all this, unfortunately with slight results, as I 
must confess. 
The most recent investigator in this domain, A. Ewald (he 
has justly announced his opposition to Gerlaclr s views), has 
recommended the isolation of the muscular fibres of the gas- 
trocnemius of the frog in a drop of 0.5 per cent, solution of com- 
mon salt, and, after washing out in distilled water, placing the 
preparation from I a minute in a 0.1 per cent, solution of 
nitrate of silver. For the examination, use a mixture of water 
100, glycerine 100, formic acid 1. To impregnate with gold, 
isolate the fibres in a solution of chloride of palladium (of the 
color of Rhine wine) and then place them either 12-18 hours in 
Gerlach’s gold solution or for a minute in a 0.2 per cent, solu- 
tion of chloride of gold and potash. This immersion, as well 
as the subsequent deprivation of water (for about twelve hours) 
is best in the dark. Ewald recommends as a fluid medium a 
mixture of glycerine 40, water 20, and a drop of a muriatic acid 
which contains 25 per cent, of chloride of hydrogen. The silver 
preparation of the muscle may be rendered more durable by a 
subsequent short impregnation with gold. 
It is much more difficult to follow the terminal forms of the 
nerve-fibres in the smooth muscles than in the transversely 
striated tissue, and our knowledge is therefore very uncertain 
on this point. The broad ligaments of the uterus of the rabbit 
(Frankenhauser), likewise the urinary bladder and the small 
arteries of the frog (Klebs, Arnold), are at present considered 
the most suitable objects for examination. Highly diluted ace- 
tic and chromic acids are to be tried here, Klebs recommends 
a 5 per cent, solution of cane-sugar to which sulphurous acid 
is added, and the subsequent immersion in phosphate of soda. 
Frankenhauser advises highly diluted chromic acid, Per 
cent., and also acetic acid of 20 per cent. Finally, we are in- 
debted to Arnold for very accurate directions. The object is 368 
SECTION FIFTEENTH. 
to be placed for two to four minutes in 4 ccm. of acetic acid of 
0.5-1 per cent., and then for half an hour in the same quantity 
of chromic acid of 0.01 per cent. This investigator found the 
gold method, and likewise the treatment of transverse sections 
of frozen muscles with chloride 
of gold and chromic-acid solu- 
tions, advantageous. Impreg- 
nation with gold by Henocque’s 
modification (p. 167) is the best 
method. 
According to the investiga- 
tions of Frankenhauser and Ar- 
nold, however, the termination 
is very peculiar. These nerves 
form manifold net-works. A sec- 
ondary plexus of this kind lies 
close to the muscular layer (fig. 
207). It consists of fine, pale, 
nucleated filaments. Still finer 
fibres spring from it to form a 
new net-work with small meshes, 
the extremely fine terminal fib- 
rillse of which are said to end in 
Fig. 207. Alleged nerve-termination in the 
muscular coat of a small artery of the frog, after 
Arnold. 
the nucleoli of the contractile fibre-cells. This condition may 
be represented to the reader by the above figure. The correct- 
ness of this statement has of late, however, again become very 
questionable. Engelmann, in a re-examination, was unable to 
see any trace of this manner of termination—and we have been 
equally unfortunate. Klein also saw, a few years since, only 
a very narrow terminal net-work. 
To examine the still imperfectly determined nerve termina- 
tion of the muscles of the heart, take the thin, transparent 
septum auriculorum of the naked amphibise, especially the 
land salamander. Highly diluted acetic acid may be used 
alone or combined with chromic acid. The recognition of this 
will be very uncertain in other portions of the heart of verte- 
brate animals. Impregnation with gold may be used, prefer- 
ably a 0.01 per cent, solution of chloride of gold and potash, 
allowing it to act for 24-48 hours ; or the action for two days 
of a2O per cent, nitric acid. Instead of this, the fresh, tissue 
may be picked apart in nearly neutral fluids, such as a solution MUSCLES AND NERVES. 
369 
of common salt (0,5) or osmic acid (0.1 per cent). The dog and 
gninea-pig are to be recommended among the mammalia. 
These directions, coming from Langerhans, have recently been 
rendered more complete in a beautiful study by the younger 
Grerlach. The latter recommends to cut the heart from a frog 
and wait till a mechanical irritation no longer produces con- 
traction. The septal parietes of the atria are then rapidly re- 
moved and placed in a mixture, consisting of chloride of gold 
and potash 1, muriatic acid 6, and water 12000. It remains in 
this solution, protected from the light, for 14-16 hours. It is 
then washed for several minutes in water containing muriatic 
acid (1 :1000), and placed in a mixture consisting of muriatic 
acid 1, water 100, and glycerine 400. Here the reduction by 
the action of light takes place in two or three days. Some in- 
crease of transparency may be obtained with a cyanide of pot- 
ash and glycerine mixture (p. 135). Immersion for about a day 
in weak picric acid, with the subsequent use of picro-carmine, is 
also useful. For isolating, Gerlach recommends maceration 
in Schultze’s reagent. 
The nerves of the cornea of the eye, which have been for- 
merly and recently frequently examined, present interesting 
objects to the microscopist. 
Soon after entering the cornea at its periphery, they lose 
their medullary sheath, become pale, and form a plexus which 
permeates the corneal tissue, of very fine fibrillse with nucleat- 
ed enlargements at their nodal points. Nerve-fibres pass from 
this net-work in two directions : those which proceed in the one 
direction terminate in the corneal tissue itself; while the others, 
after perforating the anterior homogeneous limiting layer 
(Hoyer), find their terminus in the epithelium (Cohnheim). 
The cornea, removed from an animal immediately after death, 
is naturally to be employed for examination. One may here, 
for example, with the cornea of a frog, proceed in the following 
manner (Kuhne): The point of a knife-blade is to be inserted 
near the sclerotic border, and the aqueous humor drawn out 
with a pipette; the cornea is to be rapidly separated with a 
pair of fine sharp scissors and placed on a slide, with the small 
quantity of aqueous humor from the pipette. The whole is 
then placed in the previously (p. 99) described moist chamber, 
to remain for hours under the microscope, and at the same 
time to gradually reveal not only the course of the nerves, but 370 
SECTION FIFTEENTH. 
also many other remarkable things in the most conservative 
manner. 
The procedure mentioned may also be used, with slight 
modifications, for other animals. The cornese of the smaller 
animals, the mouse, the rat, and the squirrel, are generally 
to be recommended. They are to be removed in connection 
with a narrow zone of the sclerotic, and it will generally be 
necessary to make several incisions in the direction of the 
radii. 
If one desires to employ reagents, the highly diluted acetic 
acid recommended by Kolliker for the nerves of the muscles 
(p. 365) is advisable (Muller and Saemisch). Even after 10-15 
minutes the epithelium may be removed with the forceps ; 
while at least several hours’ action of the reagent is necessary 
for the examination of the nerves. The action of very dilute 
chromic acid (0.1-0.01 per cent.), to which 0.25 per cent, of 
chloride of sodium maybe added, is also advantageous, at least 
with the frog (Kuhne), 
ISTo certain results have yet been obtained concerning the 
termination of the corneal nerves in the true corneal tissue. It 
has been assumed that there was a connection between the ter- 
minal fibrillie and the cell 
processes of the radiated 
corneal corpuscles (Kuh- 
ne). We have been inform- 
ed there is a termination in 
the nucleolus of the latter 
elements (Lipraarn, Lav- 
do wsky) ; while others 
deny all connection with 
the corneal cells, as, for in- 
stance, B. Eollett, Klein. 
Fig. 20S. The cornea of the rabbit in vertical transverse 
section, after treatment with chloride of gold, a, the 
older; 6, the young epithelial cells of the anterior surface ; 
c. corneal tissue; d, a nerve-branch; e, finest primitive 
fibres; f, their distribution and termination in the epithe- 
lium. 
To recognize the pene- 
tration of the (extremely 
fine) nerve-fibres into the 
epithelium of the conjunc- 
tiva, and thus to verify 
Cohnheim’s beautiful discovery, one should resort to chloride 
of gold (p. 166), chloride of gold and potash (Hoyer), as well as 
chloride of gold and soda (Waldeyer), and use the eyes of 
guinea-pigs and rabbits (fig. 208). The frog’s cornea shows its MUSCLES AND NERVES. 
371 
epithelial nerve-distribution even without any reagents, by 
simply remaining in the moist chamber (Engelmann). 
In consequence of the capriciousness of the gold method, 
there is here no dearth of processes. We communicate a few 
of recent origin. 
Klein uses a modification of Henocque’s process (p. 167.) 
It is said to present infallible results for these epithelial nerves. 
The fresh organ of the rabbit is placed, with its external 
surface upwards, for |-1 hour in a 0.6 per cent, solution of 
chloride of gold, then, secluded from the light for 6-10 hours, 
in distilled water, which washes it out. The original straw yel- 
low color has now changed to a gray, How place it in a small 
bottle which contains 5-10 ccm. of a nearly saturated solution 
of tartaric acid. The bottle is then to be placed in a nearly 
equal quantity of water heated to 40-50° C. A lively violet red- 
dish color is then rapidly obtained, which, on the cooling of the 
water, passes into an impure but deep brown-red color. A re- 
newed washing for several hours in distilled water then follows. 
Hoyer, in an excellent article, gives us the following direc- 
tions : Use a 0.5 per cent, solution of either chloride of gold, or 
better, chloride of gold and potash. A cornea well impregnated 
with gold should, however, still be moderately transparent and 
evenly tinged throughout gold yellow. If it remains whitish 
or cloudy in its interior, only an incomplete result is to be ex- 
pected. With smaller animals, rabbits and guinea-pigs, re- 
maining in the solution, hour generally suffices; larger ani- 
mals require a longer time or a stronger solution of gold. A 
complete and good impregnation cannot be obtained with the 
cornea of the ox. This process succeeded with fresh human 
eyes, when the solution of chloride of gold and potash of the 
above-mentioned strength, to which a little acetic acid was 
added, was allowed to act for 2-5 hours, although the latter re- 
agent cannot otherwise be pronounced advantageous. 
Hoyer recommends for the epithelial nerve-distribution the 
following : When a cornea which is well impregnated with gold 
has, after remaining for 16-24 hours in 30-60 ccm. of distilled 
water, begun to assume a weak, grayish-blue color, one or two 
drops of a photographic reproducing fluid, which contains py- 
rogallic acid, may be added to the water and the latter allowed 
to act for hour. The result is still better than by Klein’s 
method. 372 
SECTION FIFTEENTH. 
We thus become acquainted in the most certain manner 
with the penetration and termination of the finest nerve-fibres 
in an epithelial layer. 
Many additional observations of a relative nature have been 
made in modern times. 
Thus, Hensen informs us that in the tail of the frog’s larva 
he saw the terminal branches of the cutaneous nerves termi- 
nate in the form of infinitely fine filaments in the nucleoli of 
the epidermoid cells. Lipmann recently asserted the same with 
regard to the pavement epithelium of the posterior surface of the 
frog’s cornea. He employed the chloride of gold. These obser- 
vations (which would prove a parallel case with the contractile 
fibre-cells) still await confirmation. Langerhans—again with 
the help of the gold method—found that in the human cutis 
branches of pale nerve-fibres penetrate between the cells of the 
rete Malpighii; here they probably enter small radiated cells, 
the ascending processes of which are said to terminate with 
slight enlargements beneath the stratum corneum. 
In the investigation of the true terminal plexuses of the 
finer non-medullated nerve-fibres, which have been repeatedly 
examined of late, special use has been made of the gold method. 
To obtain the first view of the numerous nerves of the dental 
pulp, one of the large incisor teeth of the rabbit is to be crushed 
and the examination made in iodine-serum. The finest terminal 
fibril] m (which probably penetrate a portion of the dental tubes) 
are difficult to examine. Chloride of gold and osmic acid are 
of no service (Boll). Solutions of chromic acid are the most 
useful. 
Disregarding the higher nerves of sense at present, we here 
treat only of the so-called terminal knobs, the tactile and the 
Pacinian bodies, remarkable terminal structures which have 
been discovered and more closely investigated within the last 
few years. 
The terminal knobs, for a knowledge "of which we are in- 
debted to Krause, are represented by the drawings, fig. 209 and 
210. In mammalial animals, as it is known, they are of an oval 
form (1, a), while in man they are more globular in shape (2, a). 
They belong especially to certain mucous membranes, although 
they may also occur in the external integument. 
The ocular conjunctiva is to be selected for their examina- 
tion, and it is preferable to use the fresh, warm eye of an ani- MUSCLES AMD' NERVES. 
373 
mal, such as the calf or hog, that has just been slaughtered. 
Portions of the conjunctiva are to be carefully freed from 
the connective tissue which lies be- 
neath it, and examined without any 
fluid media. With a little persever- 
ance, the structures in question may 
be recognized in the connective tissue 
by their bright appearance. An ex- 
amination of this kind always pre- 
sents difficulties, however. 
Krause has made us acquainted 
with a good accessory, which is to be 
especially employed with organs 
which are no longer fresh, and may 
therefore be used with those of man. 
This consists in an immersion in or- 
dinary vinegar, continuing for several 
days or a week. The tissue is ren- 
dered transparent, and the arrange- 
ment of the nerves may be observed 
in an elegant manner. Single nerve- 
fibres are found to enter the terminal 
knobs which are now become cloudy 
and have dark contours. The pale ter- 
Fig. 209. Terminal knobs. 1, from the 
conjunctiva of the calf, a, knob; c, the 
modullated nerve-fibre, dividing- at * ; b, 
its pale terminal portion. 2, from man. 
minal fibres can no longer be perceived by this method, however. 
Longworth, the last investigator of the terminal bulbs, calls 
attention to the high value of osmic 
acid. A fresh eyeball, with as much 
conjunctiva as possible, is necessary. 
Sutures are placed in the border of the 
latter and sewed back in places to the 
posterior half of the eyeball. These 
prevent the conjunctiva from shrink- 
ing. The eye is then either placed in 
0.33 per cent, osmic acid, or held by a 
thread, exposed to the vapor of such a 
solution. In both cases 12-14 hours’ 
action is necessary. The epithelium 
Fig. 210. A smaller human termi- 
nal bulb, a, nerve; b, sheath; c, por- 
tions of the nerve without recogniz- 
able termination; cl, cells of the inte- 
rior ; e, nerve termination in a cell. 
may now be removed, either with a brush or by scraping with 
the point of the finger, and carefully removed portions of the 
mucous membrane examined with the addition of dilute acetic SECTION FIFTEENTH. 
acid (1-2 per cent.). Tingeing with weak solutions of carmine 
and hsematoxyline may also follow. 
By the aid of this process (and it is more serviceable than 
impregnation with gold) Longworth found the interior of the 
human terminal bulbs (tig. 210) composed of cells, and the 
nerves terminating in the latter (e). 
Merkel recently made the interesting discovery of the tactile 
cells. 
In the tongue of the bird—the duck and goose are most suit- 
able—one meets, with transparent cells of considerable size 
with a large round nucleus. A nerve-fibre terminates in this, 
with a pale axis-fibre. These simple rounded tactile cells may 
rest on each other with their broad surfaces, and thus are 
formed the complicated tactile-cell formations of our fig. 211, 
Fig. 211. Complicated tactile cells, a, from 
the cere of the duck’s bill; 6 and c, of the 
soft lingual papillae of the same creature. 
Fig. 212. Two nervous papillae from the volar 
surface of the index finger, with the tactile bodies 
and their nerves. 
a, h, c. Here, also, the axis-cylinder terminates in the proto- 
plasma of the several cells. Such tactile cells are also found 
in mammalial animals and in man, not unfrequently crowded 
into the lowermost strata of the pavement epithelium. 
For their recognition, use the tongue as well as the cere of 
the bill of the water-fowl mentioned, and place small pieces for 
a day or two in a 0.5-1 per cent, solution of osmic acid. Wash 
them out in water for an equal length of time, and then 
transfer them to strong alcohol, in which, after 14-21 days, MUSCLES AED XERVES. 
375 
they acquire the best color and consistence. In mammals onr 
structures occur in the most sensitive portions of the skin, as 
on the snout (the pig’s snout, for example), the lips, ears, the 
sacs of the tactile hairs, etc. 
The true tactile corpuscles of man (fig. 212), discovered long 
since, probably share a near relationship with these tactile-cell 
groups of Merkel. 
They occur in the corium of certain localities (the volar 
surface of the fingers and toes, the palm of the hand, and the 
sole of the foot, etc.) ; they lie embedded in a portion of the so- 
called tactile papillae, but form tolerably difficult objects for 
investigation, especially in regard to the nerve termination. 
Various methods of examination have been employed in the 
investigation of the tactile bodies. 
The freshest possible human integument, when stretched, 
permits of quite thin vertical sections being made with a sharp 
knife. These, in consequence of their fibrillated structure, re- 
quire additional measures to render them transparent. There 
are two media especially which are used for this purpose : a 
sometimes more concentrated, sometimes more dilute solution 
of soda, and the diluted acetic acid. The former affords quite 
handsome, but also very perishable specimens. Thin sections 
placed in a watch-glass swell considerably after a time, and 
then permit the epidermoidal layer to be removed. Any frag- 
ments of the rete Malpighii which may remain are to be re- 
moved by brushing. The examination is to be made with a 
strongly shaded field, and also, according to circumstances, 
with the employment of a drop of acetic acid. Other investi- 
gators have given the dilute acetic acid entire preference over 
the solution of soda, and in fact, it cannot be denied that 
many details of the tactile bodies, and especially of the course 
of the nerve to and in the same, may be more conveniently 
brought to view by means of this reagent. Such sections, 
tinged with carmine, present handsome appearances. 
Fresh integument, such as that of the point of the finger, 
may likewise, when carefully dried, present serviceable views 
in vertical sections, the more so if tingeing with carmine is also 
employed. Suitable portions of the integument with their 
natural injection, or injected with Prussian blue and treated in 
this manner, are adapted for distinguishing the two kinds of 
sensitive papillse of the skin from each other. Chromic acid 376 
SECTION FIFTEENTH. 
and even alcohol preparations occasionally show very hand- 
some tactile bodies. 
Transverse sections of the papillary bodies of the skin, 
hardened in alcohol or chromic acid, tinged with carmine, can- 
not be dispensed with. 
Grerlach, years ago, made ns acquainted with another 
method. A piece of integument removed from the volar sur- 
face of the finger is to be placed for a moment in hot, and 
then in nearly boiling water. The epidermis is then to be 
taken off, and any portions of the same which may remain are 
to be removed with a brush. The piece of skin is then to be 
hardened for several days in a solution of the chromate of 
potash. Transverse sections are now to be made from the 
papillee with a razor, and placed in water under the micro- 
scope. Strong acetic acid serves to render them transparent. 
The transverse sections of the nerve-fibres may be recognized 
within the tactile bodies. Injected skin is to be used in order 
to avoid confounding them with transversely divided capillary 
vessels. 
All these methods of investigation of a former period are 
unserviceable, however, when the termination of the nerves is 
concerned. Here the freezing method, in combination with 
the impregnation with metals, such as chloride of gold, osmic 
acid, and chloride of palladium, promises the most. 
Among these, however, we, with Langerhans and Merkel, 
give the preference to the osmic acid (0.5-1 per cent.), chloride 
of gold here renders much less service. The nerve termination 
remains dark, not less so the signification of the transversely 
oblong corpuscle of our fig. 212. They have been declared to 
be terminal pieces of the nerve-fibres, connective-tissue nuclei, 
and also optical expressions of the surfaces of separation and 
contact of the tactile cells which are stratified over each other ; 
we are therefore not yet able to state anything with certainty 
in this connection. 
There is still remaining to consider the remarkable Pacinian 
or Valerian body (fig. 213), the most complicated form of these 
terminal bodies of the nerves of sensation. 
It is preferable to select for their investigation the mesen- 
tery of the cat, in which they at once become evident to the 
eye, and are isolated by slight preparation. By the applica- 
tion of indifferent fluids they present excellent specimens, in MUSCLES AMD MERYES. 
which the structure, the concentric capsules (5), the entering 
nerve (a), with the pale terminal filament (c), may be readily 
recognized. Here, also, the latter distinctly shows a combina- 
tion of primitive, or axis-fibrillse, as was ascertained by Gran- 
dry and confirmed by Schultze, 
Michelson, and Ciaccio. Previous 
injection with cold-flowing trans- 
parent masses is a good accessory ; 
diluted acetic acid and tingeing may 
also be employed. 
Dilute chromic acid, or corre- 
sponding solutions of chromate of 
potash, may likewise be employed 
for their preservation and examina- 
tion, I find the acetic-acid-alcohol 
mixture less suitable. The best ac- 
cessory is osmic acid (0.5-1 per 
cent.). I have not yet succeeded 
very well in preserving the prepara- 
tions in acetate of potash. Sharp 
needles and the simple microscope 
serve for the detachment of the cap- 
Pig. 913. Pacinian body from the mes- 
entery of a cat. a, Nerve-fibre; 6, the 
capsules; e, the pale-contoured terminal 
filament of the nerve-tube. 
sules. Impregnation with silver also shows on these the fam 
iliar mosaic. 
Is the axis canal or the inner bulb of our structure actually 
homogeneous, as it has the appearance of being, or is it formed 
of cells, like a human terminal bulb (fig. 210) ? 
A. Budge has followed Key and Retzius in assuming this to 
be the case. After the Pacinian corpuscle has remained for a 
day or two in chromate of ammonia, a drop of eau de Javelle 
(p. 185) is to be added ; when the contours have become distinct 
it is to be tinged with a 0.2 per cent, solution of chloride of 
palladium. 
The Pacinian capsules of man are to be obtained without 
much trouble, by preparing the cutaneous nerves of the palm 
of the hand and the sole of the foot. The methods of investi- 
gation are the same as for those of the cat. 
The textural conditions of the nervous system in the foetus, 
and the history of the origin of their elements, are, as yet, by 
no means known with desirable certainty. The embryos of 
our domestic mammalia or of the hen, which have been im- 378 
SECTION FIFTEENTH. 
mersed, as fresh, as possible, in dilute solutions of chromic 
acid, or of the bichromate of potash and slowly hardened, are 
to be employed. Transverse sections of hardened embryos 
afford very fine review preparations for the spinal cord, the 
spinal ganglia, etc. The objects tinged with carmine are to be 
mounted in Canada balsam. 
Many characteristic views of the peripheral nerves of the 
foetal period may be readily obtained in the fresh larvae of the 
frog and salamander. Together with the nitrate of silver and 
the chloride of gold treatment (Eberth), a very excellent pro- 
cedure, given by Hensen, may also be employed. The larvae 
are to be dipped for 20-50 seconds in a chromic acid solution 
of from 8-4 per cent., and are then thrown, still living, into 
spring-water. Then, or after half an hour, the epithelium may 
be removed from their tails by brushing. Eberth recommends 
for the same purpose to place the frog’s larvae for a half or a 
whole hour in a weak solution of nitrate of silver (1 gr. to 5 
ounces). 
In consequence of the extreme delicacy and alterability of 
these tissues, however, the most conservative methods are 
always the best. 
Somewhat more strongly hardened embryos afford good 
preparations relating to the structural conditions of the devel- 
oping spinal cord and brain. The changes in form of the for- 
mer, and also of the spinal ganglia, with a progressing develop- 
ment, may be readily perceived. Here, also, chromic acid and 
bichromate of potash deserve decided preference over alcohol. 
Transverse sections, with the aid of carmine tingeing, suffice 
for the first examinations. 
Concerning the tunics of the central organ, it is better to 
examine the arachnoid and pia mater fresh, employing the re- 
agents which are customary for connective-tissue parts. 
The numerous capillaries, and the small arterial and venous 
branches which are associated with them, cause the latter 
membrane to appear very well adapted for the study of the 
vessels. In suitable specimens (as well as in mechanically iso- 
lated vessels of the nerve-substance) one may readily recognize 
that the formation of tubercles commences in the adventitia. 
It was thought that the rudimentary cells, which are found 
here (the so-called vascular nuclei), increased by proliferation. 
At the present time, a wandering of the lymphoid cells of the MUSCLES AND NERVES. 
379 
blood into the surrounding layer has become more probable. 
If suppuration takes place in the pia mater, in consequence of 
inflammatory irritation, the emigration of the lymph-cells from 
the blood-current may be most distinctly recognized (Rind- 
fleisch). 
The dura mater may be examined fresh, dried, or hardened 
by means of chromic acid,—methods which are also employed 
with the neurilemma of the larger nerves. The plexus choroidei 
scarcely requires special directions ; its injection with that of 
the brain readily succeeds. Here Muller’s mixture (p. 136) 
affords good preparations. The calcareous concretions of the 
same, the so-called brain-sand (which, as is known, also occurs 
in the human pineal gland), are to be studied with the employ- 
ment of acids and media for rendering them transparent, espe- 
cially glycerine. 
The pituitary gland, for which the calf is to be especially 
recommended (Peremeschko), is to be hardened in chromic acid, 
Muller’s fluid, or alcohol. Thin sections, brushed and tinged 
with carmine, readily yield the essential appearances. 
We have already noticed above the great difficulties which 
the investigation of the normal textural conditions of the cen- 
tral organs of the nervous system still present. Hence, we 
shall comprehend that their numerous pathological alterations 
are still very inadequately known, and have only been assailed, 
histologically, with slight results. It is usually accepted that 
the nervous elements indeed undergo numerous secondary pro- 
cesses of degeneration, such especially as the fatty, and also 
amyloid and colloid transformations, but that the true new for- 
mations proceed from the connective-tissue framework and from 
the vessels. The correctness of the former doctrine has more 
recently, however, become doubtful, and the lymphoid migra- 
tory cells exert at present a deep and disagreeable influence on 
the latter. The finer textural conditions of the framework 
substance are also uncommonly difficult to follow, as the very 
methods of hardening which are customary for the normal 
structure frequently render very little service in the domain of 
pathology, so that often one is able to examine only fresh ob- 
jects. For connective-tissue formations one should try very 
weak chromic acid, according to Schultze (p, 127), likewise 
Muller’s fluid, diluted with about an equal volume of water, 
also Ranvier’s injection of osmium (p. 360). Finally, immersion 380 
SECTION FIFTEENTH. 
in osmic acid, as well as the skilful employment of tingeing 
methods, will afford much additional assistance. 
Good review preparations are not unfrequently afforded by 
a method practised by Billroth,—placing small pieces of brain 
and spinal cord in powdered carbonate of potash or chloride of 
calcium for 24 hours. By this means the objects usually gain 
a degree of consistence which permits of fine sections being 
made ; these are to be examined in water (or with the addition 
of glycerine). 
To investigate the fatty degeneration of the nerve-fibres, as 
well as the textural changes which occur in the peripheral por- 
tion of a divided nerve, the animal which has been subjected 
to the above operation is to be examined, after the proper in- 
terval of time, either quite fresh or with the employment of 
the solutions of free chromic acid and of bichromate of potash, 
which have been recommended for the spinal cord and brain. 
The finest results are obtained by treatment with osmic acid 
(Eichhorst), which is to be combined with tingeing with carmine 
or hsematoxyline. This is one of the few structural changes of 
the nervous apparatus which present but slight difficulties to 
the practised observer. o£rttou Sbdccutl). 
VESSELS AND GLANDS. 
The methods of investigating the vessels differ somewhat 
according as the contained mass consists of blood or of lymph ; 
furthermore, they vary considerably in proportion to the size 
of the vessels. One variety of accessories is therefore necessary 
in the examination of the capillaries and small vessels ; others 
are required for the investigation of 
the larger and largest trunks. 
The finest canals of the blood-pas- 
sages are, as is known, the capillaries 
(fig. 214, 1 a, 2), which are very thin, 
nucleated, branched membranous 
tubes. The narrowest capillaries (1 a), 
which, however, do not occur in all 
parts of the human body, are only 
sufficiently wide to allow of the passage 
of the blood-cells singly, one after the 
other. A similar condition recurs in 
the several groups of vertebrated ani- 
mals, modified, naturally, by the size 
of the blood-corpuscles. Frogs and 
naked amphibise have therefore capil- 
laries of much more considerable diam- 
eter than are met with in the human 
body, and the capillaries of these crea- 
I’M. 214. 1. Capillary with thin 
walls and the nuclei, a and b. 2. 
Capillary with double contoured 
walls. H. Small artery with the en- 
dothelial layer a, and the middle 
layer 6. 
tures are consequently better adapted for many investigations 
than our own. 
Until recently the purport of the almost universally accepted 
history of the development of the capillary vessels was that 
they originated in the blending of the formative cells which, 
coming together in a single row, ojDened into each other, so that 382 
SECTION SIXTEENTH. 
the cell-cavities became united into a capillary tube, the mem- 
branes of the cells were transformed into the wall of the vessel, 
and the persisting nuclei into the nuclear formations of the 
latter. 
It has been ascertained by the concurrent investigations of 
several observers (Hoyer, Auerbach, Eberth, and Aeby) that 
the walls of the capillary vessels are not in reality structure- 
less, but rather that they are formed by the melting together 
of very thin and flat nucleated cells (the cavity of the capillary 
is therefore an intercellular passage). The boundary lines of 
these cells are only to be rendered visible by means of impreg- 
nation with silver, and were previously entirely overlooked. 
This important discovery may be readily verified (figs. 215, 
216 and 217). A frog, a mouse, or a guinea-pig is to be allowed 
Fig. 215. Capillary net-work from +he 
lung of the frog, treated with a solution 
of nitrate of silver. 6, vascular cells; a, 
their nuclei. 
Pig. 216. Capillary vessel 
from the mesenterium of the 
Guinea-pig, after the action 
of a solution of nitrate of sil- 
ver. a, vascular cells; 6, 
their nuclei. 
Fig. 217. A capillary from 
the mesentery of the frog, 
injected with a solution of 
silver. The stomata appear 
at a, a, and b, between the 
vascular cells. 
to bleed to death, and then a 0.25 per cent, solution of silver 
is to be injected into the vessels. The simple immersion of 
organs, such as the retina or pia mater of mammalial animals 
or of man, which are deprived of their blood, also leads to the 
desired result. The object is to be washed in spring water and 
examined in acidulated glycerine. 
More recently increased attention has been paid to a some- 383 
VESSELS AND GLANDS. 
what more complicated arrangement of the capillaries which 
occurs in the lymphoid organs, the lymphatic glands, the Peye- 
rian and solitary follicles, the tonsils, Malpighian bodies of the 
spleen, the thymus gland, and also in other glands. It consists 
in the spreading out of the reticular connective tissue of these 
organs, in the form of a membrane, 
around the primary walls of the capil- 
laries, and thus forming a second acces- 
sory layer, a so-called adventitia capil- 
laris. This may be represented by fig. 
218, i. Furthermore, microscopic vas- 
cular trunks may be surrounded with 
a larger intervening space, by a connec- 
tive-tissue sheath (a) whereby the cavity 
which is thus formed (lymph-sheath) 
serves for the current of the lymph (c). 
There are by no means many organs 
which are adapted for the primary ex- 
amination of the capillary vessels of 
man and the mammalia. The most 
suitable, and therefore, also, the most 
generally recommended, appear to be 
Fig. 218. Capillary vessels and 
small trunks of the mammalise. a, 
capillary vessel from the brain: 6, 
from a lymphatic gland ; c, a some- 
what larger trunk with a lymphatic 
sheath from the small intestine; 
and d, transverse section of a small 
artery of a lymphatic gland. 
the brain, the pia mater of the same, the retina of the adult 
body, and the lymphoid organs. 
To obtain characteristic views from the former parts a small 
blood-vessel which is barely visible in the gray substance is to 
be seized and an attempt made to remove it by traction. It is 
then to be placed in water and freed from any adherent brain- 
matter by means of the wash-bottle, or, still better, by brush- 
ing. In this way will be perceived a trunk with abundant 
ramifications and numerous capillaries as terminal branches, 
and not only these finest forms of vessels may be studied, but 
also a series of transformations into more complicated vessels. 
The pia mater when picked also affords excellent objects, es- 
pecially if portions be selected which pass over a furrow be- 
tween the convolutions of the brain. The capillaries of the 
retina are to be treated in the same manner as those of the 
brain-substance. 
The organs belonging to the lymphatic system require some- 
what greater preparations for the investigation of their capilla- 
ries. Either none at all or only extremely unsatisfactory views 384 
SECTION SIXTEENTH. 
are to be obtained from the fresh parts. For this reason, pre- 
paratory hardening methods (chromic acid, alcohol, etc.) are to 
be first employed. Thin sections from the tissue which has 
become more resistant must then be freed from the innumera- 
ble lymph-corpuscles which fill the connective-tissue net-work 
before the desired delicate capillaries can be brought to view. 
Any ordinary preparation serves for the recognition of the 
nuclei. These are rendered sharper by dilute acetic acid, like- 
wise by carmine tingeing, which, together with staining with 
hsematoxyline and aniline blue, deserves recommendation. 
Chloride of gold also affords serviceable specimens. 
We must return once more to the capillary vessels. 
Years ago, dark points, as well as smaller and larger circu- 
lar black markings, were seen at the angles of contact of these 
flat endothelial cells, after treatment with silver (Auerbach). 
It was evident that there was here a cement substance which 
might permit of the escape of the blood-cells. Arnold called 
the smallest of these formations “Stigmata,” and regarded 
them as a normal occurrence, while he considered the larger 
ones (fig. 217, h) to be caused by vascular distention, and gave 
them the name of “ Stomata.” We agree with this com- 
pletely. 
In organs with fibrous structure, even where there is a con- 
siderable vascularity, we may, as a rule, search in vain for 
capillaries except we employ especial accessories for rendering 
them prominent. The empty capillaries disappear most com- 
pletely in the fibrillary tissues. The familiar action of acetic 
acid may here be made use of, or, which is to be preferred, the 
preparation may be first colored with carmine and then subse- 
quently exposed to the action of the acid. 
After what has Just been mentioned it is unnecessary to dis- 
cuss further the great value of transparent injection with Prus- 
sian blue or carmine for rendering the capillary and larger 
vessels of an organ visible ; the silver solution (p. 189) may also 
be used with advantage. 40-60 grms. of gelatine solution may 
also be combined with 20-50 centigrms. of nitrate of silver, the 
latter being first dissolved in a little water. This method, 
originated by Chrzonszczewsky, I have not found to possess 
any essential superiority to a simple solution of silver. The 
slight trouble of injecting should, in fact, never be shunned in 
such investigations, as the structural relations of all organs VESSELS AND GLANDS. 
385 
are usually rendered much more comprehensible as soon as 
the distended capillaries have afforded a landmark for the 
eye. 
Where it is possible to retain the blood in a vascular dis- 
trict, such natural injections may replace the artificial ones, 
but the preparations should not be moistened with water. 
If a frog or a salamander be at hand, the capillaries of cer- 
tain parts of the body may be examined with advantage for 
comparison with the human textural condition. From the first 
animal (preferably killed by means of ether or chloroform) the 
lower eyelid or one of the flat, transparent muscles which we 
have mentioned above (p. 363), is to be taken. The raembrana 
hyaloidea also affords magnificent views. 
The larger blood-vessels which follow these no longer show 
the original simplicity of structure possessed by the capillaries. 
First appears the original capillary membrane (fig. 214, 3) meta- 
morpliosed with cells and longi- 
tudinally arranged nuclei (<2) ; 
then a second layer with trans- 
versely arranged smooth muscu- 
lar elements scattered through 
it, the nuclei of which are seen 
at 5. This is the earliest ap- 
pearance of a tunica media seu 
muscularis, to which in vessels 
of a somewhat larger calibre is 
gradually associated the tunica 
cellulosa, the external connec- 
tive-tissue layer. In other ves- 
sels the epithelial tube is seen to 
be surrounded by an elastic in- 
ner membrane ; this is the first 
appearance of the tunica serosa. 
We meet with other trunks 
(and these have for the most 
part the character of venous 
Pig. 219. A small arterial trunk 'without an epi- 
thelial covering, b. the homogeneous elastic inter- 
nal layer; c, the middle .layer, consisting of trans- 
versely arranged fibre-cells; d, the external con- 
nective-tissue covering. 
tubes) which present the most internal cellular layer, the elastic 
inner membrane, and the adventitia ; but, on the contrary, no 
trace of any muscular middle layer can be recognized in them. 
A complete contrast is presented by the arterial trunks (fig. 
219), the muscular middle layers of which are very strongly 
25 SECTION SIXTEENTH. 
developed, and its contractile fibre-cells are found packed 
closely together. 
The methods for investigating these vessels are the same as 
for the capillaries. Even the localities, such as the substance 
of the brain, the pia mater, and the lymphoid organs frequently 
remain the same. Together with these the mesenteric arteries 
may also be used with advantage. Advantageous use may be 
made of tingeing methods, especially of carmine tingeing with 
the subsequent action of acetic acid, and also of dilute acids 
and alkalies. Transparent injections are very useful here, 
especially for estimating the extremely variable thickness of 
the walls of small venous and arterial branches. 
The endothelium in somewhat larger trunks is to be ex- 
amined in part in fresh, unaltered specimens, or by means of 
carmine tingeing and silver impregnation (see page 259). 
Tingeing with carmine, the application of potash solutions 
of 30-35 per cent., and of 20 per cent., nitric acid are to be re- 
commended for the recognition of the muscular layer. The 
action of nitrate of silver may also be employed for rendering 
visible the contours of the individual contractile fibre-cells. 
The usefulness of still another method here makes itself felt, 
which is of unsupersedable importance in the examination of 
larger and the largest vessels—we refer to the preparation of 
thin sections through their walls. Drying was formerly em- 
ployed for this purpose. At the present time the embedding 
method of objects previously hardened in alcohol or chromic 
acid (p. 113) has taken its place. 
These preparations afford handsome sections of such vessels 
(fig. 218, d). Beale distends such arterial and venous trunks 
as much as possible by the energetic injection of uncolored 
gelatine, and then makes fine sections through the hardened 
mass. He recommends this method very properly, especially 
for the demonstration of the contractile fibre-cells. We re- 
commend for this purpose especially the Malpighian bodies of 
the spleen, the follicles of the lymphatic glands and of the 
kidney, whereby the slight trouble of a careful brushing should 
not be avoided. 
Vessels whose walls can no longer be seen in their totality 
with the microscope require the preparation of thin, partly 
longitudinal, partly transverse sections. The fresh vessel may, 
without further treatment, be dried or embedded, and then ex- VESSELS AND GLANDS. 
387 
amined with the application of acids and alkalies, or it may be 
previously boiled in vinegar or dilute acetic acid. The action 
of 20 per cent, nitric acid, likewise Schulze’s treatment with 
chloride of palladium, and the subsequent tingeing with car- 
mine, and hsematoxyline tingeing deserve to be recommended. 
As additional modern methods we also mention : 
1. The Schultze reagent (p. 124). Fresh vessels are to be 
treated with chlorate of potash and a nitric acid of only 20 per 
cent. After 10-14 days the elastic elements are destroyed, the 
muscular preserved (von Ebner). 
2. The double tingeing of Schwarz with carmine and picric 
acid (p. 159). 
3. Grerlach’s complicated tingeing (p, 161). 
4. Hsematoxyline tingeing. The muscles and their nuclei 
become intensely colored, the connective tissue slightly, the 
elastic fibres not at all (Bresgen). 
5, Treatment with chloride of palladium of 0.1 per cent, to 
tinge the muscular elements yellow. 
6. Yon Ebner’s method. Aniline red (p. 154) stains the elastic 
elements of the walls of the vessels. If we tinge first with 
solution of hsematoxyline and then with fuchsine, interesting 
but, perishable appearances are presented, as 
I can testify from my own experience. 
The various strata of elastic membranes, connective tissue, 
and muscular layers are by these various methods rendered 
most distinctly visible. The best views are obtained of the 
development of the muscular layers in arteries and veins of 
medium size, and of the retrogression of this tissue in the 
largest vessels. It will frequently be found that the epithelium 
is no longer preserved. 
A second, and indeed older procedure, consists in opening a 
vessel while it is in a moist condition, and then with the scalpel 
and forceps separating, under water, the individual layers suc- 
cessively from within outwards, or from without inwards, to 
study them with the application of suitable media. By scrap- 
ing the fresh specimen with the blade of a scalpel, larger or 
smaller shreds of the epithelial covering may be readily brought 
to view. The free border of the valve of a vessel not unfre- 
quently presents a fine view of this covering, and, at the same 
time, a good means of measuring the slight thickness of the same. 
For the recognition of the vascular nerves, a net-work of very 388 
SECTION SIXTEENTH. 
line pale filaments, which occupies the tunica media and the 
contiguous portions of the external layer, select the mesentery 
of a frog, treat it with dilute acetic acid, and remove the en- 
dothelium by brushing (His); or try the gold method. 
The arrangement of the various capillary districts according 
to the magnitude and manner of distribution of the vessels, as 
well as the size of the tissue-spaces surrounded by the meshes 
of the net-work, has occupied the attention of anatomists and 
physiologists for a long time. Even the charming appearances 
which successful preparations of this kind unfold under the 
microscope must exert an attractive influence. Then it is only 
by the vascularity of an organ that a conclusion can be made 
as to the quantity of matter which it assimilates, either in its 
own interest or for the service of other organs (glands). The 
relative arrangement of the capillaries is of great importance 
in the mechanism of the circulation. 
As the technology of injection has already been mentioned 
in detail in a previous section (p. 172), we may simply refer to 
the same. For the study of the capillaries, as has been already 
remarked, one should only examine objects injected with trans- 
parent masses in a moist condition (either quite fresh or after 
a short immersion in alcohol, and then with a subsequent addi- 
tion of glycerine), as opaque masses conceal too much, and all 
dry preparations present a distorted appearance. The simple 
injecting fluids (the cold flowing Prussian blue of Beale or of 
Richardson, see p. 187) will suffice for most of the investigations 
of the capillary net-works. If one desires to employ a double 
injection, Beale’s carmine mixture (p. 188) may be added. Grei- 
atine must be added to the coloring matter for larger portions 
of the body. 
It would lead us beyond the limits of this little work were 
we to mention here more fully the various appearances of the 
capillary net-work according to the size of the vessels and 
meshes, as well as the form of their arrangement. A few re- 
marks may therefore be sufficient, and the text-books on his- 
tology recommended for further instruction. 
Many parts of the body, as is known, remain entirely with- 
out vessels ; others are but slightly vascular, and are only per- 
meated at considerable distances by capillary vessels ; while in 
the extremely vascular organs the capillaries are closely ap- 
proximated to each other, and the meshes are smaller. VESSELS AND GLANDS. 
389 
The anatomists have distinguished two fundamental forms 
of capillary net-works, according to the shape of the parenchy- 
matous spaces surrounded by them ; namely, 1, the straight, 
and 2, the circular net-work. 
Both forms arrange themselves according to the shape of 
the tissue elements. Circular parts formed of cells or gland 
vesicles 
vessels; while those with a decided fibrous disposition, or 
have a similar shaped, that is, circular net-work of 
parts formed of glandular passages and tubes running in a 
parallel direction, present the straight capillary net-work. 
Fig. 220 shows the straight capillary net-work of the trans 
Fig. 220. Vessels of the voluntary, 
transversely striated muscle, a, ar- 
terial ;b, venous branch; c, the straight 
capillary net-work. 
Fig. 221. Vessels from a vertical section of the mucous 
membrane of the stomach; the fine arterial branch 
divides into a straight capillary net-work, which forms cir- 
cular meshes at the surface of the mucous membrane, 
and passes over into the thick venous trunk. 
versely striated muscle ; fig. 221 the same of the mucous mem- 
brane of the stomach surrounding the gastric glands. The 
latter assumes the form of a circular net-work at the surface of 
the mucous membrane, where the gland-ducts terminate with 
round apertures. 
We have already, in a previous section (p. 278), learned that 
the lobules of fat-tissue consist of groups of large globular SECTION SIXTEENTH. 
cells. The capillary net-work, fig. 232, is in accordance there- 
with, A likewise more circular, but large-meshed and pecu- 
liarly formed net-work of capillaries is seen in the inner layer 
Fig. 222. Vessels of the fat-cells. A. Arterial (a) 
and venous (b) branches, with the capillaries be- 
tween them. B, the capillaries around three cells. 
Fig. 223. Vessels of the human retina, a, arte- 
rial, c, venous branch ; b, the capillaries. 
of the retina (fig, 228). Where small papillary projections 
appear (external integument and many mucous membranes), 
we meet with simple capillary loops (fig. 224) ; where these are 
larger, with a looped net-work, as in the intestinal villi. The 
arrangement of the capillary net-works of the human organism 
Fig. 224. Capillary loops of the papillae of the shin (in others appear the tactile bodies). 
is frequently of such a peculiar nature that the practised 
observer can readily recognize, with the greatest certainty, from 
what part of the body the preparation is obtained. 
The first appearance of the vessel in the embryo, as well as VESSELS AND GLANDS. 
the subsequent formation and transformation of the foetal 
vessels, constitute, as is known, a very difficult and therefore 
still, to a great extent, deficient section of histology. 
Very young embryos of birds, mammalia, and fishes are to 
be recommended for the investigation of the origin of vessels. 
Among these, the embryos of the hen have been employed for 
many years and stand in the first line, in consequence of the 
facility with which suitable material may be obtained. The 
formation of the first capillary reticulation may be observed 
in the area vasculosa from the end of the first and on the 
second day of incubation. For this purpose, the germinal 
membrane is to be cut out beneath the surface of lukewarm 
water to which a little chloride of sodium and albumen has 
been added. It is then to be examined either quite fresh with 
the application of an indifferent fluid, or of a strongly diluted 
solution of chromic acid; or, which is to be considered as more 
advantageous for many purposes, after having been hardened 
in chromic acid or bichromate of potash, it is to be investi- 
gated with the aid of glycerine and tingeing methods. 
Sections through the area vasculosa, treated in the latter 
manner, also present instructive appearances (Kolliker), so 
that one may readily recognize the endothelial cell formation 
of the walls of these earliest vascular canals. Foster and Bal- 
four, in a beautiful little book, recommend the examination 
of the living germinal membrane with the aid of the warm 
stage, the action for a minute of a 0.5 per cent, solution of chlo- 
ride of gold, the use for half an hour of a 0.5 per cent, osmic 
acid, and the immersion for a day in the 1 per cent, solution 
of bichromate of potash which we have already mentioned. 
In order to follow the further peripheral formations of ves- 
sels one may use the embryos of the hen at a more advanced 
stage, for example, their allantois ; or the embryos of mamma- 
lia may be employed. In the latter, the urinary sac, the mem- 
brana capsulo-pupillaris and hyaloidea of the eye also afford 
admirable preparations. 
A very convenient object for examination is presented dur- 
ing the early part of the summer by the tail of the frog’s larva. 
As the living animal may be examined either on the Schulze’s 
object-bearer (p. 246), or by means of a strip of moist blotting- 
paper wrapped round its body without injury, and again placed 
in the reservoir, it is possible to follow from day to day, in one SECTION SIXTEENTH. 
and the same specimen, the alterations in the vascular forma- 
tions which take place in accurately designated places. Fur- 
ther assistance is afforded by brushing off the epithelium, as 
performed by Hensen (p. 878). 
According to the beautiful investigations of Arnold we may 
at present formulate the structure of the new vessels somewhat 
as follows: 
A protoplasma, capable of further independent develop- 
ment, is produced by the vascular cells forming the walls of 
the already existing capil- 
laries. Fig. 225, p, p, and 
fig. 226, a, a. From the 
shooting out of the proto- 
plasma are formed sprouts 
(fig. 225,1, p) and filaments 
(fig. 225, 2, 3, p, p, and fig. 
226, a, a), which, by the run- 
ning together of opposite 
protoplasma bodies, are 
transformed into cords (fig. 
225, 2, p). On the melting 
down of the axis portion of 
these cords we have proto- 
plasma tubes. By the fur- 
ther metamorphosis of the 
walls there occurs (in a 
manner very difficult to 
understand) the appear- 
ance of nuclei. The latter 
are at first small and indis- 
tinct, subsequently they 
are larger and appear more 
distinct. Up to a certain 
stage of development no 
blood-vessel shows a dis- 
Pig. 225. Development of new capillaries, from the tail 
of the tadpole, p, p, protoplasm sprouts and cords. 
tinct silver mosaic. Cell-like elements with a body consisting 
of protoplasma are then formed by a sort of segmentation of 
the parietal substance. From these, finally, arise the mature 
vascular cells, the nucleated, homogeneous lamellae of our figs. 
215, 216, and 217. 
Pathological changes of the blood-vessels, as is known, are VESSELS AND GLANDS. 
393 
met with often enough. In so far as they consist of a meta- 
morphosis of the structure, they affect the larger trunks, espe- 
cially of the arteries, much more frequently than the finest ar- 
Fig, 226. Prom the vitreous body of a foetal calf. Two vessels with an adventitia, united by a proto- 
plasma cord. At a, the insertion of the same into the primary vascular membrane. 
terial and venous terminal branches, or the capillaries lying 
between them. 
In the arterial walls of older persons there are generally 
found—increasing in frequency with the advance in life— 
changes of the inner vascular membrane in the form of smaller 
or larger whiter or yellower spots and plates projecting some- 
what above the surface. These are found, by microscopical 
analysis, to consist of collections of fat-molecules. There may 
afterwards be a softening and breaking down of these fatty de- 
generated places. 
In the atheromatous processes, also, we again meet with the 
same fatty deposits, but in the deeper strata of the interna con- 
tiguous to the muscular coats, after a proliferating thickening 
of the inner coats of the vessels has taken place as a result of 
an irritation. Here, also, a softening of the fatty infiltrated 
place occurs, and the melting process advances at the expense 
of the remaining layers of the inner coat of the vessel. When 
a regular atheromatous pulp (which may force its way into the 
blood-passage) has been formed, its elements are shown by 
microscopical analysis to consist of fat-molecules, isolated or 
united in globular conglomerations, crystals of cholesterine, and 
fragments of tissue. These thickened places in the intima 394 
SECTION SIXTEENTH, 
may, however, undergo still another degeneration, a hardening, 
which may also be combined with the former; they may be- 
come calcified, and form hard plates or tablets in the walls of 
the vessel. 
By such atheromatous changes in the arterial walls are 
caused, at least to a great extent, arterial aneurisms which in 
part permit of the recognition of all three of the groups of 
layers, although thickened and metamorphosed in part after 
the destruction of the intima, or also of the muscular coat, con- 
sist either of both coats or of the connective-tissue coat alone, 
which latter then presents transformations, thickenings of 
its tissue, etc.—matters which we cannot consider further at 
present. 
The question arises—How are such abnormities of the arte- 
rial walls to be examined ? 
In general, by means of the same methods with which we 
have already become acquainted in the examination of the nor- 
mal structure. By pulling off the individual layers from the 
fresh specimen, then on horizontal and vertical sections of the 
walls after hardening in alcohol or chromic acid, or finally by 
the aid of the embedding and drying methods. The coats, 
boiled in vinegar and then dried, also afford handsome sections 
whereby the fat-molecules of the atheromatous mass make 
their appearance in an elegant manner. Atheromatous pulp 
is, like pus, etc., to be spread out with water. 
The method of examination also remains the same for the 
pathological metamorphoses of the structure of the veins. As 
with the arteries, we here omit the dilatations of the veins, and 
the occlusions from thrombi and emboli (that is, clots which 
have originated in a remote locality, and, carried forward by 
the blood, have finally become wedged into a vessel). Only 
those layers of the walls which contain vessels, especially the 
adventitia and the middle layer, are at first concerned in the 
inflammatory processes of the veins. At the same time there 
is tumefaction, the formation of so-called exudation masses, and 
an accumulation of pus-corpuscles. The inner coat, which is 
not immediately concerned in the inflammatory process, is also 
at last, as a result of these structural changes, drawn into the 
sphere of the process. It appears cloudy, thickened, rough, 
and may become separated in shreds. 
Such rough inner surfaces of venous as well as arterial ves- VESSELS AND GLANDS. 
395 
sels frequently receive aggregations of coagulated fibrine from 
the blood. Consequently we see such deposits on the intima 
of inflamed veins, as well as on softening atheromatous patches 
and in the dilated sacks of aneurismal arteries. 
Pathological changes of small vessels, microscopic arteries 
and veins, escape the notice of the physician much more readi- 
ly, as will be appreciated, and also cause much slighter effects 
during life. 
In amyloid degeneration of the smaller arteries the middle 
coat is seen to be the seat of the deposit, and not the intima 
(as Rindfleisch asserts). Jurgen’s reagent (p. 156) is the most 
serviceable for the recognition of these deposits. The fibre- 
cells of the muscular coat lose their structure and become 
transformed into amyloid flakes; and in calcifications, also, 
the deposit of bone-earth takes place in this contractile element. 
The small arteries of the brain-substance occasionally un- 
dergo an interesting metamorphosis. In vessels of extreme 
minuteness, up to those of 0.5"' in diameter, a tearing of the 
inner and middle coats takes place ; extravasated blood be- 
comes infiltrated under and into the adventitia, and arches this 
forward, in various ways, into vesicles and knobs. If, at last, 
the external connective-tissue layer also becomes torn through, 
apoplectic effusions occur. Should it hold, however, a strik- 
ing microscopic appearance is unfolded in the gradual meta- 
morphosis and breaking down of the extravasated blood-cor- 
puscles ; so-called granule cells, aggregations of brown and 
yellow pigment, and their final dissolution may be observed. 
Fine microscopic veins and their branches, which are pass- 
ing over into capillaries, occasionally show similar varicosities 
of their lumen. Although with the above-mentioned arteries 
the bulging is caused by the laceration of the coats and the ex- 
travasation of the blood, here all three of the coats are unin- 
jured. 
Calcareous and fatty degenerations, and likewise deposits of 
pigment, have been noticed in the capillaries as well as in the 
smallest arterial and venous branches which are associated 
with them. Furthermore, emboli of the same, as well as thick- 
enings of their walls, belong to the more interesting occur- 
rences. 
Calcifications have thus far been noticed chiefly in the ca- 
pillaries of the brain; they occur very rarely. Much more fre- 396 
SECTION SIXTEENTH. 
quently, especially in tlie brain of older persons, fatty degen- 
erations, groups of aggregations of small fat-molecules around 
the nuclei, or in the place of the same, are noticed. This struc- 
tural metamorphosis is occasionally diffused, in the most ex- 
tended manner, throughout a whole brain. Deposits of black 
pigment molecules have been observed in the capillaries of the 
spleen, liver, and also of the brain, in melanaemia. 
Peculiar emboli of the finest arteries and veins from masses 
of fluid fat have also been noticed more recently in so-called 
pyaemia (E, Wagner). 
We have already mentioned above the normal occurrence of 
the adventitia of capillaries. Something of the kind is also met 
with under abnormal circumstances. The capillaries of a part 
in a condition of inflammatory irritation gradually receive an 
aggregation of spindle-shaped cells, precisely similar to those 
which occur in the normal development. Wry fine appear- 
ances of this kind may be obtained from the inflamed cornea. 
An aggregation of this undeveloped connective-tissue forma- 
tion of the gelatinous tissue may also appear as an adventitia 
around capillaries (Billroth). 
In all textural changes of the capillaries, like those of the 
larger and largest trunks, the greatest attention is to be paid 
to the nuclear formation of the so-called vascular cells, as it is 
just these epithelioid cells which rapidly assume a condition 
of luxurious proliferation, and thus give rise to numerous new 
formations (Thiersch, Waldeyer, Bubnoff, Ranvier). 
The structural changes which have thus far been mentioned 
of the smaller and smallest vessels coincide exactly with those 
of the normal body in so far as the methods necessary for their 
examination are concerned. 
A matter which has caused numerous controversies is the 
manner in which the origin of vessels takes place under patho- 
logical conditions. 
Such productions of new blood-vessels, as is known, are 
not rare occurrences, and appear in hypertrophied organs, in 
neoplasms, in so-called pseudo-membranes, and granulations. 
Quite massive new formations of blood-vessels may be recog- 
nized in the so-called vascular tumors. Numerous sack- and 
knob-shaped expansions of the dilated capillaries are met with 
in the capillary talengiectasias, especially such as occur in the 
skin. The methods for examining the tissues of the skin must VESSELS AND GLANDS. 
397 
here be employed. Preparations boiled in vinegar and then 
dried afford characteristic views. 
When snch newly-formed vessels are examined they show 
either—and this is generally the case—the character of the 
capillaries or those of the arteries and veins, while the blood 
which circulates through them presents nothing especial. 
Their diameters are either those of the normal condition, or 
they are increased frequently in the most remarkable manner. 
At the same time partial dilatations of the walls frequently 
occur. Knob-shaped pouches are also met with, especially 
in vascular tumors, which require more accurate investigations. 
At a former period, swayed by the theory of spontaneous 
cell-formation and the exudation doctrine of that time, it was 
frequently asserted that these pathological vessels (like the 
blood contained in them) originated independently of those of 
the neighboring nor- 
mal tissue, and only 
subsequently became 
united with the ad- 
jacent vessels. 
At the present day 
we may say that this 
theory was false, and 
it has also never failed 
to be frequently at- 
tacked. No new for- 
mation of vessels de- 
viating from that of 
the foetal body occurs 
in the domain of path- 
ology. In both cases 
the new vessels arise 
by growth from the 
Fig. 237. Development of the capillaries in the regenerating tail 
of the tadpole, a, b, c, d. sprouts and protoplasma cords. 
existing ones, or at the commencement by the development 
of an intermediate lacunar current. 
The former process is the same as that with which we have 
become familiar in the formation of embryonic vessels. The 
same protoplasma formations, offshoots, filaments, cords, and 
tubes are met with following each other. The tail of the frog’s 
larva, as it commences to be reproduced (Arnold), permits 
of highly interesting investigations, with which figs. 227 and SECTION SIXTEENTH. 
228 (the same vascular division twenty-four hours later) are to 
be compared. 
According to more accurate investigations which have been 
made, the formation 
of vessels in a tumor, 
like a so-called pseu- 
do - membrane, ap- 
pears to take place 
but slowly and grad- 
ually, and thus to 
form a striking con- 
trast to the rapidity 
with which, for in- 
stance, an aggrega- 
tion of pus-cells may 
take place. 
Either the fresh 
tissue or that hard- 
ened in alcohol, 
chromic acid, etc., is 
to be employed for 
examination. The 
Fig. 228. The same vascular district 24 hours later, a and d 
have become pervious ; & and c are still solid in their middle por- 
tions. 
escape of the blood-corpuscles from the newly-formed vessels, 
which readily occurs in such preparations, is a very unfortunate 
circumstance, and is responsible to a considerable extent for the 
scanty results which so many investigators have obtained in 
this direction. If the injection with transparent masses, which 
is frequently difficult, it is true, succeeds, the whole naturally 
gains extraordinarily in clearness. Thus Thiersch made the in- 
teresting observation in the healing of of the tongue, 
that at the commencement a system of lacuna-like passages is 
formed in the granulation-tissue which lead from the loosened 
arterial walls to similarly constituted veins. Conditions which 
the healthy spleen (see below) shows during life. The largest 
proportion of these “plasmatic” canals afterwards disappear, 
but a portion of them become widened and form blood-convey- 
ing vessels, and the cells of their walls are produced by the ad- 
jacent tissues. 
The lymphatics, as is known, show in their large trunks a 
structure reminding us of that of the veins, and also coincide 
with them in the abundance of their valves. The latter also VESSELS AND GLANDS. 
399 
continue in the fine branches, and give them a very character- 
istic knotty appearance. So long as such a constitution can be 
recognized, the walls of these tubes, although at last simplified 
to a structureless membrane, are formed of a special tissue 
which differs from the neighboring tissues. 
The same methods are employed for the examination of the 
walls of these vessels as for the arteries and veins. Large 
trunks may be dissected out, slit up, and examined by pulling 
off the individual layers, or, after drying, longitudinal and 
transverse sections may be made. It is best to inject small 
trunks with pure gelatine by tying in a fine canule ; after cool- 
ing, thin transverse sections may be made. The finer lymphat- 
ics appear at first to form cavities and pas- 
sages surrounded only by connective tissue. 
By the application of the dilute solution of 
nitrate of silver (preferably in the form of an 
injection), it has been ascertained, however, 
that these also have a wall consisting of 
the characteristic vascular cells (fig. 229, a). 
While the latter, in the capillaries of the 
blood-passages, however, usually presents a 
certain independence in opposition to the ad- 
. , ~ n i i i 
jacent tissues, the walls of the lymph-canals 
* . 
are intimately blended with the neighboring 
connective tissue. 
I'm. 229. A lymphatic ca- 
«ai from the large intestine 
of the Guinea-pig. a, vas- 
ceu; b, intercalary 
In investigating the arrangement of the finer lymphatics of 
an organ, the injection of cold, flowing, transparent masses of 
Prussian blue and carmine (see pp. 187-8) is to be employed, 
together with the subsequent hardening in alcohol. In doing 
this the canule is either to be tied in or the method by punc- 
ture is to be used. The injection is sometimes easily accom- 
plished in some parts of the body, occasionally only with the 
greatest difficulty. 
The natural injection, which, for the blood-vessels, may af- 
ford to the unpractised a substitute for the artificial injection, 
is, from the nature of the enclosed fluid, of very limited impor- 
tance for the lymphatics. The lymph proper disappears as a 
colorless fluid in the tissue of the organ, and the small vessels 
only glimmer forth from the tissue where a pathological color- 
ing matter, of the bile or of the blood, for example, is retained 
and mixed with the lymph. The chyle, on the contrary, forms, 400 
SECTION SIXTEENTH. 
as is known, a milk-white fluid, in consequence of the larger 
amount of fat which it contains, and hence its vessels are seen 
distended in a beautiful manner. Mammalial animals, especi- 
ally young suckling examples, killed during the digestion of 
fat (3-5 hours after its reception) afford, therefore, excellent 
objects for the study of the chyle ducts and vessels, a subject 
to which we shall return at the investigation of the organs of 
digestion. 
We cannot yet leave our lymphatic canals. We have still 
to discuss an important question of structure. 
The connective tissue, as has long been known, is manifoldly 
permeated by a system of fine clefts and passages, which con- 
tains a fluid. To this has been given the name of the juice 
clefts (Waldeyer) or juice canals (Recklinghausen). It is seen 
instantaneously and very beautifully in the cornea of the eye. 
Now, in the normal condition, does this system of the so- 
called juice clefts have a connection with the previously de- 
scribed lymph canals, perhaps also with the blood passages ? 
This has certainly been frequently asserted ; according to 
our opinion, however, not with complete justice. 
If these lymphatic passages be injected with caution and 
without immoderate consumption of time (Hyrtl, Teichmann, 
His, Frey, Langer), nothing passes over into these juice clefts. 
The “ stigmata” close here just as completely as in the blood- 
vessels (fig. 217). 
As a result of an immoderate (or also of a too long-con- 
tinued weaker) pressure—probably this scarcely ever happens in 
healthylife—however, the “ stigmata” mentioned distend into 
“stomata;” and now a direct communication is established 
between both varieties of passages. 
Such an one exists, on the contrary, in the normal condition 
between the cavities of serous sacs and their lymphatics. 
The finer blood-vessels also behave exactly similar to these 
lymph-canals. As a result of continued distention of the 
vascular tube the stigmata become dilated and permeable ; the 
injection mass now passes into these juice canals (von Wini- 
warter, Arnold). 
Passing to the methods, we find the frog the most service- 
able animal for experiment. 
The first of the two observers mentioned drew a loop of in- 
testine out through an incision in the abdomen, excited in- VESSELS AND GLANDS. 
401 
flammation in it by means of cantharidine, then returned it, and 
closed the wound with a suture. The next day the blood 
passages of the cadaver were injected with thin blue gelatine, 
using the constant pressure. A similar injection also succeeds, 
however, by the heart’s action of the living animal. The cold 
flowing mass is injected into the vena cava through a fine glass 
tube. 
Arnold, one of our most excellent histologists, has made this 
experiment to a much greater extent and with great acuteness. 
As Cohnheim had already shown, the web membrane of the 
frog may be used for this purpose, enclosing either the entire 
hind-leg or the exposed vena cruralis in a ligature. The tongue 
may also be used, placing a thread, with the aid of a fine needle,, 
around the venous trunks—either the Y. mediana or the Y. 
laterales. Then wait two or three days, when the artificial in- 
jection of the blood passages can be perceived in the animal 
after it is killed. 
If, however, it be desired to demonstrate the transition from 
the lymph passages to these juice clefts, according to Arnold, 
a broad ligature is to be placed around the thigh of a frog and 
tighten it moderately. The swollen limb is to be injected by 
the puncturing method on the third day, after killing the ani- 
mal by bleeding. The canule is to be first introduced into the 
lymph reservoir surrounding the foot joint, and from here into 
one of the smaller lymphatic spaces which are situated between 
the toes. The passages of the web membrane now become in- 
jected and we likewise perceive the passage of the mass into 
these juice clefts. 
If it be desired to follow relative (or also other) observations 
in the living creature under the microscope, it is advisable, in 
order to prevent drying, to keep a constant minimal current of 
fluid, such as a dilute solution of common salt, passing in a 
suitable manner over transparent parts. Thoma has recently 
given us excellent directions for this “ irrigation process.” Un- 
fortunately, in consequence of the narrow limits of our little 
book, we cannot enter further into the discussion of this subject, 
or the very convenient apparatus of this able investigator. 
Pathological new formations of lymphatics, especially in tu- 
mors, are of frequent occurrence, although this subject, in con- 
sequence of the difficulty of its investigation, still represents 
almost a terra incognita. Krause has communicated a few ob- 402 
SECTION SIXTEENTH. 
servations concerning them. He succeeded, in scirrhus and 
medullary sarcoma, in injecting trunks lying in the connective- 
tissue bands of the framework, and likewise large vessels in 
myoma of the labia, J. Neuman successfully injected the 
pathologically changed skin. May these experiments very 
soon be further extended ! 
The structure of the lymphatic glands has recently become 
considerably more comprehensible from the labor of a number 
of observers (Billroth, Frey, His, Recklinghausen). 
The extreme softness and the opacity of the fresh organ, 
caused by the presence of millions of lymph-corpuscles, leads 
to the employment of hardening methods and brushing. 
These methods are the customary ones. Immersion in alco- 
hol, at first in such as is ordinarily used for preparations, which 
has been diluted with about half its volume of water, leads, as a 
rule, in from 5-8 days, to the desired object, especially if the 
precaution is observed to change the fluid frequently. The 
alcohol finally added should no longer become cloudy. If a 
sufficient consistence is not obtained in this manner, stronger 
alcohol, and finally that which is almost free from water, may 
be used, and thus, not unfrequently in the middle or towards 
the end of the second week, preparations will be obtained which 
are suitable for sections and for brushing. Over-hardening is, 
however, to be most carefully avoided if the framework sub- 
stance is to be examined, while strongly indurated alcoholic 
preparations afford the best specimens for the investigation of 
the blood- and lymph-vessels of these organs. For many pur- 
poses chromic acid and bichromate of potash deserve the pre- 
ference to alcohol. Commence with weak solutions and pro- 
ceed very gradually to stronger ones. The shrivelling which 
is usually connected with alcoholic preparations may thus be 
frequently avoided to a considerable degree. Solutions of the 
bichromate of potash, of a corresponding concentration, are also 
very serviceable. All lymphatic glands once hardened by any 
of these ways may be preserved for a long time in a serviceable 
condition, and may be used for occasional observations. 
Small, fresh lymphatic glands from healthy bodies do not, as 
a rule, present any difficulties in hardening. It is otherwise 
with those which are very voluminous, or no longer fresh, as 
well as with those which are affected by many varieties of 
degeneration. Thus, for example, typhus mesenterial glands VESSELS AND GLANDS. 
403 
require much care, as a rule, and the object is not always 
accomplished. The previous injection of the hardening fluid 
through the blood or lymphatic vessels of the organ to be 
immersed is a useful accessory with such organs as are difficult 
to manipulate. Attempts may be made in vain to harden these 
very glands by immersing them for 8-14 days in alcohol of in- 
creasing strength, and finally in that which is almost absolute, 
success only being obtained afterwards by placing them in 
chromic acid solutions. 
Toldt has recommended another procedure which permits 
of the preparation of the thinnest sections, and thus renders 
the trouble of brushing unnecessary to a great extent. The 
fresh glands are to be placed for 3-4 days in very “dilute, 
wine-yellow” chromic acid. When the hardening has reached 
the interior it is to be 
placed for the same length 
of time in glycerine di- 
luted with an equal part 
of distilled water. 
It would appear almost 
superfluous to give fur- 
ther directions for the ex- 
amination of the frame- 
work of the alveoli or 
follicles (fig. 230, d) and 
lymphatic vessels (e). The 
glands of younger ani- 
mals, or such as are in a 
swollen condition, are to 
be employed for the first 
Fig. 230. Section through one of the smaller lymphatic 
glands, with the current of the lymph—half diagrammatic 
figure, a, the capsule; 6, septa between the alveoli or 
follicles of the cortex (d) ; c, system of septa of the medul- 
lary substance as far as the hilus of the organ; e, lymph- 
tubes of the medulla; f afferent lymphatic currents, which 
surround the follicles and flow through the spaces of the 
medulla ; g, union of the latter into an afferent vessel {h) 
at the hilus of the organ. 
recognition of the cellular character of the reticular tissue. 
Among the tingeing methods, that with carmine accomplishes 
most in these cases. The reagents mentioned at the smooth 
muscles are employed for the recognition of the fibres of this 
tissue at and in the septa, especially the treatment with chlo- 
ride of palladium and the double staining with picric acid and 
carmine (p. 159). 
The blood-vessels may be injected either from the small ar- 
terial branches which enter the gland when the organ is suffi- 
ciently voluminous, or, in smaller glands, by the neighboring 
large trunks; thus, for example, the pancreas Asellii of the 404 
SECTION SIXTEENTH. 
smaller mammalia may be injected from the mesenteric arteries 
and the portal vein. Here the double injection readily succeeds. 
A few years ago I gave more accurate directions for the in- 
jection of the lymphatics (/, g, h) by the afferent and efferent 
lymphatic vessels of the glands. In these cases, as a rule, 
finding the lymphatics usually causes greater difficulty than 
the subsequent manipulations. 
Transparent and—as I will add, relying on recent experi- 
ence—cold-flowing injection masses should always be used. 
But not all lymphatic glands are adapted for injecting. As 
with all injections of lymphatics, fat subjects and bodies 
already commencing to decompose are to be avoided. (Edema- 
tous portions of the body are usually best qualified. A pre- 
paratory immersion in water for several hours may also prove 
advantageous. 
If a mammalial animal be employed, the following proce- 
dure presents the greatest advantages. The animal is to be 
killed by a blow on the head, or by strangulation. The duc- 
tus thoracicus is to be immediately ligated high up, and the 
body allowed to lie for 2-6 hours. After this interval the lym- 
phatics are, for the most part, firmly distended, and readily 
permit of the injection being made in the direction in which 
their valves open. In injecting the vasa efferentia, on the con- 
trary, it is difficult to overcome the resistance of the valves, 
and it only succeeds in isolated cases. 
The various degrees of distention are here of great impor- 
tance for the intelligibility of the whole current. At the com- 
mencement, therefore, only injections which have been early 
discontinued should be used, proceeding gradually to the em- 
ployment of those which have been more prolonged. The in- 
jection of a second or even third lymphatic gland by the vasa 
efferentia of a previously injected gland affords very fine 
specimens. 
It has already been remarked, at page 201, that Hyrtl and 
Teichmann have facilitated this procedure considerably by 
means of the puncturing method ; and in fact this process ac- 
complishes a great deal for the lymphatic glands. Fine tubes, 
cautiously introduced beneath the capsules of larger and 
smaller glands, as a rule, readily fill the investing spaces of 
the follicles, and from these the passages of the medullary sub- 
stance. This method is indeed inestimable for the examination VESSELS AND GLANDS. 
405 
of the passages of pathologically metamorphosed lymphatic 
glands. It may be practised with the syringe or with the con- 
stant pressure. A skilful hand will rarely have recourse to 
the latter, however. 
True glands, belonging in the narrower sense of the word to 
the lymphatic system, will be met with only in extremely rare 
cases naturally injected with decomposed hsematine, in a con- 
dition serviceable for the microscopical analysis. On the con- 
trary, animals fed with fat, or the bodies of persons who have 
died in the act of digesting fat, present a very important and 
instructive natural injection of the chyle-glands. Take one of 
the smaller mammalia,—for example, a rabbit or a small dog, 
—and introduce a considerable quantity of milk through an 
oesophageal catheter into its stomach. The animal is to be 
killed after from 4-7 hours, and, as a rule, the most exquisite 
injection of the entire chylous system will be found. 
The recognition, by a finer analysis, of the chyle-fat in the 
interior of a somewhat more voluminous lymphatic gland is, 
however, a precarious matter. Fresh sections may be treated 
with a solution of albumen, as recommended by Brucke. At- 
tempts should be made to render preparations which have been 
hardened in dilute chromic acid or weak alcohol transparent by 
means of soda solution. I have never seen any great effects 
from drying such glands either with or without a previous im- 
mersion in boiling water. 
Extremely small chyle-glands, especially those consisting 
of a single follicle, such, for instance, as are found in the ab- 
dominal cavity of the rabbit, when examined fresh without 
further addition, and in the condition of fat assimilation, 
afford, on the contrary, handsome appearances. 
The self-injection of the lymphatic glands has also been em- 
ployed. Toldt employs for this purpose a very finely granula- 
ted aniline blue, precipitated from an alcoholic solution by the 
addition of water. It may be injected under the skin of the 
living animal, and being conveyed by the afferent lymphatic 
vessel, the injection of the neighboring gland may be ex- 
pected. Or, the lymphatic glands iying in the vicinity of the 
liver of the dog may be selected. 
As, according to Bering’s experience, the hepatic lymph of 
narcotized creatures is rich in red blood-corpuscles which have 
escaped from the blood-vessels, one may accomplish the ob- 406 
SECTION SIXTEENTH, 
Ject by injecting this aniline mass for 7-8 hours in repeated 
doses of 12 grammes about every 10-15 minutes, in the vena 
cruralis of an animal narcotized with opium. 
As is known, the human lymphatic glands are subject to 
numerous structural changes. A part of the latter are to be 
regarded as senile metamorphoses ; others are of a more patho- 
logical nature. 
Among the former (which may also occur at a relatively 
early period of life), we must especially adhere to three ; 
namely, the formation of fat-cells, the pigmentation of the 
lymphatic glands, and the metamorphosis of the framework 
substance into ordinary connective tissue with the gradual 
destruction of the entire organ. 
The fat-cells take their origin from the connective-tissue 
corpuscles of the framework of the lymphatic gland, and, as a 
rule, affect the cortical substance of the gland. It is only in 
rare cases that they are noticed in the lymph-tubes of the 
medullary substance. The glandular structure of the lymph- 
atic gland disappears more and more in proportion as groups 
of fat-cells take the place of single cells. 
The pigmentation of the lymphatic glands, as is known, 
aifects the bronchial glands chiefly, and is, after certain periods 
of life, an almost regular occurrence, although of extremely 
varying degrees. If this process be followed from its very 
commencement it will be seen that, at least in most cases, the 
exciting cause is an inflammatory irritation of neighboring 
parts of the lungs. The consecutive tumefactions of the 
lymphatic glands, which are so frequent and with which prac- 
tical physicians are familiar, are accompanied by very extra- 
ordinary enlargements of their finest blood-vessels, so that, for 
example, almost all the capillaries are found to be dilated to 
four and even six times their ordinary diameter. In conse- 
quence of these expansions, an exudation of the coloring mat- 
ter of the blood takes place in the bronchial glands (and under 
certain circumstances in the lymphatic glands of other parts 
of the body also), so that the gland, saturated with a brownish 
fluid, assumes a‘4 splenoid 5 ’ appearance. At the same time 
lacerations of individual vessels and extravasations are also 
met with here and there. The molecules of black pigment 
arise by intermediate stages from the gradual transformation 
of the coloring matter of the blood. VESSELS AND GLANDS. 
407 
Most of tlie cases of pigmented bronchial glands originate, 
however, from an entirely different source. It is inspired coal- 
dust which, having penetrated the pulmonary parenchyma, is 
brought through the lymphatics to the bronchial glands, and is 
here slowly deposited in the course of years. We shall have 
to mention this “ anthracosis ” again at the respiratory organs. 
In this manner, then, varying extremely in degree, pigmen- 
tations of the bronchial glands take place. Those of slight de- 
gree give the organ a sprinkled and spotted black appearance, 
but in higher degrees cause the black appearance to extend 
over greater distances, and even throughout the entire thick- 
ness of the organ. 
While lower phases of this melanosis prove to be relatively 
indifferent for the organ affected, stronger pigmentations lead 
to the connective-tissue metamorphosis and atrophy of the 
lymphatic gland. 
Such connective-tissue metamorphoses show bundles of stri- 
ated and fibrillary tissue, at first isolated and then developed 
in the most extensive manner at the expense of the reticular 
framework. The characteristic structure of the organ disap- 
pears more and more, and finally, together with the loss of all 
the lymphatic passages, the whole gland becomes degenerated 
into a connective-tissue mass. These processes are observed 
with pigmentations, but also without them. The external 
lymphatic glands appear to be more subject to this process 
than those which are situated deeper in the body. 
The ordinary methods suffice for the examination of the 
most prominent structural conditions. The previous injection 
of the blood-vessels with cold-flowing mixtures should, when 
possible, be at least attempted. 
The true pathological metamorphoses of the lymphatic 
glands affect in part the framework, in part the lymph-corpus- 
cles, and in part both elements together. 
The structural changes of our organ in abdominal typhus 
are not very easy to follow. In the first, so-called catarrhal 
period of this disease, a tumefaction of the organ is met with, 
which consists chiefly of one of the above-mentioned extensive 
dilatations of the finest blood-vessels. The investing spaces of 
the lymphatic-gland follicles are enlarged, and in these are 
found a number of large multinuclear cells (which may also be 
found, although in smaller quantity, in other irritated condi- 408 
SECTION SIXTEENTH. 
tions). The participation of the framework-substance appears, 
on the contrary, to be remarkably slight. At later periods 
these cells break down under fatty degeneration, and produce 
collections of very unequal extent, of a finely granular sub- 
stance, the medullary typhous matter. Not unfrequently 
these form local softenings, into the sphere of which are drawn 
the adjacent tissues, the framework with the blood-vessels. In 
favorable cases the finely granular substance is again removed 
by the efferent lymph-current. 
A similar process, only much more sluggish in its progress, 
is met with in tuberculous and scrofulous lymphatic glands. 
Here, together with the breaking down of the framework 
substance, the same degeneration also appears—a fine, molecu- 
lar, fatty, waterless matter with interposed, shrunken lymph- 
corpuscles. These “ cheesy metamorphosed ” masses may have 
various destinies allotted to them ; they may be reabsorbed, 
become indurated and calcified, or soften and give rise to the 
formation of a fistulous passage. 
A series of investigations which I was enabled to institute 
in leucaemia of our organ show that there is here essentially 
only an increase of volume. The structure usually remains 
normal. 
In other pathological conditions the participation of the 
framework substance is more extensive. Thus, in secondary 
inflammatory conditions of our organ, the meshes of the net- 
work are seen to gradually become narrower, the trabeculae in- 
crease in size, and distinct nuclei are again formed in the nodal 
points. In the more voluminous organs, where the expansions 
of the capillaries already mentioned may be recognized, there 
may be a gradual obliteration of the textural differences of the 
septa of the medullary and cortical substance. The lymphatic 
passages disappear, and the organ has become incapable of per- 
forming its functions. The later appearances of such lymphatic 
glands vary considerably, however. An interesting structural 
condition is sometimes presented in such cases, by the enormous 
thickenings of the capillary walls which are caused by the ag- 
gregation of spindle-cells. 
Allied structural conditions are presented by the hypertro- 
phies of the lymphatic glands. Here the capsule, the septa, 
and, at last, the medullary substance also, become transformed 
into a reticular tissue, which is uniform throughout the entire VESSELS AND GLANDS. 
409 
organ, and encloses numerous lymph-cells. This transforma- 
tion of the capsule enables one to appreciate how the adjacent 
connective substance may be drawn into the sphere of the same 
metamorphosis, and a fusing together of the neighboring lym- 
phatic glands take place. The reticular framework is either 
like the normal, or the meshes are seen to be narrower. In 
other cases the fibres become much more strongly developed, 
so that a coarse-banded framework, like that of a carcinoma, 
may be formed. In the latter processes the large nucleated 
cancer-cells are met with in the meshes, varying in form and 
arrangement. 
Formerly, the inflexible trabecular framework, which per- 
meates the lymphatic channels (investing spaces), appeared to 
constitute the chief starting-point of the metamorphosis in 
question, as the cancer-cells arise in its nodal points, and its 
trabeculae become the stroma of the carcinoma. At the present 
day, an original immigration of the first cancer-cells through 
the vas afferens into the investing spaces has become more 
probable. The glandular tissue becomes slowly and gradually 
atrophied. 
A newer and more successful method of investigating these 
diseased lymphatic glands consists in their injection, and in the 
study of their lymphatic channels by the aid of the puncturing 
method. In such an organ, so long as there is a simple tume- 
faction, whereby those enormous distentions of the capillary 
blood-vessels are frequently met with, the lymphatic passages 
are all permeable. If the metamorphosis of the gland progres- 
ses farther, as in typhus, and a breaking down of the lymph- 
corpuscles into the fine granular “ typhus substance” occurs, 
such places become stopped up ; the channels of hypertrophied 
lymphatic glands likewise become impermeable to a great ex- 
tent. These are a few of the results which the author of this 
work has, thus far, obtained by suitable injections. 
Many dark points still exist with regard to the origin of the 
lymphatic glands and lymphatic vessels of the foetal body. 
Many years ago we became acquainted, through Kolliker, with 
interesting lymphatic vessels in the tail of the frog’s larva. 
These run near the capillary blood-vessels, and appear as deli- 
cate, twig-like, ramified canals, without the reticular intercom- 
munications of those vessels, and are characterized by the 
numerous small pouches into which their delicate walls are ex- 410 
SECTION SIXTEENTH. 
panded. They contain a colorless fluid, almost free from cells, 
and it is certain that they are without an epithelial lining. 
Aggregations of neighboring spindle-cells are frequently met 
with on the membrane of the vessel. 
We now turn to tlie methods of investigating glandular tis- 
sue. 
Three elements participate in the formation of a gland, or 
—when its volume is greater and the structure more compli- 
cated—of its subdivisions. A transparent, apparently struc- 
tureless membrane (membrana propria), constitutes the frame- 
work, and thus determines the form of the organ or part of the 
organ ; strata of cellular elements (gland-cells) cover the inner 
surface of the latter and play an important role in the forma- 
tion of secretions. Finally, the external surface of the struc- 
tureless membrane is covered by a reticulation of capillary ves- 
sels, from the contents of which the 
matters for secretion are taken in 
the form of watery solutions. 
Our fig. 281, which presents the 
lower halves of long, simple, tubu- 
lar glands from the gastric mucous 
membrane, may afford us a repre- 
sentation of this condition. The fine 
contours of the sinuous, blind-sack- 
like tubes present the optical ex- 
pression of the membrana propria ; 
nucleated fine granular cells form 
Fig. 231. Gastric glands of the dog, with 
cells and capillary vessels. 
the contents, and a capillary net-work, spread out in the tubu- 
lar form, surrounds the individual organ with elegant incurva- 
tions. , 
None of the glandular organs of the human body are without 
capillaries and gland-cells. This is not the case, however, with 
the membrana propria. It may be absent, and, indeed, under 
manifold conditions. In the first place, we see that the fine 
membrane which is present in the earliest period of life is 
blended with neighboring parts, as in the liver. Or, the same 
has been absent from the commencement, and a firmly woven, 
connective-tissue limiting-wall encloses the aggregation of cells 
at all periods of life. Finally, we have learned through more 
recent researches that a wicker-work of flattened, multi-radi- 
ated connective-tissue cells becomes visible in this membrana VESSELS AND GLANDS. 
411 
propria (fig. 233). This condition has been especially noticed 
in racemose glands (salivary, lachrymal, and lacteal glands), 
bnt also in the tubular glands of the mucous membrane of 
the stomach. Macerating methods and sec- 
tions through hardened preparations are 
employed in these cases. An entire muster- 
roll of methods has been recommended: 
vinegar; the 33 per cent, solution of pot- 
ash ; the maceration for several days in 
iodine-serum, and then, subsequently for 
24 hours, in a chromic acid solution of 
per cent, (or, chromate of potash TV per 
cent.); the immersion in osmic acid of \ per 
cent.; and the hardening by means of alco- 
Pig. 232. Plexus of star- 
shaped connective-tissue cells 
from the membrana propria, 
isolated by maceration. Prom 
the submaxillary gland of the 
dog, after 8011. 
hol or the bichromate of potash, with subsequent carmine 
tingeing. 
However, the numerous glands of the human body are of 
such manifold natures, according to their size, their complexity, 
and their entire structure, that the example made use of above 
can in no wise suffice for their comprehension. 
Together with the simple tubular glands which we have 
already become familiar 
with in the gastric glands 
of the stomach, other more 
complicated ones occur in 
which the lower csecal ex- 
tremity, with or without 
dividing, forms a number 
of coil - shaped convolu- 
tions. These organs have 
been provided with the ap- 
propriate name of convo- 
luted glands. The most 
extended and familiar ex- 
ample of them is presented 
S2S.f.m'. 
SSS iff fS!1"7 "”r‘ 
bythe sudoriparous glands 
of the skin (flg. 333, a, 
V). The net-work of vessels 
which encircles the coil becomes a sort of wicker-work with 
rounded meshes (c). The kidney and the testicle, two large, 
voluminous organs of the body, present much longer cylindrical 412 
SECTION SIXTEENTH. 
tubes with divisions and reticular intercommunications. Fig. 
234 represents these glandular tubes of the kidney, the so-called 
uriniferous tubes (1, 2). 
Another form of glands, the racemose, is very widely dif- 
fused. 
Roundish or elongated sacks (gland-vesicles), which are 
smaller or larger, longer or shorter, have their outlets associated 
together in groups. Such groups of sacks (gland-lobules) are 
again united by short ducts and by elongations of the mem- 
brana propria, and thus, sometimes in a slightly, sometimes 
Fig. 284. Uriniferous tubes from the 
human kidney. 1, Side view; a, 6, canals 
filled with cells; c, one partially free from 
cells; 2, transverse section of the same; 
3, gland-cells. 
Fig. 235. Human Brunner’s glands. 
more considerably (fig, 235), and sometimes extremely compli- 
cated manner, the racemose gland is formed. The changes 
which are here to be observed, and the manner in which the 
efferent canal-work gradually advances to a more compound 
texture—these, as well as many other particulars, must be 
learned by reference to the text-books on histology. 
Notwithstanding many subordinate variations, there is one 
and the same fundamental design present in all, and easy to be 
observed from the mucous follicles, which are to be called 
almost microscopical, to the most voluminous examples, such 
as the salivary glands and the pancreas. 
The glands-cells (which we have still to mention more espe- 
cially) present numerous variations according to the nature 
of the actual secretion; the capillary net-work surrounding 
them, on the contrary, always exhibits circular meshes (fig. 
236). VESSELS AND GLANDS. 
413 
There is still a third form of glandular organs ; such, 
namely, in which the membrana propria constitutes a round- 
ish vesicle, closed on all 
sides, with cells in its in- 
terior, and surrounded 
externally with a net- 
work of capillaries; the 
entire organ being com- 
posed of a large or larger 
proportion of such vesi- 
cles embedded in a con- 
nective - tissue ground- 
work. 
The ovary (fig. 237) 
represents the latter ar- 
rangement, Its gland- 
vesicles, called Graafian 
follicles (c, d), contain, 
together with small 
roundish gland-cells, a 
large globular cell, the 
Pig. 286. Vascular net-work of the rabbit’s pancreas. 
ovum. The latter, by the rupture of the (rather complicated) 
wall, having arrived at the end of its existence, undergoes 
Cvary of the rabbit, a, epithelium (serosa); &, cortical or external fibrous layer; c, young- 
est follicle ; ci, a somewhat more developed older one. 
a process of cicatrization as the corpus luteum, as it is called. 
Still another variety of such glands with closed vesicles has 414 
SECTION SIXTEENTH. 
been assumed. The capsules are said to form a secretion in 
their interior from the elements of the blood, and when the 
secretion is perfected, it is consigned to the blood and lymphatic 
vessels for removal. This is a very unsatisfactory explanation 
of the dilemma, arising from the experience that such a dehis- 
cence as is exhibited by the ovary is never observed in the 
organs in question. 
They were formerly rather liberal in the acceptation of such 
organs, so-called ‘ ‘ blood vascular glands.5 ’ At present we have 
learned to separate many of them as belonging to the lymphatic 
glands, or, at least, as being nearly related to them; such as the 
thymus, the spleen, the Pey- 
erian and solitary follicles of 
the intestines, the tonsils, 
and the conjunctival folli- 
cles. Only a limited num- 
ber of enigmatical structures, 
especially the thyroid gland 
(fig. 238), the supra-renal cap- 
sules, and the hypophysis 
cerebri, still find a place here. 
The alleged membrana 
propria (fig. 238, £), which 
former observers believed 
that they saw on these struc- 
tures, appears in reality, how- 
Fig. 238. Thyroid gland of the child, a, connective- 
tissue framework; 6, capsules; c, their gland-cells. 
ever, not to exist. We believe that its presence, at least in 
the hypophysis cerebri, the supra-renal capsules, and the thy- 
roid gland, must be denied. The predecessors were deceived, 
in consequence of inefficient methods of examination, by the 
compactly arranged connective-tissue parietes. 
Finally, the cellular constituents of our organ are of greater 
importance. The gland-cells proceed, as we have learned in 
the most certain manner from Remak’s admirable investiga- 
tions, from the foetal epithelial layers, the so-called horn and 
intestine-glandular lamellse, and present originally partly solid 
cell-growths, partly hollow diverticula. In accordance with 
this, much of their character remains closely allied, in all their 
processes of life, to the nature of epithelium, and, even in the 
excretory ducts of the glands (fig. 239 a), the continual transi- 
tion into the adjacent epithelial tissues may be observed. VESSELS AND GLANDS. 
415 
The cells which we meet with in the various glands are in 
part circular, in part flattened cubical, and in part cylindrical 
nucleated cells (figs. 239 b, 240, 241, 242, and 243). 
Pig. 239. Portion of a so-called 
gastric mucous gland of the cat. 
a, efferent canal with cylinder epi- 
thelium ; b, commencement of the 
gland canal with cubical cells. 
Fig. 240. Human liver- 
cells, with a single nucle- 
us at a; one with two 
nuclei at b. 
Fig. 241. So-called mucous gastric 
glands. 1. From the cardiac portion 
of the hog’s stomach ; a, the cylindri- 
cal cells (at 1* isolated); &, the lumen. 
2. From the pylorus of the dog. 
In many cases these cellular elements are strikingly differ- 
ent in similar glands. Thus the ordinary racemose glands of 
the mucous membranes (fig. 242) have transparent hyaline cells, 
Pig. 242. Gland vesicle of the gingival gland 
of the rabbit, a, rounded; &, an elongated 
acinus. 
Fig. 243. Acini (a, round, &, oblong) of a 
so-called serous gland, from the vicinity of 
a circumvallate papilla of the cat. 
which can only be slightly tinged, while in many places, for 
example the nasal mucous membrane and the posterior portion 
of the dorsum of the tongue (fig. 243), the cellular elements have 416 
SECTION SIXTEENTH. 
delicate granules, appear cloudy, and become strongly tinged. 
The mucous and serous glands have, therefore, been very rightly 
distinguished from each other. 
As a rule, especially with a certain amplitude of the pas- 
sages, these cells clothe the inner wall after the manner of epi- 
thelium (figs. 239, 242, 243), so that a lumen still remains, and 
only narrow passages, such, for instance, as those of the liver, 
are found to be filled up by several cells placed one behind the 
other. In consequence of mismanagement in the preparation, 
as well as of cadaverous decomposition, these aggregated gland- 
cells generally become detached and frequently fill the entire 
cavity of the gland with fragmentary structures, and even free 
nuclei and molecules. 
The gland-cells display their relationship to the epithelial 
structures, at least partially, in still another, and indeed physi- 
ological manner ; namely, by a certain transitoriness of their 
existence, and by their falling off from the glandular walls. 
Although the duration of their life varies to a greater extent, 
and though many gland-cells, such as those of the liver and of 
the renal passages, are of a more persistent nature, so that the 
formation and excretion of certain secretory elements is re- 
peated by them for a longer time, there are also, on the other 
hand, many examples of a more rapid separation. At every 
act of gastric digestion numerous cells of the gastric glands be- 
come separated from their parent tissues and cover the inner 
surface of the stomach, at least in certain mammalia, with a 
thick mucous covering. Other glands which prepare a fatty 
secretion, present, as a physiological process, the fatty degen- 
eration of the cells, and in this way innumerable quantities of 
the latter are destroyed. In this manner, by the destruction 
of innumerable cells, is formed the secretion of the sebaceous 
follicles, many sudoriparous and Meibomian glands, and like- 
wise of the lacteal glands. Cells which are probably contractile 
may, it is true, also throw out particles of fat without dying. 
An example of this physiological cell destruction may be 
represented by fig. 244 A, the ovoid vesicle of a sebaceous 
gland. 
This appears at a to be lined by stratified layers of rounded 
cells in which the fat-molecules are to be recognized, sometimes 
in smaller, sometimes in larger quantities. Other cells {b) con- 
taining a larger quantity of fat, are already separated from the VESSELS AND GLANDS. 
417 
, parental tissues, and already, in part, undergoing dissolution, 
fill the cavity of the gland vesicle. In this way is explained 
the occurrence of free masses of fat in the lower educting por- 
tion of the latter; in this 
way, also, is formed the 
smegma cutaneum. The 
various cells of this 
form of gland are seen 
at B, a-f, more highly 
magnified. 
In examining the 
gland-cells (the investi- 
gation of which in the 
living condition has, un- 
fortunately, been almost 
Fig. 244. Human subaceous follicle. A, gland-vesicle with 
the cells resting on the wall at a, and separated and overloaded 
with fat at b ; B, a-f, several of these gland-cells. 
entirely neglected) the most conservative treatment is necessary. 
Sections made through an entirely fresh part yield to a knife- 
blade which is moved or scraped over it, masses which, spread 
out in an indifferent fluid, will often afford satisfactory ex- 
amples of the cells in question. Glands will occasionally be 
met with, which, in a condition of vital warmth, are so solid 
that with a very sharp and moistened razor very thin sections 
may be made from them. When these sections are examined 
in indifferent media, such as iodine-serum or extremely dilute 
chromic acid, they show the position of these cells, and also 
permit of their isolation by proper picking. Generally, how- 
ever, such procedures fail in consequence of the softness of the 
structure. We therefore recommend the freezing method as 
the best procedure at present in use for this purpose. Harden- 
ing methods have been used for a long time for the examina- 
tion of cells in situ. Drying the organ is not to be recom- 
mended, as deeper alterations of the cells and the subsequent 
separation of many of these structures can scarcely be avoided. 
It is better to employ a solution of chromic acid or of the 
bichromate of potash of gradually increasing strength, by 
means of which excellent preparations may be obtained. The 
immersion of small pieces of the glands, removed from the 
body immediately after death, in a large quantity of absolute 
alcohol, is an excellent procedure, and the proper consistence 
is obtained in a few hours. 
Tingeing the gland-cells may be best accomplished with 
27 418 
SECTION SIXTEENTH. 
hsematoxyline, glycerine-carmine, or Eanvier’s mixture of 
picric acid and carmine. 
It is scarcely necessary to mention that the application of 
numerous chemical reagents is necessary for the recognition of 
the contents of these cells, as well as that the freshest possible 
tissue is to be used for this purpose. 
Solutions of the caustic alkalies are most to be recommended 
for the demonstration of the membrana propria of the glands. 
There are various methods for us to select from for the in- 
vestigation of the relations of the last-named membrane, as 
well as of the entire structure of the glands. Drying, with the 
subsequent action of alkalies on the moistened sections, is to 
be employed with advantage for many parts, as, for example, 
for the glands of the skin and eyelids. If one desires to study 
the organs which are embedded in mucous membranes, boiling 
the piece in question in vinegar and then drying it is to be 
recommended. 
In the moist condition we can often obtain a sufficient hard- 
ening by means of pyroligneous acid. 
The three above-mentioned, so frequently employed fluids 
—alcohol, solutions of chromic acid, and of the bichromate of 
potash—appear, however, to be more important, and, in fact, 
they generally suffice for the glandular tissues. Where brush- 
ing is unnecessary, the tissues may be energetically hardened 
with stronger degrees of concentration. But if one desires to 
make use of the procedure just mentioned—and it is of the 
greatest value for the recognition of the framework of the 
glands, the vessels, incidental muscles, etc.—the matter should 
not be overdone. Notwithstanding every precaution, however, 
many variations will still be met with. Sections of the kidney 
and of the testicle, and surface sections of the gastric mucous 
membrane are generally easy to brush; it is difficult, on the 
contrary, to obtain good preparations from the liver. The 
chloride of palladium is to be used for recognizing the muscular 
elements in glands, and osmic acid for the nervous elements; 
but it should not be forgotten that shreds of fat are also black- 
ened by the latter reagent, and may thus give rise to deceptive 
appearances. 
The fine blood-vessels which encircle the glands are gener- 
ally concealed by the cellular contents of the glands, and even 
after the most careful brushing are only very imperfectly VESSELS AND GLANDS. 
419 
brought to view. The artificial injection with transparent 
masses, a light blue, should not therefore be omitted. This 
procedure naturally varies considerably according to the indi- 
vidual organs. 
Injections are employed in still another way for glands, 
naturally only the more voluminous ones; namely, for filling 
their cavities. Cold-flowing masses (either, and preferably, 
purely watery ones, or at most mixed with glycerine, but not 
alcohol), entirely fresh organs, and great care are necessary if 
such experiments are to be successful. The employment of a 
constant pressure is de- 
cidedly preferable to the 
syringe for this purpose. 
By these means, a 
plexus of very tine canals, 
the ‘4 gland-capillaries, ’ ’ 
surrounded by an ex- 
tremely delicate sheath, 
has frequently been re- 
cognized in an interesting 
manner, lying between the 
secreting cells and sur- 
rounding each one of 
them. The presence of 
this net-work in the liver 
has been known for some 
time. We shall have to 
mention these biliary ca- 
pillaries hereafter. With- 
in a few years they have 
also been discovered in 
racemose glands, as in the 
pancreas (Langerhans, Sa- 
Fig. 245. Glandular canals from the pancreas of the rab- 
bit, injected with Brucke’s Prussian blue; after Saviotti. 1 
and 2: a, larger excretory duct; b. that of an acinus; c, fin- 
est capillary duct. 3, an acinus with cells and only partially 
filled gland-capillaries. 
viotti, Gianuzzi), in the salivary glands (Pfluger and Ewald), in 
the lachrymal gland (Boll), and in the lacteal gland (Gianuzzi 
and Falaschi). Our fig. 245 may represent these remarkable 
canals, which here run partly between the cells themselves, 
partly on the surface between them and the membrana pro- 
pria. Nevertheless, there is much here which still remains 
indistinct and dark since the more recent investigations (8011, 
Schwalbe, von Ebner, Frey). 420 
SECTION SIXTEENTH. 
For the investigation of foetal glands, embryos hardened in 
absolute alcohol or chromic acid are to be chosen, and sections 
made through them in various directions. The separated skin, 
as well as mucous membranes, often present very good surface 
views. The origin of the membrana propria requires more ac- 
curate investigation than has thus far been devoted to it. 
We would add a few words in closing, touching the patho- 
logical conditions of the glandular tissues. 
The gland-cells (corresponding to their epithelial nature) 
present the phenomena of hypertrophy and degeneration, but 
scarcely that of a transformation into other tissues. This takes 
place, as a rule, more from the connective-tissue framework 
substance which permeates the organ, to which, perhaps, the 
so-called membrana propria of the gland is to be reckoned 
throughout. 
Hypertrophies of a gland show, as a rule, an increase in 
number of the secreting cells, which we at present ascribe to a 
more active process of division; although the existing cells 
may also increase in size, and thus cause an increase of volume. 
Both conditions are found, for example 
(frequently enough combined), in hypetro- 
phied livers. 
We have already mentioned above the 
accumulation of fat in the interior of the 
cells we are at present considering. For 
many glandular organs it constitutes an en- 
tirely normal occurrence. In others such 
a destruction of the cells is an abnormal 
phenomenon, a process of degeneration. 
Pigmentations of the gland-cells are more 
rare ; amyloid degenerations occur in these 
structures, at least in many cases, while, as 
a rule, they affect the vessels and the con- 
nective-tissue portions of the gland. 
Fig. 246. Colloid degenera- 
tion of the gland-vesicles of the 
thyroid, a, from the rabbit; b, 
from the calf, at the beginning. 
Colloid degenerations occur in certain glands at least, and 
affect their cells quite extensively, especially in the thyroid 
(fig. 246). 
Swelling of the connective tissue, increase of the interstitial 
substance, distention of the connective-tissue corpuscles and 
the division of their nuclei, are met with in conditions of sim- 
ple inflammatory irritation. A more persistent increase of the VESSELS AND GLANDS. 
421 
connective tissue of the gland may lead to the destruction of 
the gland-cells in the compressed cavities. That tuberculous 
and typhous degenerations, and carcinomatous new formations 
in glandular organs, also take their origin from the connective 
tissue, has hitherto been the general modern acceptation. Our 
present knowledge concerning the structural changes of the 
liver and kidneys may constitute an important starting-point 
for subsequent investigations of smaller glandular organs. 
Cysts, according to experience, frequently originate from 
glandular passages when the secretion, in consequence of ob- 
struction to its egress, accumulates more and more and dis- 
tends the duct. 
The new formation of glandular tissue and of entire glan- 
dular organs is likewise not an unfrequent occurrence. The 
former is seen in hypertrophied structures. Entire glands 
occur in mucous polypi. We also meet with tubular and se- 
baceous glands, together with hairs, teeth, etc., in cysts of the 
ovary. 
There are no special methods of investigation to be men- 
tioned here. Sertion Seocntmitl). 
DIGESTIVE ORGANS. 
The study of the digestive apparatus, its parietes, the 
glands connected with it, and the substances which it contains, 
constitutes an extensive section of microscopic investigation. 
In consequence of the decomposition which so readily takes 
place in them, most human bodies appear but little adapted 
for this purpose, so that for many textural conditions recourse 
is more advantageously had to a recently killed mammalia! 
animal. The bodies of new-born children are still better 
adapted. 
The lips present a transition of the tissue of the external 
integument to that of the mucous membrane, as well in its 
epithelial as in its fibrous layers. The finer structure of the 
same is to be examined either in dried preparations (also pre- 
viously boiled in vinegar), or those which have been hardened 
by means of alcohol or chromic acid. The small sebaceous 
follicles, which were discovered in them a few years ago, may 
be recognized without much difficulty by the application of 
acetic acid. 
In the oral and pharyngeal cavities are presented for exam- 
ination the mucous membrane with the small glands belong- 
ing to it, the teeth (already described), the tongue, the tonsils 
and lingual follicles, and finally the salivary glands as well as 
the secretion of the oral cavity, the saliva. 
In order to accomplish the injection, which is so necessary, 
of this commencing portion of the digestive tract, we would 
recommend the use of the smaller mammalial animals and the 
insertion of the canule in the arch of the aorta, as mentioned 
above (p, 359), for the brain. A complete injection of the oral 
cavity, the tongue, and the pharynx may be readily obtained DIGESTIVE ORGANS. 
in this way. A blue deserves the preference on account of the 
subsequent carmine tingeing. 
The mucous membrane, with its papillae, vessels, nerves, 
and glands, may be reviewed in vertical sections of fresh pre- 
parations made as thin as possible, and then rendered still 
more transparent by means of solutions of soda, or dilute 
acetic acid. It is always a tedious affair, however, to obtain 
these from such a soft and slippery tissue, so that naturally 
the customary hardening methods are also extensively em- 
ployed. 
The mucous membrane and numerous conical or filamen- 
tous papillae, covered by the thickly stratified pavement epi- 
thelium, may be recognized with 
facility in good alcoholic prepa- 
rations (fig. 247). The numerous 
racemose or mucous glands of 
the oral cavity are rendered ap- 
parent by the application of this 
acid or, still better, after the use 
of alkaline solutions. Their vesi- 
cles frequently appear consider- 
ably elongated (Puky Akos), 
and their gland-cells cylindrical. 
The gingival mucous membrane 
of the rabbit, the dog, and the 
cat (fig. 242) constitutes a beauti- 
ful object for this purpose. 
Fig. 247. Injected papilla from the gum of a 
child. 
It is interesting that another 
form of racemose gland, with opaque granular contents, the 
so-called serous gland (Ebner), occurs at the root of the tongue 
of man and the mammalial animals. We shall meet with an 
analogous variety subsequently at the large salivary glands, 
the submaxillary and parotid glands. 
In order to recognize the general arrangement of the nerves, 
the gradual hardening with weak solutions of chromic acid or 
chromate of potash, with the subsequent employment of a very 
dilute acetic acid, is to be recommended. An immersion of 
the fresh tissue in the acetic-acid water (1-2 drops of acetic- 
acid hydrate to 50 ccm.), mentioned at the examination of the 
muscular nerves, affords, after 12-24 hours, very suitable 
specimens, especially with the lower vertebrate animals. 424 
SECTION SEVENTEENTH. 
Pyroligneous acid lias been frequently employed here. Osmic 
acid and chloride of gold are to be tried for more accurate 
studies. 
The examination of the tongue requires various methods, 
according to the portion of the structure of the complicated 
organ which one desires to investigate. 
To follow the general arrangement of the muscles, one may 
use tongues which have been for a long time in alcohol, also 
fresh ones, which must be boiled in water, however, until they 
have become quite soft. To obtain finer sections, hardening in 
alcohol or the freezing method may be employed. Thin sec- 
tions afford beautiful specimens after being tinged with car- 
mine and washed in acetic-acid water or stained with hsema- 
toxyline, or with carmine and picric acid, after Schwarze’s 
method, and likewise by the direct application of acetic acid 
or dilute solutions of soda. The tongues of the smaller mam- 
malia deserve the preference to those of larger animals, and 
likewise those of embryos to those of older creatures. 
Considerable attention has been paid for some time to the 
divisions of the filaments of the lingual muscles. They may 
be readily discovered in the lower amphibia, frogs, tritons, 
etc., by means of the usual maceration in dilute pyro-acetic 
acid ; an immersion in a very dilute solution of chromic acid is 
also to be recommended. The strong muriatic acid (see p. 125) 
has been subsequently employed for this purpose, and the 
divided filaments have also been perceived in the human 
tongue (Rippmann). The connection of the muscular fibres, 
or their sarcolemma, which ascend into the papillae of the 
frog’s tongue with the connective-tissue corpuscles, which was 
observed by Billroth and corroborated by Key, is to be fol- 
lowed in pyro-acetic acid preparations. 
The mucous membrane of the human tongue, with its pave- 
ment epithelium, does not require any special methods. The 
epithelial processes of the papillae filiformes are often quite 
long, and their formation out of individual cells may be recog- 
nized after the application of alkalies. 
The nerve-terminations of the tongue will be mentioned fur- 
ther below at the organs of sense. 
In larger animals, also, the injection of the blood-vessels 
does not present any difficulties. The familiar puncturing 
method serves for the lymphatics and the lymph-passages in DIGESTIVE OEGAXS. 
425 
general, which are quite abundant in the tongue, and form cul- 
de-sac-like axile canals in the papilla? filiformes. 
Glycerine is adapted for mounting permanent preparations, 
or, after tingeing, Canada balsam. Excellent preparations are 
obtained by the latter method, which permit of the recognition 
of many histological details, not only of the commencement, 
but also of the entire digestive tract. 
Of late years the tongues of mammalial animals have also 
become important and profitable objects for experimental pa- 
thologists. On them Wywodzoff and Thiersch have studied 
the healing process of wounds. The injection of the blood- 
vessels with gelatine cannot be dispensed with in these cases. 
To render the tissue of 
the organ injected with 
carmine visible, Thiersch 
made use of the silver 
impregnation mention- 
ed at p. 164. 
We may rapidly pass 
over the methods of ex- 
amining the tonsils (fig. 
248) and the lingual fol- 
licles, for they are the 
Pig. 248. Tonsil of the adult (after Schmidt), a. larger ex- 
cretory duct; b, more simple one; c, lymphoid parietal layer, 
with follicles; d, lobule, reminding one of a lingual follicle; e, 
superficial; /, deeper mucous follicle. 
same as for other lymphoid organs. Here also chromic acid, 
bichromate of potash, and alcohol are employed as hardening 
media. Thin sections, cautiously brushed and tinged, readily 
permit of the recognition of the structure. In consequence of 
the numerous diseases of the tonsils, however, the precaution 
should be observed to use the bodies of new-born or small 
children; likewise the younger specimens among mammalial 
animals. Of these, I would especially recommend dogs, pigs, 
and calves. The puncturing method, cautiously performed 
beneath the investing tissues, fills the numerous lymphatics in 
the calf and ox without difficulty ; with somewhat more trou- 
ble in the dog; but, according to previous experience, ex- 
tremely seldom in a satisfactory manner in the hog. 
The glandular follicles of the tongue are difficult to inject; 
the recognition of their structure is, on the contrary, relatively 
easy. 
To obtain the salivary corpuscles which exude from the cav- 
ities of the tonsils, pressure should be cautiously made on a 426 
SECTION SEVENTEENTH. 
tonsil immediately removed from a calf wliicli lias just been 
killed. A thick, glairy mucus, containing a number of these 
cells, will then make its appearance. 
The salivary glands have been frequently examined of late. 
A whole series of methods of investigation has been given. 
Heidenhain and Pfliiger employ absolute alcohol for hardening, 
and a subsequent conservative tingeing with carmine. Picked 
preparations may be made from fine sections of the entirely 
fresh organ, by adding the gland secretion, humor aqueous, 
iodine-serum, or a very dilute chromic-acid solution (0.02-0.04 
per cent.), with a slight addition of the previously mentioned 
fluid. 
Heidenhain recommends for maceration iodine-serum, chro- 
mic acid (sV“2- gr. to the oz,), or bichromate of potash (p-16 gr.). 
Acidulated water (0.02 per cent, glacial acetic acid), with the 
subsequent immersion in chromic acid ( gr. to the ounce), 
also affords good preparations. 
Pfliiger employs the action of iodine-serum for from 4-6 
days, either alone or with the subsequent immersion in chromic 
acid of 0.02 per cent. It is furthermore very good to place the 
organ (the submaxillary gland of the rabbit) in a small glass 
vessel, and to add 4 to 8 drops of the chromic-acid solution, 
and, after an hour, when the gland has become hardened by 
swelling, to make tine sections from it for the purpose of pick- 
ing. The 83 per cent, solution of potash also deserves to be 
employed. Osmic acid serves for the nerve termination. 
We here give Pfluger’s more recent method : 
Make with a razor very fine sections from the submaxillary 
gland of the ox. Pick these apart in osmic acid of 1.003 spe- 
cific wt., and put a covering-glass over them, with something 
under it to prevent pressure. A series of such objects are then 
placed for a day in the moist chamber (p. 99). The water 
which has been added may subsequently be replaced with gly- 
cerine. The cells will be found slightly colored, but the nerves 
will be black. 
Krause employed molybdenate of ammonia, with the sub- 
sequent use of tannic or pyrogallic acid (p. 159). Finally, 
Ranvier used for macerating, dilute—for hardening, concen- 
trated picric acid, and for the latter preparations tingeing with 
picro-carmine (p. 153). The injection of the blood-vessels of the 
submaxillary gland of the dog, for instance, is not difficult. DIGESTIVE ORGANS. 
427 
For the recognition of the lymph-passages Gianuzzi recom- 
mends exciting a condition of oedema in the same organ. The 
natural injection may be employed here, the gland being ligated 
at the hilus, and removed with the preservation of the capsule, 
and hardened for a few days in a solution of chromate of pot- 
ash, and then placed in alcohol. Or the gland may be removed 
and then carefully injected by 
the artery with colored gela- 
tine, the aperture of the vein 
being left open. It is then to 
be hung in alcohol for a few 
days, in order that the capsule 
may be rendered more firm; 
and, finally, a puncture is to 
be made near the artery, at the 
place where it sinks into the 
gland-tissue at the hilus. 
The submaxillary glands of 
many of the mammalial ani- 
mals, such as those of the dog 
and the cat (but not those of 
the rabbit), are mucous glands. 
Pig. 249. The submaxillary gland of the dog. a, 
mucous cells; b, protoplasma cells; c, Gianuzzi’s 
crescent; d, transverse section of an excretory duct, 
with the peculiar cylindrical epithelium. 
In the quiescent organ (fig. 249) 
one may recognize, together with granular cells containing pro- 
toplasma (5), which frequently present a small and compressed 
semilunar structure (c) at the border of the gland-vesicle (the 
“ crescent ” of Gianuzzi), other gland-cells {a) which are larger 
and of a hyaline transparency, whose contents are not reddened 
by carmine, and which prove to be mucous. Our figure shows 
still another peculiar condition which is very easy to recognize, 
a delicate longitudinal striation of the cylindrical epithelial 
cells in the excretory duct (d). 
When Heidenhain had induced an increased secretion in the 
submaxillary gland of the dog by a prolonged irritation of the 
nerves, an entirely different appearance presented itself (fig. 250). 
The so-called mucous cells had given up the mucine ; their 
bodies were again formed by protoplasma {a). Thus, at least, 
we regard the fact, in accordance with Ewald and Ranvier. 
The gland-cells of the parotid, on the contrary, always ap- 
pear granular. No one has thus far observed a transformation 
of their substance into a homogeneous mucous mass. 428 
SECTION SEVENTEENTH. 
If it be desired to attempt the injection of the canal system 
(p. 189, note), cold-flowing blue, without alcohol, is the best in- 
jection fluid. 
Finally, the condition of the oral cavity and the fluids which 
it contains also re- 
quire a short notice. 
The latter consist of 
the mixture of mucus 
and the secretions of 
the numerous glands 
which open into this 
cavity; namely, the se- 
cretion of the salivary 
glands. By hawking 
and coughing, the se- 
cretory products of 
the air-passages, and 
Pig. 250. The same suhmaxillary gland after prolonged irritation 
of the nerves, after Heidenhain. «, protoplasma cells; b, remains 
of the mucous cells. 
by vomiting, arrested contents of the stomach, as well as re- 
mains of food and particles of dust, may be associated with 
these essential integrants. On examining the parietes of the 
oral cavity, especially the papillae filiformes on the back of 
the tongue (Fig. 251) and the gums at the base of the crown 
of the teeth, they are found to be covered by a sometimes 
thinner, sometimes thicker, slightly 
brown, fine granular covering, which 
contains, together with decomposed 
animal substances, the filaments and 
fragments of a lower vegetable organ- 
ism from the order of the Schizomy- 
cetes (Nageli). This (the Leptothrix 
buccalis of Robin) consists of a con- 
fused mass of extremely fine filaments. 
The gastric furred tongue, when in 
a rough condition, shows a prolifera- 
tion of the familiar epithelial proces- 
ses of the papillae filiformes, or, when 
the surface is smooth, a covering com- 
Pig. 251. A papilla filiformis with its 
epithelial processes, over which is 
spread out the matrix of the Leptothrix 
buccalis, from which also single fila- 
ments are growing out. 
posed of luxuriant epithelial cells, the above-mentioned vege 
table filaments and mucous corpuscles. 
The substances in question may be readily obtained from 
the living body for examination, by scraping with the blade of DIGESTIVE ORGANS. 
429 
a knife. To understand the entire arrangement, a fresh body 
should be used and recourse be had to vertical sections after a 
previous hardening. 
The vegetable organism just mentioned must, in conse 
quence of its frequency, be designated as 
a normal occurrence. Another vegetable 
parasite from the group of fungi, Oidium 
albicans, occurs in thrush (muguet), a very 
frequent disease of the earlier period of 
suckling (tig. 252). In the ordinary, slight- 
er grades of the disease, its collections ap- 
pear as whitish, later as grayish-yellow 
plates, sometimes more isolated, sometimes 
continent, and, in high degrees, almost cov- 
ering the entire oral cavity, even extend- 
ing down into the oesophagus. If we place 
a small portion of this, mixed with water 
Fig. 252. Thrush fungus, Oidi- 
um albicans of the nursing child. 
a, fungous filaments ; b, spores ; 
c, pavement epithelium of the 
mouth. 
or some alkaline fluid, under the microscope, we see much 
broader, jointed, fungous filaments (a), with spores (Z>), and 
mycelium, so that it is impossible to confound them with the 
Leptothrix buccalis, the filaments of which are so fine. 
A drop of saliva, placed under the microscope, shows air- 
bubbles entangled in it, sometimes in smaller, sometimes in 
larger numbers, then the separated pavement epithelium of the 
oral cavity which floats about in the fluid, partly hanging to- 
gether in shreds, partly isolated (fig. 253), and either unaltered 
in appearance or having already undergone maceration to a cer- 
tain extent. Finally, the salivary cor- 
puscles are noticed as an element which, 
though never absent, still varies in quan- 
tity . Fresh, living cells of this kind show, 
with a higher magnifying power, a dis- 
tinct dancing movement of the elemen- 
tary granules which occur in their bodies. 
Consequently, effete salivary corpuscles, 
which are undergoing decomposition, no 
Fig. 253. Pavement epit Helium 
of the oral cavity. 
longer present this movement phenomenon. 
Filaments of cotton, lint, etc., remains of food—for example, 
fibres of meat, granules of starch, particles of vegetable tissue, 
fragments of milk, appearing in the form of fat-globules and 
drops—form adventitious constituents of the saliva. SECTION SEVENTEENTH. 
The methods for examining the oesophagus are the same as 
those for the oral cavity, and may therefore be omitted here. 
The investigation of the stomach is, on the contrary, of 
higher importance. In its examination always, when possible, 
avoid older cadavers and, for many observations, nse only the 
recently killed, not yet cold mammalial animal. Fine sections 
through the soft tissue are difficult to make, but very easy on 
the contrary, through the frozen parietes. On these may be per- 
ceived, by the addition of indifferent fluids, the peptic-gastric 
glands of the mucous membrane, the gland-cells, and finally 
the cylinder epithelium of their apertures, as well as of the 
surfaces lying between them. A not too prolonged immersion 
in a per cent, solution of osmic acid has recently been re- 
commended for these delicate cellular coverings (Ebstein). 
The addition of dilute alkalies rapidly dissolves these gland- 
cells, so that the membranes of the tubes only remain. Hard- 
ening methods (absolute alcohol, chromic acid, chromate of 
potash, osmic acid) are necessary for the more accurate study 
of their arrangement, as well as for that of 
other elements lying in the tissue of the 
mucous membrane. Injections readily 
succeed. Either the arteria coeliaca or 
the vena portarum are to be selected in 
smaller creatures; in larger animals an 
arterial branch on the external surface of 
the stomach is to be used. To obtain fine 
views of the tubular-shaped gastric glands 
(fig. 254) it is best to prepare thin, verti- 
cal sections from the mucous membrane 
hardened in absolute alcohol; they are to 
be examined in glycerine, without the ad- 
dition of any more strongly acting re- 
agent. The simple and more complicated 
Fig. 254. Vertical section 
through the mucous membrane 
of the human stomach, a, super- 
ficial papilla;; b, peptic-gastric 
glands. 
tubular glands, as well as the several varieties of cells which 
line them, may then be readily recognized. Fine tingeing con- 
stitutes an important accessory for further details. We rec- 
ommend here, in addition to hsematoxyline, Heidenhain’s direc- 
tions for carmine and aniline staining (p. 162 and 157), like- 
wise Rollett’s method (p. 167), also picro-carmine by Gruetzner’s 
process. Fine transverse sections are naturally indispensable 
for other conditions. DIGESTIVE OEGANS. 
431 
One form of tlie gastric tubes (figs. 255, 257, bears the name of 
peptic glands. At the present time we can with certainty ascribe 
the production of the pepsin to these alone. At the first view 
their compact contents appear as large granular cells (fig. 256). 
Recent more accurate investigations (Heidenhain, Rollett), 
however, show a further composition. There are two forms of 
Fig. 256. Various forms of 
the human peptic cells. 
Pig. 255. Three human peptio- 
gastnc glands. 
Pig. 257. A gastric gland of the cat 
in profile, a, stomach-cell; 6, inner, c, 
outer intercallary piece; 6, the gland 
tube with both varieties of cells. 
the gland-cells to be distinguished (fig. 257 d). The one, smaller 
and more transparent, usually appears to line the whole in- 
terior of the tube in a coherent layer ; the other, larger and 
more granulated, appears more externally and isolated. The 
latter is the peptic cell of the writers, called by Heidenhain 
“ by Rollett, “ delomorphous” cell. The smaller 
continuous form is called by the former observer the “ Tiaupt- 
zelle” by the latter the “adelomorphous” cell. Further cell 
differences are presented by the efferent portion (5, a). 432 
SECTION SEVENTEENTH. 
A series of statements made by Heidenliain concerning the 
condition of the peptic-gastric glands in the condition of rest 
and of activity is extremely interesting. In the fasting animal 
the tubular glands appear shrunken, 
their contours are smoother, and their 
haupt-cells are transparent (fig. 268, 1). 
Several hours after the reception of 
food the peptic-gastric glands present 
an entirely different appearance (2, 3). 
They are swollen, the walls irregularly 
dilated, the haupt-cells are enlarged 
and rendered cloudy by their finely 
granular contents. Finally, at a later 
period (4) shrinking has again taken 
place, the haupt-cells are considerably 
diminished in size, but are also very 
rich in granular matter. Their suscep- 
tibility to staining is conformable there- 
with. 
If the thick mucous coating which 
usually occurs on the inner surfaces of 
the stomach of herbivorous animals, 
especially the rodents, be examined, it 
will be found to contain a considerable 
number of the gland-cells in question, 
part of which appear quite unchanged, 
part in various stages of decomposi- 
tion, and thus constitute a surplus of 
the ferment bodies which are so indis- 
pensable for gastric digestion. 
Another form of the gland-cells of 
partly simple, partly branched tubular 
glands (fig. 259, 1, 2), the so-called gas- 
Fig, 258. Peptic-gastric glands of 
the dog, after Heidenhain, the peptic 
cells darkened by means of aniline 
blue. 1, the gland of the fasting ani- 
mal ; 2, portion of a swollen one in 
the first period of digestion; 3, trans- 
verse and oblique sections of the same; 
4, tubular gland at the end of diges • 
tion. 
trie mucous glands, is tlie cylindrical, sucli as occur in the Lie- 
berkuhn’s glands of deeper portions of the digestive canal. 
While, however, the cells of the efferent (occasionally very long) 
portion of the gland coincide completely with the cylindrical 
epithelium of the gastric surface, shorter, more granular cells, 
which are rendered quite cloudy by acetic acid, occur at the 
fundus of the gland. One is reminded by them of Heidenhain’s 
haupt-cells in the peptic-gastric glands. Both varieties of DIGESTIVE ORGANS. 
433 
cylindrical cells of the gastric mucous glands also act differ- 
ently with regard to the above-mentioned methods of staining 
with carmine and aniline blue. The proper glandular cell- 
elements at the fundus of the tube ap- 
pear rich in granules during gastric di- 
gestion or gastric irritation, and poor in 
granules in the fasting animal (Ebstein). 
Unfortunately, no agreement has yet 
been obtained in the experiments con- 
cerning the fermentative properties of 
these cells (1*). 
Horizontal sections, when brushed a 
little, show the ordinary fibrous connec- 
tive tissue of the mucous membrane be- 
tween the glands (fig. 260). It is as a rule 
entirely free from lymph corpuscles. 
From existing statements of accurate 
observers it is not to be doubted, how- 
ever, that they may under certain cir- 
cumstances obtain a more reticular char- 
acter in man, and may produce lymph- 
cells. The frequent occurrence in many 
persons of scattered lymphoid follicles, 
Fig. 259. So-called gastric mucous 
glands. 1, simpler gland from the 
hog; a, the cylindrical epithelium; 
6, lumen; I*, isolated cells; 2, com- 
pound tubular gland from the dog. 
the so-called lenticular glands, in and beneath the gastric mu- 
cous membrane, is also an argument in favor of this metamor- 
phosis of the tissue of the mucous membrane. 
For the recognition of the muscular tunic of the mucous 
membrane, vertical sections from the 
fresh mucous membrane may be 
acted on for 10-20 minutes by the 
30-35 per cent, solution of potash, 
or thin sections may be made from 
good alcoholic preparations and 
stained with carmine (with the sub- 
sequent action of acetic acid). 
Schulze’s chloride of palladium 
method with carmine tingeing, and 
Schwarz’s double staining with car- 
Fig. 260. Transverse section through the 
gastric mucous membrane of the rabbit a 
tissue of the mucous membrane ; b trans- 
verse sections of empty and injected’ blood- 
vessels, c, d, spaces for the peptic-gastric 
glands. 
mine and picric acid, deserve recommendation here, as well as 
for the entire digestive apparatus. The immersion of the fresh 
gastric mucous membrane in very dilute acetic acid or pyro- 434 
SECTION SEVENTEENTH. 
ligneous acid also deserves to be mentioned. These two fluids 
constitute the most important accessories for the investigation 
of the gastric nerves which contain small ganglia. They may 
be readily recognized in the submucous tissue, but, having en- 
tered the mucous membrane proper, they escape further ob- 
servation. 
Tor many years all efforts to find a system of lymphatic 
canals in the mucous membrane of the stomach were in vain. 
Finally the dexterity and perseverance of Loven were rewarded 
by making this beautiful discovery. Fig. 261, kindly presented 
Fig. 261. Lymphatic of the gastric mucous membrane of the human adult. 
us by the Swedish investigator, presents an interesting view of 
this mightily developed lymphatic apparatus. We are fam- 
iliar with it, moreover, from autopsies. 
Pathological changes of the walls of the stomach are of 
rather frequent occurrence. 
As a result of chronic catarrh, as well as after small hemor- 
rhagic effusions, the mucous membrane not unfrequently as- 
sumes a slate color over larger or smaller places, and the mi- 
croscope shows an embedment of black-pigment molecules. In 
slighter degrees of the disease the gastric glands are found to 
be well preserved; although they often appear distended by 
large masses of cells, the contents of the latter being opaque 
(Forster). In such conditions the mucous membrane is not un- 
frequently found to have an uneven “ mammillated ” surface, DIGESTIVE OEGANS. 
435 
which is dependent partly upon lymphoid follicles, partly on 
a local hypertrophy of the mucous membrane and its glands, 
and occasionally also upon a development of fat-lobules in the 
submucous tissue. Higher degrees may assume the form of 
polypous protuberances. A new formation of smooth muscu- 
lar tissue may also take place from the muscular tunic at the 
pylorus, which then produces an annular constriction of the 
latter, and has formerly been frequently erroneously regarded 
as a gastric carcinoma. Vertical sections from the hardened 
tissue would, in such cases, show the 
' ' 
disposition without difficulty. 
The microscopic examination of 
vomited matters has, thus far, yielded 
only relatively slight results for the 
purposes of the practical physician. 
Among them (fig. 262) appear, first, 
the constituents of the food which has 
been taken. These are naturally of the 
most manifold varieties, and appear 
r- 
partly unchanged, partly slightly al- 
•' cx x <J 
tered, partly commencing to decompose 
. 3 J- J ° x 
in consequence of the action of the luke- 
warm gastric fluid, or in various stages 
sea. Elementary constituents 
of vomited masses, a, peptic cells; 
», cylindrical epithelium; c, mucous 
corpuscles; d, pavement-cells of the 
oral cavity ; e, sarceua ventriculi; /, 
Cryptococcus cerevisise; ff. starch 
K fat dr°Ps; *. muscular 
of digestion from the fermentative action of the gastric juice. 
At the same time it should not be forgotten to take into ac- 
count the textural changes which have already been caused in 
the elements of the food by its preparation. 
Thus we meet with various conditions of the granules of 
starch {g\ which, as is known, have a dissimilar appearance 
according to the several varieties of the starch (rye, wheat, 
barley, peas, potatoes). The addition of iodine (p. 132) serves 
for their recognition, if the observer should ever be in doubt. 
Furthermore, we meet with the greatest variety of vegetable 
cells, spiral fibres, and other structures of vegetable origin. 
If we proceed to the examination of the animal food we find 
molecules and drops of fat ill) coming from milk and fat-tis- 
sue ; furthermore, connective-tissue parts with hyaline inter- 
stitial substance, but unchanged cells, and the likewise unal- 
tered elastic fibres. Muscular fibres (i), in consequence of our 
mode of life, constitute a very general constituent of vomited 
masses of food. These, in consequence of the free gastric 436 
SECTION SEVENTEENTH. 
Juice, frequently appear in the stage of transformation which 
we have already mentioned (p. 329), as the effect of the 0.1 per 
cent, solution of hydrochloric acid, that is, with distinct trans- 
verse lines and the separation into plates or disks. Pieces of 
cartilage will be more rarely found in matters vomited by man, 
and still less frequently a fragment of bone. While the cer- 
tain recognition of these constituents suffices for the practi- 
tioner, their metamorphoses present an interesting phenome- 
non for the histologist and the physiologist. It is also very 
desirable that a systematic study might be made of the action 
of the gastric Juice on the various animal tissues—a research 
which could be readily instituted with artificially prepared 
gastric Juice. 
With these constituents of the food which has been taken 
are also associated, as admixtures of very unequal quantity, 
the separated epithelium of the digestive canal—pavement-cells 
of the oesophagus, and the parts lying higher (d), cylindrical 
cells of the gastric mucous membrane (b); likewise the cellular 
elements of the mucous and tubular glands (a), frequently, 
however, visible only in fragments; and finally, the mucous 
corpuscles having a granular appearance (c). 
Pathological conditions of the organ in question may natu- 
rally associate new elements with the vomited matters. 
In the watery, opalescent, and generally sour fluid which is 
vomited in so-called pyrosis, we recognize principally epithe- 
lial cells and mucous (salivary) corpuscles. Green vomit does 
not show anything special by microscopic examination. The 
color is, as is known, due to the coloring matter of the bile. 
Large numbers of mucous corpuscles, together with sepa- 
rated pavement epithelium from the oral and nasal cavities, 
may also be recognized in the rice-water-like substances which 
are vomited in Asiatic cholera. One notices, on the contrary, 
but few other cells, such as those of the gastric glands and cy- 
lindrical epithelium. 
In the brown and black coffee-ground-like masses, such as 
occur in certain diseases, gastric hemorrhages, gastric carcino- 
ma, and yellow fever, the color is caused by decomposed blood 
and hsematine. Here one meets with partly more normal, 
partly changed blood-cells, lumps of decomposed blood, epi- 
thelial and other cells, which appear saturated with hsematine, 
and colored brown. DIGESTIVE ORGANS. 
437 
Masses vomited during abnormal fermentative processes 
of the gastric cavity show interesting microscopical pheno- 
mena. 
In fermenting fluids, as well as in bread, a fungus, the 
Cryptococcus cerevisise, consisting of oval cells (fig. 262, /), 
occurs. From our mode of life, we frequently receive this with 
our food, without any injurious effects. Under certain circum- 
stances, however, a very extraordinary increase of these cells 
takes place in the stomach, and the discharged matters contain 
large numbers of them. 
Another more interesting parasite, though more obscure as 
to its natural history, is the sarcena ventriculi (e) discovered 
many years ago by J. Groodsir. This—very probably a form 
of Schizomycetes—consists of regularly united, cubical aggre- 
gations of roundish cells. The latter are found united in series 
of 4, 8, 16, 32, Definite disturbances of the gastric functions 
do not coincide with the occurrence of the sarcina, so that they 
are of no pathological importance. 
The above-mentioned thrush-fungus of the nursing child 
(fig. 252), in higher degrees of the disease also occurs in large 
quantities in the stomach, as would be naturally expected from 
swallowing the masses of fungus. 
The methods of examining the intestinal canal are, for 
the most part, the same as have been mentioned for the stom- 
ach. 
Concerning the cylindrical epithelium of the intestines, and 
the seam which is permeated by porous 
canals, the essentials have already been 
mentioned at page 261. Nevertheless, 
we must here mention a structural con- 
dition which has recently been more 
accurately investigated. Together with 
the ordinary cylindrical cells (fig. 263, 
l>), others (a), which were characterized 
by varying contents, a difference of 
Fig, 263. Cells of the epithelium of 
the human intestinal villi, treated 
with Muller’s fluid (after Schulze). 
a, Becher-cells; b, cylindrical epithe- 
lium. 
form, and above all by the absence of a cell-membrane at the 
upper free extremity, were discovered long ago at more or less 
regular distances from each other, and varying in number. The 
structures in question resemble sometimes a pear, sometimes a 
wide-bellied drinking glass. F. E. Schulze met with them 
throughout the entire intestinal canal, and in its tubular glands SECTION SEVENTEENTH. 
in the vertebrate animals, in the passages of the lungs, and in 
creatures living in water (fishes and amphibia), on the skin. He 
has given them the name of “ Becherzellen ” (cup-shaped cells), 
and declares them to be mucous-secreting structures. 
A recently killed animal is to be used for their investiga- 
tion, and the examination made either immediately, with the 
addition of indifferent media, such as iodine-serum, or after 
immersion for several days in Muller’s fluid. Nitrate of silver 
has also been employed. 
Our lymphoid cells penetrate into the interior of the cylin- 
drical epithelial cells, as probably do also in the rabbit the 
still so enigmatical Psorosperms (Klebs, Frey, and others), 
and not only into the cylindrical cells of the small intestines, 
but also into those of Lieberkuhn’s glands as well as those of 
the biliary passages. 
The resorption of the chyle-fat by the cylindrical cells of the 
intestinal villi may be observed in fresh and hardened speci- 
mens. The handsomest appearances may be obtained in the 
smaller mammalia by the previously mentioned injection of 
milk. Seldom, and only by a rare chance, can the body of a 
human being who has suddenly died during the digestion of 
fat be obtained. The examination must naturally be made as 
soon as possible, as the decomposition which takes place so 
rapidly in the digestive canal obliterates the delicate textural 
relations. Older cadavers are entirely useless, as the fine 
chyle molecules in the intestinal villi usually flow together 
into large drops, and nothing remains of the cylindrical epi- 
thelium. 
The contents of the Lieberkuhn’s glands also show beauti- 
fully and distinctly in quite fresh intestines, by the addition 
of indifferent fluids ; likewise in alcohol and chromic acid pre- 
parations. Their cylindrical gland-cells (between which, as 
Schulze saw, cup-shaped cells occur) are also quite perishable, 
so that one often meets with only the finely granular, nucleated 
contents of the tubular glands as an artefact. 
Hardening methods are to be employed for all the remaining 
structural conditions. The drying process was formerly em- 
ployed, in consequence of the poverty of the technique of that 
period. There is one investigation, the study of the Brunner’s 
glands (fig. 264), and their peculiar cells (fig. 265), for which we 
would still recommend this procedure, modified by previously DIGESTIVE OEGAXS. 
439 
boiling the tissue in vinegar. In fact, handsome preparations 
may thus be obtained, and the marvellously elegant ramifi- 
cations of the efferent passages may often be followed in the 
interior of the body of the racemose gland, especially in 
thin vertical sections. 
Schwalbe recently rec- 
ommended pyroligne- 
ous acid for a simi- 
lar purpose. Never- 
theless, at the present 
day the same purpose 
is also fulfilled by 
hardening with chro- 
mic acid, chromate of 
potash, and especially 
with absolute alcohol, 
methods which, togeth- 
er with that of freezing, 
constitute the most im- 
portant accessories for the remaining structures of the intesti- 
nal canal. With them, one may even recognize the oblong, 
complicated form of the acini and the cylindrical form of the 
cells of the Brunner’s glands (Schlemmer). 
Fig. 264. Human Brunner’s gland. 
The latter are quite different from the elements of the Lie- 
berkiiliiTs tubes, but quite similar to those of the gastric mu- 
cous glands (Schwalbe). 
The circumstance is interesting that the cells of the quies- 
cent and active Brunner’s glands (like those of the submaxil- 
lary gland and gastric tubes) also differ from 
each other (Heidenhain). 
Tingeing and brushing may be added ac- 
cording to necessity for the further study of 
the intestines. 
The tissue of the mucous membrane (fig. 
266) is differently constituted from that of the 
stomach. 
In the latter organ we meet with ordinary 
Pig. 265. Isolated cells 
of the Brunner’s gland of 
the hog. 
fibrous connective tissue. A looser reticulated substance, with 
nuclei in individual nodal points, has here taken its place. 
Lymphoid cells (a) lie embedded in the meshes, and are especi- 
ally numerous in the small intestine. We have here, therefore, 440 
SECTION SEVENTEENTH. 
a variety of the reticular lymph-cell producing connective sub- 
stance, which is similar to the framework substance of the 
lymphatic glands (comp. p. 275). The tissue of the intestinal 
mucous membrane, however, bears 
a character of irregularity and 
mutability which we do not meet 
with in the lymphatic glands, at 
least under normal conditions. 
This tissue becomes condensed in- 
to a more homogeneous membra- 
nous layer around the glandular 
tubes at the surface of the intes- 
tinal villi, and also forms the limit- 
ing layer of the lymphatic canals 
which pass through the mucous 
membrane. In places, especially 
toward the surfaces of the larger 
Fig. 366. Prom the small intestine of the 
rabbit, a, tissue of the mucous membrane ; 6, 
lymph-canal; c, spaces for the Lieberkuhnian 
glands; d, transverse section of the Lieber- 
kuhnian glands filled with cells. 
blood-vessels and lymphatics, the tissue of the mucous mem- 
brane may assume a different appearance, and may even 
permit of the recognition of the wavy fibrous bundles of the 
ordinary connective tissue. On the other side, however, as 
will soon be shown, the tissue in question passes continuously 
over into the regular reticulated framework of the solitary and 
Peyerian follicles. 
In conformity with this is a textural condition which is in- 
teresting for the nature of connective tissue in general. Within 
a certain space we perceive, at slight distances from each other, 
the one variety of connective tissue becoming metamorphosed 
into the other, occurrences which, as is known, pathological his- 
tology has so frequently shown to take place temporarily after 
each other. 
The conditions which have just been mentioned are related 
first of all to the small intestine of man, the mammalia, and 
birds. The tissue of the mucous membrane of the large intes- 
tine appears to be modified more in accordance with the fibrous 
connective tissue, and is usually poorer in lymph-cells. 
Brushing the reticular tissue of these mucous membranes 
may be accomplished with tolerable facility, and in young 
creatures the recognition of the nuclear formations is not 
difficult. In those which are older the number of the nuclei is 
indeed diminished. DIGESTIVE ORGANS. 
441 
The Lieberkuhnian glands of the small intestine (fig. 267) 
and the tubular glands of the large intestine (fig. 268), which 
are quite identical with the former, repeat in their arrangement 
Fig. 269. Apertures of the 
glands of the large intestine 
(representing at the same 
time the transverse sections 
of deeper-lying portions of 
the glands) from the rabbit. 
Pig. 967. Lieberkuhnian 
glands of the cat, with de- 
composed contents. 
Fig. 268. Tubular glands of the 
large intestine of the rabbit after 
treatment with caustic soda. 
and frequency the conditions of the stomach. They are to be 
examined with the same accessories. On thin horizontal sec- 
tions of freshly immersed parts one may become convinced of 
the epithelium-like arrangement of the cells, and see how these, 
conically sloped towards each other, turn their bases outwards 
and their narrow terminal surfaces towards the axis of the tube 
(figs. 266, 269). A special membrana propria to demarcate 
them from the surrounding tis- 
sue of the mucous membrane, 
that is, an independent and firm 
boundary layer of the adjacent 
loose connective tissue, cannot 
be denied. 
The muscular tunic of the 
mucous membrane is brought 
to view by means of the same 
accessories as were used for that 
of the stomach. 
Peculiar phenomena are pre- 
sented by the intestinal villi 
Fig. 270. Small intestine of the cat, in vertical 
section, a, the Lieberkuhnian glands; b, the in- 
testinal villi. 
which are met with in the shape of variously-formed projec- 
tions, pressed closely together in large numbers over the whole 
surface of the small intestine (Fig. 270, 5). 442 
SECTION SEVENTEENTH. 
Their tissue (fig, 271) bears the same character as that of the 
remainder of the mucous membrane, and is, as was remarked, 
membranously thickened at the outer surface, as well as towards 
the chyle vessel {d) which passes through its axis. In birds I 
succeeded, years ago, in bringing to view a 
distinctly reticular external surface (as on 
the surface of a lymphatic gland-follicle) with 
the greatest certainty. Eberth also found 
the same in the goose, and was able to recog- 
nize a similar condition of the surface of the 
villi in the mammalia and in man. The in- 
testinal villi of the rat are best adapted for 
this purpose. Hardening for a month in 
Muller’s eye-fluid has been recommended by 
that investigator. Longitudinally arranged 
smooth muscular cells (c) also occur embed- 
ded in the tissue of the villi, and give these 
organs their vital contractility, which has 
been known for a long time, and which is so 
important for the onward movement of the 
chyle. 
Fig. 271. An intestinal vil- 
lus. a, the cylindrical epi- 
thelium with its thickened 
seam; b, capillary net-work; 
c, smooth muscular tissue; 
d, central chyle-vessel. 
Horizontal sections of the villi may be 
made from well-hardened intestines by means 
of a very sharp razor with tolerable facility ; I find it difficult, 
on the contrary, to obtain a good vertical section, even from 
the voluminous villi of larger mammalia, whether the dried or 
the hardened intestine, or an embedding process be employed. 
The submucous tissue is to be investigated with the cus- 
tomary methods. The accessories which have been already 
mentioned (p. 345) serve for the examination of the ganglionic 
plexuses which occur here (figs. 195, 196). 
Their arrangement is to be studied partly on vertical sec- 
tions, partly on surface views of the submucous tunic from which 
the muscular and mucous membranes have been separated. 
The muscular tunic is to be examined according to the direc- 
tions previously given for that tissue (p. 317). 
The remarkable ganglionic plexus, discovered by Auerbach 
between the circular and longitudinal muscular-layers of the 
intestine, has also been noticed at the nervous system (p. 347). 
Injections of the blood-vessels of the intestinal canal suc- 
ceed with such relative facility (in the smaller creatures, by 443 
DIGESTIVE ORGANS. 
the coeliac and mesenteric arteries as well as by the portal vein; 
in larger ones, by the arterial and venous branches, after the 
ligation of those which supply the neighboring districts), and 
afford such a permanent landmark, that they should never be 
neglected. A capillary net-work encircles the tubular glands 
with an abundant, extended, reticular formation in the same 
manner as in the stomach, so that there, where the surface of 
the mucous membrane remains smooth, the arrangement is 
quite the same. Our fig. 272, which presents the capillary 
Fig. 272. Semi-diagrammatic figure of the vascular 
arrangement in the gastric-mucous membrane (repre- 
senting at the same time that of the colon). 
Fig. 273. The vascular net-work of an intestinal 
villus of the hare, with the arterial trunk, 6, the 
capillary net-work, c, and the venous branches, a. 
net-work of the gastric mucous membrane in vertical section, 
may also be regarded as a figurative representation of the 
blood-vessels in the deeper portions of the colon. 
There, however, where projections, papillae, and villi occur 
—and this is the case for the entire small intestine, as also, 
occasionally, for portions of the large intestine—we meet with 
corresponding modifications of the vascular arrangement. In 
the intestinal villi especially, the latter become very character- 
istic and elegant. There is here a so-called looped net-work, 
that is, two or more larger trunks pass over into each other in 
a loop-like manner at the summit of the villus, and are united 
in their course by an intermediate, more circular meshed net- 
work. In larger villi, as our fig. 273 shows, the arrangement 444 
SECTION SEVENTEENTH. 
may become considerably complicated ; in small specimens, 
those of the monse, for instance, it remains much more simple. 
The capillary net-work always lies in the peripheral portion 
of the villus, so that the central portion is occupied by the lac- 
teal vessel which is soon to be described. 
The blood readily remains in this vascular district, so that 
those who shun the trouble of an artificial injection may obtain 
quite handsome views of the capillaries of the villi from the 
body of an animal which has been killed several hours previ- 
ously by strangulation. 
The villus-like projections which may make their appear- 
ance in the large intestine, such, for instance, as occur in re- 
markable perfection in the upper portion of the rabbit’s colon, 
have a similar arrangement of the blood-vessels, but differ com- 
pletely from the glandless villi of the intestines, by being, like 
the smoothly spread mucous membrane of the colon, permeated 
by glandular tubes in close apposi- 
tion. 
Finally, as regards the lymphat- 
ics of the intestinal canal, or the so- 
called lacteals of these parts, much 
may be recognized, even without in- 
jections, in bodies in which the di- 
gestion of fat has commenced, and, 
in fact, in former times, many ob- 
servers have obtained valuable in- 
formation in this way. The accumu- 
lation of chyle may be observed with 
facility in the axis of the intestinal 
villi (fig. 274), and with somewhat 
Vig. 274. Intestinal villus of a kid, killed 
during digestion, witli the lacteal vessel in 
the axis. 
greater difficulty the vessels filled with fat of the mucous mem- 
brane and submucous layers (p. 400). A suitable medium for 
rendering such preparations transparent is still wanting, and it 
is also impossible to keep them in a moist condition for a long 
time. My attempts, at least, have been entirely frustrated. 
The artificial injection by means of the puncturing method 
was, therefore, a great improvement, and has, within a few 
years, increased our knowledge of the lymphatics of the intes- 
tinal canal considerably. I believe that I have simplified and 
facilitated the procedure essentially by the employment of the 
cold-flowing transparent mixtures. DIGESTIVE OEGANS. 
445 
These injections succeed with greater or lesser facility, and 
occasionally only with difficulty, according to the frequency 
and extent of the lymphatic passages and lymphatics with 
valves which lie in the submucous tissue. The small intestine 
of the sheep forms a very favorable object, as the submucous 
layer is occupied, or rather constituted, by a surprisingly large 
number of very extensive lacteals. The rabbit must also be 
designated as an animal adapted for these investigations, but 
the thinness of the intestinal parietes renders the introduction 
of the fine canules somewhat difficult. The procedure succeeds 
with less facility, in consequence of the narrowness and greater 
sparsity of the lymphatics, in the calf and the hog, the dog 
and the cat; still less in man, although, with some persever- 
ance, one may also succeed with infantile as well as (quite 
fresh) adult bodies. 
With such intestines as are difficult to manage, one may 
commence with the Peyerian follicles, which are generally 
easier to inject, and thus from them fill the neighboring portions 
of the small intestines with their villi. In the sheep and rab- 
bit, on the contrary, where the canule is well introduced, a 
practised hand almost always succeeds in forcing the mass over 
more considerable surfaces. Filling the lymphatics of an entire 
intestine of the sheep, by means of a series of individual injec- 
tions, of which Teichmann speaks, is, in fact, no great proof of 
skill. 
It would lead us too far, were we here to describe more mi- 
nutely the relative arrangements of the horizontal lymphatic 
plexuses in the submucous tissue, the vessels which pass from 
them into the muscular-tunic, as well as the canals which pass 
up between the tubular glands and frequently reunite in a 
plexiform manner (fig. 275, d). In the intestinal villi, which 
vary considerably in form and size, being long and thin, and 
also quite broad and low, there are lacteals of varying diameter 
with coecal extremities ; in the first case they are single {a), in 
the latter, double (6) or manifold (c). They may then pass into 
each other at the extremity of the villus in an arched manner 
(c), or still maintain the independent coecal termination (b). 
Transverse branches occur more frequently in the deeper por- 
tions of these more complicated lymphatics. 
The injection of the lymphatics in the large intestines, that 
is, in their mucous membrane, is much more difficult to accom- 446 
SECTION SEVENTEENTH. 
plisli. Their occurrence is considerably less frequent, and the 
entire arrangement is quite variable in the different animals. 
Horizontal reticulations, passing through the mucous mem- 
Fia. 275. Vertical section through the human ileum, a, intestinal villi with single; 6, with double; c, 
with triplicate lacteals; d, lacteals of the mucous membrane. 
brane with short knotty vertical passages, and level ramifica- 
tions passing along the base of the mucous membrane with 
longer canals, ascending at right angles, etc., also occur. 
These lymphatics, which have essentially increased our knowl- 
edge of the processes of absorption in the intestinal canal, are 
at present recognized in the ruminantia, the rodentia, and the 
carnivora. In man (where they are certainly not wanting), the 
experimental proof of their presence has not, as yet, been ad- 
duced. 
Have these lymphatics of the intestine a special vascular 
wall, or are they merely cavities bounded by connective tis- 
sue ? 
Recent investigations leave no further doubt that beneath 
the serous coverings, and in the muscular layers of the intes- 
tinal canal, true “vessels” contain the chyle. Their knotty 
appearance, caused by the valves, speaks in favor of this, and 
the walls are also recognizable after the connective tissue has 
been rendered transparent by means of acetic acid, pyrolig- 
neous acid, etc. In part, perhaps in most of the mammalia, 
this texture is still maintained in the lymphatics of the sub- 
mucous tissue, while in others there is even here a formation 
of passages with lacunae, that is, vessels without an independ- 
ent vascular wall. Throughout the mucous membrane proper, 
on the contrary, it is certain that only the latter are present. 
They are all, nevertheless, lined with the peculiar vascular DIGESTIVE OEGANS. 
447 
cells (see p. 399). These lymphatics are therefore bounded by 
a very thin but entirety connected epithelium, and this invest- 
ment is so accurate as to serve the same purpose, at least for 
the normal condition, as any vascular membrane. Not a 
granule of the injection mass passes into the adjacent tissue 
without a rupture, notwithstanding the “stigmata” (p. 384) 
which occur between many of the vascular cells. We have 
frequently injected the small intestines with the finest mix- 
tures under a high degree of pressure, so that the ducts of the 
intestinal villi, being considerably distended, compressed the 
spongy tissue of the latter powerfully, but even then not a 
molecule of the injection mass passed into the tissue. That, 
on the contrary, an individual immigration into the lymphatics 
of the relatively gigantic lymph-corpuscles, such as are pro- 
duced in such abundance by the reticular tissue of the mucous 
membrane, may occasionally take place is evident. Neverthe- 
less, according to our views, these cells of the intestinal mucous 
membrane are, under normal conditions, without a future ; 
they arise and disappear in the meshes of the reticular tissue. 
On the other hand the possibility cannot be denied, that in 
morbid processes a more plentiful transmigration into the 
lymphatic current may take place through the dilated stigmata, 
the stomata of Arnold. 
Lymphatic follicles are to be found, although varying in 
quantity, in the intestinal canals of all of the higher verte- 
brates and of man. They occur partly isolated or in very 
small groups, and are then called solitary follicles; they are 
also, in part, united into larger collections and form the 
plaques of the Peyerian glands. 
The latter structures are most plentiful in the lower por- 
tions of the small intestine, but may also—and this is a regu- 
lar occurrence in many mammalia—be met with in the large 
intestines. Generally the isolated follicles also show similar 
conditions. 
The structures with which we are occupied, especially the 
Peyerian glands which are the most thoroughly understood, 
are embedded in the mucous membrane and the submucous 
tissue. Thus we see in the vertical section of the small Peyer’s 
patch of a rabbit (fig. 276) the bases of these follicles (b, c) with 
a globular form in the submucous layer. 
Other follicles are much higher and more slender, frequently 448 
SECTION SEVENTEENTH. 
assuming an appearance resembling the sole of a shoe, and are 
accompanied by an increased thickness of the mucous membrane 
and submucous tissue. 
At an earlier period, 
which was poor in methods 
of investigation, the study 
of these organs was diffi- 
cult, so that notwithstand- 
ing the interest awakened 
by the participation of 
these structures in dis- 
eases, especially those of a 
typhoid nature, our knowl- 
Fig. 276. Vertical section through a fresh Peyer’s patch 
of the ileum from the rabbit, a. intestinal villi; 6, c, follicles. 
edge of them could not be made to progress properly. At the 
present time the hardening methods, especially the immersion 
in alcohol or chromic acid (drying is not so good) are conducive 
to the purpose. With these must naturally be associated the, 
in general, not easy (complete) injection of the blood-vessels, 
Pig. 277. Vertical section through a human Peyer’s patch, with its lymphatics injected, a, intestinal 
villi with their laoteals ;6, Lieberkiihnian glandsc, muscular layer of the mucous membrane; a, apex 
of the follicle; e, middle zone of the follicle ;/, basis portion of the follicle; g, continuation of the lacteals 
of the intestinal villi into the mucous membrane proper; h, reticular expansion of the lymphatics in the 
middle zone; i, their course at the base of the follicle ; k, continuation into the lymphatics of the submu- 
cous tissue ; I, follicular tissue in the latter. 
and the sometimes easier, sometimes more difficult, injection of 
the lymphatics. 
The Peyerian follicle (fig. 277) consists, as was remarked, of 
a sometimes more globular, sometimes more oblong basis por- DIGESTIVE ORGANS. 
449 
tion (_/) extending freely into the submucous tissue. In many 
creatures there is a system of connective-tissue partition walls 
between the basis portions. Secondly, we find the follicle 
(corresponding to the entire form) projecting freely into the in- 
testinal canal, with a sometimes higher, sometimes flatter apex 
(d). These, covered with cylindrical epithelium, are surround- 
ed by more or less prominent elevations of the mucous mem- 
brane, which are generally furnished with villi (a, a). 
Between the apex and base a middle zone (e) remains. In 
it the demarcation of the two follicular portions is wanting. 
In vertical and horizontal sections it is seen, on the contrary, 
how in this middle strata all the follicles of one plaque pass 
into those of another, and then how this zone is continued 
**• The tissue of the Peyerian follicle of an adult rabbit, exposed by brushing, a, capillary ves- 
s) o, reticular framework; c, lymph corpuscles. 
uninterruptedly into the adjacent tissue of the mucous mem- 
brane (I). This is the metamorphosis of the reticular connec- 
tive tissue of the mucous membrane into the reticular frame- 
work of the lymphatic gland follicle, of which we have 
already spoken on a previous page. 
Here also the net-work of the follicle (fig. 278, h) is essen- 
tially the same as occurs in the large lymphatic glands; in 450 
SECTION SEVENTEENTH. 
young bodies it is a cellular reticulation, in older ones it con- 
sists more of trabeculae with, shrunken nuclei in individual 
nodal points. Towards the periphery of the basis portion the 
tissue assumes a more finely reticulated character (as also oc- 
curs towards the investing spaces of the follicles of the lym- 
phatic glands); in the 
central portions, on the 
contrary, the meshes are 
not unfrequently larger. 
The blood-vessels of 
the Peyerian glands have 
recently been frequently 
described, so that it must 
appear superfluous to al- 
lude to them more thor- 
oughly again. Only the 
remark, together with 
several examples, may 
Fig. 279. Vertical section through an injected Peyerian 
capsule of the rabbit, with the capillary net-work of the same, 
a, the larger lateral vessels, &, and those of the intestinal villi, c. 
here find place, that a non-vascular central portion of the fol- 
licle does not, as a normal occurrence, exist. Incomplete in- 
jections, it is true, give, frequently enough, the false image of 
capillary loops in the internal portions of the follicle. Our 
figures 279 and 280 represent this arrangement of the vessels 
in a small Peyerian patch of the rabbit, from a very complete 
injection mounted dry. We have also, in addition, accurately 
re-examined the arrangement in moist specimens from a series 
of consecutive sections. 
Good injections of the lymphatics teach the following:— 
The lymphatic vessels (fig. 277, a, a) which return from the in- 
testinal villi (the so-called lacteals) form a reticulum {g) around 
the tubular glands (h) which occur in the villous elevations, 
and this is continuous with a net-work of reticularly enclosed 
vessels (Ji) which surrounds the middle zone of each follicle. 
The latter then open either into a simple investing cavity which 
surrounds the basis portion like a shell (rabbit, sheep, calf), 
exactly similar to that of the alveolus, or this is replaced by 
a net-work of separated passages and lacunae encircling the 
basis of the follicle in a similar manner, so that this portion of 
the Peyerian follicle (7q i) appears like a toy-ball around which 
a thread is wound (as in man, the dog, and the cat). From 
the latter system of vessels (or from the simple investing DIGESTIVE ORGANS. 
451 
space) finally arise the efferent lymphatics of the submucous 
layer (&). 
The reader will comprehend that follicles of the latter vari- 
ety are more difficult to inject than those of the first form with 
the simple shell-like in- 
vesting spaces. 
The vermiform pro- 
cess, as well as the small 
and scanty caecum of 
many carnivora consists, 
in a remarkable manner, 
of only a closely crowded 
collection of follicles. 
The processus vermifor- 
mis of man and of the 
rabbit represents, in fact, 
a Peyerian plaque which, 
largely extended, forms 
an entire portion of in- 
testine. Teichmann suc- 
ceeded in injecting them 
in man ; the injection of 
the vermiform process of 
the rabbit is a mere 
Pig. 280. Transverse section through the equatorial plane of 
three Peyerian capsules of the same animal, a, the capillary 
net-work ; b, the larger annular-shaped vessels. 
child’s play, and the entire organ deserves to be most urgently 
recommended to any one who desires to study the Peyerian 
follicles. 
Numerous pathological metamorphoses of the intestines be- 
come objects of microscopic investigation. The same methods 
■which we have mentioned in the investigation of the normal 
structures are generally employed. It should be made a rule 
to obtain the freshest possible objects, as the decomposition 
which soon commences changes the soft tissues in such a man- 
ner as to render them unintelligible. The pathological new 
formations in the intestinal canal are, in general, the same as 
m the stomach. Thus we meet with similar pigmentations, 
connective-tissue productions, lipomata, etc. Carcinomatous 
tumors occur in the large intestines, especially in the rectum. 
Tubercles, on the contrary, are met with chiefly in the ileum, 
less frequently in the jejunum and colon. It is the lymphoid, 
The solitary, as well as the agminated (Peyerian) follicles of 452 
SECTION SEVENTEENTH. 
these parts which, like other lymphatic glands, are especially 
affected by this process. More accurate histological investiga- 
tions of this metamorphosis with the aid of modern accessories 
would be in place. Tumefactions of the follicles show them- 
selves conjointly with capillary distentions and cell prolifera- 
tions. Later, the destruction of numerous lymph-cells takes 
place and the finely granular so-called tubercle mass is formed. 
This softens and occasions the formation of ulcers. Usually, 
the lymphatic glands of the mesentery also take part in this 
process. 
The structural conditions of the follicles in abdominal typhus 
are very similar in an anatomical point of view. In the first or 
catarrhal period, the capillaries of the Peyerian follicles are 
frequently widened to a considerable degree. Large multinu- 
clear lymph-corpuscles are met with here, exactly in the same 
manner as in the typhoid metamorphosis of the lymphatic 
glands (p. 407), By means of several injections made at an 
earlier period, I was able to obtain the conviction, at least, that 
in this stage the lymphatics of the Peyerian glands are still 
thoroughly permeable. Later, with the destruction of the 
cells, the former appear to become stopped up and imperme- 
able. It does not seem to be in place here to speak further of 
the associated processes of absorption, of the softening of the 
contents of the follicles, and of the formation of intestinal 
ulcers and sloughs. The latter masses consist of fine granular 
matter, nuclei, cells, cell remains, etc. The associated process 
of cicatrization takes place naturally, by a new formation of 
connective tissue. Accurate conclusions are not easily ob- 
tained in these cases, as I know from my own experience, so 
that a careful investigation of the cases at hand is very desir- 
able. 
Finally, with regard to the methods of preserving microscop- 
ical preparations of the digestive canal. The vertical and hori- 
zontal sections may be preserved moist, with or without pre- 
vious staining, either in watery or more concentrated glycerine. 
If they have been carefully washed before being placed in the 
latter fluid, they keep well, as a rule, as do also preparations 
of their vessels and lymphatics injected with transparent 
masses (carmine, Prussian blue). According to previous expe- 
rience, the nervous and ganglionic plexuses of the intestinal 
canal may be best preserved by freeing them from the residue DIGESTIVE ORGANS. 
453 
of their acid by washing in distilled water some time before 
mounting. The method of depriving tinged preparations of 
their water by means of absolute alcohol, and the subsequent 
mounting in Canada balsam dissolved in chloroform, must be 
designated as very serviceable for many of these purposes. 
Beautiful and durable review preparations for low powers may 
be obtained in this way. If it be desired to mount thicker 
masses, as, for instance, a portion of intestinal mucous mem- 
brane with the villi erect, glass cells are to be employed. A 
skilful manipulator will be able to make a handsome prepara- 
tion with one, even with Canada balsam. 
There remains for us to consider, finally, the intestinal con- 
tents, and the faecal masses which are formed from the latter. 
Although these are not often objects of medical examination, 
and though disgust deters many observers from the investiga- 
tion of the latter substances, nevertheless, in consequence of 
the multiplicity of their elements, they are both very instruc- 
tive, and not always easy objects of microscopic examination. 
The alimentary pulp which has been altered by the saliva and 
the gastric juice, and has left the stomach, has, as you know, 
received the name of the chyme. In its further progress there 
become mixed with it the secretions of the liver, of the pan- 
creas, and of the various follicles of the mucous membranes, 
as well as exfoliated epithelium, gland-cells, and the mucous 
corpuscles of the intestinal canal; 
while other matters, such as fat, 
albuminous bodies, and salts are 
removed by absorption into the 
lacteal system. The chyme natu- 
rally presents very considerable 
differences according to the na- 
ture of the food ; in the carnivora 
it is different from that of the 
herbivora. 
We omit here the substances 
which are dissolved in the chyme. 
Its elements consist of molecules 
and drops of fat, altered muscu- 
Fig. 281. Contents of the small intestine of 
a rabbit. 
lar fibres, portions of connective tissue (in carnivorous animals 
fragments of cartilage and bone), starch-granules, various vege- 
table tissues, etc. Fig. 281, which represents the contents of SECTION SEVENTEENTH. 
the small intestine of a rabbit, may give ns a conception of the 
constitution of the chyme after a vegetable diet. In the speci- 
men we meet with starch-granules in various stages of dissolu- 
tion, in part already changed into empty hollow vesicles, epi- 
dermoidal tissue, prosenchyma cells, spiral fibres, etc. 
By the onward movement through the large intestine, the 
mass undergoes further changes. The digestive properties of 
the so-called intestinal juices make themselves felt; the lym- 
phatics absorb the fluid portions, and, by the transformation 
of the biliary pigment, as well as by putrefactive decomposi- 
tion, the masses assume the color and smell of faeces. 
Numerous elementary particles of the food, such as fila- 
ments of muscular substance, fat-tissue, bundles of connective 
tissue, elastic fibres, etc., are still to be met with. The mus- 
cular fibres are frequently separated into disks, and have a 
greenish tinge from the biliary pigment. Numerous remains 
of vegetable alimentary matters, starch granules, spiral vessels, 
epidermoidal tissue, substances which we have already men- 
tioned in speaking of the contents of the small intestines, show 
themselves in the human excrements. Remarkable faecal dis- 
charges which cause great solicitude to hypochondriacs, and 
may also astonish the physician, may frequently be readily 
demonstrated by the microscopical examination to be merely 
remains of food. 
The human faeces are always very rich in fragments and 
filaments of the Leptothrix. 
With the name of meconium has been designated the dark, 
pitch-like stools of the new-born child. They contain decom- 
posed bile, separated and decaying epithelium and cells of the 
intestinal canal, as well as small hairs from the integument 
which have been swallowed with the amniotic fluid. The me- 
conium is rich in fats, and the ethereal extract forms a deposit 
of numerous crystals of cholesterine. 
Numerous alterations in consistence, color, and constituents 
are presented by the faecal masses in disease. The most re- 
markable stools are found in dysentery, abdominal typhus, 
and cholera. The alimentary constituents here diminish more 
and more, as does also, as a rule, the decomposed bile ; the 
intestinal secretions and the separated cells, on the contrary, 
increase. Albuminous masses, coagulated fibrine, and blood 
may be associated with them. DIGESTIVE ORGANS. 
455 
Dysenteric stools contain desquamated cylindrical cells, 
mucous and pus corpuscles, cell nuclei, gland-cells, fibrinous 
coagula, blood-cells, and clots of blood. 
The peculiar evacuations which occur in abdominal typhus, 
at the height of the disease, show, together with epithelium, 
gland-cells, pus corpuscles, and a fine granular substance with 
nuclei, which has been regarded as the cast-off ulcerative prod- 
ucts of the Peyerian and solitary glands. Not unfrequently, 
blood-corpuscles also occur in these evacuations. 
We mention, finally, the cholera stools. The rice-water-like 
dejections in this disease contain very large numbers of mu- 
cous corpuscles, but, on the contrary, only very little cylin- 
drical epithelium. 
Crystalline deposits of the ammonio-phosphate of magnesia 
Fig. 282. Crystals of the ammonio- 
Phosphate of magnesia. 
Fig. 283. Crystals of taurin. «, completed six-sided prisms; 
6, indefinite sheath-like masses from an impure solution. 
(fig. 282) are found in the alkaline faeces of healthy as well as 
of diseased persons. They present a rhomboidal form, and 
most frequently appear as three-sided prisms with the two cor- 
ners corresponding to one side blunted, in the so-called coffin- 
lid form. 
In consequence of the general diffusion of the phosphatic 
salts of magnesia in the solid and fluid portions of the organ- 
ism, the double combination we are at present considering 
forms one of the most frequent occurrences as a result of the 
development of ammonia. 
Seldom, on the contrary, do we find in the intestinal canal 
(but even in the stomach, however) crystalline deposits of 
taurin, a conjugate compound of one of the two biliary acids 
(fig. 283). Further chemical procedures are necessary, as a 456 
SECTION SEVENTEENTH. 
rule, for tlie recognition of this body, as well as of clioles- 
terine. 
We cannot leave the microscopical analysis of the faeces 
without first mentioning certain of its animal parasites. 
A large infusory animalcule, covered on all sides with cilia, 
the Paramaecium coli of Malmsten, has hitherto had no practi- 
cal significance. It has been observed a few times in the large 
intestines of human cadavers, as well as in the stools. The 
same is also true of the Cercomonas intestinalis, a small crea- 
ture provided with a whip-like cilia, discovered by Lambl. It 
has been met with in the hyaline intestinal excretions of chil- 
dren, in intestinal catarrhs, as well as in typhoid and choleraic 
diseases (Davaine). Quite fresh intestinal evacuations, or such 
as have not yet become cold, should be used for their investi- 
gation (Ekecrantz), 
The microscopical recognition of the ova of the most familiar 
human helminths is, on the contrary, of much greater practical 
importance (Davaine, Lambl, Leuckart, and others). Leaving 
out of consideration the trichina, the embryos of which creep 
out in the maternal body and then perforate the intestinal 
walls, the ova of the remaining nematodes do not become de- 
veloped in the human body, but are expelled and appear in the 
stools ; likewise, although merely casually, those of the tape- 
worms which have been set free by the rupture of a proglottis. 
It is easy to recognize the ova of the parasites dwelling in the 
lower portion of the intestine, especially of the Oxyuris vermi- 
cularis, numbers of which are presented by every microscopical 
preparation taken from the external surface of a portion of 
faeces (Vix). It is more difficult, on the contrary, to discover 
the ova of the nematodes which live higher up in the intestinal 
canal, such as the Ascaris, as they do not occur in the mucus 
which envelopes the solid faecal masses, but rather in the in- 
terior of the latter. 
The more solid masses of the faeces are to be spread out with 
water for the examination, or the coating of slime is to be se- 
lected (with Oxyurs). The mucous coating scraped from the 
intestinal walls with a spatula also presents an abundance of 
this helminth (Vix). 
We give a short resume of the characteristics of the ova of 
these helminths (fig. 284), after a drawing kindly furnished 
us by Leuckart. DIGESTIVE ORGANS, 
457 
Tricoceplialus dispar (2). Ova double contoured, oval, trun- 
cated at both poles, shell and vitellus of a brownish color. 
Length, 0.0289-0.0257'" ; breadth, 0.0111"'. 
Ascaris lumbricoides (1). Ova roundish or oval, measuring 
Fig. 284. Ova of the most familiar helminths of man, from a drawing communicated by Prof. Leuckart 
(all magnified 370 diameters). 1. Ascaris lumbricoides. 2. Tricocephalus dispar, 8. Oxyuxis vermicu- 
laris. 4. Distoma hepaticum. 5. D. lanceolatum. 6. Taenia mediooanellata. 7. T. solium. 8. Bothrio- 
cephalus latus. 
0.0363-0,0886", next to the largest of all. The shell of the 
ovum has a double contour and is still covered by the transpar- 
ent, indentated areole of an albuminous enveloping substance. 
Oxyuris vermicularis (3). Ova mostly transparent, double 
contoured, oval shell (frequently having an asymetrical curva- 
ture). Length, 0.0231-0.0248"'; width, 0.0102-0.0115'". 
Distoma hepaticum (4). Eggs oval, very large, yellowish. 
Length, 0.0572-0.0616"'; breadth, 0.0332-0.0399'". The ante- 
rior pole with the operculum more flattened. Egg-shell double, 
contents a cell aggregation and vitelline spheres. 
Distoma lanceolatum (5). The brown double-shelled oval 
eggs are much smaller, 0.0177-0.0199'" long, 0.0133'" broad, 
are evacuated at a later period than the previous variety, and 
contain an oval embryo, measuring 0.0115-0.0133"', with clusters 
of granules in the posterior parts of its body. 
Bothriocephalus latus (8). Eggs oval, averaging 0.0310"' 458 
SECTION SEVENTEENTH. 
in length and 0.0199'" in the middle transverse diameter ; they 
are enveloped by a simple, hard, brown shell, whose anterior 
pole constitutes a distinctly interrupted, hood-shaped oper- 
culum. 
Tsenia solium. The ova, which develop within the so-called 
proglottides, present variations in accordance with their age. 
The ovum (7), which contains an embryo sometimes, shows an 
oval enveloping layer of albumen and a globular, thick, mani- 
foldly contoured, brownish inner shell 0.0183'" in diameter, 
the surfaces of which are covered with closely arranged cilise. 
This contains the spherical embryo, which measures 0.008'", 
and is provided with six booklets. Sometimes the outer layer 
of substance (which formed the original vitelline layer) is 
wanting. Undeveloped ova are smaller, globular, at first with- 
out the inner envelope, and enclose a vitelline sphere and a 
special aggregation of embryonic cells. 
Taenia mediocanellata. Ova (6) quite similar, but markedly 
oval and almost regularly provided with the original vitelline 
membrane. The size and other characteristics of the egg-shell 
the same as in the previous animal. 
Together with these, the presence in the faeces of the 
familiar hooks of the Tsenia and their younger forms, as well 
as, in the trichina disease, the sexually mature examples of 
these worms, is applicable for the diagnosis of a helminthic 
disease. Section Qsigl)teentl). 
THE PANCREAS, LIVER, AND SPLEEN. 
We have still remaining the two large glandular organs con- 
nected with the intestinal canal, the pancreas and the liver. 
The spleen is also to be discussed here. 
We can dispatch the pancreas—concerning which Langer- 
hans and Heidenhain have recently instituted excellent studies 
—with rapidity. 
The water salamander or, among mammalial animals, the 
gland of the rabbit, spread out flat, are adapted for the first 
examination of our organ. If, after the manner of Heidenhain, 
the dog be used, take the thicker portions of the gland for hard- 
ening in absolute alcohol, and remove the mesenterial cover- 
ing, as the latter shrinks very much in the reagent mentioned 
and presses the gland-cells together. The human pancreas 
appears less convenient. 
Even in this manner one may recognize the peculiar dispo- 
sition of the gland-cells, which appear hyaline peripherically, 
and granular towards the centre. Heidenhain recommends, as 
an additional accessory, osmic acid of 0.15-0.2 per cent., and 
then (as the best reagent) neutral chromate of ammonia in 5 
per cent, solution. The last-mentioned reagent is excellently 
adapted for the isolation of Langerhans’ spindle-cells of the 
efferent system of canals, as well as the numerous trunks of 
pale nerve-fibres of the pancreas. 
In order to isolate the peculiar gland cells, use a 6 per cent, 
solution of hydrate of chloral, which is to be renewed. 
As water exerts an uncommon distending effect on the 
granules of the pancreatic gland-cells, it cannot be supposed 
that the latter are of a fatty nature. A warmth of 50° C. ex- 
cites coagulation. 
Injections of the blood-vessels succeed readily ; those of the 460 
SECTION EIGHTEENTH. 
gland-ducts (fig. 285) are to be attempted with cold flowing 
mixtures, with Briicke’s soluble Prussian blue, for example. 
The syringe may suffice for this purpose, when carefully di- 
rected. The constant 
pressure renders better 
service for injecting the 
finest capillary passages 
(c) which run between the 
gland-cells. 
The liver, on the con- 
trary, requires a more ac- 
curate discussion, in con- 
sequence of its numerous 
peculiarities. The inves- 
tigation of this, the most 
voluminous of all the 
glands of the body, is in 
fact difficult, so that 
some of its structural 
conditions still remain 
matters of controversy. 
Each of the previous- 
ly mentioned glandular 
organs shows the observ- 
er at once, together with 
Fig. 2£5. Glandular canals of the rabbit’s pancreas, after 
Saviotti. a, Larger excretory duct; b, that of an acinus; c, 
finest capillary ducts. 
the parenchyma cells, an investing membrana propria (which, 
it is true, may be replaced by the adjacent connective-tissue 
layer). While now the cells of the liver are to 
be recognized with the greatest facility, the ques- 
tion as to the existence of the membrana pro- 
pria causes the microscopist great embarrass- 
ment. 
The most simple procedure suffices to dem- 
onstrate the hepatic cells (fig. 286). If the fresh 
organ be cut into, and a knife-blade scraped over 
the cut surface, the brownish mass, diluted with 
some fluid, presents numerous examples, either 
single, in series, or in reticulated fragments. The 
adjacent figure shows the characteristic form, the 
Fig. 286. Human he- 
patic cells. a, with 
single ; b, with double 
nuclei. 
finely granular cell-contents, very generally intermingled with 
isolated fat-molecules and the nucleus, two of which not un- THE PANCREAS. LIVER, AND SPLEEN. 
461 
frequently lie in one cell-body (according to our present views, 
a proof of the cell-division). A special cell-membrane cannot, 
however, be demonstrated on the cells of the liver ; its place 
is occupied much more by a somewhat hardened cortical layer. 
The so-called hepatic lobules have been distinguished for a 
long time. These islets of the substance of the tissue are some- 
times brownish red internally with a brownish periphery, some- 
times the colors are reversed. In most mammalia they become 
blended with each other at their peripheries, but are, neverthe- 
less, here and there more distinctly demarcated. 
The microscope shows as a cause for such a sharp division 
of the hepatic lobules a strongly developed connective-tissue 
boundary layer. The liver of the cat, the sheep, and more 
especially that of the pig, is of this variety. Many things which 
are only to be recognized with difficulty in the organ of other 
animals and of man, appear more distinctly in the last-men- 
tioned animal. The pig’s liver has, therefore, very properly 
been recommended by modern histologists as an extremely 
suitable object for examination. 
With the aid of a sharp scalpel a fine transverse section may 
be obtained from such a lob- 
ule of the quite fresh organ, 
just beneath the surface, for 
instance. Valentine’s double- 
knife (p. 107) has been recom- 
mended by others for this 
purpose. It is much better, 
as we shall have to mention 
hereafter, to make use of liv- 
ers hardened in alcohol or 
chromic acid for the prepara- 
tion of such specimens. We 
also recommend the freezing 
method. 
Fig. 287. Transverse section of a human hepatic 
lobule. 
(fig. 287) shows the columns of the liver-cells or the cell-network 
arranged in a general radiated manner, and, at the same time, 
these columns of cells united together in a reticular manner 
by short transverse rows. In human and mammalian livers the 
cells of such a net-work usually lie in single rows, and are only 
double in places at the nodal points ; nevertheless, many varia- 
Such a transverse section 462 
SECTION EIGHTEENTH. 
tions occur. A system of similar spaces appears in such prep- 
arations, for the most part with great distinctness. 
If for the purpose of further investigations the blood-vessels 
be tilled with transparent substances (either as a single injection 
by the vena hepatia or the portal vein, or with two masses by 
the two veins simultaneously), the radially arranged capillary 
net-work appears with surprising beauty, and one is at the 
same time convinced that the origin of the above-mentioned 
spaces, which were shown by the transverse section of the 
hepatic lobule, is due to the capillaries of the vascular net- 
work, and likewise that the rounded central space (fig. 287) is 
the transverse section of 
a branch of the hepatic 
vein (vena intralobularis 
of Kiernan). 
Fig. 288 may repre- 
sent to the reader the 
finer arrangement of the 
blood - vessels. Several 
lobules appear to be sup- 
plied by each branch of 
the portal vein with finer 
ramifications, running in 
a lateral direction, which 
are confined to the inter- 
Pig. '2SB. The injected liver of the rabbit with the branches 
of the portal and hepatic veins. 
vening spaces between the lobules (venae interlobulares), and in 
the centre are noticed the branches of the hepatic nervous sys- 
tem. A few branches of the hepatic artery also enter the capil- 
lary net-work at its peripheral portion, so that the injection 
may be practised by the latter vessel with the same success as 
by the portal veins. 
Even in the fresh condition, the previously injected liver 
shows the capillary net-work occupied by the columns of the 
hepatic cells, so that two kinds of net-work, that of the blood- 
vessels and that of the cellular trabeculae, are actually thrust 
into each other. 
In well-hardened organs, however, where the razor affords 
very fine sections, these investigations may be made in a much 
finer manner. Simple alcohol may be employed, and likewise 
Clarke’s mixture of alcohol and acetic acid (p. 139). 
Beale especially recommends the use of alcohol to which a THE PANCREAS, LIVER, AND SPLEEN. 
463 
few drops of a solution of soda lias been added (p. 140). Such, 
preparations, freed from adherent matters by washing, and 
tinged with carmine or (which is likewise to be highly recom- 
mended) luematoxyline, afford exactly the appearance as if the 
cells were embedded quite free in the spaces of the capillary 
net-work. 
This view was, in fact, maintained for a long time, although 
the contrary opinion might also have been defended with the 
same propriety, namely : that a cellular net-work, enclosed in 
a homogeneous membrane, was permeated by the reticulated 
lacunar system of capillary blood-currents. 
The modern accessories have led us a considerable step 
further in this matter. 
Fine sections from a liver hardened to the consistence suit- 
able for brushing (I generally 
employ alcohol for this purpose, 
at first with considerable water, 
then with less) permit of the re- 
moval of the liver-cells, although 
only over more limited spaces 
(fig. 289). In this way there is 
left a fine and extremely delicate 
net-work (a) formed of a homoge- 
neous membrane which separates 
the blood-current from the cell 
columns. If carmine tingeing 
be resorted to, the columns of 
Fig. 289. Framework substance from the liver 
of the rabbit, a, homogeneous membrane with 
nuclei; 6, thread-like strip of the latter; c, sev- 
eral hepatic cells not removed by the brushing. 
removed by the brushing will appear very beautifully ; then, 
however, one will also recognize in this hyaline membrane of 
the reticular framework, together with the capillary nuclei, a 
few small and more rounded nuclei which are, in adult crea- 
tures, for the most part shrunken. 
hepatic cells which were not 
If the liver of a new-born child, of a human embryo of the 
later months, or of a mammalial animal of a corresponding 
period of life, be used, the fine hyaline membrane alluded to 
appears in places with great distinctness as a double membrane, 
one of the layers of which corresponds to the capillary walls, 
while the other limits the cellular net-work. 
According to this, there is no longer any doubt that a thin, 
often indeed fine layer of homogeneous connective- 
tissue supporting substance (in continuity with the connective SECTION EIGHTEENTH. 
tissue which envelopes the hepatic lobules), condensed more 
like a membrane towards the cellular net-work, constitutes or 
replaces the long-sought membrana propria of the hepatic-cell 
columns. To it belong, as a system of connective-tissue corpus- 
cles, those nuclei which occur more abundantly in the earlier 
periods of life, and are often surrounded by a distinct cell- 
body. 
While these two membranes, the connective-tissue frame- 
work substance and the membrane of the capillary vessels, ap- 
pear at first separated, in older creatures they often make the 
erroneous impression as if they were blended (see below). The 
beautiful results which Remak made known years ago concern- 
ing the manner of formation of the liver may, therefore, be con- 
firmed on the organ of the new-born and the adult. We are 
indebted in part to Beale, but especially, however, to E. Wag- 
ner, for a knowledge of the facts to which allusion has been 
made. 
We come now to the discussion of the biliary ducts. Their 
branches, provided with a fibrous membrane and a covering of 
shorter cylindrical epithelium cells, surround the lobules, in 
parts more continuous, as an extremely delicate circular net- 
work (cat, rabbit, guinea-pig), in part in the form of separated, 
sinuous, ramified passages ; thereby maintaining a course sim- 
ilar to that of the branches of the portal vein. With careful 
injections of the ductus hepaticus, these passages (the muscular 
tissue of which, as Heidenhain has shown, is rendered apparent 
by treatment with chloride of palladium, 1 : 900) may be recog- 
nized with tolerable facility; likewise, after having once ob- 
served these canals on fine sections of the hardened organ, with 
the assistance of brushing and staining. Here and there the 
latter procedure will also, occasionally, show still finer passages 
wdiich run towards the interior of the lobule. 
The aid of finer injections of the biliary passages is naturally 
necessary for the further examination of their structure, and 
the relation of the ultimate biliary ducts to the cell-columns is 
to be decided by them. In consequence of the extreme deli- 
cacy of the structure of the lobules, and the impediment which 
the bile accumulated in these canals presents to the injecting 
fluid, this procedure is difficult, and is also, as a rule, especially 
with solutions of gelatine, thwarted by rapidly appearing ex- 
travasations. THE PANCREAS, LIVER, AND SPLEEN. 
465 
It is only recently that success has been obtained in arriving 
at a decided result (Budge, Andrejevic, MacGfillavry, Frey, 
Bering, Eberth); namely, in injecting a line and extremely ele- 
gant biliary net-work which permeates the entire hepatic lobule, 
and surrounds the individual hepatic cells with its meshes. An 
analogous condition has since been discovered in the racemose 
glands (p. 460). 
For this purpose use the quite fresh liver of an animal which 
has just been killed, and either the apparatus for constant 
pressure described at pages 192-5 and represented in figs. 88, 
90, and 91, or that of Bering. A previous removal of the bile is 
unnecessary. An aqueous solution of Prussian blue (p. 189, 
note) serves as an injection fluid which is capable of filling the 
marvellous net-work of a lobule by a very moderate pressure 
(20-25 mm. of mercury); in other cases only by a cautious in- 
crease of the pressure (40-45 mm.). A rounded net-work of ex- 
tremely narrow cylindrical tubes, measuring only 0.001-0.0008r//, 
will then be seen to permeate the entire hepatic lobule. Inter- 
woven with the capillary net-work of the blood-vessels, it at the 
same time sur- 
rounds the gland- 
cells with its indi- 
vidual meshes, so 
that a portion of 
the surface of each 
hepatic cell comes 
into intimate con- 
tact with these 
finest passages, 
which have been 
appropriately 
named “biliary, 
capillaries” (Mac- 
Grillavry). Our 
woodcut, fig. 290, 
Pig. 290. Biliary capillaries of tire rabbit’s liver. 1. A part of a lobule. 
a, vena bepatica ; b, branch of the portal vein ; c, biliary ducts : cl, capil- 
laries ; e, biliary capillaries. 2. The biliary capillaries (6) in their rela- 
tion to thecapillary blood-vessels (a). 3. The relation of the biliary cap- 
illaries to the hepatic cells, a, capillaries; 6, hepatic cells; c, biliary 
ducts; cl, capillary blood-vessels. 
affords the reader a primary representation of this structure : 
1 shows the arrangement in the lobule with a low power ; 2 
shows the biliary capillaries and the capillary blood-vessels ; 
and 3 these, together with the hepatic cells, more strongly mag- 
nified. 
The recognition of this delicate condition was at tirst sue- 466 
SECTION EIGHTEENTH. 
cessful only in a few varieties of the mammalial animals. The 
injection succeeds with tolerable facility in the rabbit; it is 
more difficult in the dog, the cat, the hedgehog, the calf, and 
the guinea-pig. Essentially the 
same structure was afterwards 
noticed in the remaining class- 
es of the vertebrate animals 
(Hyrtl, Hering, Eberth). The 
injection of indigo carmine 
in the vein of the living ani- 
mal (comp. p. 191), which, ac- 
cording to the statements of 
Chrczonszczewsky and Eberth, 
is likewise capable of bringing 
out the net-work of the biliary 
capillaries, is also to be recom- 
mended for such studies.* 
Wonderfully beautiful injec- 
tions are often obtained with 
the dog; they are more diffi- 
cult with the rabbit. 
Peszke lias recently given 
more accurate directions for the 
former creature. He uses ani- 
mals which have been previous- 
ly highly fed, and slowly in- 
jects during one hour and a 
half, with pauses of a quarter 
of an hour, each time 10-25 
ccm. of indigo carmine. Then, 
after a quarter of an hour, a 
concentrated solution of chlo- 
Fig. 291. The finest biliary passages of the liver: 
1. of the coluber natrix (after Hering): 2. of the sala- 
mander (after Eberth); 3. of the rabbit, a, blood- 
vessels ; b, hepatic cells; c, biliary capillaries. 
ride of calcium is injected into the cadaver, through the por- 
tal vein. In subsequently injecting the blood passages with 
carmine-gelatine, avoid exceeding a temperature of 35° C. 
* Asp showed how the finest biliary passages may be rendered visible, filled with 
their natural contents. He injected into the ductus choledochus of a living animal 
15 grammes of a saturated solution of gum or tallow. Several days later the crea- 
ture was killed and the liver hardened in absolute alcohol, chromic acid, or bichro- 
mate of potash. The biliary capillaries then appeared as fine gold-yellow, shining 
filaments. THE PANCREAS, LIVER, AND SPLEEN. 
467 
What is, however, the more accurate relation of the biliary 
capillaries to the cells and blood-vessels of the liver ? 
The coluber natrix (fig. 291, 1) shows, in the most elegant 
manner, the transversely-divided, finest biliary passages (c) 
surrounded by a wreath of gland-cells (b) and separated by 
these from the capillary vessels (a). A similar arrangement is 
also presented by the liver of the salamander (2). 
In the mammalia, on the contrary, the fine system of biliary 
passages assumes the reticular arrangement represented in fig. 
290, in consequence of the extensive development of the lateral 
branches. Here, now (fig. 291, 8), we see the surface of each 
hepatic cell (b) coming in contact one or more times with the 
biliary capillaries (c). The biliary capillaries and capillary 
vessels (a) are, however, never contiguous to each other, but, 
rather, a gland-cell or a portion of one always separates the 
biliary from the blood current. Even in the mammalial ani- 
mal, therefore, notwithstanding all complications, the old fun- 
damental plan is retained. 
If the injection with constant pressure has succeeded—the 
process should be discontinued as soon as a few lobules on the 
surface of the liver become slightly blue—the organ may be 
examined fresh. It is more suitable to afterwards fill the 
blood-vessels with strongly-acidulated gelatine and carmine, 
and when the liver has cooled, to cut it in pieces and harden it 
in strong alcohol to which a few drops of acetic acid has been 
added. If a weak tingeing with carmine be subsequently em- 
ployed, the preparations obtained are very handsome and in- 
structive. 
If the injection be continued too long, or if too strong a 
pressure is used, there follows, according to MacGillavry, an 
extravasation into the lymphatic vessels, into the extremely- 
developed lymphatic net-work of the lobules. It is believed, 
at the first glance, that the capillary blood-vessels have been 
filled, so deceptive is the appearance; more accurate inves- 
tigation shows that the injection mass surrounds the blood- 
vessel like a mantle. The investing lymph-current (which 
reminds one of a similar condition of the central nervous 
system, therefore, occupies the space intervening between 
the capillary walls and the connective tissue which surrounds 
the trabecular cell net-work after the manner of a membrana 
propria. 468 
SECTION EIGHTEENTH. 
Such extravasations into the lymphatic system, which finally 
lead to the filling of the interlobular lymphatic passages, read- 
ily occur, and have been, here and there, erroneously accepted 
by earlier experimentalists for successful injections of the bili- 
ary passages. 
The larger lymphatic canals may be recognized in the vicin- 
ity of the lobules. They are regularly arranged and have a 
partly isolated course, and are partly united into net-works of 
unequal size. Even here these lymphatics begin to encircle, in 
a reticular manner, the blood-vessels and biliary canals lying 
between the lobules, which is always the case with the larger 
branches of the latter vessels. Furthermore, according to 
Teichmann’s statements, the human liver has a single layered 
net-work of superficial passages, contained in the peritoneal 
covering. The meshes are of different sizes and vary in diam- 
eter ; they are now and then enlarged into considerable lymph- 
receptacles. 
The nerves of the liver come from the plexus coeliacus and 
consist in part of medullated, in part of Remak’s fibres. They 
have been seen to pass to the vessels, the biliary dncts, and the 
covering of the organ. According to Phuger’s statement, 
which is certainly erroneous, besides these, numerous ends are 
connected with the hepatic cells. 
Take the quite fresh liver of the dog or pig, and make a 
large number of very fine sections. Place these carefully in a 
watch-glass filled with Beale’s carmine solution. Here they 
remain for a considerable time, protected from dust, beneath an 
inverted box. After two weeks, but often even sooner, these 
objects are in condition to be examined, and remain in this 
condition for many weeks. A section may now be taken from 
the watch-glass and washed oft by moving it about in a drop 
of osmic acid of 1003 specific wt., on the glass slide; a new 
drop of the reagent just mentioned is then poured over the 
preparation, which is then picked apart with needles. In 
doing this avoid pulling as much as possible. The nerves 
should now appear as black fibres, even with a magnifying 
power of 180-200. 
He recommended the following process : 
The examination of the hepatic secretion of the fresh nor- 
mal bile shows the microscopist a clear colorless fluid, without 
granules or drops of fat, at the most with a few separated THE PANCEEAS, LIVEE, AND SPLEEN. 
469 
cylindrical cells tinged with, coloring matter. The cellular ele- 
ments of the hepatic substance proper, in contradistinction to 
many other glands, is entirely wanting in the secretion, so that 
we still find ourselves in the dark with regard to their destiny 
and duration of life. 
Under more abnormal conditions, sediments are formed in 
the contents of the gall-bladder. The microscope may show 
slimy masses, with larger quantities of separated cylindrical 
epithelium and granulated spherical cells (mucous and pus cor- 
puscles). In bile which has been long retained in the gall- 
bladder one meets only very rarely with crystals of cholesterin 
(comp. p. 362); occasionally, on the contrary, cue sees deposits 
of the red biliary coloring matter or bilirubin (cholepyrrhin, 
biliphsein, bilifulvin). These have, for the most part, amor- 
phous structures, and appear as sausage- 
shaped, bulbous masses. 
By treatment with chloroform, larger 
and more perfect crystals, rhomboidal 
prisms, needles, and lamina are obtained. 
The use of sulphuret of carbon is still more 
advisable. Our fig. 292 shows magnificent 
crystals of bilirubin, which were obtained 
in the latter manner by Staedeler from hu- 
man gall-stones. It has not as yet been de- 
finitely decided whether bilirubin and has- 
matoidin are similar or only nearly related 
bodies. 
w 0l blUrl. 
Pathological changes of the hepatic tissue are frequently 
met with. Our knowledge of them has recently been especi- 
ally promoted by a classical work of Frerichs and the interest- 
ing investigations of E. Wagner. Here, as in other glandular 
organs, we find the cells capable of increase and of manifold 
changes, but rarely (?) of a transformation into new tissue ele- 
ments ; while here also the new formations may proceed, for 
the most part, from the small cell-like structures of the connec- 
tive-tissue frame-work. 
The method of examination is, as a rule, simple. Harden- 
ing in alcohol, and tingeing with hsematoxyline, presents the 
best objects. 
In hypertrophy of the liver we see an enlargement of the 
existing gland-cells ; so that they have gained twice and even 470 
SECTION EIGHTEENTH. 
three times their normal circumference, and frequently enclose- 
two and sometimes three nuclei. In other cases the microscope 
shows small, rounded, pale cells, with a large nucleus. These 
young formations, which have proceeded from the normal hepa- 
tic cells, may constitute the greater portion of the parenchyma 
of the liver, but may also be met with in smaller numbers, to- 
gether with the large cells mentioned. 
A few brown molecules of biliary pigment are met with in 
the hepatic cells of healthy persons. In obstructed biliary ex- 
cretion the number of these molecules increases (especially in 
the cells adjacent to the hepatic vein), or the cell body becomes 
yellow. The nucleus may also become tinged, and solid, 
rounded, bulbous or rod-shaped masses of a yellow, brownish- 
red or greenish color appear in the cell contents. Where the 
disease has continued for a longer period, concretions of the 
biliary pigment, frequently in the form of rod-shaped struc- 
tures, fill the distended biliary capillaries (0. Wyss). 
The deposition of fat molecules and drops of fat in the 
hepatic cells has already been mentioned 
above. Higher degrees of this process con- 
stitute very frequent physiological, as well as 
pathological occurrences (tig, 293). A fatty 
or otherwise luxurious diet, combined with 
deficient bodily exercise, frequently produces 
such a condition, a so-called fatty liver. It 
fig. 293. ceiia of the 
is thus found in the cadavers of quite healthy individuals 
who have perished suddenly, as well as in nurslings. If cod- 
liver oil be added to the food of a dog, the hepatic cells of the 
animal will be filled to a considerable degree with drops of fat, 
even after a few days, and after eight days they will be quite 
overloaded with the same. If the cod-liver oil be withheld, 
this superfluous fat will, after a time, disappear entirely from 
the cells. The stuffing process produces in geese such a fatty 
liver, which is highly esteemed by gourmands. The same con- 
dition is observed in other cases of a morbid nature, as, with 
especial frequency, in pulmonary phthisis and dyscrasia pota- 
torum. Locally circumscribed overcharging of the liver with 
fat also frequently occurs. 
If we follow the increasing infiltration of the liver-cells with 
the microscope, we see the, at first, small drops of the mole- 
cules of fat become more and more numerous (a, h), then flow THE PANCEEAS, LIYEE, AND SPLEEN. 
471 
together into a few drops (c); finally these also unite into a 
single drop {d). 
By the aid of the above-mentioned methods, the deposition 
of the fat will readily be found to proceed in an interesting 
manner through the cells of the lobule. 
Introduced by the portal vein, the fat is first deposited in 
the cells which belong to this capillary district, that is, in the 
peripheral portion of the hepatic lobule. The process then 
advances step by step in a central direction, so that soon only 
the central cellular trabeculae, which are adjacent to the 
hepatic vein, remain free from fat; finally, the deposition of 
fat also takes place in the latter. 
Such a fatty liver will indeed astonish us by the slight 
quantity of blood which it contains, and will accomplish less 
for the secretion of bile than the normal organ ; but its cells 
(reminding us of those of fat-tissue) tolerate this fatty deposit 
well, on the whole, and frequently resume their former condition. 
It is otherwise, on the contrary, with the actually fatty 
degenerated liver. Here, as indeed everywhere, the structure 
is destroyed by the process of degeneration. Such a meta- 
morphosis is found, for the most part, only in limited portions 
of the hepatic tissue, in the vicinity of inflammatory foci and 
tumors. 
In a very remarkable, and, in its exciting causes, still com- 
pletely enigmatical disease, the acute or yellow atrophy of 
the liver, there is observed a quick, and often very rapid de- 
struction of the hepatic cells, so that in their place, in cases of 
a high degree, only a detritus is found, consisting of partly 
colorless, partly brownish granules, fat-molecules, and drops 
of fat, as well as crystalline products of decomposition (leucin 
and tyrosin), which are then partially removed by the urine. 
The framework of the cellular trabeculae persists, however, so 
that it may be readily isolated with the brush ; the same is 
also true of the capillary walls. If, however, the attempt be 
made to inject the latter, numerous extravasations soon take 
place, obviously because now, in the place of the former cells, 
the softened substance of the capillary walls no longer affords 
any support. 
We have just alluded to the crystalline products of decom- 
position, the occurrence of immense quantities of which in the 
so-called yellow atrophy was first observed by Frerichs. 472 
SECTION EIGHTEENTH. 
In infections diseases, in typhoid, so-called pyaemic and 
septic affections, as well as in cases of malignant intermittent 
fevers, matters occur in the 
liver, as evidences of an al- 
tered assimilation, which in 
the normal organ are either 
entirely wanting, or are only 
present in very much smaller 
quantity. Among these are 
to be enumerated a series of 
crystalline substances which 
are attributable to organic 
bases. 
Among these tyrosin and 
leucin stand in the first line. 
Tyrosin (fig. 294) appears in 
white needles of a silk-like 
lustre, which occur in part 
more isolated {a), in part, how- 
ever, united into delicate smal- 
Fig. 994. Crystalline forms of tyrosin. 
ler and larger groups (5, 5). Its reactions may be ascertained 
from a text-book on zoochemistry. 
Leucin (fig. 295) is seen in various forms in the examination 
of the human body. Among these are frequently seen pecu- 
liar druses of characteristic 
appearance, partly small 
spheres (a), partly semi- 
spherical structures (5), 
partly aggregations of such 
masses (c, d), whereby not 
unfrequently numerous 
small, flattened segments of 
spheres rest upon a larger 
spherical body (<?,/). Strati- 
fied spheres {g, g) with 
smooth borders remind one 
of starch granules; others 
have a rough surface. Quite 
Fig. 295. Various crystalline masses of leucin. 
similar druses of fine crystalline needles likewise occur. 
Hypoxanthine (or sarcine), a third variety of these products 
of decomposition, has been much more rarely met with in the THE PANCREAS, LIVER, AND SPLEEN 
473 
diseased liver. With regard to their further properties, we 
must again refer to the text-books on chemistry. Their com- 
Pig. 297. Crystals of nitrate and muriate 
■tig. 296. Crystals of the nitrate and muriate of hypoxanthine. of xanthine. 
binations with nitric and muriatic acids produce characteristic 
crystalline forms. Our fig. 296 shows, in its upper half, the 
appearance of the nitric acid salt, while the lower portion af- 
fords a representation of the muriatic salt. The smaller, 
cucumber-shaped crystals of the nitrate of hypoxanthine are 
of a particularly characteristic na- 
ture. 
There is still another nearly re- 
lated body, xanthine, which con- 
stitutes an element of the urine, and 
is also met with in various organs ; 
it occurs in the healthy and diseased 
liver, and may here be casually men- 
tioned, Fig. 297 shows the crystal- 
line forms of the combinations with 
nitric and muriatic acids. The up- 
per half represents the nitrate of 
xanthine ; the lower portion of the 
Pig. 298. Crystals of cystine. 
figure is occupied by the characteristic crystals of the nitrates. 
Cystine (fig. 298), a product of the decomposition of the 
body characterized by the large proportion of sulphur which it 474 
SECTION EIGHTEENTH. 
contains, lias also been observed crystallized in colorless, six- 
sided laminae or prisms in the products of decomposition of 
the liver, in the above-mentioned infectious diseases. It like- 
wise occurs in the normal organ. 
While the above-mentioned pathological processes show a 
transformation of the hepatic cells, in many other diseased 
conditions of the organ the latter either remain entirely unaf- 
fected, or are changed in a secondary manner, and then only 
subsequently, as, for instance, by compression. 
In many cases of malignant intermittent fever an extensive 
development of melanine has been observed in the tissue of the 
spleen. Pigmented cells and flake-like bodies, the latter fre- 
quently of considerable size, pass through the vena lienalis into 
the blood of the portal vein, and from here into the vascular 
district of the liver. If the brown, island-like figures of the 
lobules, which are often visible to the naked eye, be examined 
it will be seen that the capillary vessels, and also larger branches 
which belong to the portal and hepatic veins, are obstructed by 
these pigmented masses. Similar emboli are also met with in 
other organs, especially the kidney and the brain. Whether 
the cerebral symptoms which have been observed in such dis- 
eases are to be thereby explained still remains uncertain. 
The so-called waxy, lardaceous, or amyloid degeneration of 
the liver, which, equally and together with that of the spleen 
and kidney, is not a rare occurrence, does not affect the hepatic 
cells alone. We have already mentioned this process cursorily 
at the vascular system (p. 395). The nature of the homogene- 
ous, dull glistening, peculiarly reacting substance was for a 
long time a subject of controversy, and a definite conclusion 
has not been arrived at even at the present time. We are now 
aware, at least, that all the above names are wrong, inasmuch 
as a product of the metamorphosis of albuminous matters is 
present, but not fatty substances, or even amylon and cellulose 
(Kekule, C. Schmidt). The microscopic examination has shown 
that the walls of the small arterial branches and of the hepatic 
capillaries undergo this metamorphosis. The walls of the ves- 
sels affected become thickened, stiff, homogeneous, and glisten- 
ing ; a decrease, occasionally an occlusion of the lumen 
takes place, so that a colorless cylinder results. The normal, 
fine-granular contents of the cell itself disappear more and more, 
to make place for a homogeneous substance, and the nucleus THE PANCREAS, LIVER, AND SPLEEN. 
475 
is gradually destroyed. The cells, which are transformed into 
flakes, sometimes hang firmly together in the form of consist- 
ent, irregular-shaped lamellm. 
We have already mentioned above (p. 182) the peculiar re- 
action of iodine and sulphuric acid on the substance in question. 
We will here discuss this more thoroughly by way of example. 
The section, which has been made from the fresh hepatic 
tissue and washed out, is to be placed in a weak aqueous solu- 
tion of iodine ; it is well to continue the immersion for some 
time, and, to facilitate the saturation, the preparation should 
be turned over a few times. Even now a characteristic reddish- 
brown is noticed. The greater portion of this fluid should then 
be removed and a covering-glass placed over the preparation ; 
concentrated sulphuric acid should then be allowed to flow in 
from the side as slowly as possible. At very unequal periods, 
either immediately or after several minutes or hours, or even 
later, there is either an increase of the red color or a dirty vio- 
let, more rarely a blue color produced. Another procedure is, 
however, more advantageous. Fine sections from preparations 
hardened in alcohol are to be placed in a glass box with distilled 
water and 10-20 drops of tincture of iodine added. Then, gen- 
erally after five minutes (when the coloring of the amyloid 
substance usually takes place), the preparation is to be washed 
and again placed in clean water and 3-6 drops of concentrated 
sulphuric acid added. The characteristic tinge is obtained 
sometimes rapidly, sometimes only after 2-3 hours, when the 
examination is to be made with the addition of glycerine. 
Such objects may be preserved for a sometimes shorter, some- 
times longer period ; but not, however, according to previous 
experience, in the form of permanent cabinet preparations. 
Aniline-iodine-violet, the new reagent discovered by Juer- 
gens (p. 155), renders incomparably greater service, and presents 
the most charming appearances. My glycerine preparations, 
up to the present time, leave nothing further to be desired. 
In tubercle of the liver the ordinary elements are first recog- 
nized ; nuclei, small cells in the condition of shrinking, to- 
gether with these, large, flake-like structures with several nuclei. 
It was formerly considered that these substances originated in 
the interstitial connective tissue. At the present time, the vas- 
cular ramifications are considered to be the points of origin of 
the tubercles. 476 
SECTION EIGHTEENTH. 
A hypertrophy of the connective-tissue framework substance 
which permeates the liver, with a corresponding transformation 
of the compressed lobules and gland-cells, is found in the so- 
called granulated liver, cirrhosis hepatis. The examination 
may be made in various ways. Sections from the fresh tissue 
may be picked and treated with reagents, or, which we would 
prefer, suitably hardened objects may be used. At the com- 
mencement of the process it is noticed that the scanty connec- 
tive tissue which separates the hepatic lobules proliferates con- 
siderably ; its cells increase and the interstitial substance be- 
comes transformed into a firm, fibrillated substance reminding 
one of cicatricial tissue. This, by its further increase, com- 
presses the hepatic lobules more and more, so that gradually 
only island-like remains of the same, with shrivelled, brownish 
cells, are to be met with. These are in part tinged with hsema- 
tine ; they contain in part yellow corpuscles or fatty substances, 
or finally, amyloid. The membrana propria may hereby be 
still recognizable, but is likewise finally transformed into con- 
nective tissue. The groups and aggregations of brownish mol- 
ecules which are found embedded in the connective tissue pro- 
ceed from the remains of disintegrated hepatic cells. The 
capillaries likewise gradually atrophy, and in the same propor- 
tion that the gland-substance disappears, while the interacinous 
biliary passages often remain permeable for a long time. In- 
jections rarely succeed. Hcematoxyline, of a suitable strength, 
affords charming preparations. 
In carcinoma of the liver the connective-tissue framework 
of the organ is very probably transformed immediately into 
the framework or stroma of the carcinoma. The origin of the 
carcinoma cells remains obscure. 
We have finally to discuss the spleen. This organ, which 
still presents so much that is enigmatical concerning its physi- 
ology, was also, until within a few years, only imperfectly un- 
derstood with regard to its structure, and, in fact, numerous 
accessories are requisite if we would obtain a knowledge which 
is in any degree satisfactory concerning the latter. The ex- 
treme softness, the excessive vascularity of the spleen, and the 
numerous elastic septal formations render the manipulation 
very difficult. The latter system of septa (and herein a close 
parallel with the related lymphatic glands of the creature is 
shown) is, in large mammalial animals, highly developed and THE PANCREAS, LIVER, AND SPLEEN. 
477 
presents a complicated framework, while in small creatures it 
diminishes more and more, even to an almost complete disap- 
pearance. The spleens of the smaller rodents (rabbit, guinea- 
pig, squirrel, etc.) form, therefore, like the lymphatic glands of 
these creatures, the most suitable objects for the primary in- 
vestigation. 
One would be very much deceived if one were to expect to 
lind in the fresh spleen, even with the most careful preparation, 
more than isolated elements, blood-cells, contractile lymph-cor- 
puscle, vascular epithelium, etc. In consequence of the great 
softness of the organ, there is scarcely an appearance of even 
fragments of the delicate but developed connective-tissue 
framework which permeates the whole gland. Injections are 
also frequently frustrated by the extreme softness of even the 
freshest spleen. We are here, therefore, admonished to use 
hardening accessories, and, as the drying methods are not to be 
thought of, to employ alcohol, chromic acid, and the bichro- 
mate of potash. 
Assuming that we wish to prepare in this manner the spleen 
of a small mammalial animal (rabbit, guinea-pig), the whole 
organ may be immersed. With the spleens of larger creatures 
it is judicious to expose only a portion to the influence of the 
above reagents, and to previously force a stream of the fluid 
through the blood-vessels with a syringe. 
For many purposes alcohol is quite sufficient, especially if 
it is used diluted at first, and then, after a few days, replaced 
by alcohol which is stronger. After 6-8 days (occasionally, 
however, only after a few weeks) the spleen is in a condition 
suitable for making sections, and has also gained such a con- 
sistence that it may be conveniently brushed. Increased hard- 
ening no longer permits of the latter important procedure, or 
only very imperfectly ; and, as a rule, nothing further can be 
done with such spleens. Frequently a spleen is only rendered 
fit for injecting after an immersion for 24-28 hours in ordinary 
preparation alcohol. Injected spleens (and here again only 
transparent, partly solidifying, partly cold-flowing masses 
should be used) are also, as a rule, to be hardened in alcohol. 
For many textural conditions, however, chromic acid renders 
decidedly better service than alcohol. Portions not too large 
should be placed in an ample quantity of the fluid, and at first 
a weak solution of the acid, 0,2-0.1 per cent., is to be used. 478 
SECTION EIGHTEENTH, 
This is, after several days, to be exchanged for one of twice the 
strength, and afterwards perhaps for one that is still more con- 
centrated. If test sections be made from time to time with the 
razor and the brush, good objects will be obtained. 
1 have seen the finest results, however, from the use of the 
chromate of potash. If a solution of about 1 per cent, be com- 
menced with, and the concentration slightly increased daily, 
after several days a period arrives when the organ, which is not 
yet sufficiently hardened, must be still further hardened by 
means of alcohol. After a few days further the entire tissue 
has, with great preservation, gained the proper condition. 
Mueller’s fluid is also excellent. 
Klein recommends another process. With dogs and cats, 
he first drives a 0.5 per cent, solution of common salt through 
the vessels under a pressure of 60-160 mm. mercury. When 
the fluid runs out of the vein clear he injects a 0.1 per cent, 
solution of osmic acid for 20-30 minutes, at first with a column 
of mercury of 60, and finally of 160 mm. The preparation is 
placed in Mueller’s fluid, and after 8-12 days it is cut in alcohol. 
The method of further investigation consists in the prepara- 
tion of thin sections in various directions, which are to be ex- 
amined partly unbrushed, partly freed from blood- and lymph- 
corpuscles by means of the brush. An immersion for several 
hours in pure glycerine is useful, and tingeing with carmine 
and hmmatoxyline is of the same importance as for the lym- 
phatic organs. The system of septa likewise comes out very 
beautifully in this way. Acids, the reagents customary for 
the demonstration of smooth muscular fibres, such as chloride 
of palladium and the double staining with carmine and picric 
acid, serve for the recognition of its finer texture. 
Nevertheless, although the directions given lead to the 
hardening of fresh, moderately consistent mammalial spleens, 
do not think that every human organ can be thereby mastered. 
The maceration which we meet with in our post-mortems, the 
often considerable softening which may be found in diseased 
bodies, not unfrequently render the suitable hardening of the 
spleen a difficult piece of work, for the termination of which, not 
only days, but also weeks and months are necessary. Here 
the weak, watery alcohol is soon to be replaced by that which 
is stronger; finally, operate with absolute alcohol. Billroth 
recommends the action of chromic acid in very concentrated THE PANCREAS, LIVER, AND SPLEEN. 
479 
solution (even to 20 per cent.) on small portions of spleen, for 
hardening in typhoid affections of the organ. The framework 
and the relative arrangement, it is true, become visible in fine 
sections in this way ; the cell metamorphoses and other delicate 
textural conditions must be followed sooner on the fresh organ 
or on a portion which is but slightly hardened, for a chromic 
acid of such strength produces great shrinking. 
Preparations of the spleen are to be mounted partly in the 
ordinary moist way in glycerine, partly dry, whereby, how- 
ever, absolute alcohol and Canada balsam dissolved in chloro- 
form should always be used. Sections from transparent injec- 
tions, somewhat strongly tinged with carmine, afford by the 
latter method very handsome preparations for examination. 
The system of trabeculae also appears finest by such treat- 
ment. 
If now we inquire what information as to the structure of 
the spleen has been obtained 
by the aid of these acces- 
sories, the answer may be 
given that our organ consti- 
tutes a complicated lymph- 
atic gland, in which the 
lymph-current is replaced 
by a blood-current, and is 
therefore a blood - lymph 
gland, as we might express 
ourselves in brief. 
The Malpighian corpus- 
cles of the spleen (fig. 299, 
a) show the structure of the 
lymphatic - gland follicles, 
and, in so far as they do not 
pass over into tubes or the 
tissue of the pulp, they 
Pig. 299. Transverse section of a rabbit’s spleen, a. 
Malpighian corpuscles : 6. the reticular framework of the 
pulp, with the spaces filled by the venous blood-current. 
have likewise on their surface a more narrow-meshed, reticular 
border. Nuclei occur in a portion of the nodal points, espe- 
cially in younger animals. The capillary system presents 
nothing remarkable, and, with suitable objects, brushing usu- 
ally succeeds with facility. We would recommend the spleen 
of the sheep as being very suitable. 
In many small creatures (rodentia, for example, the rabbit, 480 
SECTION EIGHTEENTH. 
guinea-pig, and marmot) there is also, at some distance from 
the periphery, a narrow-meshed, concentric layer of reticular 
connective tissue, the significance of which requires, however, 
further elucidation. 
The pulp (fig. 299, h) consists of a system of tubes arising 
from the Malpighian bodies and united together in a reticular 
manner, which present a much finer and narrower-meshed reti- 
cular framework (fig. 300, a), and which is much more difficult 
to isolate. We are 
indebted to Billroth 
for its recognition. 
Permeated by capil- 
laries, it encloses in 
a sometimes more re- 
ticular, sometimes 
variable form a sys- 
tem of passages 
which serve for the 
reception of the ven- 
ous blood—a discov- 
ery to which I was 
led in the year 1860 
by the injection of 
the human 
and which was after- 
Pig. 800. Prom the pulp of the human spleen, brushed preparation 
(combination), a, pulp strand with the delicate reticular framework; 
transverse section of the cavernous venous canal; c, longitudinal sec- 
tion of such an one : d, capillary vessel in a pulp tube, dividing up at 
e; f, epithelium of the venous canal; fir, side view of the same; h, its 
transverse section. 
wards also confirmed by Billroth. This system of venous pas- 
sages reminds one essentially of the cavernous canals which 
permeate the cortical substance of the larger lymphatic canals 
and serve for the removal of the lymph. 
These passages of the spleen pulp (c) are, however, without 
a membranously thickened wall, inasmuch as the same tine 
reticular tissue which occurs within the pulp-tubes also en- 
closes the venous current. The passage is also lined by an un- 
stratified epithelium (/), which in man has a peculiar spindle 
shape, and the rounded nuclei of which project into the lu- 
men. 
The spaces of the spleen are, as the first examination shows, 
tilled with lymph-cells. As the walls of the fine veins do not 
appear to be membranously thickened, a wandering of these 
cells into the venous current, and, with a more considerable 
increase of the current, a forcible penetration of blood-cells THE PANCREAS, LIVER, AND SPLEEN. 
481 
into the pulp-tubes is conceivable. We therefore see the col- 
ored blood-corpuscles in part unchanged, in part in various 
stages of ruin, and, by no means rarely, free in the tissue of 
these passages. 
Peculiar flake-like structures containing blood-corpuscles 
and reminding one of cells were described, even many years 
ago, as being found in the spleen (Kolliker, Ecker, Gerlach, 
and others). The localities of their occurrence as well as their 
genesis require renewed investigations, although there is cer- 
tainly here an admission of an amoeboid cell. 
With regard to the course of the blood-vessels, it may be 
said that the greater portion of the arterial trunks can be 
readily followed in injected preparations ; likewise the division 
of the venous branches. It is also easy to perceive how the 
capillary vessels of the Malpighian corpuscles are formed by 
the breaking up of the former. A single or double arterial 
branch is generally met with on and in the Malpighian cor- 
puscle ; veins do not occur here. 
The recognition of the capillary blood-vessels in the spleen- 
pulp, as well as their connection with the venous passages, is, 
on the contrary, extremely difficult, and even to the present 
time there is no agreement of opinions concerning this impor- 
tant structural question. Many investigators assume, after 
the example of Gray (whose fine monograph is still too little 
known in Germany), a direct continuation of moderately large 
capillaries into the venous canals; others believe that they 
have convinced themselves that a very close net-work of ex- 
tremely fine capillary tubes occur here (Key, Stieda). Accord- 
ing to our own observations (and we find ourselves in harmony 
with the most thorough monographist of the organ, with W. 
Muller), the passage of the arterial splenic blood into the 
venous roots takes place, on the contrary, in man and the 
mammalia by wall-less currents. These pass through the reti- 
cular framework of the pulp-tubes by using the interstices of 
the fibres and lymph-cells, we might say, somewhat as the 
water of a failing brook takes its course between the pebbles 
of the bed. Our fig. 300 shows a capillary vessel d which at e 
is distributed into the net-work of the pulp, and may represent 
to the reader the commencement of the intermediate pulp- 
current. The blood or the injection mass then passes from the 
spleen pulp through the spaces of the limiting layer (c) into 482 
SECTION EIGHTEENTH. 
the commencement of the veins. Fig. 301 will render this con- 
tinuation (5, c) intelligible, and at the same time show that a 
reticular, scale-like coagulation of the injection mass over the 
lymph-cells of the pulp-tube explains 
the pretended capillaries of Key and 
Stieda. 
For the recognition of these impor- 
tant conditions we recommend the in- 
jection of a sheep’s spleen, as cautious- 
ly as possible, but also as completely 
as possible, with a very intense blue 
gelatine mass, and to tinge the sections 
Fig. 301. From the sheep’s spleen 
(double injection), a, reticular frame- 
work of the puip; 6, intermediate puip- 
current: c, its continuation into the 
venous roots with incomplete walls; d, 
venous branch. 
made from the hardened organ with 
. ~ 
carmine. The comparison with the 
~.>,. . n , 
natural IUJ 6C tIOU IS Of lligll Value as a 
. ml . 
control. The organ, hardened in a 
solution of chromate of potash (1 per cent.) and afterwards in 
alcohol, shows us, in fine sections treated with glycerine, the 
uninjured blood-corpuscles in the same places in which we have 
met with the blue injection fluid (W. Muller). 
Lymphatics are, as a rule, very readily recognized in the 
capsules of large mammalial animals (ox, pig, sheep). Their 
injection almost never leads into the interior of the organ, and, 
with the puncturing method, the reticular venous canals are 
regularly tilled. The opinion seems justifiable, therefore, that 
lymphatics are wanting in the tissue of the spleen (Teichmann, 
Billroth, Prey). Subsequently, however, Tomsa succeeded in 
injecting lymphatic vessels in the system of septa of our 
organ. 
The trabecular framework of the human spleen (which 
arises from the capsule and divides the organ into innumerable 
irregular compartments) consists of connective tissue, elastic 
fibres, and scanty muscular elements. It requires the same 
methods of investigation as the equivalent structures of the 
lymphatic glands (comp. p. 403). 
For the study of the splenic nerves the fresh, thoroughly 
washed-out spleen is to be treated with alkalies and acetic 
acid; organs immersed in pyroligneous or chromic acid are 
also to be used. 
It is known that the spleen frequently participates in the 
more general processes of disease. In certain infectious dis- THE PANCREAS, LIYEE, AND SPLEEN. 
483 
cases, as in intermittent and typhoid, its swellings present 
characteristic occurrences. Attention has more recently been 
paid to a surcharging of the blood with colorless cells, in- 
duced by enlargement of the spleen and lymphatic glands. 
This condition, leucaemia, we have already mentioned at the 
blood (p. 286). These metamorphoses of the organ, as well as 
its various degenerations and new formations, are known in 
their coarser relations, but not, however, or only very incom- 
pletely, in their finer texture. In a case of this affection of a 
high degree I once met with a considerable hypertrophy of the 
pulp and an astonishing development of the capillary system 
lying in the pulp-tubes. 
Several years ago Billroth, an observer who has accom- 
plished very much for the knowledge of the spleen, made an 
inroad into this domain by the aid of the improved methods. 
The finer changes of the spleen in abdominal typhus are 
still very imperfectly known. The more or less swollen organ 
does not show, in injected preparations, the remarkable disten- 
tion of the veins and capillaries which we have mentioned 
above as occurring under the same conditions in the lymphatic 
glands and Peyerian follicles (comp, pp, 407 and 452); still, 
there are certainly slight dilatations of the vessels. 
Of interest is, on the contrary, the occurrence in abdominal 
typhus of the large multinuclear cells in the venous spaces, 
the same as we have formerly mentioned as occurring in the 
passages of the lymphatic glands. Here, also, in the later 
periods, the characteristic molecular ruin of these cell-masses 
takes place, in so far as they are not previously removed from 
the spleen by the blood-current. 
The numerous granules which are met with in our organ in 
miliary tuberculosis are, as a rule, located in the tissue of the 
pulp and only rarely in the Malpighian corpuscles. Their 
contents is the familiar fine granular substance with shrivelled 
nuclei and cells. 
In the so-called hemorrhagic infarctions of the spleen, 
which, as is known, are not rare occurrences, the microscopic 
analysis shows in the overloaded venous passages the appear- 
ance and the phases of metamorphosis of masses of coagulated 
blood. 
In the ordinary hypertrophy, the reticular tissue of the 
pulp may present great thickening, so that sometimes it ap- 484 
SECTION EIGHTEENTH. 
pears similar to that of the Malpighian corpuscles. In condi- 
tions of high degree the lymphatic cells of the latter disappear ; 
in their places fine granular substance and yellowish pigment 
are noticed. 
In cases of malignant intermittent those pigmentated flakes 
and pigment-cells are produced, which, passing out through 
the vena lienalis, may give rise to embolia of frequently consid- 
erable size, first in the liver and then in other organs, such as 
the kidneys, brain, etc. (comp. p. 287). 
We have already, at the liver, mentioned the amyloid de- 
generation of the tissue of the spleen which occurs so fre- 
quently. The organ, which has become more firm, readily per- 
mits of hardening in alcohol, whereby (as was casually remarked 
at the liver) the capability of reacting of the amyloid substance 
is not lost, and fine sections permit of the recognition of the 
deposits in a convenient manner. In many cases we notice the 
Malpighian corpuscles first attacked; in other cases the pari- 
etal layer of the venous canals in the pulp has undergone amy- 
loid degeneration. 
The first form of deposit, known to the pathological anato- 
mists under the name of the “ sago spleen,” shows the arterial 
walls to be the point of origin. 
In the other, more rarely occurring variety, the lardaceous 
spleen, on the contrary, the transverse sections of the venous 
passages of the pulp are surrounded by a thicker, homogeneous 
amyloid layer. 
Attempts at preserving such preparations of pathologically 
metamorphosed spleens must be made according to the direc- 
tions given for the normal tissue. Section Mmteentl). 
RESPIRATORY ORGANS. 
The investigation of the respiratory apparatus presents 
relatively less difficulties to the microscopist than that of the 
organs described in the previous section. 
The larynx, trachea, and bronchi consist of tissues which 
have already been described by us in previous chapters, so that 
the methods there given are to be repeated here. 
The epithelium of the parts mentioned, layers of ciliated 
cells, with the exception of the stratified epithelium on the 
lower (true) vocal cords, are examined either by scraping them 
off in the fresh condition, or after being hardened in alcohol on 
thin stained sections. The latter method also serves for the 
recognition of the texture of the mucous membrane and the 
racemose glands which occur here. The latter not unfrequent- 
ly become changed in consequence of catarrhal processes, their 
vesicles become enlarged, and their cell-contents changed. 
The cartilages may be examined either fresh or after being 
hardened. Calcifications and ossifications of the same, which, 
as is known, are frequent occurrences in after life, are to be ex- 
amined fresh or after having been decalcified by chromic acid. 
The distributions of the nerves are to be studied in acetic or 
pyroligneous acid or gold preparations ; lymphatic vessels are 
to be injected by the puncturing method from the submucous 
tissue. 
The same methods of treatment serve for the larynx, tra- 
chea, and bronchi; their smooth muscular elements require the 
so-frequently mentioned accessory which is used for the demon- 
stration of that tissue. 
The investigation of the lungs is, however, quite different. 
Portions of the fresh tissue when picked readily show the elas- 
tic fibres and membranes, especially after the application of 486 
SECTION NINETEENTH. 
acetic acid or alkalies. The epithelial structures of the alveoli 
and the finest bronchial ramifications may also be recognized. 
But in general the results are limited to these, and such exam- 
inations are not unfrequently considerably impeded by the 
numerous air-bubbles in the preparation. 
Other methods of treatment are therefore necessary. 
These consist of the use of the same hardening solutions 
which we have already so frequently mentioned. If possible, 
the blood-vessels should always be previously injected, and for 
many investigations it is almost indispensable to have the re- 
spiratory canals distended. 
The whole lung, or portions of the same, when carefully 
dried, assume a consistence which permits of sections being 
conveniently made in all directions. These, when softened, per- 
mit of the satisfactory recognition of the greater portion of 
their details ; and the application of staining methods, of acetic 
acid and alkalies, constitute further advantageous accessories. 
It is preferable to moderately inflate the lung which is to be 
dried by the bronchus or the air-passages, and after tying 
these, to hang it in the sun or near a stove to harden. The in- 
jection of the air-passages (from which the air may be pre- 
viously removed by means of an air-pump) with uncolored 
(also colored) gelatine is a very good method. Not less to be 
recommended, according to Rindfleisch, is a preparatory injec- 
tion of strong alcohol, and a subsequent imbedding method. 
Injections of the blood-vessels with transparent colors and a 
menstruum which solidifies, such as gelatine, permit of the 
same treatment. Sections made from these and softened, pre- 
sent beautiful appearances, especially if the injection fluid was 
not too watery. With smaller creatures the injection should 
be made by the arteria and vena pulmonalis ; with those which 
are larger, generally only by single branches of each of these 
vessels. The injection is in general to be regarded as an easy 
one, even with small mammalia, if the syringe is only very 
cautiously managed. 
If the finer textural relations are to be examined, alcohol, 
chromic acid, and chromate of potash are to be used for the 
immersion of portions of the uninflated lung or the whole or- 
gan, whereby it is also well to inject the bronchi with the hard- 
ening fluid. The employment of these fluids also forms the 
chief means for the recognition of pathological structural RESPIRATORY ORGANS. 
487 
changes. Still better, even here, is the preparatory inflation of 
a whole organ, or the injection of its air-passages with un- 
colored gelatine, the blood-vessels having been previously filled 
with cold-flowing transparent mixtures. If such a lung be sus- 
pended by the trachea, in a large ves- 
sel filled with alcohol, it affords, after 
several days, excellent views of its 
entire structure; and if it was fresh 
when exposed to this preparatory 
treatment, even the alveolar epitheli- 
um, that cellular covering which was 
so extensively disputed years ago, 
and which is nevertheless so easy to 
recognize, may be seen. 
Fig. 302. A portion of the lung of an 
ape (cercopithecus) injected with quick- 
silver. a, end of a bronchial trunk; c, 
finer canals; b, infundibula. 
The ultimate terminal ramifications 
of the bronchial passages (fig. 302, a) pass over into a system of 
acute-angled ramified canals (c), which present thin, sinuous 
walls. These are beset laterally as well as terminally by groups 
of the alveoli or lung-vesicles, the so-called infundibula (fig. 
302, b, fig. 303, a), while other alveoli (fig. 303, b) constitute the 
sinuosities mentioned on the walls of these passages (Schulze). 
The infundibulum corresponds to the primary lobule of a race- 
mose gland, and may be seen in sec- 
tions of lungs which are simply dried, 
or in those of which the air-passages 
have been filled with transparent 
materials. Another way of obtaining 
a view of them is by the corrosion 
method. The air-passages are to be 
injected with a colored resinous mass, 
and then the lung-tissue destroyed 
by the long-continued action of con- 
centrated muriatic acid. The rela- 
tion of the pulmonary lobule to its 
bronchial tube is, however, not easy 
to recognize. 
For the closer examination of the 
Fig. 303. Two so-called infundibula of 
the lungs (af. with the finest bronchial 
twigs (c), and the pulmonary vesicles (6). 
air-vesicles and their more minute structure, fine sections of 
the tissue which has been hardened in fluids are used. 
For this purpose an entirely fresh lung, which has been 
carefully isolated and injected, is selected; it should be im- 488 
SECTION NINETEENTH. 
merged in alcohol to harden, and the sections when made are 
to be carefully colored in the familiar mixture of equal parts 
of the ammoniacal solution of carmine and glycerine (p. 149), 
and finally washed out in water containing a little acetic acid. 
To proceed with more certainty, the sections may be taken 
from the surface of the organ, as recommended by Eberth. In 
this way one obtains a great number of surface and profile 
views of the alveoli, and is thoroughly protected from mistak- 
ing them for transverse sections of the finer bronchial branches. 
The walls of the air-vesicles (fig. 304, b) are rather thin and 
Fig 304 Section through the lungs of a child 9 months old. Elastic trabeculae (a) between the alveoli. 
b ; <l, capillary vessels curved in a tendril-like manner; c, remains of the simple pavement epithelium of 
the alveoli. 
the alveoli. 
consist of elastic fibres (a). Between the latter there is a 
homogeneous connective substance, which is also to be recog- 
nized as a limiting layer towards the cavity. These walls 
appear to be without muscular elements, nevertheless Rind- 
fleisch has recently re-entered the lists for their existence. 
We meet with a wonderfully rich network of capillaries, 
the meshes of which are small, but vary in size with the degree 
of distention of the alveoli (fig. 305, b, 304, d). There are one, 
two, or three small, very transparent, rounded and polygonal 
nucleated cells (fig. 305, c) lying in each of the meshes according 
to its size. In transverse sections of the pulmonary vesicles, 
the epithelial cells are seen to spring forward in a slightly con- RESPIRATORY ORGANS. 
489 
vex manner into their cavities. Very dilute acetic acid may 
also be used to demonstrate their nuclei; it should not be too 
concentrated, as a free nuclear formation remains which has 
been erroneously taken for nuclei of the alveolar tissue. Fre- 
quent use of the silver impregnation has also been made of 
late, and a connected epithelium (tig. 806) has been recognized 
Pig. 305. A pulmonary alveolus of the 
calf, a, larger blood-vessel ; b, capillary 
net-work; c, epithelial cells. 
Pig. 306. Pulmonary epithelium o£ an adult 
cat. 
by its aid. Tingeing with hsematoxyline renders excellent 
service. This epithelium (Schulze) is homogeneous in the foetus, 
and is formed of fiat but granular (therefore containing proto- 
plasma) cell bodies. When respiration has once taken place, 
however, only a portion of our cells maintain their former ap- 
pearance. Others become larger, hyaline, and their nuclei fade. 
Such plates increase in number, and they are met with through- 
out where a re-entering portion of the pulmonary tissue, capil- 
lary vessels for instance, is to be covered over (Elenz, Schulze.) 
In pathological conditions of irritation these homogeneous 
plates of epithelium may, undoubtedly, subsequently regain 
the protoplasmic condition of a former period and undergo 
further transformations (Ranvier). 
But we must again have recourse to the injected preparation 
(tigs. 304, 305). If a portion of the capillary net-work be re- 
garded from the surface, the wavy undulations and loop-like 
curves of the vessels are seen. If viewed from the side, the 
tendril-shaped curves are seen to pass more or less beyond the 
walls of the alveoli, according to the degree of distention of the 
latter, so that they often project into the air-vesicles as loops 
of considerable size, projections which, in pathological condi- 
tions, may be met with in a much higher degree (Buhl). 490 
SECTION NINETEENTH. 
The numerous lymphatics of the lungs are to be injected by 
the puncturing method. A single-layered net-work with large 
meshes is found beneath the pleura; this communicates with 
the deeper lymphatics accompanying the bronchi by means of 
branches which pass between the lobules towards the interior of 
the organ. The commencement of the lymphatics appears in 
the walls of the pulmonary vesicles in the horse, in the form 
of lacuna-like dilatations (Wywodzolf). 
The nerves of the lungs pursue the same course as the bron- 
chi and vessels (especially the pulmonary artery), and may be 
followed deep into the interior of the organ. Microscopic gan- 
glia occur at the points where their branches are given otf. The 
treatment with chromic acid or diluted pyroligneous acid serves 
for their primary recognition ; osmic acid may be recommended 
for more accurate studies. 
The gland-like structure of the whole organ may be recog- 
nized in a beautiful manner in foetal lungs, especially those of 
embryos from the first half of intra-uterine life. After being 
hardened in alcohol, thin sections are to be made and carefully 
stained; in these the covering of cylindrical epithelium of the 
glandular canals and the connective-tissue framework (Darm- 
faserblatt of Remak) are easily seen. 
Numerous structural changes of the respiratory organs, es- 
pecially of the lungs, come under the observation of the physi- 
cian. The methods of investigation are either the same as, or 
quite similar to, those for the normal organ. Some of these 
conditions, which present considerable microscopical interest, 
may here be briefly mentioned. 
Pigmentations, that is, collections of fine melanine granules, 
which give the organ a spotted appearance, are met with in all 
human lungs after a certain period of life, so that they are to 
be denoted as normal occurrences. They sometimes lie in the 
inter-alveolar elastic tissue, sometimes in the connective-tissue 
interstitial substance of the pulmonary lobules. The cells of 
the alveolar epithelium may also undergo this pigmentation, 
and, evacuated by coughing, occur in the sputum (p. 495), as 
in other cases they are found to have undergone fatty degener- 
ation. 
Now where do these black molecules originate ? They are— 
and we may at the present time assert it with confidence—of a 
double origin. They may consist of the ordinary dark pigment RESPIRATORY ORGANS. 
491 
of the organisms of melanine. Here, as in the bronchial glands 
(p. 406), the cause may be small apoplectic effusions from the 
pulmonary capillaries, which are so readily surcharged with 
blood; likewise transudations of dissolved hsematine into the 
tissue. Then also, in civilized life, the individual surrounded 
by smoke and soot inspires the finest particles of coal. They 
penetrate into the cell-bodies of the alveolar epithelium, then 
into the lung-tissue, and from here (probably with the aid of 
migratorially inclined lymphoid cells) into the bronchial glands. 
This condition, anthracosis, may be artificially induced in mam- 
malial animals by shutting them up in a sooty room (Knauff). 
Coal-workers show the highest degree of the disease. Another 
observation of Zenker's is very interesting. Operatives in fac- 
tories where they have much to do with oxide of iron, present 
exactly the same condition of the lungs, only everything is red 
instead of black. 
A senile alteration of the pulmonary tissue and of the alve- 
oli, which accompanies the atrophy of the capillaries, consists 
of the disappearance of the walls of some of the air-vesicles, 
and the union of several of these into larger cavities. To pre- 
pare such lungs for examination they should be inflated and 
dried ; in certain cases the blood and air-passages may be pre- 
viously injected. 
Pathological new formations of the lungs still give rise to 
many difficulties for the microscopist, especially in recognizing 
the normal cellular elements of the organ from which the for- 
mer take their origin. 
The lymphoid cells which have emigrated from the blood- 
vessels are represented here also, at least in part, by the pus- 
corpuscles. Such an extravasation of these cells appears to be 
very much facilitated in the pulmonary alveoli, where the so 
numerous vessels are covered only by a thin layer of epithe- 
lium. They may also occur here in the interior of cylindrical 
or irregularly formed epithelial cells, probably having, however, 
only penetrated from without, and not having been produced 
in the latter. 
The generally more rapidly progressing inflammation of 
the pulmonary tissue, the so-called croupous pneumonia, 
shows at the commencement a considerable distention of the 
respiratory capillary net-work, then a filling up of the alveoli 
and infundibula with coagulated fibrin, as well as with extrav- 492 
SECTION NINETEENTH. 
asated red and colorless blood-cells. Later, the lung-tissue 
proper also becomes infiltrated with cells. The softened mass 
is at last met with under the form of pus. The role which the 
alveolar epithelium plays in this disease, according to Ranvier’s 
statements, still remains to be investigated. 
The primary microscopical appearances of the above-men- 
tioned contents of the air-passages in a case of pneumonia may 
be obtained by scraping the cut surfaces. For closer examina- 
tion the tissue is to be carefully hardened in solutions of chro- 
mic acid of increasing concentration, in Muller’s fluid, or 
absolute alcohol. Injections of the vessels of inflamed lungs 
do not readily succeed, in consequence of the distention of the 
alveoli and the numerous lacerations of the capillaries. 
Tuberculosis of the lungs is of extremely frequent occur- 
rence, partly in the form of so-called tuberculous infiltration, 
partly in the form of scattered aggregations and numberless 
small nodules. Very many investigations have been made of 
this matter, and much has been written about it, but our 
knowledge of the subject still leaves much to be desired. Al- 
though it is well established that the tubercular substance is 
formed of shrunken nuclei and cells, and from the fragments 
of these structures and a fine granular matter, and that the 
neighboring vessels which lie between them also become atro- 
phied, the point of origin still remains uncertain. The alveolar 
epithelium is certainly frequently concerned in this process, 
and hence the position of the tubercular mass within the 
alveoli is readily accounted for. On the other side, however, 
the tissue of the lung itself gives rise to such masses. In con- 
sequence of the absence of connective-tissue corpuscles from 
the walls of the alveoli, and the sparseness of this tissue 
between the primary lobules, attention should be directed 
firstly to the emigration of the lymphoid cells, and secondly to 
the cells of the capillary vessels and the adventitia of the finer 
blood-vessels; and, in fact, recent investigations have discov- 
ered such a point of origin of the miliary tubercles. 
The proliferations of the nuclei of vessels, which have been 
noticed by several observers to take place in such cases, are 
rendered all the more probable from the fact that a quite simi- 
lar process occurs in the adventitia of similar vessels of the 
brain, and also leads to the formation of miliary tubercle. 
Further investigations appear to be necessary to determine EESPIKATOEY ORGANS. 
493 
whether the nuclei of the true primary capillary membrane are 
also capable of undergoing such a metamorphosis. How im- 
portant for all such investigations the previous injection of the 
blood-vessels with transparent masses is, it is unnecessary to 
mention. For hardening, chromic acid is to be used, com- 
mencing with weaker solutions (0.1-0.2 per cent.), and then 
passing to those which are stronger (0.5-1 per cent.); Muller’s 
fluid or absolute alcohol; the organ should, naturally, be im- 
mersed in small pieces. 
We must leave the further consideration of these masses of 
tubercle to the text-books on pathological anatomy. The sub- 
stance we have described usually becomes softened and leads 
to the formation of cavities, in consequence of the destruction 
of the tissue of the lung. If we examine the contents of such 
a cavern we find softened tuberculous matter, pus-cells, blood- 
corpuscles, blood coagula, and elastic fibres. The latter may 
be coughed up and appear in the sputum, and thus confirm the 
diagnosis. We shall return to this point. The walls of these 
caverns are seen to be formed of compressed lung-tissue. 
The examination of the fresh tissue of the pleura may be 
made by scraping the epithelium and tearing the connective 
tissue of the serous membrane, with the assistance of the usual 
reagents. Thin sections may also be made from hardened 
preparations. These methods, besides being used for the other 
serous sacs of the body, as the pericardium and peritonaeum, 
may also be employed for the examination of pathological 
conditions. 
Effusions of a watery or purulent nature are to be treated 
in the same way as other fluids which contain cells ; more solid 
masses of exudation, which show rounded cells enclosed in 
coagulated fibrine, are to be examined partly fresh, partly in 
sections from the hardened preparation. The new formations 
of connective tissue in the form of looser or firmer bands, 
which unite both walls of the pleura, require no further men- 
tion, as they are to be investigated in the same manner as con- 
nective tissue. 
The masses expelled by hawking or coughing are called 
sputa. They do not originate exclusively from the respiratory 
organ, however, as matters from the mouth as well as from 
the posterior nares may become mixed with the products fur- 
nished by the respiratory apparatus. In the examination of 494 
SECTION NINETEENTH. 
the sputa, therefore, we must always expect to find not only 
the elements of the respiratory apparatus, but also the epithe- 
lium of the two systems of cavities mentioned, fragments of 
food which have remained in the mouth, grains of starch, for 
example, the Leptothrix buccalis, etc. 
The microscopical treatment is, on the whole, very easy. 
The specimen for examination is to be obtained, according to 
its consistence, either with a glass rod, or, if pretty tough, by 
means of the forceps and scissors; it is then to be examined 
floating in its natural fluid with a power of medium or greater 
strength. Reagents are to be employed as circumstances may 
require, though their action may be 
impeded, it is true, by the mucus of the 
fluid. 
It is relatively difficult, however, to 
preserve such objects as permanent 
specimens. The attempt may be made 
to preserve them in camphor-water, 
very dilute solutions of chromic acid, 
the Pacinian or some similar fluid (pp. 
217 and 218). 
The constituents of the sputum (fig. 
307) are, together with entangled air- 
bubbles, epithelium, the cellular ele- 
ments of glands, mucous and pus cells, 
blood - corpuscles, pigmentated cells, 
Pig. 307. Elements of the sputum. 
a, mucous and pus corpuscles; b, so- 
called granule cells; c, with black 
pigment (alveolar epithelium); d, 
blood-cells; e, ciliated cells after the 
loss of the cilia and such a cell with 
cilia; /, spherical ciliated cell in 
catarrh of the respiratory passages; 
g, ciliated cells which have pus-cor- 
puscles in their interior; h, pulmo- 
nary fibres. 
those in a condition of fatty degeneration, and fragments of 
pulmonary tissue. Crystals rarely occur, and are of minor 
importance. We find the organized constituents either un- 
changed or more or less altered by the action of endosmosis 
and of maceration. 
The pavement epithelium is derived from the mucous 
membrane of the cavity of the mouth, but a few such cells 
may also come from the larynx, where they cover the lower 
vocal cords. Smaller pavement or rounded cells come in part 
from the glands of the mucous membrane, and in part, doubt- 
less, from the alveoli of the lungs, although it is scarcely pos- 
sible to recognize the latter with certainty in sputum. The 
quantity of this pavement epithelium from the mucous mem- 
brane is naturally quite variable. The tough masses which 
many persons are accustomed to hawk up in the morning are, 495 
EESPIEATOET OEGAXS. 
as a rule, rich in them ; their number also increases in the spu- 
tum when the digestive organs are in an irritated condition. 
Ciliated cells, which occur, however, by no means frequently 
in the sputum, originate in part from the posterior portion of 
the olfactory organs, in part, and chiefly, from the respiratory 
passages. They may be met with entirely unchanged in form 
(e) or, which is more frequently the case, after their cilia) have 
fallen off (e, g). At the commencement of catarrhal affections 
of the air-passages one may see, here and there, cells coughed 
up which still vibrate, partly in their normal shape {e below), 
and partly changed to spherical shapes (/). The nuclei ap- 
pear either single or we notice a few granulated structures 
(;g), which are probably mucous and pus corpuscles within 
the cylindrical cells, so that migratory conditions of these 
cells, similar to those we have formerly mentioned, are prob- 
ably also repeated here. Then the granulated elements des- 
ignated as mucous corpuscles (a) are also found in all sputa. 
Their number, and with them the appearance of the sputum, 
is subject to very great variations. If the latter be yellow and 
thickened, the number of the former structures is enormous, 
and one then speaks of pus-corpuscles. It is evident that this 
most extensively disseminated element of the sputum is to be 
met with changed in many ways, which is due in part to en- 
dosmoticinfluences and to maceration, as well as to the various 
stages of life of the cell. Dark, granulated cells, overloaded 
with molecules of fat, are considered as older forms, and this 
view is certainly correct. Larger structures, with similar fat- 
like contents, are partly due to pus-corpuscles, but partly also 
to changes of the alveolar epithelium. The name of granule 
cells or inflammatory globules id) was formerly given them. 
Their physiological prototypes are represented by many gland- 
cells overloaded with fat (sebum cutaneum, colostrum). 
Similar spherical cells may contain a brown, still somewhat 
soluble pigment, though they are of rare occurrence. The same 
cells with black pigment granules (c) form more frequent con- 
stituents. They are observed in more severe diseases of the 
lung-tissue, but also in simple catarrhal irritations. They are 
degenerated alveolar epithelium (p, 491). 
On a previous page we mentioned the quite superficial posi- 
tion of the pulmonary capillaries. We can easily understand 
that the red blood-corpuscles readily pass out through the 496 
SECTION NINETEENTH. 
uninjured capillary walls, and that tlie latter also frequently 
become ruptured in consequence of their over-distention with 
blood, and hence the frequent occurrence of blood-corpuscles 
in the sputum {d). According to the quantity of the former, 
the latter appears to the naked eye either as blood or as spotted 
and striped with blood, or, if the mixture be more intimate, 
more of a yellow, reddish, or rust color. Very small quantities 
of blood-cells are only to be found with the aid of the micro- 
scope. The blood is either still fluid or coagulated, and then 
the cells, together with other structures, are concealed in the 
fibrous coagulum. They sometimes appear entirely unchanged, 
with the familiar depression in their centres (p. 234), sometimes 
shrunken and in a crenated form, or, finally, swollen into a 
globular shape, and then, not unfrequently, they are in various 
stages of discoloration. One sees in part single cells, in part 
lumpy aggregations, and in part the familiar groups resembling 
rolls of coin (with which fig. 105, p. 238, is to be compared). 
The most frequent arrangement of the blood-corpuscles in the 
sputum is such, however, that the borders of the cells touch 
each other. The tough mucus may, finally,—and this change 
of their form is frequently met with,—tear the soft blood-cor- 
puscles considerably. 
The presence of elastic fibres and shreds of elastic membrane 
in a sputum is, finally, of greater importance to the practical 
physician for the purposes of diagnosis. If these are not frag- 
ments of food, which is sometimes the case, they indicate a 
destruction of the pulmonary tissue in consequence of softened 
tubercle or gangrene. Still, they are by no means of frequent 
occurrence in the former widely disseminated disease, so that 
their absence from the expectoration does not possess any 
negative importance. One finds in part single fibres, in part 
several lying near each other, or also hanging together like a 
net-work (fig. 307, h). The difficult solubility of these structures 
and their entire optical relations secure those who are some- 
what practised from any danger of mistaking them. The 
beginner might, accidentally, mistake threads of lint and the 
like for them, and it would therefore be well for him to con- 
sult an experienced observer. A highly meritorious observer, 
Remak, has long since given us a good method for finding the 
lung-fibres. Each sputum that the patient coughs up should 
be placed by itself on a dish or, where the whole expectorated 497 
RESPIRATORY ORGANS. 
mass is obtained for examination, it is to be placed in a glass 
cylinder filled with water, and smartly shaken. The masses 
thus separated will, after a short time, form a sediment, and 
in this the fibres in question are to be sought for. 
Crystals of the ammonio-phosphate of magnesia, as well as 
needle-shaped concretions of fatty substances, may be met with 
in decomposed masses of sputum. Tablets of cholesterine are 
rare. 
We cannot leave the respiratory apparatus before having 
made mention of two organs lying in its neighborhood, the 
thyroid and thymus glands. 
The thyroid gland, an organ which is entirely enigmatical 
in its physiological regard, belongs to a naturally related series 
of gland-like, ductless structures, to which, in the human body, 
we also reckon the supra-renal capsules and the hypophysis 
cerebri. Although it does not share with these organs the near 
relationship with the nervous system, it nevertheless agrees in 
this, especially with the supra-renal capsules, that it is also 
subjected to an earlier senes- 
cence, and, like the latter, 
is met with in the adult body 
in a condition of retrograde 
metamorphosis. While, how- 
ever, the supra-renal capsule 
undergoes fatty infiltration, 
the thyroid gland presents 
another, namely, the colloid 
metamorphosis, the com- 
mencement of which may? 
indeed, begin even at the end 
of embryonic life. 
-f i n,i j"i Fra. 308. Portion of the thyroid gland of a child, a, 
106 irameWOrK OI tne tny- the connective-tissue framework: ft, the rounded cells 
roid gland (fig. 308, a) consists lnner ,i”d wlth etilMta” w' 
of an ordinary fibrillated connective tissue intermingled with 
elastic fibres, which is permeated by numerous vessels and a not 
inconsiderable number of lymphatic canals. It encloses groups 
of rounded cavities (5) in which an especial membrana propria 
is wanting (p. 414). From these groups are formed the lobules, 
and from the latter the larger lobes. 
A foetal thyroid gland, or one which is not as yet altered, 
shows the cavity lined by a layer of nucleated cylindrical cells 
32 498 
SECTION NINETEENTH. 
(c) which are shorter and more flattened against each other, and 
within the same a homogeneous viscous fluid. The cavity is 
surrounded by a close capillary net-work which is easily injected 
from the artery. In the connective tissue of a group of cavities 
run fine canals, originating in the numerous superficial lympha- 
tic vessels with valves, forming sometimes closed, sometimes 
irregular circular-shaped, sometimes only arched columns. 
Still finer lymphatic canals not unfrequently pass between a 
few cavities. Their injection may also be readily accomplished 
by means of the customary puncturing method in the new-born 
and the child, in the dog and the rabbit. 
Hardening in chromic acid or alcohol serves for the prepara- 
tory treatment. Thin sections show many things more beauti- 
fully after tingeing than in an uncolored condition. The frame- 
work is easy to isolate by brushing. The 
thyroid gland of the calf, macerated in 
pyroligneous acid, is to be recommended 
for the recognition of the nerves (Pere- 
meschko). Osmic acid has not afforded us 
here any results worthy of mention. 
In the place of the viscous fluid mass 
there occurs (and it is indeed frequently 
noticed even in the bodies of new-born chil- 
dren), together with dilatations of the gland- 
ular cavities, another homogeneous, more 
solid contained matter, the colloid, a modi- 
fied albuminous substance (fig. 309), It is 
formed by the metamorphosis of the cell- 
contents of the epithelium, whereby the 
Fig. SO9. Colloid metamor- 
phosis. a, Gland vesicle of the 
rabbit; b, commencing colloid 
metamorphosis of the calf. 
cells are destroyed. We have already mentioned the colloid 
degeneration, which, though not constituting a very frequent 
occurrence, appears in the similarly formed hypophysis cerebri, 
also attacks the cells of carcinomatous neoplasms, and may give 
rise to colloid carcinoma (p. 289). In the slighter degrees, the 
dilatation of the cavities, and the compression of the interstitial 
connective tissue coincident therewith is moderate, so that al- 
though narrowed, and here and there atrophied, the lymphatic 
passages may be rendered apparent by injection. The capillary 
net-work retains the old permeability, and the epithelial cells 
still appear preserved. 
Higher degrees of this colloid metamorphosis show, together 499 
RESPIRATORY ORGANS. 
with an increase of volume, that the whole organ is permeated 
by transparent, sometimes smaller, sometimes larger colloid 
lumps. The epithelium of the distended cavities has disap- 
peared, and the compression of the connective tissue has be- 
come such that, though the blood still passes, an impermeability 
for the lymph has taken place. All attempts at injection re- 
main unsuccessful, and, from the nature of the colloid matter, 
a resorption through the capillary walls is no longer to be 
thought of. Thus arises the goitre, that disease which is still 
so obscure in its etiological relations. 
With further accumulations of the colloid masses the connec- 
tive-tissue interstices disappear, and as the excavations unite, 
these masses become joined together. In this way larger and 
larger spaces become filled with such masses, and the connec- 
tive-tissue stroma lying between them appears as if macerated. 
An entire lobe may finally present a single collection of colloid. 
Sections of the injected organ, deprived of their water by 
means of absolute alcohol, may be mounted in Canada balsam; 
the remaining preparations are to be mounted moist in dilute 
glycerine. 
Hot less obscure in its function and in its structure, the 
thymus appears, at the present time, to be not entirely compre- 
hensible. It also undergoes, although later, a transformation, 
that is, a metamorphosis into fat-tissue. 
The elements which constitute the lobes of our organ have 
been described by authors as granules or acini. They remind 
one in their texture of a lymphatic follicle, and show the same 
connective-tissue reticular framework, with nuclei at the nodal 
points and permeated with capillaries ; likewise the same filling 
up of all the intervening spaces by an innumerable quantity of 
lymphatic cells. Nevertheless, a more thorough investigation 
also reveals many deviations. In fine, transverse sections of 
hardened organs, the thymus follicle contains in its centre a cav- 
ity filled with a cloudy fluid, the further explanation of which 
is obtained by side views. In such, cul-de-sac-like ducts appear 
to come from the follicle, and these canals from each lobe be- 
come conjoined below. Herein lies, according to my view, the 
rudiment of the further diverticulated, foetal thymus-gland tube, 
and not a lymphatic canal-work, as His, in a beautiful work, 
has declared the same to be. Firstly, notwithstanding numer- 
ous attempts, it has not been possible for us to accomplish a 500 
SECTION NINETEENTH. 
lymph injection of the organ and of these passages ; then—and 
npon this point greater weight may be laid—the more recent 
investigations have demonstrated entirely different arrange- 
ments of the lymphatic channels in the lymphoid follicles. A 
delicate vascular net-work (but also not entirely corresponding 
to the ordinary arrangement of that of the lymphatic follicles) 
permeates the follicles of the thymus. In the calf (tig. 310) 
the peripheral portion of 
the latter is surrounded in 
a circular manner by arte- 
rial (a) and venous (h) 
branches, and the capillary 
net-work (c) resembles that 
of a Peyerian follicle, but 
naturally bends with all its 
tubes around the central 
canal{d) in a loop-like man- 
ner (His). In the human 
thymus, on the contrary, 
the arterial branches run 
in the interior of the lob- 
ules and follicles. The ven- 
ous ring of the latter re- 
Fig. 310. Portion of the calf’s thymus, after His. The 
rings of the arterial branches (a) and venous branches (6) 
with the capillary net-work (c) and the cavities of the 
acini (dj. 
mains, however, the same as in the calf. 
Some time after birth (pretty early in well-nourished calves, 
probably much later in man) commences an extensive transfor- 
mation of the stellate cells of the thymus stroma into globular 
fat-cells, and of the neighboring reticular-fibres into a more 
homogeneous matter which envelops the latter. The microscopic 
examination shows interesting transformations of the capillary 
net-work and a gradual disappearance, frequently united with 
fatty degeneration, of the lymph-cells of such metamorphosed 
localities. A quite similar process may also, as I have shown, 
attack the follicles of the lymphatic glands. 
Peculiar structures of the contents of the thymus are pre- 
sented by the so-called concentric corpuscles. Their stratified 
investment consists, according to Paulitzky, of pavement- 
shaped epithelial cells (comp. p. 270). 
The methods for examining the thymus gland are various. 
For hardening, use at first very watery, later somewhat stronger 
solutions (chromic acid from 0.1-0.2, then from 0.5 per cent., RESPIRATORY ORGANS. 
501 
chromate of potash in corresponding strength, strongly diluted 
alcohol). Only in this way can the reticular framework be 
brushed out over larger distances. Increased hardening leads 
to the recognition of the passages described, and of the walls of 
the blood-vessels. 
Kolliker recommends boiling in ordinary water to render the 
canal-work of the thymus visible. Subsequently hardened in 
alcohol, such organs are said to permit of good sections being 
made ; that observer also recommends the boiling of this organ 
in vinegar. 
The blood-vessels are not very easy to inject, as it is always 
necessary to ligate a number of them, or to compress them with 
the sliding forceps. An opaque mass, chrome-yellow, for ex- 
ample, is very handsome for review preparations (which may be 
mounted dry); for histological purposes select carmine and 
Prussian blue. Watery glycerine serves for their preservation. 
It has already been remarked above that, thus far, attempts 
at injection have not shown any lymphatics in the interior. 
May another be more fortunate, and thus elucidate in this 
structural relation that organ which, as the at present last of 
its species, must awake the interest of histologists. ocction Stocntietl), 
URINARY ORGANS. 
The investigation of the urinary apparatus, and especially 
of the secretion produced by it, lays claim in a high degree to 
the interest of the medical world ; indeed, the signification of 
the urine at the sick-bed has been valued for thousands of 
years, and often also overestimated in the most ridiculous 
manner. 
The kidney, as is known, constitutes the most important 
organ of the urinary apparatus. 
An external brown-red mass, the cortical substance, en- 
velops in the mammalia and man an internal, paler mass, the 
medullary substance, which presents even to the naked eye a 
radiated fibrous appearance. The latter, in most mammalial 
animals, enters the pelvis of the kidney with a single ridge- 
shaped point; but is, on the contrary, in man (and also the 
pig) separated into a number of larger conical-shaped divisions 
which turn their points towards the hilus. These are the so- 
called Malpighian or medullary pyramids. The cortical tissue 
extends down between the lateral surfaces of the same like a 
septum (columnse Bertini). A connective-tissue supporting 
substance permeates both substances, and consequently the 
whole organ. 
The essential conditions of the finer structure of the kidney 
also seemed for a long time to be firmly settled. 
The radiated fibrous medullary substance was regarded by 
the anatomists and physiologists as consisting of the urinifer- 
ous canalicules which opened free at the pyramidal points, and 
which, from here, with numerous acute-angled divisions and 
diminutions in size induced thereby, passed towards the corti- 
cal substance. In passing over into the latter, they were said to 
lose their previous rectilinear direction, to assume an extremely URINARY ORGANS. 
503 
complicated tortuous course, and finally, enlarged in a spheri- 
cal manner, to terminate as capsules of the Malpighian vas- 
cular coils (fig. 311). 
the manner of termination (or 
origin) of the uriniferous canali- 
cules just mentioned, the struc- 
ture of the mammalian kidney 
was regarded as assured and 
near to a conclusion. 
Especially after Bowman, in the year 1842, had discovered 
The merit is due to Henle of 
having brought a new element 
of agitation into this subject. 
He discovered, a number of 
years ago, in the medullary sub- 
stance of the organ, together 
with the long-known open uri- 
niferous canals, a system of 
finer, loop - shaped passages 
(which turn their convexities 
towards the points of the papil- 
lae). He also succeeded, in sev- 
eral mammalial animals, in in- 
jecting, from the ureter, the 
straight canals of themedullary 
substance, as well as their rec- 
tilinear continuations through 
the cortex to close beneath the 
renal capsules. As, however, 
Fig. 311. From the cortical substance of the hu- 
man kidney, a, Arterial trunk giving oil the affer- 
ent vessels 6, of the glomerulus c*, c'; c, efferent 
vessels of the latter; d, the capsule of Bowman, with 
its continuation into the convoluted uriniferous ca- 
nalicnle of the cortex (e). 
all attempts to inject, from these passages, the loop-shaped 
canalicules of the medulla as well as the convoluted ones of 
the cortical substance failed, this savant took—as we now 
know, erroneously—the loop-shaped passages for a system of 
closed canals not connected with the former, and maintained 
that each of the two sides of the loop terminated, finally, in a 
convoluted tube ending in a Bowman’s capsule in the cortical 
layer. 
Henle came, hereby in conflict with several older reports 
of injections, which told of successful injections of the entire 
canal-work as far as the capsule of the glomerulus, in mam- 
malial animals and in man (Gferlach, Isaacs). Neither could 504 
SECTION TWENTIETH. 
the (occasionally easy) injection of the entire canal-work of 
the kidney from the ureter, which may be accomplished in the 
lower vertebrates, be made to coincide with this (Hyrtl, Frey). 
In consequence of a large series of new investigations 
(among which we would designate the work of Ludwig and 
Zawarykin, as well as that of Schweigger-Seidel as the most 
important), Henle’s statements have been modified and our 
knowledge of the mammalial kidney not inconsiderably en- 
larged, although even now there are still many points in the 
structure of the kidney remaining to be investigated. 
The primary fundamental view of the structure of the kid- 
ney may be obtained with any mammalial animal; the most 
conveniently and summarily, it is true, in the organs of very 
small creatures (guinea-pig, marmots, moles, 
quite especially, however, the bat and the 
mouse). 
A fine longitudinal section from the med- 
ullary substance of the fresh organ shows the 
open, uriniferous canalicules, covered by a 
transparent, low, cylindrical epithelium, and 
a distinct lumen. Their ramifications may 
be represented by fig. 312 (a preparation 
which, however, was obtained by another 
method). These may be readily distinguished 
from the blood-vessels, if the latter have been 
previously injected with cold-flowing Prus- 
sian blue. A cautious picking apart with the 
preparing needle will also isolate a few of 
these uriniferous canalicules, and lead to the 
recognition of the acute-angled divisions. 
With a sharp razor one may also succeed in 
obtaining sufficiently thin, transverse sec- 
Fig. 312. The ramifica- 
tions of a urinif erous canal 
from the medullary sub- 
stance of the new-born cat 
(muriatic acid preparation). 
a-e, divisions of the first to 
the fifth order. (Original 
sketch by Schweigger-Sei- 
del.) 
tions of the cortical substance to show the meandering con- 
volutions of their uriniferous canalicules, the1 darker, more 
granular, thick epithelium of the latter, the Bowman’s cap- 
sules, and (if a moderately large amount of blood has remained) 
the reddish-yellow Malpighian vascular coils. The latter ap- 
pear most beautifully and sharply with all artificial injections. 
Even here a diligent picking enables the observer to recog- 
nize isolated continuations at least of the uriniferous canals into 
the widened capsules (fig. 311, e, d), although this communication URINARY ORGANS. 
can only be recognized with difficulty in this way. The most 
favorable for the recognition of the latter are the kidneys of the 
lower vertebrates, such, for example, as the frog, the triton, and 
salamander (although their structure is not the same) ; among 
the mammalial animals I would most recommend the organs 
of the mole. The gland-cells become transparent by the addi- 
tion of alkalies, and their structural condition is not unfre- 
quently rendered more distinct. 
The earlier knowledge of the kidney was obtained in this 
way, and, towards the close of the first half of this century, 
our information concerning the same remained stationary at 
about this stage. 
The more recent times have made us acquainted with sev- 
eral other very important methods of investigation. Let us 
mention first the section through the artificially hardened 
organ. Most (and especially almost all pathologico-histologi- 
cal) examinations are at present made in this manner. Here 
also the freezing method proves to be extraordinarily conserva- 
tive. Recourse may, furthermore, be had to chromic acid, its 
potash-salt, or—which is best—to absolute alcohol. We ob- 
tain in this manner, without trouble, very fine and instructive 
longitudinal views and—what is of the greatest importance for 
many textural conditions—good representations from trans- 
verse sections of the kidneys. 
We would also recommend here 
the previous injection of the ves- 
sels, in small kidneys, with cold 
flowing, in more voluminous or- 
gans, with solidifying, transparent 
masses. The slight trouble will be 
richly repaid in the subsequent ex- 
amination. Staining methods are 
of the highest value for the recog- 
nition of the renal tissue in the 
healthy and pathologically altered 
condition. 
Fig. 313. Transverse section through a renal 
pyramid of the new-born child, a, collective 
tubes with cylindrical epithelium; 6, descend- 
ing side of the looped canal with flat cells; c, 
returning side of the loop with granular cells; 
d, transverse sections of vessels; e, connective- 
tissue framework substance. 
again recognize, in vertical sections, the relations of the fresh 
preparation; in transverse sections (fig. 313), on the contrary, 
the lumina of the uriniferous canals, the straight ones with their 
cylindrical epithelium (a) as well as the loop-shaped ones with, 
In the medullary substance we 506 
SECTION TWENTIETH. 
for the most part, quite flat cells (5), reminding one of vascu- 
lar epithelium, and also the connective-tissue stroma of the 
medullary substance (e). 
Fine longitudinal sections of the cortical substance (fig, 
314) show, on the contrary, how this, the stratum of the con 
voluted nriniferous 
canals {B), is perme- 
ated at rapidly fol- 
lowing intervals by 
thin bundles of uri- 
niferous tubes, hav- 
ing a straight course 
(Jl) which diminish 
in size as they pass 
outwards, and only 
become lost in con- 
volutions {d) Just be- 
neath the surface of 
the kidney. These 
groups of straight 
passages, whose cali- 
bre is also variable 
(a, b), penetrate the 
layer of the convolut- 
ed canals in the same 
manner, we might 
say, that a board is 
perforated by numer- 
ous pegs driven close- 
ly together into it. 
These bundles of 
straight canals which 
I?ig. 314. Vertical section through the renal cortex of the new- 
born child (semi-diagrammatic). AA, medullary rays; B, cortical 
substance proper; a. collective tube of the medullary ray; b, finer 
nriniferous canalicules of the latter; c, convoluted canalicules of the 
cortical substance ; d. their peripheral stratum; e, arterial branch ; 
/, glomeruli; g, continuation of a nriniferous canal into the Bow- 
man’s capsule; h, the renal tunic with its lymph-spaces, i. 
were previously seen, and which are continuations of the famil- 
iar straight passages of the medullary substance, have been 
called pyramidal processes (Henle) or medullary rays (Lud- 
wig). We shall soon return to the consideration of their sig- 
nification. The tissue of the convoluted uriniferous canals 
lying between them may be considered, although indeed only 
factitiously, as consisting of individual pyramidal pieces which 
have their bases turned towards the renal capsules. These are 
the cortical pyramids of Henle. TJEINAEY OEGANS. 
Transverse sections of the cortex (fig. 316) show both varie- 
ties of the nriniferous canals ; those of the medullary rays cut 
transversely (a), those of the ordinary cortical substance (b), in 
all possible forms. The connective-tissue stroma may also be 
readily recognized at the same time. 
If the study of the epithelium be renounced, I would here 
recommend still another 
method which became 
known to me through 
Billroth. If a portion of 
kidney be treated for a 
very short time with boil- 
ing vinegar it will, after 
having been dried, or 
hardened by means of 
chromic acid or alcohol, 
afford very handsome 
views of the glandular 
passages in the medulla 
and cortex. 
Fig. 315. Surface section through the cortical substance of 
the kidney of the new-born child (semi-diagrammatic), a. 
Transverse section through the uriniferous canalicules of the 
medullary ray; b, convoluted canals of the cortical sub- 
stance proper; c, glomeruli and capsules of Bowman. 
The chemical method of isolation has more recently assumed 
the greatest importance in the investigation of the kidney. 
The fresh tissue (or also that which has been hardened in alco- 
hol), treated with strong muriatic acid (p. 125), suffers, after a 
series of hours, an almost complete destruction of the connec- 
tive-tissue interstitial substance, while the blood-vessels, and 
especially the uriniferous canals, remain completely intact; 
and not unfrequently even their epithelium is almost entirely 
preserved. These canals may then be isolated by very slightly 
shaking or a gentle manipulation with the needles, or, already 
floating in the fluid, they may be fished out with a curved glass 
rod. The whole has, it is true, become very frail and readily 
destructible; nevertheless, we may frequently succeed in tinge- 
ing them slightly with carmine, and mounting them very hand- 
somely in watery glycerine. 
The muriatic acid may be used in various ways for this pur- 
pose. 
The ordinary commercial muriatic acid has frequently been 
diluted with water until it ceased to fume, and the object im- 
mersed in it from twelve to twenty-four hours. Schweigger- 
Seidel employed the officinal, pure muriatic acid of the Prus- 508 
SECTION TWENTIETH. 
sian pharmacopoeia (of 1120 sp. wfc.), and allowed the pieces taken 
from an animal killed about a day previously to macerate in it 
from fifteen to twenty hours. Stronger acid acts rapidly, but 
attacks the gland-cells energetically; that which is weaker 
requires more time. The pieces must afterwards be carefully 
washed with distilled water, and a subsequent maceration of 
the same for one or more days in water will, for the most part, 
essentially further the isolation. Boiling with this acid or 
with alcohol containing muriatic acid, has also been recom- 
mended. 
If the chemical isolation has been successfully accomplished 
(which is not always the case, however), such objects (fig. 312, 
figs. 316-819) afford the circumspect observer extremely im- 
portant information. 
It is naturally impossible, even with the most conservative 
manipulation, to isolate a uriniferous canal throughout its 
entire course ; it is here, therefore, only a question of obtaining 
the longest possible fragments and of their combination. The 
expert will obtain these in lengths of from l-2;//, at least here 
and there. In consequence of the enormous length of the canal- 
work in question in the kidneys of the larger creatures, a suc- 
cessful result becomes much more difficult in them than in the 
organs of the smallest mammalia. The kidneys of the mole, the 
bat, the marmot, the mouse, rat, and guinea-pig deserve to be 
chiefly recommended. As Prussian blue is preserved in the 
acid macerating fluid, the blood-vessels are to be previously in- 
jected, a precautionary measure which is extremely important 
for the study of the medullary loops. 
If the examination be commenced with the medullary sub- 
stance from the apex of its pyramids, one may recognize how the 
open canals, with their characteristic epithelial covering, form a 
number of rapidly following forked divisions (fig. 312, a-e, 316, 
a, h\ and then, the branches having become narrower, assume a 
straight course and pass unchanged for long distances through 
the medullary substance (fig. 316, c) until they arrive at the ex- 
ternal portion of the medulla, which is characterized by tuft- 
shaped blood-vessels (boundary layer of Henle). Between them 
appear, throughout all the layers of the pyramids, the much 
narrower loop-shaped canaliculi (td), which are lined with 
flat, transparent cells. Their returning sides, that is, the 
ones which again tend towards the cortex, may show them- URINARY ORGANS. 
509 
selves to be enlarged and filled with darker granular gland- 
cells. 
The open canals in leaving the boundary layer pass, for the 
most part single, more rarely by twos, into each medullary 
ray, through, which they continue towards 
the surface of the kidney (fig. 314, A). The 
appropriate name of collective tubes has 
been given them {a). The above-indicated 
differences in the epithelium here become 
less distinct. The remaining considerably 
narrower canals of the medullary ray con- 
sist of the descending (that is, turned 
towards the hilus) and the returning sides 
of the loop-shaped canals (5). 
The collective tube, having arrived near- 
er the surface of the kidney, gives off more 
numerous branches (figs. 318, c, 319, c), and 
terminates above in arched ramifications 
(figs. 318, d, 319, d), which, especially in 
the smaller animals, may present a zigzag 
appearance (‘ ‘ intercal- 
ary portions ” or “ con- 
necting canals ”), From 
them, but also deeper 
from the stem of the 
collective tube, rapidly 
narrowing canals of vari- 
ous forms arise, the de- 
scending sides of the 
loops (e), whose en- 
trance here from the 
medullary substance 
has been shown in other 
macerated preparations. 
Having thus become 
acquainted with the one 
side as an offshoot or a 
terminal branch of the 
open uriniferous canals, 
Fig. 316. Vertical section through the medullary pyramids of the pig’s kidney (semi-diagrammatic), a, 
the trunk of a uriniferous canal opening at the apex of the pyramid ; b and c, its system of branches; d, 
the loop-shaped uriniferous canals; e, vascular loops, and/, divisions of the vasa recta. 510 
SECTION TWENTIETH. 
the question still arises, what becomes of the other, the re- 
turning side (figs. 818, and 319, g, g). 
This, accompanied by the canalicules of the medullary ray, 
bends deeper or higher from the group in a lateral direction 
Fig, 318. Vertical section from the kidney 
of the guinea-pig (muriatic acid preparation). 
a, Trunk of a collective tube; 6, its branches; 
c, further division ; d. convoluted canal (in- 
tercalary portion); e, descending side of a 
loop-shaped uriniferous canal; /, loop; g, 
returning side; and h, continuation into con- 
voluted canals of the cortical substance. 
Fig. 319. Vertical section from the kidney of 
the mole (muriatic acid preparation), c, Term- 
inal branch of the collective tube; d, convolut- 
ed portion of canal; e, descending side of the 
looped canal; f. loop; g, h, returning side and 
continuation into the convoluted canalicules i; 
k, neck-piece of the latter; I, Bowman’s capsule; 
m, glomerulus. 
(figs, 818, 7i, 319, 7c), assumes another convoluted course, gains 
at the same time an increased diameter and a darker granular 
epithelium, and becomes an ordinary convoluted uriniferous 
canal of the cortical substance proper, and, finally, with nu- 
merous windings and curves, terminates as the Bowman’s cap- 
sule of the glomerulus (fig. 319, 7c, I). We must here pass over 
in silence many peculiarities of a subordinate nature. 
We will only mention two conditions here, namely, that of TJEINAEY OEGANS. 
the epithelial lining of the Bowman’s capsule (fig. 820), and 
the nature of these more cloudy epithelial cells. The inner 
surface of the Bowman’s capsule has a layer of pavement-cells 
(g) of considerable size, which may 
be easily rendered visible by means 
of nitrate of silver (either by simple 
immersion or by injecting from the 
artery). More difficult of recogni- 
tion, and in a singular manner not 
permitting of the impregnation with 
silver, is a layer of smaller and 
higher cells, which cover the sur- 
face of the glomerulus (/). They 
are to be seen in the frozen organ, 
according to Chrzonszczewsky, and, 
according to Heidenhain, also in 
kidneys which have been treated 
with simple chromate of ammonia 
(o per cent.) and picked apart. An- 
other good method consists, accord- 
ing to the last-mentioned investiga- 
tor, in injecting the renal veins with 
Fig. 320. Glomerulus of the rabbit (dia- 
grammatic). a, Vas aflierens ;6, yas efler- 
ens; c, glomerulus; d. under portion of the 
capsule (without epithelium); e, neck; /, 
epithelium of the glomerulus; and g, that 
of the inner surface of the capsule after 
treatment with silver. 
absolute alcohol and then coloring the sections with carmine 
solution. First use the embryonic organ, and subsequently 
that of a mammalial animal. 
Heidenhain has acquired great merit in furthering our 
knowledge of these more cloudy epithelial cells. Besides oc- 
curring in the convoluted uriniferous canals, they may also be 
found in the ascending side as well as in the so-called interca- 
lary portion. 
This superior investigator here found an unsuspectedly 
complicated structure. The cell, his “rod-cell,” showed the 
portion of its body which is turned outwards transformed into 
rods. 
In order to confirm this entirely correct statement, one may 
use, in the first place, the entirety fresh organ of the hedge- 
hog, rat, and dog (that of the ruminantia and rodentia is not 
so good), and the highest magnifying powers. Positive fluid 
media are to be carefully avoided, for these rod-cells prove to 
be very delicate, and subject in the highest degree to disten- 
tion. 512 
SECTION TWENTIETH. 
If it be desired to explore the remarkable cell structure in 
hardened objects, harden fresh pieces in absolute alcohol (but 
not for too long a period), and subsequently use glycerine or 
a muriatic acid of 0.1 per cent. Both purposes are accom- 
plished at once, however, by absolute alcohol strongly acidu- 
lated with pure acetic acid. Tingeing accomplishes nothing 
here. Or, the fragments of the fresh kidney may first be placed 
for twenty-four hours in the above-mentioned ammonia salt, 
and subsequently, when carefully washed, in absolute alcohol. 
Finally, the organ may also be injected by the blood-vessels 
with a saturated solution of chloride of calcium, and then 
pieces placed in absolute alcohol. 
In order to make isolation preparations with the needles, it 
is advisable to employ the action for several hours of our sim- 
ple chromate of ammonia. 
Not less important for the investigation of the structure of 
the kidneys is the injection of their glandular canals from the 
ureter. Cold-flowing mixtures are to be used for this purpose. 
The addition of alcohol is not suitable for such investigations, 
although also not an absolute hindrance, as has been here and 
there asserted. It is most suitable to select a watery Prussian 
blue or carmine, to which glycerine or gum-arabic may be added 
(see p. 139). 
The varying pressure of the injecting syringe is less suitable 
than the constant pressure of a column of fluid or quicksilver 
(comp. p. 193), which may be gradually increased. Such in- 
jections then require many hours, and, notwithstanding every 
precaution, not unfrequently remain without the desired re- 
sult. While the simply-constructed kidneys of a frog or of a 
coluber natrix may be injected with facility, the attempts mis- 
carry in small mammalial animals from speedy extravasations 
into the venous system. Only embryonic kidneys, in conse- 
quence of the slightly developed medullary substance, occa- 
sionally afford the cautious experimenter a successful result. 
As a rule, the organs of the dog, the sheep, the calf, and the 
pig are to be used, and in as fresh a condition as possible. The 
pig’s kidney may be injected under the pressure of a quick- 
silver column of 50-100 millimetres and more. 
One succeeds with comparative facility, after filling the 
open canals of the medulla (fig. 316), in forcing the injection 
mass to the end of the medullary rays and their systems of URINARY ORGANS. 
branches. The descending sides of the looped canals, which 
are turned towards the hilus, may also be filled with relative 
facility, and are characterized by their smaller diameter. The 
colored fluid passes with greater difficulty through the loop 
itself, and into the returning 
side. The most rarely—and it 
is appreciable from the nature 
of the contents and the convo- 
lutions—does one succeed in 
forcing the injection mass 
through the convoluted canali- 
cules of the cortex into the 
capsules of Bowman. ISTumer- 
ous successful results have, how- 
ever, been more recently ob- 
tained, and thus the inferences 
presented by maceration con- 
fir me d (Ludwig - Zawarykin, 
Kollmann, Chrzonszczewsky, 
Hertz, Prey, and others.) 
Our diagram, fig. 321, may 
represent to the reader the re- 
sults of the injection, of which 
only the chief points have been 
described. 
To recapitulate, let us again 
follow the course which the se- 
cretion must take from the 
glomerulus. Surrounded by 
the capsule of Bowman it 
passes over into the convolut- 
ed uriniferous canalicule (/), 
which, after its convolutions, 
assumes a straight course to- 
wards the apex of the papilla 
Fig. 321. Diagrammatic representation of the 
conrse of the uriniferous canal in the perpendicu- 
lar section (very much shortened). R. cortex; 
M. medulla; *, margin; a, efferent canal-work 
with the system of branches h\ c, transition- 
canal (or intercalary portion) in the ascending or 
returning portion ; e, descending; /, convoluted 
uriniferous canal of the cortex ; g, capsule with 
glomerulus. 
Changing the epithelium, it 
passes more or less downwards, through the papilla (<?), bends 
around in a loop-like manner, and again returns with the other 
side to the cortex {d). This side, later or earlier, alters its 
character, becomes broader and more convoluted (c), and enters, 
sooner or later, in connection with other similarly constituted 
passages, into the collective tube (6), which, uniting with others 
33 514 
SECTION TWENTIETH. 
at an acute angle (a), finally pours out the urine at the apex of 
the papilla. 
The new method, the self-injection of the living animal, 
with which Chrzonszczewsky has made us acquainted, has al- 
ready been mentioned in a previous section of this book (p. 
190). Although the appearances thus obtained are variable 
and not always comprehensible, repetitions of the experiment 
with injections of a solution of carmine into the jugular of 
the rabbit have nevertheless afforded me good results. And 
the injection of indigo-sulphate of soda has succeeded still 
better. 
We cannot yet, however, leave this subject, this injection of 
the indigo-sulphate of soda. We have still to mention a more 
recent, excellent study of Heidenhain’s, the technical portion of 
which we have already mentioned in part at p. 191 of our book. 
The highly important physiological fact was ascertained that 
it is not the glomerulus of our organ, but rather the convoluted 
system of canals which secretes this blue coloring matter. I 
had already seen this a few times before, with von Ewetzky, in 
the rabbit. 
Heidenhain subsequently communicated some additional 
technical directions. These relate to the further treatment of 
the kidneys when their canals have thus been filled. The 
organ is to be directly injected by the blood-vessels with abso- 
lute alcohol, then separate the capsule, and place small pieces, 
2-3 mm. thick, in the fluid just mentioned. Quite fresh kid- 
neys may also be examined at once in glycerine saturated with 
chloride of calcium. They afford the same result. 
We have still to mention the connective-tissue stroma, as 
well as the blood and lymph passages of our organ. 
The course of the vessels in the kidney has been so fre- 
quently described (in an especially excellent manner by Hyrtl), 
that we may here limit ourselves to the most necessary state- 
ments. The branches formed by the division of the renal artery 
and vein pass through the medullary substance between the 
several Malpighian pyramids. At the basis of the latter, bow- 
like arrangements of both varieties of vessels are noticed. 
From the arterial arches arise then, in the form of branches, 
the coil-supporting arteries of the cortical substance, which 
keep in the axial part of a portion of cortex (cortical pyramid) 
bounded by two medullary rays, and towards the periphery URINARY ORGANS. 
515 
give off the afferent vessels of the glomerulus (fig. 314, e, f; fig. 
323, b). 
This, the vas afferens, undergoes, in man, further acute-an- 
gled divisions within the coil-shaped convolutions (fig. 311, b. 
and fig. 322), and forms, after the con- 
volutions, by the reunion of the latter 
branches, the efferent vessel, the vas 
efferens (fig. 311, c, 323, d). The lat- 
ter then disappear in a capillary net- 
work with elongated meshes which 
encircles the straight uriniferous ca- 
nals (fig. 323, e). From the periphery 
of the latter are first formed those 
capillary tubes {/) which encompass 
Fig. 322. Glomerulus of the pig’s 
kidney. 
with rounded meshes the convoluted uriniferous canalicules {i) 
of the cortical substance proper. 
The most superficial stratum of the cortical substance, which 
is free from vascular coils, receives its capillaries substantially 
from the efferent vessels of the superficial glomeruli; much 
more sparsely (and certainly not in all mammalial animals) 
from several of the terminal branches of the glomerular arte- 
ries, which pass directly and im- 
mediately forward to this periph- 
eral layer. 
Venous roots appear close be- 
neath the capsule in the form of 
star-shaped figures ; other venous 
roots arise deeper in the connective 
tissue. Generally coalescing into 
larger trunks, both varieties of 
venous branches empty at the 
boundary of the cortex and med- 
ulla into the arched vessels. 
Fig. 323. From the kidney of the pig 
(semi-diagrammatic), a, arterial branch; 6, 
afferent vessel of the glomerulus, c; d, vas 
efferens; e, breaking up of the same into the 
straight capillary plexus of the medullary 
ray; /, rounded plexus of the convoluted 
canals, i ; g, commencement of the venous 
branch. 
The long, rectilinear vascular 
tufts, which appear between the 
uriniferous canicules in the med- 
ullary substance (its boundary 
layer), then extend downward and either pass over into each 
other in a loop-like manner, or form a delicate net-work 
around the apertures of the uriniferous canals at the apex of 
the pyramid, and are called vasa recta (fig. 316, e, f). Be- 516 
SECTION TWENTIETH. 
tween these there also appears a capillary net-work of finer 
tubes. 
A great diversity of opinion prevails concerning the origin 
of these vasa recta. 
According to our observation, they have essentially, if not 
also exclusively, a venous character, as they are formed from 
continuations from the capillary net-work 
of the medullary rays. The vasa effer- 
entia of deeply situated glomeruli are 
joined to them as arterial supplies. Quite 
unimportant, finally, are the arterial 
branches (arteriolse rectse), which, even 
before the giving off of the glomeruli, 
have left the coil-bearing artery, and be- 
come buried in the rectilinear vascular 
district (fig. 324, f). 
Fig. 324. From the boundary 
layer of the human kidney, a, 
Arterial trunk; &, one branch, 
and e another which furnishes the 
vasa afferentia of two glomeruli at 
c and d ; /, a third branch (arteri- 
ola recta), with its division into 
rectilinear capillaries of the med- 
ullary substance, g. 
As we have above remarked, the lar- 
ger trunks frequently divide, in a tuft of 
tassel-like manner, into these vasa recta. 
Exactly the same appearance is, in 
general, also presented by the meeting of the returning straight 
vessels. Their insertion takes place in the arched veins, which 
we have become acquainted with above, as occurring at the 
margin of the cortex and medulla. 
The ascertaining of such extremely complicated conditions 
premises, naturally, extensive studies of injections and very 
careful examinations of the preparations. 
Notwithstanding the facility with which the kidney may be 
injected by the arteria renalis (so that it constitutes a good 
exercise for beginners), and however little it can be called a 
display of skin to accomplish an extensive injection of the 
medullary substance, the question as to the finer vessels of the 
organ requires entire series of other injections. We would 
advise, first, the very early discontinuance (at various stages) 
of the injection by the artery, as soon as some coloring-matter 
has reached the cortex. We would then recommend other, 
somewhat longer continued arterial injections, with which the 
medullary rays, but not the capillaries of the portions of cor- 
tex lying between them are injected. 
Other instructive preparations are afforded by the injection 
by the vein, which is likewise to be discontinued at various UEIXAEY OEGAXS. 
517 
stages. Even an extensive venous injection usually clogs at 
tlie glomerulus. Thin fluid masses may be injected into them, 
however, even by the vein. 
The double injection is, finally, very instructive. It should 
be commenced by the vein, and be continued sometimes more, 
sometimes less by the arterial or the venous side. Greater 
practice is here necessary. If a gelatine mass has been selected 
for the complete filling of the veins, it is advisable, for the 
recognition of the boundary district of both varieties of ves- 
sels, to undertake the subsequent injection of the arteries with 
cold-flowing masses. The latter is not absolutely necessary, 
however. 
We would chiefly recommend the kidneys of dogs, cats, 
and rabbits. Of larger animals, those of the pig and sheep 
are to be used. If the system of uriniferous canals has been 
filled with Prussian blue, the carmine mass and the transpar- 
ent yellow of Thiersch (p. 185) is to be selected for the injec- 
tion of the blood-vessels. Human kidneys, even from bodies 
which are no longer fresh, frequently afford good results. In- 
jections of the organ in Bright’s disease are also usually more 
or less successful. 
A connective-tissue stroma is met with as the framework of 
the kidney. It consists, in the cortical substance, of a but very 
little developed connected septal system of connective-tissue 
cells and homogeneous or striated interstitial substance. It 
appears somewhat thicker on the adventitia of the larger ves- 
sels and the capsules of Bowman, and, metamorphosed at the 
surface of the organ into a connective tissue with numerous 
spaces, is continued into the renal capsules. This connective- 
tissue stroma becomes somewhat firmer in the medullary rays ; 
it reaches its greatest, although absolutely slight development 
in the medullary substance (fig. 318, e). Thin sections from 
the organ which has been hardened in alcohol or chromic acid 
afford the very best views when brushed or tinged with car- 
mine. The star-shaped connective-tissue cells may be beauti- 
fully isolated by macerating in muriatic acid (Schweigger- 
Seidel). 
The attempts to inject the lymphatics of the kidney by 
means of the puncturing method have been, for the most part, 
unsuccessful. It succeeds best by the swollen vessels of or- 
gans (of the dog) which have been rendered oedematous by liga- 518 
SECTION TWENTIETH. 
ting the ureter. The parenchymatous lymphatics occupy the 
interstices of the connective tissue (fig. 314, i), abounding in 
spaces, which lies beneath the capsule, and pass inwards from 
here through the spaces of the connective-tissue stroma, be- 
tween the uriniferous canals, around the capsules of Bowman 
and the finer blood-vessels. While the intercommunication of 
these lymphatics in the cortical tissue is very free, it is only 
subsequently that the narrower spaces of the medullary rays, 
and finally the passages of the medullary substance itself, 
become filled. The whole, moreover reminds one strongly of 
the lymphatics of the testicle (see below). 
Through the industry of competent investigators we have 
become more intimately acquainted with the numerous patho- 
logical changes of the renal tissues. Here, also, the predomi- 
nant participation of the connective-tissue framework in the 
morbid textures was for a long time firmly maintained, and 
the new formations were also said to take their origin from its 
cells, while, in this regard, the structureless membrane of the 
glandular passages was considered as playing a subordinate 
role. The gland-cells themselves were capable, indeed, of 
swelling, the production of granular contents, of increase, as 
well as of degeneration (especially the fatty), and of decay 
(and these occurrences are very frequent), but corresponding to 
their epithelial nature, did not pass over into other tissue ele- 
ments,—all acceptations which properly meet with renewed 
doubts at the present day. 
Increase of the connective-tissue framework substance, 
partly local, partly diffused, is frequently met with in the 
kidney. After the application of the methods already men- 
tioned, the connective tissue appears sometimes homogeneous 
and compact, sometimes split up into fibrillge with its cells 
usually more distinct. The related substance of the membrana 
propria, especially in the capsule of Bowman, also undergoes 
thickening, now and then with a stratified appearance. 
Whether the cell-like bodies which may be rendered visible 
under such conditions are actually connective-tissue cells be- 
longing to the capsular membrane, we will leave undecided. 
From these connective-tissue cells commence additional pro- 
cesses of multiplication, which may lead, in part, to the for- 
mation of new connective-tissue corpuscles, in part to the pro- 
duction of spherical cells, similar to the elements of the lymph UEINAEY OEGANS. 
519 
and pus, whereby, however, the emigration of the colorless 
blood-corpuscles will also play its part. The pus of the renal 
tissue also consists of such cells. A similar process of prolif- 
eration, but accompanied by shrivelling and fatty degenera- 
tion, is produced by tuberculosis of the kidney, while miliary 
tubercle here also frequently takes its origin from the sheaths 
of the arteries. Other, and especially carcinomatous new for- 
mations are also said to take their origin from this connective 
tissue. This has recently been denied, however, so far as the 
cells of the former are concerned, as they are thought to origi- 
nate from the glandular epithelium (Waldeyer), 
Brief mention may here be made of the deposits of fatty 
and pigment molecules as well as of the amyloid degeneration. 
Even in the normal kidney one may meet with a few molecules 
of fat in the tine granular contents of the glandular epithe- 
lium ; the number of the same is occasionally not inconsidera- 
ble. Large collections of them, which may produce a fatty 
degeneration of these cells leading to their destruction, are, in 
pathological conditions, of extraordinarily frequent occur- 
rence. These fat-granules also appear within the trabeculae 
and the connective-tissue corpuscles of the connective-tissue 
framework. Gradually flowing together in the connective- 
tissue cells, they may lead to the formation of globular fat- 
cells. 
Remarkable pigmentations of the kidneys (preponderating, 
however, in the gland-cells) may be met with in persons who 
have been destroyed by an obstruction of the biliary ducts. 
We have already (p. 470) mentioned the changes which occur 
in the liver-cells with such a retention of the bile. Such kid- 
neys present an olive-green color. Yariously tinged epithe- 
lium is seen in the uriniferous canals of the medullary sub- 
stance, likewise epithelium with variously colored masses of 
pigment in the cell-bodies. In cases of high degree the urini- 
ferous canals are observed to be filled with lumps of hard, 
brittle black substances. A similar but blacker pigmentation 
is also met with in the convoluted uriniferous canals of the 
cortex, as well as in the capsules of Bowman, that is, in the 
epithelium of the glomerulus. 
Melansemia, the passage of pigmentated cells and flakes 
from the spleen in malignant intermittents (p. 484), causes em- 
bolia in the renal vessels by means of the structures mentioned. 520 
SECTION TWENTIETH. 
The masses of pigment are found in the vessels of the glome- 
rulus, the capillaries of the cortex, more rarely in those of the 
medulla. A few such pigment aggregations may be met with 
even in the uriniferous canals. 
The participation of the gland-cells is probably somewhat 
greater in the not unfrequent amyloid degenerations of the 
kidneys which are to be examined with the aid of Jurgen’s re- 
agent (p. 155). They become transformed into the character- 
istic flake-like bodies, similar to those which we have men- 
tioned above (p. 474) at the equivalent degeneration of the 
liver. The seat of the degeneration is predominantly in the 
vascular walls, especially those of the glomerulus (vas afferens, 
convoluted canals, and efferent vessels). The membrana pro- 
pria may also undergo the process of degeneration. 
An interesting succession of the Just-mentioned metamor- 
phoses of these several elements—the glandular and the con- 
nective-tissue elements, together with the vascular—is shown 
by the process called “Bright’s disease.” This commences 
with an increased inflammatory congestion and swollen, granu- 
lar gland-cells, leading to an extensive destruction of the gland- 
cells of the organ as well as of its blood-vessels, with which is 
also associated a considerable increase of the connective- tissue 
framework substance, and a further metamorphosis of the 
glandular tissue. 
At the commencement periods, especially of severe and 
rapidly progressing cases, one notices in the cortical substance, 
where these pathological processes first take place, a consider- 
able repletion of the finer vessels with blood, and somewhat 
cloudy, granular gland-cells. The vascular coils appear more 
distinct, small extravasations from ruptured vessels are fre- 
quent, and glassy cylindrical masses of albuminous substances 
begin to appear in the straight uriniferous canals. These “ fibrin 
cylinders” (which are to be distinctly recognized in hardened 
kidneys as masses filling the glandular canals) sometimes pre- 
sent more of an appearance of pure fibrin, sometimes they ap- 
pear to be more impregnated with a few blood-corpuscles and 
separated gland-cells. At a later period the quantity of blood 
contained in the cortex of the kidney diminishes ; injections 
of the organ, which is frequently increased in volume, now 
succeed with greater difficulty. A fatty degeneration takes 
place extensively through the glands-cells, and even the fibrin URINARY ORGANS. 
521 
cylinders frequently contain such fragments of cells and free 
grannies of fat. Other gland-cells shrivel, without presenting 
these fat-molecules. In well-hardened preparations the con- 
nective-tissue framework substance is, for the most part, found 
to be increasing by proliferation. If these cylinders are not 
washed away by the current of the urine (in which case they 
appear as urinary constituents), the obstructed uriniferous 
canals become widened and sinuous, and in this way may give 
origin to the formation of cysts. If the process continues, the 
glandular canals are found to be deprived of their epithelium 
filled with detritus, and, in part, collapsed and gradually dis- 
appearing in the increasing connective tissue. Concentric de- 
positions of connective tissue also occur around the shrinking 
capsules of Bowman. In this manner are formed, here and 
there, these metamorphosed connective-tissue places in kidneys 
which are decreasing in volume. Between them remain portions 
of glandular tissue, widened canals filled with granular masses, 
etc. These are the so-called “granulations” of pathological 
anatomy. 
The structural changes in question can only be inadequately 
and unsatisfactorily followed in the fresh organ, although such 
examinations should always be made, especially on account of 
the metamorphoses of the cells. Hardened kidneys must serve 
for further investigations. This procedure may present some 
difficulty if the softness be extreme. The object will be ob- 
tained after a time, however, especially if the pieces immersed 
are not too large and a certain accuracy be observed. The 
injection should, so far as possible, always precede the immer- 
sion ; in many processes, such as the formation of tubercles, 
amyloid degeneration, and Bright’s disease, the microscopical 
preparations frequently gain thereby a surprising intelligibility. 
Tingeing with carmine and with aniline blue also deserves to be 
urgently recommended to the physician for these cases. Where 
more considerable connective-tissue new formations are con- 
cerned, the preparation is to be boiled in vinegar, and then 
immersed either in alcohol or in chromic acid. With the 
latter treatment, especially, many things become very hand- 
some. 
Several extensive deposits in the renal canaliculi, origina- 
ting in the urinary constituents, are also to be mentioned here. 
The so-called uric acid infarction, which occurs in infants in the 522 
SECTION TWENTIETH. 
first days after birth, is a common occurrence. A yellowish, 
somewhat red substance fills, in streaks, the open uriniferous 
canals of the pyramids, and may be readily pressed from their 
openings with the fingers. The microscope shows, mingled 
with glandular epithelium, a sometimes homogeneous, some- 
times coarse granular mass of uric acid salts, from which the 
characteristic uric acid crystals may be separated by means of 
a drop of acetic acid. The altered assimilation which the pul- 
monary respiration induces in the body of the new-born is 
probably the cause of this condition, which is not of itself 
important. JSTot unfrequently such masses also appear in older 
persons, and may become united to concretions of uric acid 
salts. They are met with, for example, in Bright’s disease. 
Molecules of the carbonate of lime, as dark granular masses, 
may, especially in advanced age, obstruct the loop-shaped urini- 
ferous canals (lime infarction). They dissolve with efferves- 
cence by the addition of acetic acid under the microscope. 
Kidneys injected with transparent masses tinged with car- 
mine, and deprived of their water by means of absolute alcohol, 
afford handsome preparations for a collection when mounted in 
Canada balsam. Other preparations are to be preserved in the 
customary manner with glycerine. Concerning the methods of 
examining the efferent portion of the urinary apparatus, the 
ureters, bladder, urethra, etc., a few remarks may suffice. 
The calices and pelvis of the kidney, the ureters, and the 
bladder scarcely require discussion, as the methods of investi- 
gating their constituent layers are sufficiently well known to 
the reader. The stratified epithelium of these parts presents 
numerous and peculiar forms, with which it is necessary to be 
acquainted in order to avoid embarrassment in examining the 
urine. The most superficial layer of the epithelium of the 
bladder (fig. 325, c) shows large, more flattened cells with de- 
pressions on the under surface, the one turned towards the 
next following layer of cells. The arched ends of the cylindri- 
cal cells of the following layer fit into these cavities ; neverthe- 
less, the cells of the deepest of these two layers are extremely 
irregular in form. We recommend for the examination, ma- 
ceration in 10 per cent, solution of common salt (p. 134) or 
Czerny’s mixture (p. 137). A similar condition is also shown 
by the ureters and the pelvis of the kidney. The cells of the 
deepest layer appear more rounded. URINARY ORGANS. 
Of greater importance for the practical physician is the 
chemical and microscopical examination of the urine, of which, 
however, we can here only consider the latter. 
Fresh normal urine presents a clear fluid which holds its 
numerous organic and inorganic matters in watery solution, 
and contains but few elementary constituents from the mucous 
membrane of the urinary passages. The latter, pavement epi- 
thelium and mucous corpuscles, usually sink to the bottom of 
the vessel as a light cloud. A more abundant admixture of 
tissue elements may appear in the urine as a result of patho- 
logical conditions of the urinary apparatus, as well as of the 
efferent passages. They may cause cloudiness and changes of 
color in the fluid just evacuated, 
which, after standing, deposits 
sediments. Among these are to 
be enumerated the pavement- 
shaped epithelial cells of the 
bladder, ureters, and pelvis of 
the kidney, pus and mucous 
corpuscles, blood-cells, gland- 
cells of the uriniferous canals, 
and so-called exudation cylin- 
ders of the latter (fig. 325). To 
these may also be added para- 
sitical structures. 
Fig. 325. Organized constituents of the urine. 
a, mucous- and pus-corpuscles; 6, gland-cells of 
the uriniferous canals, partly filled with fat, part- 
ly breaking down; c, pavement epithelium of the 
bladder; d, blood-cells; e, /, g, h, i, various 
forms presented by the fibrin cylinders. 
have been already mentioned. Pus and mucous cells {a) usual- 
ly occur in considerable numbers in the urine in catarrh of the 
bladder ; at the later periods only with a very scanty admix- 
ture of pavement epithelium (c). At the commencement, the 
latter cells are more abundant, and just in the first periods lar- 
ger metamorphosed epithelial cells are met with, which pre- 
sent, together with their nucleus, a number of these pus-cor- 
puscles in the cell-body. So that even here the epithelial origin 
of these structures has been accepted, as has already been 
stated concerning other mucous membranes, under similar pro- 
cesses. Blood-corpuscles {cl) appear spherically distended in 
the thin fluid medium of the urine; gland-cells (6), washed out 
of the uriniferous canals, present various appearances. 
Nearly all these elements 
We have already, in sketching the Morbus Brightii, mem- 
tioned the fibrin or exudation cylinders {e-i) characteristic of 524 
SECTION TWENTIETH. 
this disease. In the rapidly progressing form of the disease 
the urine is usually at first bloody. It deposits a sediment in 
which appears, together with swollen blood-cells, mucous and 
pus corpuscles as well as epithelium from the pelvis of the kid- 
ney, the ureters, and bladder (c), homogeneous fibrin cylinders 
enclosing (sometimes numerous, sometimes scanty) blood-cells 
(e). These occasionally contain crystals of uric acid or oxalate 
of lime (/'). At a later period these exudation cylinders no 
longer contain any blood-cells, but, on the contrary, gland-cells 
of the uriniferous canalicules or their remains {h, g). If the 
epithelium of the passages has been entirely destroyed, one 
may meet with completely hyaline, homogeneous exudation 
cylinders {i). In the slowly progressing form of the disease 
with which we are occupied, this admixture of blood-corpuscles 
is wanting. Mucous corpuscles and gland-cells of the urini- 
ferous canals (6) appear, and likewise, varying exceedingly in 
their characteristic, the fibrinous coagula. They are at first 
covered by the gland-cells, if the exudation has taken place in 
uriniferous canals which are still uninjured. Such a covering 
of cells may also be met with on these exudation cylinders, 
even in later stages, if the latter have been formed in passages 
which, up to that time, have remained intact. If, on the con- 
trary, the fibrinous effusion has taken place in canals which 
have already lost their epithelium, pure fibrin cylinders, or 
those containing only a few fat-granules may appear. If 
rapidly expelled, they are pale; after remaining for a longer 
time in the uriniferous canals they become darker contoured 
and more yellow, and do not rapidly become pale on the ap- 
plication of acetic acid. If a more considerable fatty degen- 
eration of the gland-cells has taken place, such cells, their re- 
mains, or fat-molecules may occur on or in the cylinder (f, g, 7i). 
Shrivelled cells may also show themselves in the fibrinous 
coagulum, and even one and the same exudation cylinder may 
appear different in its various portions. 
The quantity of the fibrinous coagula, affording a measure 
of the extension of the process in the kidney, is extremely va- 
riable. These exudation cylinders in the urine generally form 
an expression of the renal changes ; but not an accurate one, as 
the degeneration may be met with in different stages in various 
portions of one and the same kidney ; furthermore relapses, 
that is, a local recommencement of the process, may occur URINARY ORGANS. 
525 
(Frerichs). Further remarks concerning the methods of inves- 
tigation are unnecessary. 
Among the vegetable parasites which occur in the freshly- 
evacuated urine may be mentioned the sarcina, with which we 
have become acquainted from the contents of the stomach (p. 
487). The urine may receive casual admixtures from the semen, 
as well as from other secretory productions of the male and fe- 
male genital mucous membranes. 
Our fluid much more frequently forms sediments from amor- 
phous and crystalline precipitates of the organic and inorganic 
constituents dissolved in it. Among these are to be enumera- 
ted in the first line, as the most extensive, the precipitates of 
uric acid, uric acid salts, oxalate of lime, and the amnionic- 
phosphate of magnesia. With these are associated other rarer 
forms. 
These precipitates, to which allusion is here made only in 
so far as their forms are concerned, are caused in part by the 
phenomena of decomposition taking place in the evacuated 
urine, the acid and alkaline fermentation, and are therefore 
constant occurrences, in part de- 
pending on increased concentra- 
tion and altered composition, and 
are therefore isolated, and fre- 
quently pathological occurrences. 
All strongly-concentrated hu- 
man urine deposits, on cooling, 
a finely granular yellow or brick- 
colored sediment, which shows, 
by microscopical analysis, small, 
dark-contoured, yellowish mole- 
cules which appear in irregular 
groups and aggregations, and in 
part united in dendritic figures 
(fig. 326). This is the urate of 
soda, which is soluble on warm- 
ing. It was formerly erroneous- 
ly regarded as a combination of 
Fig. 826. Crystalline and amorphous precipi- 
tate of the urate of soda. 
uric acid with ammonia. The figure mentioned shows in its 
lower portion such precipitates of the uric acid salt in question. 
In the upper portion we perceive developed crystals which 
come from urine which had been evacuated for a longer time, 526 
SECTION TWENTIETH. 
and in which the acid fermentation had passed off and the alka- 
line had commenced. Several crystals of the oxalate of lime 
appear among the molecular sediments. 
The uric acid soda salt also occurs in gouty concretions. 
Urine which has been exposed to the atmosphere for some 
time after its evacuation undergoes at first, for several days 
(occasionally weeks), an acid fermentation whereby lactic and 
acetic acids are formed and the acid 
reaction increases. This fermenta- 
tive process usually commences 
rapidly in febrile diseases. In con- 
sequence of the same, the uric acid 
salt (urate of soda) becomes decom- 
posed, and the uric acid, which is 
difficult of solution, is separated 
and forms a reddish sediment. 
Our fig. 327 shows the crystals 
of the same which are thereby 
formed. One usually recognizes 
rhomboidal tablets with rounded, 
obtuse angles, and colored by the 
Fig. 327. Crystals of uric acid from the 
acid fermentation of the urine. 
urinary pigment, as represented below and to the right of the 
figure. They have received the name of the 4 4 whet-stone form ’ ’ 
(44 Wetzsteinform”). By their union are formed the druses 
which are shown at the upper half of the right side. Viewed 
from the side, these 44 whet-stones ” frequently present cask- 
shaped figures. When slowly precipitated, uric acid (fig. 327 
to the left) may form druses of four-sided prisms with straight 
terminal surfaces which remind one of those of the urate of 
soda. 
That these, however, are not the only crystalline forms of 
uric acid, that the latter much more presents the greatest 
changes, is well known. 
If the acid with which we are occupied be precipitated from 
fresh urine by the addition of several drops of muriatic acid, 
large, tinged, often peculiar forms of crystals are produced, a 
few of which are represented by our fig. 328. Other forms are 
obtained by precipitating the pure uric acid (it is to be dissolved 
in a solution of potassa and the potash salt reduced by means 
of muriatic acid). The forms aof our fig. 329 are then produced. 
Abortive forms of the uric acid crystals constitute those pe- URINARY ORGANS. 
527 
culiar masses of the figure c. They have been called “dumb- 
bells.” Their form is partly that of a drum-stick, partly that 
of the dumb-bells used by gymnasts. They occur at times 
Pig. 328. Crystals of uric acid artifici- 
ally precipitated. 
Pig. 599. Uric acid in its various 
crystalline forms. At a, a, a, crystals 
such as are obtained by the decom- 
position of uric acid salts; at b, 
crystallizations of uric acid from the 
human urine ; at r, so-called dumb- 
bells. 
Fig. 330. Crystals 
of the oxalate of 
lime, 
naturally in the urine, at times artificially, from the decompo 
sition of urate of potash. 
Tiie surprising variety of forms in which we meet with the 
uric acid crystals sometimes make it very desirable for the mi- 
croscopist to test them chemically under his instrument. This 
may be done with great facility, ity 
the addition of a few drops of a potash 
solution, the crystals in question may 
be dissolved, to be then reprecipitated 
in the ordinary crystalline forms (fig. 
329, a) by the aid of muriatic acid. 
The acid fermentation not unfre- 
quently leads to the precipitation of 
crystals of the oxalate of lime, the fam- 
iliar octahedra which are shown by our 
fig. 330. Under what conditions this 
combination here takes place has not 
yet been determined. They may also 
Fig. 331. Various crystalline forms of 
chloride of sodium, mostly from animal 
fluids. 
occur in neutral and alkaline urine, and majr likewise form 
constituents of pathological sediments. Chloride of sodium 
(fig, 331) also assumes the form of octahedra from the presence 528 
SECTION TWENTIETH. 
of urea. In consequence of its ready solubility, however, it 
never crystallizes from fluid urine. To demonstrate it, the 
drop of fluid must be allowed to evaporate. 
Numerous small fermentative fungi make their appearance 
in the urine as a sign of the acid fer- 
mentation. They quite remind one of 
the yeast fungus (Cryptococcus cere- 
visirn), but are smaller. Comp. tig. 
384 (to the right and below). 
Fig. 332. Crystals of ammonio-phos- 
phate of magnesia. 
If the urine remains standing for 
a longer time after its evacuation it 
becomes decomposed, and the fluid assumes a neutral and 
subsequently an alkaline condition, produced by the decom- 
position of the urea into carbonate of ammonia. The urine 
hereby grows somewhat paler; the former sediments dis- 
appear, it becomes more and more offensive to the smell, is 
cloudy, a whitish pellicle is formed on its surface, and a 
Fig. 333. Precipitates of the urate of ammo- 
nia from alkaline urine, together with crystals 
of the oxalate of lime and ammonio-phosphate 
of magnesia. 
Fig. 334. Fermentation—mould andvibrionic 
formations in the urine. 
similarly colored sediment is deposited at the bottom of the 
vessel. This consists of the familiar crystals of the ammo- 
nio-phosphate of magnesia (fig. 382). The precipitates of the 
urate of ammonia also show themselves. This consists of 
strongly contoured, often quite dark globules, which are fre- 
quently covered with fine points, and thus remind one of UEINAEY OEGAN'S. 
529 
morning stars, or they may also have club-like, corrugated 
processes on them, and thereby assume an appearance similar 
to bone-cells. Fine needle-shaped masses may also be met 
with. Fig. 833 represents these conditions, together with crys- 
tals of the oxalate of lime and the ammonio-phosphate of mag- 
nesia. 
The fermentative fungus also disappears from the acid 
urine, and in its place appear the elements of mould and nu- 
merous confervoid growths. Numerous fine granular masses, 
vibrionse, likewise make their appearance. Our fig. 334 may, 
in its middle portion, represent such mould formations, while 
to the left and below vibrionse are delineated. The upper por- 
tion is occupied by the fungus of the cryptococcus cerevisise 
from yeast, the right lower corner by the fermentative fungus 
of diabetic urine. 
Alkaline fermentation of the urine may take place, in an 
abnormal manner, very soon after its evacuation. In conse- 
quence of the fermentative action of the mucus and pus of the 
bladder, urine which has been retained there is decomposed 
into carbonate of ammonia, and may thus be evacuated in an 
alkaline condition. The needle-shaped groups of urate of am- 
monia represented in the upper part 
of fig. 333 came from such urine in 
a case of paralysis of the bladder. 
Spontaneous deposits of other 
matters are rare phenomena. In a 
few cases only have crystals of cys- 
tine—those readily recognizable, 
delicate six-sided tables, such as 
are represented by fig. 335—been 
found in human urine. 
The remarkable and rapid de' 
struction of the liver-cells, which 
has received the name of yellow 
atrophy of the liver, has been mentioned on earlier pages of 
this book (p. 471), and it was remarked that this degeneration 
produced large quantities of leucine and tyrosine. These, ex- 
creted by the kidneys, appear in the urine of such patients. 
Brownish spherical druses of tyrosine have been noticed in 
the urinary sediment deposited. A drop evaporated on the 
microscopic glass slide shows yellowish tyrosine druses em- 
-34 
Fig. 335. Crystals of cystine. SECTION TWENTIETH. 
bedded between membraniform and globular deposits of leu- 
cine (Frerichs). 
Among the remaining precipitates of urinary constituents 
which are only to be obtained as a result of further chemical 
procedures, let us here mention only the crystalline forms of 
combinations of urea with nitric and oxalic acids (fig. 336). 
Fig. 836. Crystals of the combinations of urea with nitric and oxalic acids, a, a, nitrate, 6, 6, oxalate of 
urea. 
Their production, as also the occurrence of other matters, such 
as sarcocine, xanthine, etc., we must leave to the text-books on 
physiological chemistry. 
The anatomical methods of examining the various sediments 
of the urine are of a very simple nature. After standing for 
some time, the clear fluid is poured from the vessel and the re- 
mainder is placed in a watch-glass, glass box, or glass beaker, 
from which a drop is to be removed by means of a glass rod or 
a pipette and placed on the microscopic glass slide. It is con- 
venient to have a small burette with a caoutchouc tube and 
clamp, after the manner of the larger one used for titrition (fig. 
87, 1, p. 143), with a fine glass tube for the exit. The burette 
is to be filled with the sediment, or the still clear urine which 
is to form a sediment, and the drops are allowed to flow on to 
the slide by opening the clamp. 
With regard to the preservation of urinary sediments in 
the form of objects for a collection, it may be stated that those 
which consist of tissue elements are not capable of being kept 
permanently. Crystalline sediments, on the contrary, are to 
be allowed to dry on a glass slide and then mounted with 
Canada balsam, or some other resinous body. UEESTAEY OEGANS. 
531 
A few words may be devoted, at the close of this section, 
to the supra-renal glands. These organs, which are remark- 
ably developed in the earlier foetal period, occur in a less 
vigorous condition in the adult, and are then frequently very 
fatty, almost fatty degenerated. They show, as is known, a 
firmer, reddish-yellow cortex (fig. 337) which, in human beings, 
Fig. 337. Cortex of the human supra- 
renal gland in vertical section, «, small- 
er, b, larger gland-cylinders; c, capsule. 
Fig. 338. Cortex of the human supra- 
renal gland, more strongly magnified, a, 
gland-cylinder ; 6, interstitial connective 
tissue. 
also permits of the recognition of a narrow, darker, and, after 
death, not unfrequently liquefying inner zone, and a softer, 
grayish-red medullary substance. The former (fig. 338) con- 
sists of the same connective-tissue stroma (&) which we have 
already described for the hypophysis cerebri and thyroid 
gland, and which is prolonged inwards from the capsule in 
radiated lamellae. Numerous cavities are found in it; they 
grow smaller and smaller in an outward direction (fig. 337, a); 
in the middle they are oblong and cylindrical (5). Their con- 
tents are a varying number of granular cells. In the medul- 
lary substance there is a much finer connective-tissue stroma 
which contains transversely oval cavities filled with variable cells, 
but which contain but little fat. The latter, but not the cellu- 
lar elements of the cortex, become brown in a remarkable man- 
ner, as Henle found, from the action of bichromate of potash. 532 
SECTION TWENTIETH. 
In certain mammalia! animals the medullary substance is very 
rich in nervous plexuses containing ganglion-cells, and, indeed, 
a connection of our organ with the embryonic sympathetic 
can scarcely be denied. The number of the blood-vessels is 
also quite considerable. Delicate fine capillaries, formed from 
the numerous smaller arterial branches from the capsule, en- 
circle the cavities of the cortex and pass over into a highly 
developed venous net-work. The vessels of this net-work are, 
however, increased in diameter ; they pass through the con- 
nective tissue of the medulla and lead into the large single or 
double veins which lie in the interior of the organ. The lym- 
phatics require more accurate investigation ; the puncturing 
method has thus far yielded me no results, while the blood- 
vessels, for example, those of the calf, may be readily injected 
by the artery as well as by the vein. Very handsome injec- 
tions may be obtained with the guinea-pig, as well as the rat, 
from the aorta and lower vena cava. 
The supra-renal bodies of the new-born and very young 
animals, and also those of embryos, from the later periods of 
embryonic life, are to be selected for examination. 
Some things may be recognized, even in sections from fresh 
organs, with the aid of acids and alkalies. Far better views 
are afforded by supra-renal glands which have been hard- 
ened in chromic acid, Muller’s fluid, or absolute alcohol, with 
the assistance of brushing and tingeing. The nerves may 
be studied on the fresh organ with the addition of alkalies 
or osmic acid, or on preparations which have been immersed 
in dilute acetic or pyroligneous acid, as well as in weak chro- 
mic acid. Sections deprived of their water by means of abso- 
lute alcohol are to be mounted in Canada balsam or similar 
resinous matters, or, when moist, in glycerine. Section STiucntn-jTirst. 
SEXUAL ORGANS. 
Among the female generative organs the uterus and the lac- 
teal glands are the most important. 
The ovary (fig. 339) shows, as is known, the rounded, closed 
Fig. 339. The ovary, a, the stroma; 6, smaller Graa- 
fian follicles; e, a larger one; d, a fresh corpus luteum, 
with the proliferated cell-layer of the inner surface *; 
e, an old corpus luteum ; g, veins with their ramifica- 
tions, ft in the organ. 
Fig. 340. Mature ovum of the rabbit. 
a, zona pellucida; 6, yolk; c, germ ve- 
sicle ; d, germinal spot. 
glandular capsule (h, c) which contains the primitive ovum 
embedded in a firm connective-tissue framework or stroma. 
These ova are set free by the rupture of this capsule, or 
the Graafian follicle; this takes place in the human female at 
periods of four weeks, corresponding to those of menstruation ; 
in the mammalia it occurs at the period of heat. The follicle 
itself cicatrizes by a connective-tissue formation, and disap- 
pears. By this metamorphosis it produces the so-called cor- 
pus luteum {d, e). 
Other ova probably undergo dissolution in the unopened 
gland capsule (Slavjansky). 
If one desires to obtain a primary view of the ovum (figs. 340 SECTION TWENTY-FIRST. 
and 341, a), this most beautiful cell-formation of the body, 
the ovarium of a mammalial animal just killed is to be used. 
The larger Graafian follicles (fig. 341) may be readily cut out 
from the stroma with a curved scissors and opened on the 
microscopic glass-slide. The ovum may be perceived as a 
Vig. 341. Mature follicle, a, ovum: epithelial stratum covering the same, 6, and lining the cavity, c 
d. connective-tissue wall; e, outer surface of the follicle. 
small white point in the exuding, slightly cloudy contents, by 
a sharp eye, even without any further accessories; while a 
less perfect organ of vision requires a loupe, or the very weak 
magnifying power of a microscope, for its discovery. The 
adherent, frequently thick covering of follicular epithelium 
(fig. 341, b) is to be removed by means of a cataract needle ; a 
very thin and light covering glass is to be used, with the inter- 
position of a piece of human hair. The cell capsule, zona 
pellucida (fig. 340, a), the contents of the yolk (&) and the 
nucleolus, the so-called germinal spot (d), may be readily 
seen ; the recognition of the fine contours of the germinal vesi- 
cle of the nucleus (c) will, on the contrary, cause some diffi- 
culty. 
A 3-400-fold enlargement is to be employed for this purpose. 
A cautious pressure made on the covering glass with the point 
of a needle, while the observer looks through the instrument, 
will then cause the rupture of the thick envelope of the ovum SEXUAL ORGANS. 
and permit of tlie recognition of the nature of the exuding yolk 
substance, as well as the germinal vesicle with the germinal 
spot. 
With human females, the freshest possible ovaries of youth- 
ful individuals are to be selected, preferably those who have 
died suddenly. Persons who have been lying sick for a long 
time, and those of a more advanced age, frequently cease to 
show the ova with any distinctness. 
If the trouble of separating the Graafian follicles from their 
attachments, especially the very diminutive ones of our smaller 
mammalial animals, be feared, the ovulum may also be ob- 
tained by scraping the cut surface of the ovary. An indifferent 
fluid medium will here be necessary. 
Young, smallest possible follicles, carefully separated from 
the stroma, may be reviewed in their totality with low magni- 
fying powers; in this way they will show the ovulum, the 
epithelium, and the parietes of the glandular capsule. 
The examination of the fresh ovaries may also suffice to es- 
tablish the main points concerning the nature of the framework 
substance, as well as the cell changes which take place in the 
corpus luteum. 
If, on the contrary, a more accurate analysis of the ovary 
is to be made, the fresh organ must be hardened. If the freez- 
ing method be omitted, the ordinary fluids are to be employed, 
among these I would give the first place to absolute alcohol and 
chromate of potash. The blood-vessels should also, when pos- 
sible, be previously injected. Tingeing with hsematoxyline or 
carmine, and in the latter case combined generally with wash- 
ing in acetic acid water, constitutes an additional excellent ac- 
cessory. 
The connective-tissue framework forms towards the centre a 
nucleus of the organ, and is extremely rich in blood- and lymph- 
vessels ; externally it is a non-vascular framework, in the 
smaller and larger spaces of which are contained the ova. The 
youngest of the latter appear in extraordinary numbers in its 
peripheral portion (fig. 342, c, cl), the “zone of the primordial 
follicles.” Here lie the most unripe ova, beautiful cells with- 
out envelopes, surrounded by a mantle of small, epithelium- 
like elements (fig. 343, 1). The developing ovulum (2) soon 
shows the latter cells as a double layer, and on it itself a cap- 
sule, the zona pellucida (2, a) is perceived. A cavity (fig. 342, d) SECTION TWENTY-EIEST. 
is afterwards formed by the separation of the follicular epithe- 
lium, and finally we receive the appearance of the ripe follicle, 
Fig. 842. Ovary of the rabbit, a, epithelium (serosa) ; &, cortical or external fibrous layer; c, youngest 
follicles; d, a somewhat more developed older one. 
represented in fig. 341. The latter occur only in limited num- 
bers in the ovarium. They have a connective-tissue wall. An 
inner stratum {d) shows an extraordinarily rich net-work of cap- 
illaries, while larger vessels are contained in 
a more peripheral layer (e). If we add the 
layer b of our fig. 342 as a connective-tissue 
boundary layer to the organ, and remark, 
finally, that a stratum of cylindrical cells, the 
ovarian or germinal epithelium (a), covers the 
surface, then we have presented in a few sen- 
tences an outline of the structure of the ovary. 
Fine transverse sections of the hardened 
ovary show these relations without difficulty. 
If the plane of the section be favorable, the 
ovulum may also be perceived in large fol- 
licles, embedded in the epithelial layers of 
the latter (very frequently lying to the inner 
side). Occasionally, with strongly hardened 
ovaries, such fine sections of the smaller folli- 
cles may be obtained with a sharp knife, that 
cie?from3 
isastmAfhVutthaezOTap™iua 
tife ovum a)ces 
the ovulum may likewise be seen in the section ; sometimes 
only the zona, after the loss of the yolk and nucleus. SEXUAL ORGANS. 
537 
We have more recently received very important informa- 
tion, through Pfliiger, concerning the formation of the Graafian 
follicles, which established the truth of the older but no longer 
regarded observations of Valentine and Billroth, and afforded 
an interesting parallel between the testicle and the ovary. 
Other observers afterwards coincided, and Waldeyer has pro- 
duced a beautiful monograph. Ac- 
cording to this, the ovary consists 
originally of ordinary oblong, oc- 
casionalty, however, also of quite 
irregularly formed cell aggrega- 
tions, the follicular chains or ovular 
strands (fig. 344). In these primor- 
dial follicular rudiments are formed 
the ova; the follicles become sepa- 
rated from them by constriction, 
but may still remain connected with 
each other in rows, and may conti- 
nue to increase in size (Pfluger’s 
“follicular chains”). The whole 
formation, although possibly it may 
also repeat itself in after-life, is, 
however, very transitory, and was 
consequently overlooked for so long 
a time. Young kittens in the first 
weeks of their life are to be recom- 
mended here; as fluids, weaker so- 
lutions of chromate of potash, or 
the Miiller’s eye-fluid. A stratum 
Fig. 344. Follicular chains from the ovary 
of the calf. 1. With ova forming. 2. At 
a, showing the constriction into a Graafian 
vesicle. 
of free ovum cells, which is said to have been observed close 
under the surface of the ovary (Schrbn, Grohe), does not exist, 
as the small cells of the so-called formatio granulosa surround- 
ing these ovula were destroyed by the action of the reagents 
(alcohol and strong chromic acid). 
Now whence came the ovular strands and the ovules which 
they contain ? 
The peculiar ovarian epithelium (fig. 345, a), which we have 
previously mentioned, sends conical proliferations (5) into the 
peripheral stratum of the organ. Some of the cells of the cone 
become ova, and by separation from the epithelial matrix the 
ovular strand is formed. 538 
SECTION TWENTY-FIEST. 
The Graafian follicle constantly approaches the surface of 
the organ in proportion as it approaches its maturity, so that, 
finally, entirely matured, it is only covered by a thin fibrous 
layer of the albuginea. 
It is well known that as a result of increased congestion of 
Fia. 345. From the ovary of a young slut, after Waldeyer. a, germinal epithelium; &, ovarial tube 
c, the same in oblique and transverse sections ; c, a racemose group of young follicles. 
the walls of the follicle, the collection of fluid in a Graafian 
vesicle becomes greater and greater, and that thus a rupture of 
the latter may take place, naturally at the point of the slightest 
resistance, that is, at the surface of the ovary. 
This bursting of the follicular walls, which frees the ovulum 
and renders its further development possible, is also promoted 
by still another phenomenon, a cell-proliferation at the base 
and on the lateral walls of the follicle. 
A recently ruptured follicle of the human female occasion- 
ally presents us a lump of coagulated blood (coming from the 
lacerated parietal vessels), but always, however, the layer of 
plicated substance which has a yellowish appearance from the 
fat it contains. Our fig. 339 at d* shows this proliferating 
stratum, which probably consists of derivatives from the cap- 
sular epithelium, but principally, however, of the cells of the 
inner parietal layer, and which also, at this time, contains nu- 
merous emigrated lymphoid cells (Waldeyer). While a portion 
of these cells are destroyed by fatty degeneration, an active 
formative process is maintained in others, in consequence of 
which a vascular young connective tissue is formed, which di- 
minishes the interior space more and more, and not only com- 
pletely fills the cavity of the follicle, but also causes a consid- SEXUAL OKGAXS. 
539 
erable hypertrophy. The presence, at this time, of a rich, deli- 
cate, vascular net-work in the corpus luteum is proved by injec- 
tion. We recommend for this readily practicable experiment 
the ovarium of the sow, in which the oviducts and uterus also 
afford very handsome objects. 
The progressive metamorphosis has herewith reached its 
height. The young connective-tissue contained substance 
shrivels more and more (probably with a simultaneous atro- 
phy of the vessels), the tissue becomes firmer, more like a cica- 
trix. Such remains of the corpus luteum may still be seen for 
a longer period. The whole process, 
however, proceeds much more rapidly 
in a corpus luteum caused by an ordi- 
nary menstruation than in one where 
the escaped ovum has been impregnat- 
ed. It has been asserted, in accordance 
herewith, that there are two forms of 
the corpora lutea. 
In the portion of the blood-clot which 
remains behind, the crystallization of 
the hsematoidine (fig. 346), which we 
have already mentioned, takes place. 
Fis. 346. Crystals of heematoidine. 
Among the pathological occurrences, the formation of cysts 
are, as the practical physician knows, of extraordinary fre- 
quency in the human ovaries, A portion of these—and, in- 
deed, the greater—certainly correspond to hydropically dis- 
tended Graafian vesicles. Others of these formations origi- 
nate, on the contrary, from a proliferation of the stroma of the 
ovarium. The walls are formed of connective-tissue substance, 
and the mucilaginous contents of colloid degenerated con- 
fluent cells. Innumerable quantities of such structures, with 
very slight dimensions, may be found in an ovary. A number 
of larger ones may be met with, or one grown to a gigantic size 
may be found. The most remarkable form of ovarian cyst is 
that, however, where a part of the parietes has assumed the 
structure of the corium, with papillae, hair follicles, sebaceous 
and sudoriparous glands, and where hairs, occasionally united 
into long bundles, are met with (dermoid cysts). Even teeth, 
pieces of bone, and hyaline cartilage may be found in such 
cysts. The remaining contents are formed by a pap-like mass, 
consisting of desquamated epithelium, fat molecules, and crys- 540 
SECTION TWENTY-FIRST. 
tals of cholesterine. (Similar capsules, with such strange con- 
tents, have also been found in other organs; for instance, in 
the lungs.) An explanation of the remarkable production is, 
at the present time, impossible. 
The contents are to be examined in the fresh condition, 
bones and teeth after the manner of the normal structures, and 
the walls on objects hardened by means of alcohol. 
Preparations of the ovaries, tinged and deprived of their 
water by means of alcohol, may be very suitably mounted 
in Canada balsam; otherwise, dilute glycerine is to be se- 
lected. 
Concerning the efferent passages, the oviducts, it may be 
said that their mucous membranes, muscular and serous lay- 
ers, are to be examined in the same manner as those of other 
large glandular canals. The ciliated epithelium requires quite 
fresh objects; a previous hardening is most suitable for the re- 
mainder. Injected organs are to be selected for the investiga- 
tion of the folds of mucous membrane which are frequently 
quite complicated. 
The womb or uterus also possesses an epithelial layer 
formed of ciliated cells, and a tubular-shaped mucous mem- 
brane containing glands. These tubular follicles, lined with 
cylindrical cells, are to be observed in fresh female mammalial 
animals, partly immediately, partly after hardening, by means 
of vertical and horizontal sections. In the human female the 
uterine follicles appear particularly fine during menstruation 
or in the first months of pregnancy. 
The increase in volume of the womb during pregnancy is ex- 
hibited principally by its muscular portion, which consists of 
contractile fibre-cells. We first see an increased growth of 
these elements, in part into structures of gigantic length. 
Even on this account the massiveness of the muscular portion 
must be considerably increased. Besides this, a new forma- 
tion of such muscular cells also takes place (although in its 
details not yet explained), especially in the first half of preg- 
nancy. The mucous membrane also increases considerably, 
becomes loosened in its connection with the muscular layer, 
and forms the decidua of the ovum. 
After the birth the contractile fibre-cells return to a shorter 
length ; a part of them are, however, without doubt, destroyed 
by fatty degeneration. Numerous depositions of small fat SEXUAL OEGAXS. 
541 
molecules in the fibre-cells are, besides, a quite extended phe- 
nomenon. 
The remains of the mucous membrane are then removed in 
childbed by the lochial secretion. The manner in which the 
new mucous membrane of the uterus is formed requires more 
accurate investigation. 
The energetic proliferating vegetation, the active change of 
its elements which the uterus presents under abnormal condi- 
tions, asserts itself in the sphere of pathology, and thus pro- 
duces the so frequent new formations, among which the so- 
called fibroid, hard fibrous tumors, are the most widely dif- 
fused. These consist sometimes exclusively of fibrillated con- 
nective tissue permeated by blood-vessels, sometimes of the 
above, mingled with contractile fibre-cells, occasionally, how- 
ever, also, almost entirely of smooth muscular tissue. They 
supplant the normal tissue in proportion to their growth. If 
connected with the wall of the organ by means of a pedicle, 
they are called uterine polypi. Their examination is to be 
made in accordance with the directions which have been given 
for the developed connective tissue. 
Cancerous tumors of the womb are also of frequent occur- 
rence. They frequently appear in the form of epithelial can- 
cer. 
We may pass over the methods of investigating the uterus, 
the vagina, and the external genitals. The accessories are in 
part the same as those which we have already mentioned above 
for mucous membranes and smooth muscles, in part those of 
the skin, which are to be discussed in the following section. 
Let it here be mentioned, however, that it has been recom- 
mended for the uterine muscular tissue to boil the uterus for a 
few minutes, and to join with this an immersion in carbonate 
of potash. Furthermore, the maceration in pyroligneous acid, 
and the employment of alcohol, with subsequent drying, after 
which thin sections are to be exposed to the action of the 20 
per cent, nitric acid. 
Cabinet preparations of the tissue of the womb, and of the 
textures of the external genitals are to be prepared by the me- 
thods now employed for the mucous membrane, the skin, and 
the muscular tissue. 
The mucous secretion of the female genitals originates first 
and principally from the cervix uteri, the mucous membrane 542 
SECTION TWENTY-FIRST. 
of which contains numerous fossse or mucous follicles; and 
then from the glandless vaginal mucous membrane. The for- 
mer has an alkaline reaction, appears hyaline, tough, and te- 
nacious, and contains numerous mucous corpuscles together 
with scanty pavement epithelial cells. In contact with the 
acid vaginal mucus it becomes cloudy. The latter, an almost 
limpid fluid substance, is very scanty in young maiden bodies, 
except during the menstrual periods; in blennorrhoeas of the 
genital mucous membrane, as well as with women far advanced 
in pregnancy, it increases in quantity, and the vaginal mucus 
becomes cloudy, milk or pus-like. The elements of the vagi- 
nal secretion, which are shown by the microscope to increase 
in quantity in proportion to the increase of consistence and 
opacity, are again mucous corpuscles and pavement epithe- 
lium. 
In the vaginal mucus of non-pregnant persons, but espe- 
cially, however, in the pregnant, there occurs, together with 
several vegetable parasites, as for example, oidium albicans 
(p. 429), an interesting animal parasite, the Trichomonas vagi- 
nalis, discovered by Donne. This is an infusorium which is 
provided with a flagellum and vibratile cilise; it moves actively 
in pure mucus, but very sluggishly, on the contrary, in that 
diluted with water. This infusorium appears to be entirely 
absent from the normal secretion of the vagina of unimpreg- 
nated females (Kolliker and Scanzoni). 
A speculum is to be employed in order to obtain the secre- 
tion in question. The vaginal mucus may be obtained by 
scraping with a spatula. It is difficult to obtain the mucus 
from the cervix unmixed with vaginal secretion. The addition 
of water is naturally to be avoided in the microscopical exami- 
nation of the Trichomonas. 
The menstrual blood from the ruptured capillaries of the 
uterine mucous membrane has usually (perhaps from the ad- 
mixture of secretions from the mucous membrane) lost its co- 
agulability. It shows, together with the blood-cells, numer- 
ous granulated structures, mucous corpuscles, also separated 
ciliated cells which have lost their vibratory cilise. Shreds or 
connected masses of the uterine mucous membrane may be 
caused by more considerable separations, so that a formal 
decidua spuria has been spoken of. 
The lochial secretion consists at first almost entirely of blood SEXUAL ORGANS. 
which comes from the torn vessels of the contracting nterns. 
In the first days after the birth, when a brown-red mucous 
fluid, with a few flakes and shreds, usually come away, the 
microscope shows as elements, together with sometimes unal- 
tered, sometimes swollen or indented blood-corpuscles, pave- 
ment-shaped cells, granulated structures (mucous and pus cor- 
puscles), effete cells as well as their ruins, fat-molecules, and 
likewise, here and there, cholesterine tables. In the latter 
periods, where the blood-corpuscles decrease more and more 
in numbers, and finally disappear altogether, the number of 
the granulated cells usually increases in an inverse ratio. 
Towards the end the lochial secretion gradually assumes the 
Fig. 347. 1. Rudiment of the lacteal 
gland in the foetus, a, b, epidermis; c, 
cell aggregation; d, fibrous layer. 2. From 
a seven-months’ foetus, a, central sub- 
stance ; &, larger, c, smaller outgrowths. 
Pig. 348. The milk-gland of another embryo, a, 
the central club-like mass, with smaller internal, 
6, and larger external, c, outgrowths. 
character of a mucus rich in cells. The examination presents no 
kind of difficulty. For its reception, flat oval plates may be 
used (Werthheimer). 
The lacteal glands are formed in the fourth and fifth month 
of human embryonic life, after the manner of other cutaneous 
glands, by solid papillary projections of the foetal epidermoidal 
cells, covered by a fibrous layer of the corium (fig. 347,1, d). 
Several weeks later (fig. 347, 2, and 348) such a club-like pa- 
pilla (a) has, by division of its cells, sent down new papillm 
(6, c), from which the chief excretory passages are afterwards 
formed, which, by further proliferations of this kind, produce 
the first rudiments of the gland-body. Even at the hour of 
birth, however, a rudimentary formation of gland vesicles has SECTION TWENTY-FIRST. 
not taken place, and, while the ducts become hollow, their out- 
growths remain at the stage of solid cell-aggregations. The 
larger gland divisions keep to the periphery, the smaller ones 
to the inner portions of the whole organ. 
The lacteal glands preserve this undeveloped, more foetal 
character, even during the period of childhood, in the male as 
well as in the female sex. 
While it is true that even here the lacteal gland of the 
female has advanced more rapidly than that of the male, it is 
only at the entrance of puberty that a further development of 
the former becomes energetic. Numerous gland-vesicles are 
the result. Nevertheless, the organ still remains far behind its 
complete development, for which the first pregnancy is neces- 
sary. After the delivery it generally receives that organization. 
Atrophy is first introduced by the period of involution; fat- 
tissue takes the place of the gland-body. 
The lacteal gland of the male, on the contrary, remains at 
the lower stage throughout the whole life. 
The developed gland of the sexually mature female contains, 
in a condition of rest, an epithelial lining of ordinary rounded, 
polygonal gland-cells. 
In the gland-vesicles of the cow, the same finest reticular 
canal-work which we mentioned formerly (p. 460) at the pan- 
creas and other racemose glands has been injected (Gfianuzzi 
and Falaschi). 
The mammary gland, as is known, presents manifold patho- 
logical new formations. In many of them the development 
takes place from the proper gland-bodies. Thus, for example, 
at the period of involution small cysts, filled with a mucila- 
ginous fluid, are of frequent occurrence. They arise from a 
metamorphosis of the gland-lobules, the distended vesicles of 
which become united with each other. New formations of 
gland-substance, under pathological conditions, have also been 
ascribed to the organs under consideration, and have been 
described as “ adenoid ” tumors. Soft, but especially hard 
cancers, cysto-sarcoma and simple sarcomatous tumors also 
occur. Concerning the point of origin, the same uncertainty 
prevails here as elsewhere. 
The examination of the lacteal glands (normal as well as 
diseased) is, for the most part, to be made (in the usual man- 
ner) on hardened organs, by means of fine sections. A prepar- SEXUAL ORGANS. 
545 
atory immersion in very dilute acetic acid, in diluted pyro- 
ligneous acid, or a brief boiling, is useful. For the first rudi- 
mentary appearances, human embryos at about the fifth month 
are to be selected ; for the later appearances, the bodies of 
children. The material necessary for the recognition of the 
completely developed gland can only be obtained from a 
female who has borne children. The active organ may be ob- 
tained from the bodies of the lying-in. Injections of the larger 
glandular passages from the lacteal sinuses succeed with toler- 
able facility ; the constant pressure is to be employed for the 
injection of the finest passages. 
The milk of the human female and of the mammalia is 
formed by the liberation of the fat produced in the cells of the 
lacteal glands, which thus becomes suspended in the glandular 
fluid rich in albumen and sugar. 
The secretion under consideration presents a near relation- 
ship, in this regard, with the less fluid substance secreted by 
the sebaceous follicles of the external integu- 
merit, and, in fact, we are in a position to vin- 
dicate, by the aid of facts in embryology, the 
same manner of origin of both varieties of glands. 
Ordinary milk shows, in a clear fluid, an in- 
numerable quantity of globular fat-drops, the 
so-called milk globules (349, a). These, which 
may be examined even with medium powers, 
never flow together after the manner of free 
fat, but rather possess a delicate investment of 
coagulated casein. It is only when this is dis- 
Pig. 349. Elemen- 
tary forms in milk, a, 
ordinary milk - glob- 
ules; 6, so-called co- 
lostrum corpuscles. 
solved by means of acetic acid or alkalies, that the union of 
the free drops of fat is noticed under the microscope. 
If the secretion of the milk takes place less energetically, 
as is the case with the so-called colostrum, and the secretion 
which occurs during the latter period of pregnancy, as well as 
in the first days after the delivery, this rapid destruction of the 
gland-cells is absent, and we still meet with them in part (over- 
loaded with fat to a high degree, it is true) as constituents 
of the evacuated fluid. We also meet with fragments of these 
cells and membraneless conglomerations of fat. These are the 
so-called colostrum corpuscles of the authors (fig. 349, &) ; they 
do not appear to be wholly without vital contractility (Strieker, 
Schwarz). A few remain for a long time in the milk of women. 
35 SECTION TWENTY-FIEST. 
A larger number of such structures in the milk, months after 
the delivery, must, on the contrary, be denoted as abnormal. 
Abnormal constituents of the milk are of secondary impor- 
tance. Blood-cells, and also lymphoid corpuscles, may be met 
with in it; their recognition is not difficult. 
Remarkable colorations may occur in milk which has stood 
for some time ; thus blue and yellow colors have been observed. 
In such cases the microscope has shown vibrionic, and also pro- 
tococcus formations. 
A drop of milk spread out in a thin layer will, without any 
further manipulation, present its elements to view in the same 
manner as other cell-containing fluids, as, for instance, the 
blood. Strong magnifying powers are unnecessary ; permanent 
preservation will hardly be undertaken. 
Among the parts of the male generative organs we will first 
speak of the testicles, taking it for granted 
that the coarser structural conditions are al- 
ready known. 
Numerous, but not complete connective- 
tissue septa, arising from the fibrous tunic 
(the tunica albuginea) converge to unite, in 
the upper part of the testicle, in a firmly wo- 
ven, connective tissue, wedge-shaped mass, 
the so-called corpus Highmori. The gland 
substance, consisting of reticularly united and 
convoluted canals, the so-called seminal ca- 
naliculi, is thereby divided into conical, lobu- 
lar convolutions. 
The appearance of such a seminal canali- 
cule may be represented by the adjoining fig, 
860. It is filled with cellular elements (5), 
which have yet to be more particularly dis- 
cussed. Its walls, which are quite thick in 
man, consist of several strata of cell-lamellae 
imbedded one over the other and united in a 
membraniform manner. The innermost lay- 
ers of these strata close completely, while 
Fig. 350. Human semi- 
nal canaliculi, with the 
gland-cells 6, and the con- 
nective-tissue tunic a. 
the more external ones have a reticular arrangement 
A soft, loose connective tissue is met with between the 
seminal canaliculi. In smaller mammalial animals, for example 
the rabbit and the rat, which latter was recommended by von SEXUAL ORGANS. 
547 
Ebner, this is very scanty and soft, so that these canals may 
regularly fall apart. 
The organ of such creatures, hardened in Muller’s fluid 
and alcohol, requires, therefore, a preliminary imbedding (p. 
118) when fine sections are to be obtained. In other animals, 
for example, the calf (Frey), the cat, and the boar (Mihalkovics), 
the latter procedure may be dispensed with. We would rec- 
ommend hsematoxyline as the best coloring material. 
For the isolation of the seminiferous canals, employ the 
maceration in muriatic acid (p. 125). Mihalkovics recommends 
for the human testicle, the immersion in f hydrochloric acid and 
i water, allowing the action to continue for a day or two at a 
temperature of about 80° C. and subsequent removal to dis- 
tilled water, till the preparation comes apart, 
The remainder is completed with the prepar- 
ing needles. 
We have already (p. 280) mentioned the 
coarsely granulated, so-called plasma-cells 
of the connective tissue (fig. 351) which be- 
sides occurring in other organs is also pro- 
fusely developed in the testicles of many 
mammals as an investing substance, around 
the finer blood-vessels. We recommend the 
Fig. 851. So-called plasma- 
cells, 6, surrounding a blood- 
vessel, «, of the rat’s testicle. 
rat and the cat for their study, and hsematoxyline as a color- 
ing medium. The preliminary puncturing method and the in- 
jection of weak (0.25 per cent.) solutions of osmic acid, with 
subsequent hardening in absolute alcohol, affords excellent 
views of these cells, as well as of the genesis of the seminal 
filaments which is to be discussed hereafter. 
The seminal canals then coalesce and finally form a single 
vessel, a tolerably large canal, which, with innumerable convo- 
lutions, forms the so-called body and tail of the epididymis; 
it afterwards straightens and becomes the vas deferens. The 
epididymis shows, in addition, a ciliated lining of its convo- 
luted seminiferous canals (Becker), in places with gigantic 
cells and vibratile cilise. 
The blood-vessels, which are very easy to inject, pass from 
without and from the corpus Highmori into the organ, per- 
meate the septula, and finally encircle the seminiferous canals 
with a wide-meshed (but not particularly abundant) net-work 
of capillaries. 548 
SECTION TWENTY-FIEST. 
The first accurate information concerning the lymphatics 
was furnished by Ludwig and Tomsa. In fact, nothing is 
easier than the injection of the organ by means of a puncture. 
A surprising picture of numerous vessels (Ludwig and Tomsa) 
unfolds itself here, and, as it appears, in exactly the same 
manner in all mammalial animals. A very extensive net- 
work of lymphatics, with valves, lies under the serous cover- 
ing, permeates with its branches the albuginea, and spreads 
itself out beneath the same to a likewise very compact net-work 
of passages enclosed by connective tissue. Some of these pas- 
sages pass at once between 
the seminal canals; the 
greater portion, however, 
first pass through the fam- 
iliar septula, and finally 
likewise enter the loose 
connective tissue lying be- 
tween the glandular pas- 
sages (fig. 352, a, b). The 
spaces of this connective 
tissue, in so far as they are 
not occupied by seminifer- 
ous canals and blood-ves- 
Fig. 352. Prom the testicle of the calf, a, seminiferous 
canals seen in more oblique, 6, in more transverse sec- 
tions ; c, blood-vessels; d, lymphatics. 
sels (c), are filled with lymphatic fluid (d). We meet with this 
in a remarkable manner, in small mammalial animals especi- 
ally, the seminal canals of which, having but very little inter- 
stitial connective-tissue, are regularly bathed in lymph. Mihal- 
kovics recommends for the closer study of the lymphatics the 
injection of a 0.25 per cent, solution of osmic acid. For the re- 
cognition of the endothelial cells of our lymphatics, either the 
injection of a solution of nitrate of silver or the immersion of 
the sections in such a solution of 0.25-0.125 per cent, may be 
employed (Tommasi). 
To obtain the entire arrangement of the seminal canals, 
they are to be injected with transparent cold-flowing masses or 
with gelatine. 
Gerlach gives us the following directions for the injection 
of these passages with gelatine : The testicle is to be placed 
in a weak solution of potash for 4-6 hours, to dissolve out the 
cells and the entire contents as much as possible. An attempt 
is then to be made to remove the mass by cautious pressure, SEXUAL OEGAXS. 
549 
after which the organ is to be washed off in water. The air 
contained in the glandular canals is to be drawn out as 
thoroughly as possible, and the injection fluid (colored with 
carmine or chromate of lead) is to be forced in very slowly. 
During this procedure the organ should be kept in warm 
water. 
The vas deferens must be studied hardened in fluids. A 
mammalial animal just killed is to be used for the ciliated 
epithelium of the epididymis. 
The most frequent pathological new formations of the testicle 
are soft tumors, appearing in the form of medullary carcinoma 
and sarcoma. In the so-called cysto-sarcoma we meet with 
larger or smaller vesicles partly filled with water, partly with 
colloid substance, which proceed from transformations of the 
seminal canals. 
Concerning the deeper, efferent, and copulating organs of 
the male generative apparatus, it may be remarked that the 
ductus ejaculatorii and seminal vesicles have the same struc- 
ture as the vas deferens, and are to be examined in a similar 
manner. In the latter is found, together with spermatic fila- 
ments, a transparent albuminous substance, which undergoes 
a gelatinous coagulation, to afterwards resume a fluid condi- 
tion. It is the same substance which the evacuated sperm 
contains. 
The prostate, a racemose glandular aggregation, is very rich 
in smooth muscular tissue. The latter elements may be exam- 
ined in the fresh organ with the reagents usually employed 
for this tissue, such as the potash solution or a 20 per cent, 
nitric acid. For the investigation of its further structure, the 
organ is to be hardened, either with alcohol, or first with 
Muller’s fluid, and then tinge with hsematoxyline or picro- 
carmine. One may then recognize the absence of a membrana 
propria, and the development of a double layer of the gland- 
cells (Langerhans). 
The prostatic secretion contains an unaltered albuminous 
body, which is tinged violet-blue by the excellent Jurgen’s 
reagent (p. 155). The prostatic stones, concentric structures, 
occasionally of considerable size, are tinged by this aniline- 
iodine-violet, sometimes blue or blue-violet, sometimes in the 
centre red and at the periphery blue, whereby all transitions of 
color may be wanting. The same condition prevails in the 550 
SECTION TWENTY - FIEST. 
familiar corpuscula amylaceo. We believe with Jurgens that 
the red color belongs to the developed amyloid stage, and the 
blue-violet to the albuminous primary stage. 
The glands of Cowper are 
to be examined in the same 
way as other racemose 
glands. Osmic acid, Mul- 
ler’s fluid and the customary 
tingeing methods are also 
employed. 
The tissue of the caver- 
nous organs consists of elas- 
tic and connective - tissue 
fibres, intermixed with 
smooth muscles. The latter 
are to be studied in a fresh 
condition, the remainder, on 
alcoholic preparations, 
where we would recommend 
the previous injection with 
uncolored gelatine. These 
also afford opportunity, es- 
pecially in transverse sec- 
tions, for studying the male 
urethra. To follow the vas- 
cular arrangement of the cor- 
pora cavernosa (fig. 858), in- 
Fig. 353. Prom the peripheral portion of the corpus 
cavernosum penis, by a low magnifying power. 1. a, 
so-called superficial, and b, deeper cortical net-work. 
2. Insertion of arterial branches (a) in the passages of 
the deeper cortical net-work (copied after Langer.) 
jections are to be made with transparent blue or red gelatine 
fluid, and the preparation somewhat strongly hardened. The 
lymphatics of the glans penis are to be injected by the punctur- 
ing method (Belajeff), 
We have finally to consider the semen (sperm). A drop of 
evacuated human seminal fluid spread out in a thin layer, 
without any further addition, on the microscopic slide, shows, 
with a magnifying power of about 400 diameters, a number of 
peculiar structures, the so-called spermatic filaments, spermatic 
animalcules (spermatozoa, zoosperms). These (fig. 354) permit 
of the recognition of an anterior broader flattened portion, the 
head (a); and a more posterior long filament, with a relatively 
thick commencing portion, the so-called middle-piece (h); and 
a terminal filament (c) of extreme fineness. SEXUAL ORGANS. 
551 
The remarkable movements which these structures present in 
evacuated living semen have at all times awakened the aston- 
ishment and interest of the observer; and, in fact, a wonderful 
appearance is presented on looking down into this confused 
mass and observing the spermatic filaments dart- 
ing wildly about. A closer investigation of this 
busy multitude shows that the individual sper- 
matic element makes undulating and whip-like 
movements of the filament, and is thereby pushed 
from the place. 
An independent change of position, directed to- 
wards a definite object, for which earlier observers 
mistook the phenomenon (and in harmony there- 
with declared the spermatic elements to be animal 
beings), is, however, in no wise the case. If the 
0/77 7 
phenomenon be followed throughout a longer pe- 
riod, it will be seen how, after the manner of the 
7 7 
nearly related ciliary motions, the movements 
Fig- 354- sPey 
matozoa of the 
- er-seideL 
«-he.ad; b, mid- 
dle-piece; c, taxi. 
gradually become extinct; how the energy of the filament- 
ary movements decreases more and more, and thereby the 
change of place ceases ; how weaker and weaker contortions 
of the filaments are then to be noticed in the spermatozoa, 
which can no longer move from the place, until finally the 
whole becomes quiet. We would, in addition, repeat here a re- 
mark which we have already made ; namely, as each excursion 
appears very much exaggerated by the strong objective (p. 97), 
the irregular advance of the spermatozoa should not be over- 
estimated. It is in reality but very slow. 
More indifferent fluids, blood-serum, lymph, white of egg, 
iodine-serum, solutions of sugar (1060-1030 sp. wt.), urea (10-5 
per cent.), neutral salts of the alkalies (chloride of sodium, one 
per cent.), and earths may be employed as media. Pure water 
increases the energy of the movement of mammalial sperma- 
tozoa, at most for a very short time, to lead to a rapid cessation, 
whereby the filamentous extremity bends itself into the form 
of a loop. Every thing, on the contrary, which acts chemically, 
generally arrests the movement once for all. Spermatozoa 
which have become quiet from too watery media may fre- 
quently be temporarily restored to life by means of a concen- 
trated solution (of sugar, chloride of sodium or albumen), and 
inversely. As on the motus vibratorius, so also on the move- 552 
SECTION TWENTY-FIRST. 
merits of the spermatozoa a peculiarly stimulating effect is 
exerted by dilute solutions of the alkalies and caustic potash 
of 1-5 per cent. (Kolliker). The alka- 
line fluids of the body therefore also 
maintain the vitality of the spermatic 
filaments for a long time. In a similar 
manner a suitable solution of sugar 
with 0.1-0.05 per cent, of caustic potash 
also acts excellently. Moreover, accord- 
ing to Mantegazza, human spermatozoa 
preserve their vitality and capability of 
motion within the broad thermometric 
limits of from 16 to +47 degrees of 
the centigrade thermometer. 
Pig. 355. Portion of a transversely 
divided seminiferous canal of the rat 
(osmic acid preparation), a, parietes 
with cell nuclei; 6, parietal cells with 
spermatoblasts c, the latter with small, 
narrow nucleus-like corpuscles; d, in- 
ner cell layer. 
In order to examine the cellular con- 
tents of the seminiferous canals, use 
transverse sections through the suitably 
hardened organ. The same process is also advisable for the 
investigation of the still controversial 
genesis of the spermatozoa. Von Ebner 
has properly recommended the rat in con- 
sequence of the size and peculiar struc- 
ture of the head of its seminal filament. 
We recognize that the outer cell layer 
of the seminiferous canal presents a pris- 
matic radial form, and that the develop- 
ment of these remarkable structures takes 
place from this, while the inner cellular 
elements remain without a future. From 
the former arise quite peculiar structures 
(fig. 855, h). When developed, they re- 
semble somewhat a thick, ill-shaped can- 
delabrum. These “ spermatoblasts,” as 
they have been christened by von Ebner, 
each produce a nucleus (c) in their nodu- 
lar offshoot. It becomes the head of the 
Pig. 356. Spermatozoa of the 
rat, undergoing development. 1. 
Spermatoblast, a, with the head, 6, 
and filament, c. 2. Nearly mature 
spermatozoon with adherent re- 
mains of the protoplasma. 
seminal filament (fig. 366, 1, b), while the 
protaplasma of the cellular thing which is 
turned inwards, that is towards the axis- 
canal, grows out into a filament (c). Each of the Ebner’s sper- 
matoblasts (a), accordingly, produces several spermatic fila- SEXUAL ORGANS. 
ments, which are at last set free (2), and lie in the seminiferous 
canal with their tails directed upwards and downwards. Thus 
we view the matter, at the present time, in accordance with Neu- 
mann, von Ebner, and Mihalcovics. 
The relatively resistant substance of which the spermatic 
filaments consist readily permits of their being preserved dry 
as cabinet preparations, and also of being softened with water 
from dried seminal stains, and thus recognized with the micro- 
scope. 
From the great importance which the recognition of the 
latter is for the medical Jurist (and it may still be accom- 
plished after years), the simple procedure may here find its 
place. 
The suspicious portions are to be cut from the body or bed 
linen, and having been reduced to small pieces, placed in a 
watch-glass or glass box, with the addition of a small quantity 
of water. After a time, a quarter or half hour, during which 
the pieces of linen have been several times stirred about in the 
water with a glass rod, this fluid is to be examined, and then 
the fluid pressed drop by drop from the fragments on to the 
microscopic slide. Any spermatozoa which may be present 
will thus be discovered with certainty, and there is scarcely any 
possibility of mistaking them. Section Suicntij-seconb. 
ORGANS OF SENSE. 
1. The human skin consists of the epidermis, the corium, 
and the subcutaneous cellular tissue ; the latter being rich in 
fat. Numerous nerves, blood-vessels, and lymphatics per- 
meateit; innumerable glands 
lie imbedded in it; the hairs 
and nails, finally, constitute 
special organs. All these 
have already been individu- 
ally mentioned in previous 
sections, so that we can only 
present a short recapitula- 
tion of the whole. 
The structure of the skin 
may be represented by fig. 
357, a vertical section of the 
same from the point of the 
finger. The cornified epider- 
mis appears at a with its 
numerous layers of flattened 
cells; the (punctated) layer 
beneath it (5) represents the 
so-called Malpighian rete 
mucosum. The papillse of 
the cutis appear at c, and 
beneath them commences the 
Fig. 357. Human skin in transverse section, a, su- 
perficial layers of the epidermis; 6, Malpighian rete 
mucosum. Beneath the latter is the corium, forming 
the papillae above at c, and terminating below in the 
subcutaneous connective tissue, in which, at h, aggre- 
gations of fat-cells appear; q, sudoriparous glands, with 
their excretory ducts e and/,- d, vessels ; i, nerves with 
tactile bodies. 
superficial extension of the corium, which is sometimes thinner, 
sometimes thicker, and passes into the subcutaneous cellular 
tissue without any sharp line of demarcation. Among the con- 
stituents of the latter we perceive the coil-shaped bodies of the 
so-called sudoriparous glands, g, the ascending ducts of which OEGAN'S OP SENSE. 
555 
may be recognized at f, as well as the aggregations of fat-cells 
7i. A similar section through a hairy portion of the integument 
would present us, in addition, the hairs, with their follicles and 
the sebaceous follicles. 
Such preparations may be obtained in various ways from 
the freshest possible corpses. We can, although with some 
trouble, still without any further addition, prepare pretty thin 
sections, and render them transparent by means of weak alka- 
line solutions. If the fluid medium is of a proper degree of 
concentration, we then obtain a satisfactory, although very 
perishable preparation. It is preferable, however, even here, 
to previously give the object a greater degree of firmness by 
means of artificial hardening. The drying method, as well as 
(which I prefer) the immersion in absolute alcohol, accomplishes 
this purpose. Many views will be obtained in a better form if 
boiling in vinegar precedes the drying, or a precursory immer- 
sion in pyroligneous acid, after which the object is placed in 
alcohol. Others (Krause, Reynold) have recommended Mul- 
ler’s fluid, a two per cent, solution of the bichromate of ammo- 
nia, and also osmic acid. 
Tingeing first with carmine and then with hsematoxyline, 
are excellent. Sections from an injected portion of the skin, 
thus tinged and deprived of their water by means of alcohol, 
afford very handsome review preparations when mounted in 
Canada balsam. 
To enter here into the methods of examining the epidermis 
would be superfluous, as the essentials have already been men- 
tioned at pages 265 and 266, and the peculiar surfaces of the 
younger cells discussed. The nails (p. 269) and hairs (p. 270) 
have likewise been treated of in the same section. 
Fine sections of dried preparations, or those hardened in 
alcohol, with the addition of acetic acid, serve for the discov- 
ery of the elastic fibres, as well as of the connective-tissue cor- 
puscles of the corium. A longer immersion in undiluted 
glycerine, by rendering the connective-tissue bundles extreme- 
ly transparent, permits us to see the elastic elements. 
The same methods are also used for the recognition of the 
sudoriparous glands and sebaceous follicles. It is well, how- 
ever, not to select too thin sections. The former gland forma- 
tion, which attains to gigantic dimensions beneath the skin 
of the axilla, may be readily isolated in this place in a fresh SECTION TWENTY-SECOND. 
condition, and, with the employment of the familiar methods, 
the structure of the walls and the nature of the cells may be 
examined. 
Surface sections are of relatively less frequent necessity. 
Made through the upper portion of the epidermis, however, 
they are of importance for the ducts of the sudoriparous 
glands, and laid deeper on the border of the former towards 
the coriurn, for the study of the papillae. 
The primary examination of the sebaceous follicles (fig. 
368) may be made on the labia minora, likewise on the skin of 
the scrotum, by picking fine sections 
with the needles and employing acetic 
acid. Good views may likewise be ob- 
tained, where the gland cells are not to 
be preserved, by means of dilute alkaline 
solutions. The dried integument of other 
portions of the body, by similar treat- 
ment, also shows the organs in the vicin- 
ity of the hair-follicles. Preparatory 
boiling in vinegar affords a good acces- 
sory for such skin. If it is proposed to 
examine the cells and the remaining con- 
tents of the sebaceous follicles, the skin 
Pig. 358. A sebaceous follicle, a, 
the gland-vesicles; 6, the excretory- 
duct ; c, the sac of a lanugo-hair; 
d, the shaft of the latter. 
is, according to Kolliker, to be previously softened ; then, with 
the epidermis, the hairs, with their root-sheaths and the cell 
masses of the sebaceous follicles, are often rendered very finely 
prominent, though, even here, hardening in absolute alcohol 
accomplishes more than all these old methods. 
The blood-vessels of the skin are to be examined on fine 
vertical and horizontal sections of transparently injected or- 
gans. In the papillae, at the point of the finger, an extensive 
natural injection is frequently met with, so that the transverse 
section of the dried skin, by the addition of a 80 to 40 per 
cent, solution of potash, affords very handsome views of the 
vascular loops. 
The puncturing method serves for injecting the lymphatic 
passages, which are likewise only enclosed by connective tissue 
(Teichmann). It is advisable to loosen the epidermis in water 
to which acetic acid and alcohol have been added, as directed 
by J. Neumann. In a very excellent work, that author used 
carmine with glycerine or carbonate of lead, rubbed up with OEGANS OF SENSE. 
557 
the fluid mentioned, for injecting the lymphatics. It is well— 
as we can recommend from our own experience—to stretch the 
piece of skin to be injected over the index finger of the left 
hand in making the punctures. The latter should penetrate 
sometimes less, sometimes more deeply in various places. 
We find a deeper, wider net-work, and a more superficial 
one with narrower passages. From the latter pass up to the 
papillae of the skin partly cul-de-sac axis canals, partly loops. 
The subcutaneous connective tissue, the lobules of the fat 
cells, the follicles of the hairs and the sudoriparous glands, 
also have their lymphatics. 
Finally, Neumann has the merit of having successfully 
attacked the lymphatics of the pathologically metamorphosed 
skin, following certain preliminary statements of Teichmann 
and Biesiadecky. 
For the study of the muscular tissue of the skin, the tinge- 
ing with carmine and subsequent treatment with acetic acid, 
the already frequently mentioned double tingeing of Schwarz, 
and the application of the chloride of palladium (I. Neumann) 
and also hsematoxyline, are to be recommended. 
Concerning the cutaneous nerves, we would first refer to 
what was mentioned at page 375 about the Merkel’s tactile cells 
and also the tactile bodies. For the study of these elements 
in other localities, the same methods, the treatment of thin 
sections from the fresh or dried skin, with acetic acid and 
alkalies, and furthermore with Muller’s fluid or the so much 
praised chloride of gold, and likewise osmic acid, are to be 
taken into consideration. 
The Pacinian corpuscles, which, together with terminal 
knobs, also occur on the external genitals of both sexes 
(Krause, Schweigger-Seidel), are to be examined by the meth- 
ods customary for these structures. 
Peculiar organs nearly related to the terminal knobs were 
met with by Krause on the sensible nerves of the penis and 
clitoris. These, the “genital nerve-corpuscles,” are embedded 
in the corium and mucous membrane proper (not in the papil- 
lae), and differ from the ordinary terminal knobs by their more 
considerable dimensions and more irregular forms. For their 
examination, the discoverer recommends: firstly, quite fresh, 
when possible still warm, preparations without any media; 
then injections, and an immersion in 3 per cent, acetic acid. 558 
SECTION TWENTY-SECOND. 
More recently in otlier portions of the integument, fine, 
non-medullated nerve-fibres are said to have been seen to ter- 
minate with button-shaped swellings between the cells of the 
Malpighian rete mucosum (Langerhans). The treatment of 
the freshest possible thin sections with chloride of gold has 
been recommended for their recognition. 
The embryos of man and the mammalial animals, hardened 
in chromic acid, are used for the foetal skin. On small foetuses 
the latter generally separates very readily, and is to be exam- 
ined on surface sections with glycerine, whereby a conservative 
tingeing with hsematoxyline or carmine renders good service. 
With older embryos fine vertical sections are to be made with 
a razor. It is relatively easy, on such, to see the first rudi- 
ments of the sudoriparous glands and hairs, and also on the 
latter the sebaceous follicles, and to follow their further de- 
velopment. 
The pathological changes of a part so complicated in its 
structure as the human integument are of a very manifold 
nature. A few, such as are connected with the epidermis, have 
been already mentioned (pp. 269,270). Inflammatory conditions 
show sometimes an implication of the whole skin, sometimes 
of only the superficial portions. Extensive emigrations of 
colorless blood-corpuscles occur there (Yolkmann and Steud- 
ener). Desquamations of entire layers of epidermis (scarla- 
tina), local separations of the horny layer from the Malpi- 
ghian stratum, by collections of a fluid containing pus-cells, 
occur as a result of this vascular congestion. 
The numerous diseases of the skin affect sometimes the 
epithelial, sometimes the connective-tissue portion, sometimes 
both at once. 
Elephantiasis shows a more extended and enormous hyper- 
trophy of the corium and of the subcutaneous cellular tissue. 
Local proliferations of the tactile papillse of the skin are pre- 
sented by the warts and condylomata, whereby dilatations and 
enlargements of the capillaries are met with. The vascular 
nsevi and telangiectasia in general form more extended super- 
ficial occurrences of the latter kind. Follicular tumors and 
cysts, of frequent occurrence in the skin, proceed undoubtedly 
in many cases from dilatations and degenerations of the hair- 
sacs and their sebaceous follicles. These frequently present 
the so-called atheromata ; that is the follicle, lined with a pave- ORGANS OF SENSE. 
559 
ment epithelium, contains a grit-like pnlpaceous mass, in 
which the microscope enables us to recognize exfoliated epithe- 
lial cells, fat-molecules, and crystals of cholesterine. 
The maggot-pimples or comedones present slighter meta- 
morphoses of the sebaceous follicles and hair-sacs, produced 
by accumulated secretions. If this accumulation is confined to 
the sebaceous follicles (to be explained by impeded evacuation), 
hordeolum or milium is produced. The degeneration of the 
hair-sacs is accompanied by that of the respective sebaceous 
follicles. 
The number of vegetable and animal parasites found in and 
on the human skin is a considerable one. Many of these con- 
stitute quite indifferent phenomena ; others cause appreciable 
effects, and become causes of diseases, the appreciation of which 
dates from the discovery of these structures by means of the 
microscope, and which appear in part on and in the hairs, in 
part on the horny layer of the epidermis, partly also in the 
nails (though the nail fungi require further investigation). 
Among the epiphytes or vegetable parasites we will next 
mention the Tricophyton tonsurans of Malmsten. It leads to 
the destruction of the hairs of the head in the form of rounded 
patches (herpes tonsurans). One finds only spores of about 
0.0022'", or also rows of the same. These first develop in the 
root of the hair, then in the shaft, which it splits extensively, 
so that in consequence the hair breaks off at about a line be- 
yond its exit; the root and shaft of the hair are likewise de- 
stroyed. The systematic position of the Tricophyton tonsurans 
is still a matter of controversy. 
Another vegetable parasite of the hairs of the human head, 
the Microsporon Audouini of Gruby, which causes the porrigo 
decal vans, behaves in a similar manner. It consists of rounded 
and oval spores (of 0.0004-0.0022"') and a net-work of curved 
undulating filaments. These develop externally on the shaft 
of the hair, and occur dn such numbers around the portion of 
hair which projects from the skin, that it becomes destroyed, 
and remnants ito 1 line long stand out from the skin. The 
case is said to have been one of herpes tonsurans, however. 
Another fungus of the same name, the Microsporon menta- 
grophytes of Robin, grows by preference in the follicles of the 
beard hairs, and causes an inflammation and the formation of 
pus around the hair-follicle—the so-called mentagra. The 560 
SECTION TWENTY-SECOND. 
microscope shows ns between the hair-sac and shaft larger 
spores and filaments than in the previous variety. The last 
two varieties are nninvestigated botanically. Finally, in the 
Microsporon fnrfnr of Robin groups of double-contoured spores 
of 0.002"' longitudinally arranged cells and branched filaments 
of 0.0004-0.0002'" in diameter may be recognized. The basis 
for the development of this epiphyte is, however, different; 
namely, the horny layer of the epidermis, where it causes 
yellowish spots and a furfuraceous exfoliation (pityriasis versi- 
color). 
The favus-fungus, Achorion Schoenleinii of Remak, occurs 
principally on the hairy portions of the skin of the head, and 
is the cause of the scall, porrigo favosa—an eruption occurring 
mostly during childhood. It becomes developed first in the 
hair-sac, where it surrounds the hair and grows into it; then, 
and indeed principally, on the epidermis. There may be dis- 
tinguished, according to Robin, the 0.0013"' broad inarticulate 
filaments of the mycelium, the somewhat broader unbranched, 
but articulated receptacula, in the interior of which series of 
round and oval spores, 0.0013-0.0026'" in size, develop. 
The nature of this parasite is still doubtful; possibly it is a 
mould-fungus. The favus-scab shows under the microscope a 
fine granular mass, which surrounds the fungus-substance 
proper. Externally this consists principally of the mycelium, 
more internally of the receptacula, and quite internally of the 
spores. 
The examination of all these epiphytes requires in general 
strong, 4-600-fold, magnifying powers. For the study of the 
hair fungi, the stumps are to be pulled out with forceps and 
rendered transparent by means of pure glycerine or oil of 
turpentine. With the fungi growing on the epidermoidal 
scales, the addition of alkalies, the dilute solutions of potash 
and soda are to be employed. 
Among the animal parasites, epizoa, of the human skin, 
two may here be mentioned, both mites of lower organization : 
the hair-sac mite, Demodex folliculorum, Owen ; and the itch- 
mite, Sarcoptes hominis. Both live in the skin and produce 
quite different effects. While the first animal constitutes a 
quite indifferent parasite, the Sarcoptes scabii causes the fam- 
iliar complication of symptoms known under the name of the 
itch (scabies). ORGANS OF SENSE. 
561 
The Demodex folliculorum (fig. 859) shows a sometimes 
more, sometimes less elongated body without bristles or hairs. 
On the fore part of the body in the young creature there are 
three, on the mature animal four pairs of stump- 
like legs. The length of this small parasite is from 
It lives generally in scanty numbers in the 
excretory ducts of the sebaceous follicles and hair- 
sacs, that is, the space between the hair-shaft and 
the root-sheath, and deposits its eggs in its dwell- 
ing-place. It occurs in the sebaceous follicles of 
the face, and with especial frequency in those of 
the nose. If the respective glands of the latter 
locality are strongly developed, the smegma may 
be squeezed from the opening by pressure, the 
mass spread out in water, and the mites examined. 
Fig. 359. Hair- 
sac mite, Demodex 
folliculorum. 
With dead bodies vertical sections of the skin are to be pre- 
pared. 
Hot to be confounded with the hair-sac mite is the larger 
itch-mite. This, which is represented very much enlarged in 
our fig. 360, has a rather broad, oblong body, from Ht'" in 
length, covered with hairs and bristles. The first two pairs of 
legs are placed very far in front; they are short, and with a 
stalked sucker. After a considerable interval follow the last 
two pairs of stump-like legs, which terminate in long bristles. 
The ovum, which is not unfrequently found in the body of the 
female animal, is (as also in the Demodex) of considerable size, 
and the young animal is likewise six-footed. 
The itch-mite most frequently infests the human skin be- 
tween the fingers and on their inner surfaces ; they may, how- 
ever, occur on all parts of the body. It penetrates beneath the 
epidermis, and forms beneath the same a serpentine passage, 
which appears brown from the faeces of the animal. The 
animal is met with as a small white point at one end of this 
passage. 
To obtain the mite for microscopic examination (which does 
not require a strong magnifying power), the passage is to be 
slit np with a cataract-needle, and the white point lifted ont 
on the point of the needle. For a more accurate study, the 
portion of skin which contains the acarns is to be made into 
a fold, and this epidermis and upper portion of cutis removed 
with a curved scissors. Spread out on the microscopic slide, 562 
SECTION TWENTY-SECOND. 
the preparation is to be allowed to dry gradually, and then 
rendered transparent by means of oil of turpentine or Canada 
balsam. A longer immersion of the moist piece of skin in 
BTg. 360. The itch-mite, Sarcoptes hominis, from a photograph. 
concentrated glycerine also affords the necessary degree of 
transparency. 
2. The organ of taste has already been discussed in describ- 
ing the organs of digestion (p. 424) ; so that we may refer to 
the same, and here treat only of the manner of termination of 
the nerves of sense. 
Investigations which were earlier instituted on the human 
and mammalial tongues, on their papillae fungiformes and cir- 
cumvallatse, in regard to the distribution of the nerves, yielded 
an unsatisfactory result, and showed only the nerve-trunks 
with divisions and plexiform communications, terminating 
finally in pale, non-medullated fibres. Terminal knobs were 
described here years ago by Krause. In the circumvallated 563 
ORGANS OF SENSE. 
papillae of man and the mammalia, Loven and Schwalbe recent- 
ly discovered peculiar terminal apparatuses, denoted by the 
name of the “gustatory buds.” They occur especially in the 
lateral walls of these papil- 
lae, but not unfrequently 
also at the inner surfaces of 
the surrounding ledges of 
mucous membrane. 
Our fig. 361, a transverse 
. iin -| . i 
section through the lateral 
Fig. 361. From the lateral gustatory organ of the rabbit. 
The gustatory ledges in vertical section, after Engelmann. 
gustatory organ at the root of the tongue of the rabbit, discov- 
ered by Engelmann and Wyss, may afford us a primary repre- 
sentation of this terminal apparatus of the gustatory nerves 
embedded in the epithelium. We may obtain a more accurate 
appreciation from fig. 362. 
The parietes of the gustatory bud (1) consist of flattened, 
lancet-shaped cells (2 a), which stand 
perpendicularly by the side of each 
other, comparable to the staves of a 
barrel or the sepal leaves of a flower- 
bud. These are the “cover-cells.” 
The pointed portion of our organ 
perforates the epithelial covering. 
Small roundish spaces occur here. 
They are formed in part by several 
epidermis cells, in part only by twos, 
or finally even by a single one. 
In the interior of the organ appears 
a second cell-formation, the “gusta- 
tory cell” (2 5). A spindle-shaped 
body, as we see, extends above into a 
rod, and is prolonged below to a thin 
branched filament. It penetrates in- 
to the tissue of the mucous membrane. 
Fig. 362. 1. Gustatory bud of the 
rabbit. 2. r/, cover-cells; 26, rod-cells; 
2 c, a rod-cell with a fine terminal filar 
ment. 
At tll6 SUmm.it of tile rod, finally, a 
? 
short fine CiUum ShOWS itself, 
A plexus of medullated and non- 
medullated nerve-fibres has been met with beneath the gusta- 
tory bud. The communication of these'with the lower fila- 
mentous termination of the gustatory cells still remains to be 
proved. 564 
SECTION TWENTY-SECOND. 
The circumstance is interesting that an analogons gustatory 
organ also occurs in man, according to Krause and Ajtai. It 
is a structure with folds, resting on its lateral border, with 
gustatory buds, the papillae foliacea. It had already been seen 
in old .times. 
Even earlier they succeeded in recognizing, with some prob- 
ability, the termination and the terminal structures in the 
frog’s tongue (Shultze, Key). 
Fungiform papillae stand separated over the tongue of the 
frog. The lateral portions of these projections and the edges 
of the surfaces are covered by ordinary cylindrical epithelium. 
The plateau of the papillae shows, on the contrary, surrounded 
by ciliated cylinders, another covering of non-ciliated cells 
which, on suitable chromic acid preparations, after brushing off 
the ordinary epithelium, may sometimes be brought to view 
sitting like a crown on the gustatory papillae. Between these 
non-ciliated cells lie other structures, spindle-shaped cell-bodies, 
which pass upward into a fine rod, terminating at the surface 
of the epithelial crown. Downwards, on the contrary, it runs 
out into a very fine filament, which, with certain reagents, 
appears varicose, and which must be regarded as the terminal 
branch of an axis cylinder which has been split up in a tuft- 
like manner. The nerve-fibres, therefore, split up into fine 
fibrillse, pass over into these rod-bearing gustatory cells. These 
statements of Schultze and Key have, however, been more re- 
cently modified by Engelmann. He denies this connection of 
the nerve-fibres with the “ gustatory cells,” and describes a 
third (hitherto confounded with the gustatory cells) structure, 
the “forked cell,” with a small ellipsoid body, which is pro- 
longed above and below into forked processes. The central 
processes of the forked cells, with great probability, pass over, 
under further division, into the axis-cylinders of the nerve- 
fibres. Possibly, however, both varieties of cells are of a 
nervous nature. 
Engelmann has recently collected the methods of investiga- 
tion. 
For the primary examination, the dried mammalial tongue 
(appropriately that of the rabbit) may be employed. The sec- 
tions are to be softened in dilute acetic acid and glycerine. 
The organ may also be hardened for a day in osmic acid (0.5- 
1.5 per cent.). The freezing method also affords good results. OEGANS OF SENSE. 
565 
For the study of the finer structure, the maceration in 
iodine-serum and the immersion for several days in chromic 
acid (1-2 per cent.) to which an equal volume of glycerine 
may be added, are to be recommended. Such preparations 
must then be subjected to a very careful picking under the 
simple microscope. According to Engelmann’s experience, 
extremely fine-pointed glass rods are superior to the finest 
steel needles. Wyss gives the preference among all methods 
to an immersion for about three weeks in Muller’s fluid. 
Fried tongues, or those which have been frozen in a suit- 
able manner, serve for following the nerves. Sections obtained 
by the freezing method may be subsequently treated with 
chloride of gold (0.1-0.5 per cent.) or osmic acid (0.25-2 per 
cent.). The nerve expansions under the gustatory nerve be- 
came distinct for Schwalbe after a maceration for several days 
in chromic acid (0.02 per cent.) or bichromate of potash (0.5-1 
per cent.). Wyss made use of the gold method. 
3. Further advanced, especially by the admirable investiga- 
tion of M. Schultze, is, on the contrary, our knowledge of the 
organ of smell, that is, of the manner of termination of the 
olfactory nerve. Before we consider the remarkable structural 
conditions of this locality, however, let us mention the other 
portions of the organ of sense. 
No portion of either of the chief cavities, except the upper- 
most parts, participates immediately in the perception of smell, 
and does not contain any fibres of the specific nerves, but only 
those from the trigeminus, the terminations of which are at 
present still unknown. 
Disregarding the entrance to the nose, a ciliated epithelium 
is found as a covering to the proper nasal fossae and the ac- 
cessory sinuses. The mucous membrane, thinner in the ac- 
cessory sinuses, is, in its submucous connective tissue, firmly 
united with the bones, so that it constitutes at the same time a 
periosteum. In the proper nasal fossae it becomes thicker, and 
very rich in blood-vessels and racemose mucous glands. 
The particular manner in which these parts, as well as the 
cartilage and bones of the parietal system, are to be investigat- 
ed, does not require further discussion. 
In catarrhal conditions of the nasal mucous membrane we 
see at first an extensive exfoliation of the ciliated cells, which 
are met with in the mucus coming under examination partly 566 
SECTION TWENTY-SECOND. 
still ciliated (and even in motion), partly without cilise. To- 
gether with the regularly shaped cylindrical cells, others of a 
more irregular and more rounded form are met with. Large 
cellular structures, which have arisen from the metamorphosis 
of the normal epithelial formation, contain, at this commencing 
period of the nasal catarrh, in addition to their nucleus, granu- 
lated lymphoid cells (mucous or pus-corpuscles) which have 
penetrated from without. Nearly all these elements soon dis- 
appear, with the exception of the last-mentioned structures, 
which are met with in enormous quantities in the thick yellow- 
ish secretion of the later periods. Phenomena which we have 
previously alluded to under similar irritated conditions of the 
respiratory organs (pp. 491-2) and of the urinary bladder (p. 
528) also repeat 
themselves here. 
As was said, the 
greater portion of 
the olfactory re- 
gion does not par- 
ticipate immedi- 
ately in the per- 
ception of smell, 
as the termination 
of the specific nerve 
of sense is met with 
only in a limited 
portion. Such 
places, called re- 
giones olfactorise 
(fig. 363), occur in 
all vertebrate ani- 
mals, but present 
Fig. 863. The regio olfactoria of the fox in vertical section. B, The 
cylindrical epithelium of the same, a, Stratum of the nuclei; 6, of the 
olfactory cells; c, of the pigment. A, The adjacent ordinary ciliated 
epithelium, e, The boundary between them. C, Ordinary racemose 
mucous glands. 1), Bowman’s glands, with the duct d, E, Branch of the 
olfactory nerve. /, Ascending branch with further divisions. 
numerous differences. While the walls of the remaining por- 
tion of the olfactory cavity are covered with ordinary ciliated 
cells (A), there appears, as a covering for the regio olfactoria, a 
likewise unstratified, but non-ciliated cylindrical epithelium of 
a peculiar kind {B), mingled with cells terminating in rod-like 
processes, similar to those we have just become acquainted with 
in the frog’s tongue. The signification of nervous terminal cells 
cannot be denied to these structures, although the continual 
transition of the lower varicose terminal fibre into the fibrillse OKGrANS OF SENSE. 
of the olfactory nerve, cannot yet be demonstrated with cer- 
tainty (either by Schultze or others, as for instance C. K. Hoff- 
mann). The extraordinary delicacy and decomposability of 
the tissue-elements under consideration (which can only be 
managed by macerating and preserving fluid of a definite 
composition), render it appreciable that during a long period 
witb cer- 
K. Hofi- 
the microscopists either did not re- 
cognize the complicated structure at 
all, or interpreted it erroneously. 
In the mammalia and in man the 
regio olfactoria distinguishes itself 
from the remaining nasal mucous 
membrane by a peculiar color, by a 
yellow or yellow-brown tinge. This 
proceeds from fine pigment mole- 
cules, which are embedded partly in 
the bodies of the non-ciliated cylin- 
drical epithelial cells, partly in the 
cells of an especial gland-formation 
occurring here. Vertical sections of 
the part which has been hardened in 
strong chromic acid serve for the pri- 
mary survey. These nucleated cylin- 
drical cells (fig. 864,1 a, 2a) may be 
recognized from suitable side views. 
They send filamentous processes in 
a downward direction, which pass in- 
to communication with each other by 
Fig. 364. 1. Cells of the regio olfactoria 
of the frog, a, An epithelial cell, termi- 
nating below in a ramified process; &, ol- 
factory cells with the descending filament, 
d, the peripheral rod c, and the long vi- 
bratile cilia) e. 2. Cells from the same re- 
gion of man. The references the same, 
only short projections, e, occur (as arte- 
facts) on the rods. 3. Fibres of the ol- 
factory nerve from the dog; at a, divid- 
ing into fine fibrilte. 
means of branches, and, having ar- 
rived at the margin of the mucous 
membrane, they undergo a further 
more prof use division, so that they, at least in places, pass over in- 
to a reticulum which is very delicate and difficult to understand, 
and which often spreads into a kind of homogeneous lamella 
(similar to the membrana limitans of the retina). Between these 
cylindrical cells are noticed in considerable numbers the so- 
called olfactory cells (fig. 364, 1 b, and 2 b), structures which 
are analogous to the gustatory cells. At very different eleva- 
tions between the epithelial cells lies a spindle-shaped nucleated 
cell-body (1, 2, b), which extends upwards into a fine rod(c), and 
downwards into an extremely fine varicose filament (d). 568 
SECTION TWENTY-SECOND. 
The end of the rod which has reached the surface appears 
to terminate quite naked in all mammalial animals ; small and 
quite short styliform projections (2 e), which may be noticed on 
it, are the contents which have swollen out from the effects of 
reagents. This appendix is also absent in fishes which smell in 
water. In birds and amphibia, which smell in the air, on the 
contrary, quite large in part, extremely long cilise, sometimes 
slightly, sometimes not at all movable, occasionally single, oc- 
casionally in numbers, appear on the free extremity of the rod, 
so that the surface of the regio olfactoria is surmounted by a 
regular hair-forest. It is thus shown in our fig. 364, le, from 
the frog. However, we may not conceal the fact that the latest 
observer, Exner, denies this sharp demarcation between the two 
varieties of cells completely. 
Seen from the surface, one may recognize how the pig- 
mented cylindrical cells are surrounded in a circular manner 
by these rods ; while by the side view the rods are to be per- 
ceived between the cylinders, as well as stratified in a deeper 
position, the spindle-shaped cell-bodies of the structures with 
which we are at present occupied. 
Very fresh cadavers are necessary to obtain the same struc- 
tures, cylinder- and olfactory-cells, in man. Particularly wor- 
thy of recommendation for this purpose are the bodies of new- 
born children. In the adult, where the numerous nasal ca- 
tarrhs have preceded, the sharp difference in color between the 
regio olfactoria and the remaining portion of the nasal mucous 
membrane is, for the most part, wanting, and the textural pe- 
culiarities are likewise, as a rule, not so accurately demarcated 
as in the mammalial animal. Otherwise, entire conformity 
prevails. 
Peculiar glands (fig. 863, I)), intermediate in form between 
simple cylinders and racemose glands, and called “Bowman’s 
glands ’ ’ by Kdlliker, in honor of their discoverer, are situated 
in the middle portion of the regio olfactoria, and permeate this 
remarkable cell-stratum with their narrowed excretory ducts. 
Their bodies, lying in the connective tissue, have no membtana 
propria, and consist of those yellow or yellow-brown pigmented 
gland-cells of which mention has just been made. The adja- 
cent mucous membrane, on the contrary, shows ordinary race- 
mose mucous glands (C). Although an ordinary ciliated 
epithelium is found in places in the human regio olfactoria, yet ORGANS OF SENSE. 
569 
these true racemose gland-formations follow immediately. Of 
interest is the circumstance that the Bowman’s glands occur 
in all the higher vertebrate animals, but are absent in fishes 
which smell in the water. 
The olfactory nerve (fig. 368, JSJ) presents only non-medul- 
lated elements in its branches. These appear at first as pale 
nucleated fibres, quite similar to those which we meet with in 
many sympathetic nerves, as, for instance, in 
those of the spleen. By suitable treatment, 
however, one succeeds in separating the olfac- 
tory nerve-fibre into extremely fine fibrillse en- 
closed in homogeneous sheaths ; it is therefore 
a primitive bundle. 
The finer branches of the olfactory nerve 
(fig. 363, /, g) ascend between the glands of the 
regio olfactoria, and thus arrive at the margin 
of the epithelium. Here they divide into the 
finest filaments or primitive fibrillse. These, 
quite similar to the processes of the olfactory 
cells, and appearing varicose under the same 
conditions as those, permeate the fine latticed 
reticulum formed by the spreading of the pro- 
cesses of the cylinder-cells, to finally, as we 
must admit and have already remarked, be- 
come united with the processes of the olfactory 
cells (fig. 365). 
Such a union is, however, totally denied by 
Exner. 
According to him, the branches of the olfac- 
tory nerves terminate towards the surface of 
the connective tissue of the mucous membrane 
in a nucleated net-work. The epithelial and 
olfactory cells shoot outwards from this net- 
work. This net-work with both varieties of 
cells constitute, therefore, the terminal appa- 
ratus of the olfactory nerve. 
Fig. 365. Probable ter- 
mination of the olfactory 
nerve in the pike (after 
Schultze). a, Olfactory 
cells ; 6, rods ; c, lower 
varicose filament, e, ax- 
is-flbrillEe in the sheath 
f; d, spreading out of 
these; at wanting 
connection with the 
same fibrill®, c. 
In his excellent monograph, Schultze has given us a long 
series of directions for the demonstration and investigation of 
these extremely subtile textural relations, and thereby made an 
extremely important contribution to microscopic technology. 
To obtain a primary view of the cells of the regio olfactoria 570 
SECTION TWENTY-SECOND. 
from the body of a mammalial animal just killed, thin sections 
obtained with the scissors may be placed under the microscope, 
with the addition of the most indifferent possible fluid media. 
In these the olfactory cell-rods will be discovered between the 
non-ciliated epithelial cylinders as hyaline rods. However, 
even with the employment of vitreous fluid, one will soon see 
hyaline drops, which proceed from the decomposing olfactory 
cell-rods, coming out over the margin of the epithelial surface, 
a decomposition which takes place with even greater rapidity 
from the addition of water. Schultze found the addition of a 
not too watery glycerine useful. Fine vertical sections of or- 
gans, hardened in stronger chromic acid, or dried and softened 
in acidulated water, also fulfil this purpose. 
To isolate the epithelial structures (and this separation is 
more difficult to accomplish in warm-blooded vertebrates than 
in cold-blooded ones), the employment of conservative and 
macerating fluids is necessary. This effect is rapidly and 
thoroughly obtained by the use of the 30-40 per cent, solution 
of potash, or one of soda of 20-25 per cent. If quite fresh 
pieces of the ethmoid bone, with the adherent mucous mem- 
brane, be immersed in this and, after the lapse of a half or a 
whole hour, the epithelium be scraped off, the separation 
may be accomplished on the microscopic slide. With weaker 
solutions one must wait two or three hours. The well-pre- 
served cylinder-cells and rods, a portion of them still in con- 
nection with the splindle-shaped olfactory cells, may then be 
readily recognized, and in amphibia and birds, even the olfac- 
tory cilise ; on the contrary, there is usually nothing preserved 
of the descending fine filamentous processes of the latter. 
To obtain a surface view, the epithelial covering, macerated 
in a solution of potash or treated with glycerine, is to be used. 
Better, though much more slowly, commencing (from two 
to three days) effects may be obtained by maceration in a very 
dilute solution of chromic acid (whereby the immersed portion 
should not be too small, nor the quantity of fluid too great) 
0.05-0.03 per cent, solutions are to be recommended for the 
quite fresh mammalial animal. For the human olfactory or- 
gan, when it can be obtained, about twelve hours after death, 
Schultze employed the action of a chromic acid solution of 
0.05 per cent, for from one to three days. Cold-blooded verte- 
brate animals require somewhat stronger solutions than the ORGANS OF SENSE. 
571 
mammalia; birds somewhat weaker ones (to 0.01 per cent.). 
(The division of the bundles of the olfactory nerves into primi- 
tive fibrillse may also be accomplished in this way.) 
The extraordinary advantage which such solutions present 
for the study of the regio olfactoria, consists in rendering visi- 
ble varicose swellings on the very fine lower filamentous pro- 
cesses of the olfactory cells, as well as the finest terminal fibril- 
Ise of the nerves of sense (a superiority which also belongs to 
the reagent for analogous textural conditions of the remaining 
higher nerves of sense). As has already been frequently men- 
tioned, the bichromate of potash may be employed instead of 
chromic acid; its action takes place slowly. Schultze em- 
ployed solutions of 0.1-0.5 per cent., and obtained the desired 
preparations after 1-6 days. 
The Muller’s fluid, which is, as I found, very suitable for the 
examination of the cochlea when diluted with water, I also 
recommended years ago in several degrees of dilution. Ac- 
cording to Hoffmann’s experience, diluted with an equal part 
of water, and sometimes acting only one or two days (frog), 
sometimes for nearly two weeks (mammalia), it in fact consti- 
tutes the best of all macerating media. 
Schultze has discovered and recommended still other simi- 
lar acting fluids. 
The concentrated watery solution of oxalic acid preserves 
(p. 129) the olfactory cells, their rods and varicose filaments 
(but not the cylinder-cells) quite exquisitely ; and one has the 
great advantage of not being too dependent upon the time, so 
that the examination may be made even after a few hours, 
and also after days. The connective tissue swells in it and 
becomes more transparent, while albuminous tissues retain 
their sharp contours and become somewhat harder. 
Sulphuric acid in a condition of high dilution, in medium 
of 0.6 per cent. (0.2-1 per cent, and more), also preserves the 
olfactory cells very well, and still more diluted it renders the 
filaments varicose. The connective tissue, however, does not 
swell in it as in the previous acid, but is rendered much more 
beautiful and sharp. Here also too small pieces should not be 
taken, and the preparation is to be tried even after a few 
hours. The immersed pieces keep for days and weeks if they 
are not ruined by the formation of mould. This acid is less 
praised by Hoffmann. 572 
SECTION TWENTY-SECOND. 
Exner praises as the best reagent the immersion for a quar- 
ter or half hour in a 0.5-2 per cent, osmic acid. The object 
has then to macerate in water for hours, days, and even weeks. 
A few drops of acetic acid may be added to the water. Epi- 
thelium is to be exposed to this treatment for a longer period 
than nervous elements. 
Finally, Babuchin has here employed impregnation with 
gold. 
To obtain degrees of hardening which are suitable for the 
preparation of thin sections, and which should present the 
arrangement of the mucous membrane, the glands of Bowman 
and the course of the nerves, one may employ, together with 
the Muller’s fluid, higher degrees of concentration of chromic 
acid and chromate of potash, and subsequently examine with 
glycerine, acetic acid, etc. Moleschott’s so-called strong acetic- 
acid mixture (p. 189) has also been especially recommended by 
Balogh. 
Strongly hardened objects, as well as the preparations of 
the remaining portions of the nasal mucous mem- 
brane, one should attempt to mount in glyce- 
rine. The olfactory cells and the cylindrical epi- 
thelium lying between them may be still more 
suitably preserved in Muller’s fluid diluted with 
an equal quantity of water. 
4. The organ of vision, from its greater com- 
plication, requires a more detailed discussion. 
The eyelids, with the cutis accompanying 
them, their connective-tissue so-called tarsal car- 
tilage, and the embedded Meibomian glands (fig. 
366), which in their form remind one of those of 
Bowman in the olfactory organ, as well as the 
conjunctiva of their posterior surface and of the 
eyeball, together with the epithelial covering 
Fig. 306. A human 
Meibomian gland. 
which clothes it, require but brief discussion. Their tissues are 
to be examined in general in accordance with previous direc- 
tions. 
It is advisable, as Waldeyer states, to take the freshest 
possible eyelid, stretch it moderately on a cork plate, place it 
in absolute alcohol, or first in Muller’s fluid, and then, after 
washing, harden it in the former fluid. Hardening in a 0.5 
per cent, solution of chloride of gold is also to be recommend- OEGANS OF SENSE. 
573 
ed. Hsematoxyline or carmine is to be used for tingeing sec- 
tions. It may be well to subject the latter tinged preparations 
to the energetic action of acetic acid, as it renders the embedded 
glands, hair follicles, etc., more distinct. 
To isolate the epithelium, use a 10 per cent, solution of 
common salt, and also Czerny’s mixture of Muller’s fluid and 
saliva (pp. 136-7). 
The lachrymal glands are to be examined in the same man- 
ner as other racemose glands (pp. 412, 417). 
The conjunctiva of the eye (frequently a lymphoid infil- 
trated connective tissue) contains throughout the entire line of 
transition numerous racemose mucous 
glands, while in the conjunctiva of 
the eyeball (the portion surrounding 
the cornea) of the ruminantia, coil- 
shaped glands, quite similar to those 
of the skin, have been discovered 
(Manz). Maceration in dilute acetic 
acid or pyroligneous acid will make 
them readily visible. For the recog- 
nition of the peculiar nerve termina- 
tions in the Krause’s knobs (fig. 367), 
the fresh, still warm eye of one of our 
slaughter-house animals may be used. 
The conjunctiva is to be removed with 
rapidity, but with the utmost caution, 
and searched with low powers and 
without the addition of any medium. 
The necessary details concerning the 
reagents have already been mentioned 
at pp. 373-4. According to Ciaccio 
and Longworth, the gold method may 
also be used with advantage. 
Fig. 367. Terminal knobs; 1, from 
the calf; 2, from man. 
We have also previously mentioned (p. 370 and fig. 208) the 
remarkable termination of very fine nerve fibrillse in the epi- 
thelium of the corneal conjunctiva, as well as the methods 
usually employed at present. 
The blood-vessels of the conjunctiva present nothing re- 
markable. The lymphatics of the human conjunctiva form a 
highly developed net-work of passages of considerable size 
over the sclerotic, which also occupies the peripheral portion SECTION TWENTY-SECOND. 
of the cornea for about one millimetre in breadth, and consist- 
ing here of finer canals with bow-like terminations (Teich- 
mann). Among mammalial animals I have succeeded in inject- 
ing such canals in the calf. 
Interesting phenomena of the conjunctiva are presented by 
the trachoma glands, as they have been called; lymphoid folli- 
cles very similar to those of the intestinal canal, and quite 
variable in number and arrangement. The injection in the ox 
(fig. 368) shows that knotty 
lymphatics (a) of consider- 
able size run towards their 
lower surface, and, after the 
loss of their vascular walls, 
form a highly developed net- 
work of lymphatic canals 
around them, from which finer 
reticular canals encircle the 
follicle and spread themselves 
out in a delicate manner (c) in 
the lymphoid stratum, unit- 
ing the follicles (5). Their most 
Fig. 368. Trachoma gland of the ox, with injected 
lymphatics, in vertical section, a, submucous lym- 
phatic vessel; c, its distribution to the passages of 
the follicle 6. 
superficial portions, that is, those turned towards the epithe- 
lial layer, run more horizontally, and send off fine terminal 
canals which present quite superficial csecal terminations. 
The whole is enclosed in connective tissue, and the entire ar- 
rangement is related in the most intimate manner to that of a 
Peyerian plaque; only the blood-vessels of the follicles are 
here less abundant and less regular. Our structures are en- 
tirely wanting, however, in new-born animals (Blumberg, 
Schmid), 
The eyes of younger oxen or older calves, and cold-flowing 
mixtures are to be used for injections, which should be made 
in the so-called Bruch’s aggregation of the trachoma glands 
of the lower eyelid. The other aggregation may, however, also 
be very readily injected ; and furthermore, the injection of the 
blood-vessels by the smaller arteries also succeeds without great 
difficulty, while with smaller mammalial animals the entire 
head must be injected from the aorta with colored gelatine. 
The procedure is difficult in man and many other mammalial 
animals. The preparations are to be hardened in alcohol for 
examination. 575 
ORGANS OF SENSE. 
With regard to the eyeball itself, it may be said that its 
examination is one of the most remunerative labors of the 
microscopist; but at the same time, however, in one of its ele- 
ments (the retina) combined with the greatest difficulties. One 
should always use the quite fresh, still warm eyes of the larger 
slaughtering animals, especially those of the ox, calf, and 
sheep, as well as indifferent fluid media, such as the vitreous 
and aqueous humors which are always at hand. If the eyes 
have been removed with a little care, the artery may be readily 
found lying near the optic nerve and employed for injecting 
(the injection of the human eye is more difficult in consequence 
of the smallness of the artery). Such injections, when they are 
to be followed by histological investigations, are always to be 
made with cold-flowing mixtures, the Prussian blue or carmine. 
The injection of an eye of one of the larger animals, after the 
numerous divided vessels have once been ligated, usually suc- 
ceeds in from two to three minutes. Even after a quarter of 
an hour one may commence with the dissection and examina- 
tion. The system of the uvea, especially, shows many things 
in a much more instructive manner than in the injected organ, 
and the unpigmented tapetum of such eyes affords a further 
advantage for many investigations. Where especial reference 
is to be made to injected preparations, inject with carmine gel- 
atine. The eyes of the smaller mammalial animals are to be in- 
jected from the aorta simultaneously with and under the same 
precautions as the brain (pp. 358-9). White rabbits afford 
excellent objects. The eyeballs of this animal, divided in halves 
and mounted in glass cells with Canada balsam, which have 
been put in circulation by Thiersch, may be recommended as 
true models of the modern injection technique. If it be desired 
to accomplish a double injection, Prussian blue is to be first 
thrown into the artery, and a second injection of carmine gela- 
tine is then to be made by the same vessel. Leber has recently 
instituted excellent studies of this kind, with cold-flowing 
masses and the use of the constant pressure. 
We have recently obtained, through Schwalbe, excellent 
investigations of the lymphatics of the eyeball. This author 
used in part cold-flowing, colored masses, in part gelatine 
solutions, as well as solutions of nitrate of silver. He recom- 
mends the puncturing method, with very fine canules, the points 
of which are ground under an angle of 40° to the long axis. SECTION TWENTY-SECOND. 
To inject the posterior lymphatics, puncture the sclera be* 
tween the corneal margin and the equator of the eyeball, 
avoiding, however, the vicinity of the venae vorticosae. For the 
anterior lymphatics, puncture partly in the anterior chamber, 
partly in the canal of Petit. 
For further particulars we must refer to the original. 
The investigation of such fresh eyes requires in part trans- 
verse sections, as of the cornea and sclerotic; but generally, 
however, a dissection of the membranous structures. These 
may be first reviewed unpicked with vitreous fluid, or the ad- 
dition of reagents, and hereby folds which are artificially made 
are for the most part very instructive, or they are to be divided 
with fine needles. Much may be recognized in such a manner 
concerning the texture of the eyeball, and even of the retina. 
In this way all the former (and in part adequate) knowledge of 
the same was obtained ; and even with the employment of other 
more modern methods, the criterion of the fresh condition can 
never be dispensed with. Certain elements of the eyeball, on 
the contrary, are in part so transparent, in part so delicate and 
soft, that hardening (and darkening) methods of treatment be- 
come indispensable. And it is frequently only in this way 
that thin sections succeed either with the free hand or with the 
aid of the microtome. Many structural conditions, the termi- 
nation of this and that structure, the relations of continuity of 
the one with the other, etc., can only be ascertained with ade- 
quate certainty from such preparations. Those two methods 
which we have already had to mention in connection with so 
many organs, the drying and the hardening by means of re- 
agents, are also employed here. For the former purpose the 
eyeball is to be divided at the equator, and the vitreous body 
(generally also the lens) removed. Both segments should be 
spread over the surface of cork, cut into semispheres. This 
drying method is, however, of subordinate importance, and 
has, therefore, of late been more and more abandoned. For 
hardening, use either absolute alcohol or—what is far more 
customary—chromic acid (0.5-0.2 per cent.) and chromate of 
potash. The bulb may be either divided, only cut open, or 
even left entirely unopened (in which case a stronger solution 
of the hardening medium is to be selected). The Muller’s eye- 
fluid (p, 136) is very excellently adapted for hardening the un- 
opened immersed eyeball. It is necessary, it is true, to wait OEGANS OF SENSE. 
577 
two or three weeks for the adequate effect; but the eye may 
also be allowed to lie in it for months and even years without 
any harm, and with this accessory very handsome specimens 
of most parts of the bulb may be obtained. The mixture has 
therefore, with propriety, come more and more into use among 
ophthalmologists. If a weaker action is aimed at, it is to be 
diluted with water; to ob- 
tain stronger hardening, a 
little chromic acid is to be 
added. Injected eyes may 
also be hardened in this man- 
ner, though the color suffers 
somewhat. If it be desired 
to avoid this, employ cold- 
flowing baryta masses (p. 
188). 
Let us next examine the 
methods for investigating 
the capsular system, the cor- 
nea and sclerotic. 
The structure of the cor- 
nea (fig. 369), with both its 
epithelial layers, the strati- 
fied of the anterior (cZ), and 
the simple cell-covering of 
the posterior surface (e), with 
the two hyaline boundary 
layers of the so-called lamina 
elastica anterior (Z>), and the 
membrane of Descemet (c) 
appearing under them, as 
well as the ordinary corneal 
substance (a) and their cel- 
lular elements, have been so 
frequently treated of and dis- 
Fig. 369. The cornea of the new-born in vertical 
section (but considerably shortened), a, Corneal tis- 
sue ; b, anterior, c, posterior hyaline layer; d, stratified 
pavement epithelium ; e, simple epithelial layer. 
cussed of late that it would be superfluous to enter further into 
the textural relations in question. The best descriptions of the 
cornea are those of His, Kuhne, Engelmann, Schweigger-Seidel, 
Hollett and Waldeyer. 
We have received a number of methods of examination in 
the course of time. 578 
SECTION TWENTY-SECOND. 
For the recognition of the effete corneal corpuscles and their 
contents, use very weak acetic acid, or extremely dilute chro- 
mic-acid solutions of 0.01 per cent. Here, however, as with all 
the following methods, artificial (and often very considerable) 
alterations are not to be avoided, as the interstitial substance 
swells and the cells usually shrink. 
Drying is also useful for certain purposes. Very thin sec- 
tions, either only softened in weakly acidulated water, or first 
tinged in carmine and then washed out with diluted acetic acid, 
afford good review specimens. 
For many purposes of investigation, however, the quite 
fresh transparent cornea is indispensable. The structure is 
taken from the animal immediately after death, and a cut 
is made in it from the side. Humor aqueus may serve for 
moistening, and the moist chambers (p. 99) for its preservation. 
Frequent use has more recently been made of the most un- 
injured possible cornea of the frog (Kfihne, Recklinghausen, 
Engelmann). The cornea is to be examined with its posterior 
surface turned upwards, preferably without any covering glass 
and with an immersion system. 
At first one sees next to nothing in the hyaline transparent 
tissue ; at most, striations of the same and traces of the corneal 
nerves. After a more close examination one finds small isolat- 
ed, dull glistening structures of a sometimes rounded, some- 
times elongated, occasionally crooked form. The observer con- 
vinces himself that these bodies stretch out delicate processes 
and draw others in ; in short, constantly change their form and 
location. These are the already mentioned (p. 252) wandering 
cells of Recklinghausen. 
If we wait half an hour longer, the corneal corpuscles begin 
to stand out from the tissue in the form of extremely pale, 
polygonal appearing dull spots. If about another half hour be 
allowed to pass, our corneal corpuscles become more distinct; 
the dull spots are connected with each other by radiated pro- 
cesses ; the reticulum of cells is visible. Nuclei are not yet to 
be discerned in the latter. Kuhne asserts that he has con- 
vinced himself of a vital contractility in these stellate cells. 
Engelmann saw no trace of this in his re-examination. The 
change of form and location of the wandering cells is, on the 
other hand, to be observed now as before (and with proper 
treatment for a long time yet). OEGANS OF SENSE. 
579 
We will here mention still another interesting and impor- 
tant observation concerning the latter cell-formation. We have 
already (p. 98) alluded to the reception of small granules into 
the interior of such amoeboid structures. If a small incision 
be made at the sclerotic border of the cornea of a living frog, 
and granules of cinnabar or carmine be rubbed into it, the cor- 
nea, isolated after twelve hours or more, will show a number 
of these cells with the colored molecules in their interior, occa- 
sionally considerably removed from the wound, wandering 
through the tissue. 
His, a meritorious investigator of our membrane, recom- 
mends first the acetic acid with iodine staining, to cause the 
corneal cells to appear through the transparent interstitial sub- 
stance. 
According to him, however, the immersion in purified pyro- 
ligneous acid, diluted with an equal volume of water, or even 
more, constitutes a main accessory. The cells, with more 
cloudy contents, then appear through the somewhat swollen, 
more transparent interstitial substance. The hardening prop- 
erty which, as is known, is also associated with the distending 
power of the pyroligneous acid, is also of great worth here for 
rendering fine transverse sections feasible. These may be ver- 
tical, exactly similar to those from the dried object, and then 
(which is not possible with the latter material) the very much 
more instructive horizontal sections. Entire corneas may also 
be preserved for years in pyroligneous acid. 
Another mixture, mentioned by Remak, consisting of dilute 
pyroligneous acid, watery alcohol, and a weak solution of sul- 
phate of copper, causes less swelling, but otherwise yields quite 
similar appearances. Chromic acid presents no advantage 
over pyroligneous acid. 
Hypermanganate of potash (Rollett) or a 10 per cent, solu- 
tion of common salt (Schweigger-Seidel) may be used for the 
demonstration of the corneal fibrillse. 
Other reagents, such as concentrated chromic acid, Muller’s 
fluid, saturated solutions of sugar, dilute alcohol of 50 per 
cent., and Merkel’s chromic acid and chloride of platinum mix- 
ture (pp. 137-8), exert a shrinking effect on the interstitial sub- 
stance, and have been recommended for demonstrating a fibril- 
lary structure of the corneal tissue. 
Rollett praises, furthermore, exposing the cornea, mois- 580 
SECTION TWENTY-SECOND. 
tened with humor aqueus, to the action of iodine vapor. Use a 
somewhat high moist chamber, after the manner represented 
by tig. 75, p. 99. The cornea adheres to the under surface of 
the covering glass, the bottom of the chamber is covered with a 
watery solution of iodine (metallic iodine shaken in water). 
Waldeyer has subsequently, however, and very properly, de- 
clared this method to be too positive in its action. 
Frequent use has also been made of the silver method in the 
examination of the cornea and a reticulum of star-shaped fig- 
ures, which appear sometimes bright out of a darker basis sub- 
stance, sometimes 
dark with bright- 
er surroundings, 
pronounced to be 
the net-work of 
corneal cells. 
We have re- 
cently received a 
whole series of di- 
rections in refer- 
ence to this sub- 
ject, for the re- 
Fig. 370. The human cornea impregnated with silver, with the trans- 
parent so-called corneal corpuscles (cleft system); to the left below, four 
metamorphosed parenchyma cells. 
sumption of the study of the process of inflammation has late 
ly led a number of investigators to our organ. 
We present a few of these. 
One of our most distinguished histologists, Waldeyer, rec- 
ommends placing the entire, completely fresh eyeball (with 
small animals the whole head, after removing the lids) in the 
silver solution. The epithelium should previously be removed 
from the anterior surface, however. This is best accomplished 
by the action of the warm vapor of water, continued till a 
slight cloudiness occurs, and thereupon the careful use of a 
brush moistened with humor aqueus (Recklinghausen), 
Use weak solutions of silver, from 0.5-1 per cent. The 
period of action may extend from a half to a whole hour, for 
example, with the frog (Eberth). 
Washing the silver preparation and then tingeing it with 
hsematoxyline often affords the most charming preparations. 
Yon Thanhoffer places the whole globe, without the pre- 
vious removal of the epithelium, in a 1-2 and 8 per cent, solu- 
tion of nitrate of silver. The reagent should act in the dark ORGANS OF SENSE. 
581 
for 5-15 minutes. The mammalial eye is to be removed from 
such solutions after 5-8 minutes, and the epithelium scraped 
olf. It is then to be returned to the silver solution for 5-10 
minutes ; still treating the object in the dark. 
The chloride of gold and its potash and soda salts are more 
protective, and, therefore, present more reliable results. The 
cellular elements and the nerves are either alone or predomi- 
nantly colored, and the latter preserve every detail (Cohnheim), 
even should the nuclei of the corneal cells become distended 
(Waldeyer). The reagent is, therefore, here of the first rank. 
Its hardening property enables us, besides, to prepare sections 
perpendicular and parallel to the surface. Unfortunately, 
from the capriciousness of the gold method, some trials have 
succeeded, while others have not, and thus a number of meth- 
ods have been introduced. The latter, naturally praised by 
their inventor, are usually more or less censured by the imita- 
tor. 
We have already, in an earlier section of our little book (p. 
167), mentioned the process which the inventor of the gold 
method, Cohnheim, has used, as well as the methods of He- 
nocque, Bastian, and Bottcher. The latter, intended primarily 
for the cells, gave us unsatisfactory distentions. 
Hoyer recommends the method mentioned at p. 371 for the 
corneal nerves. 
Finally, we would again call attention (also for the corneal 
nerves) to a method of Kleins (p. 371), which is claimed to be 
infallible. 
Corneas, impregnated with gold, likewise permit of subse- 
quent tingeing with hgematoxyline. 
A combination of the silver and gold methods has been used 
for the cornea. 
For this purpose Rollett exposes the cornea of the frog to a 
0.5 per cent, solution of nitrate of silver, then to a solution of 
chloride of gold of the same strength, after which it is placed 
for a longer period in slightly acidulated water. Then, after 
the reduction has taken place under the action ot light, the 
corneal cells appear granular and yellowish in the dark ma- 
trix. 
Yon Thanhoffer uses, for the study of the nerves and cells 
of the frog, osmic acid of 1 per cent., in which the whole eye- 
ball is immersed for 5-10 seconds with the cornea turned 582 
SECTION TWENTY-SECOND. 
downwards. It is then placed in a silver solution of the same 
strength for 5-10 minutes, protected from the light. If the cor- 
nea has acquired a grayish brown color, it is placed in a solu- 
tion of common salt or pure water, and exposed to the sun- 
light until after a few minutes a dark coffee-brown color ap- 
pears. Glycerine is used for the examination. 
To inject the canal-work of the corneal tissue, take larger 
mammalial animals, and use the puncturing method. Waldeyer 
recommends a turpentine solution of alcannine and the deep 
brown ethereal extract of anacardium nut. 
Concerning the two hyaline limiting layers of the cornea, it 
may be stated that the membrane of Descemet may be readily 
isolated by scraping with the firm pressure of a scalpel. An 
incomplete separation of the membrana elastica anterior from 
the deeper corneal tissue may be accomplished by maceration 
in muriatic acid. 
Dried sections mounted in Canada balsam are to be em- 
ployed for recognizing the double refraction of the interstitial 
substance. 
The organ of smaller embryos affords handsome prepara- 
tions for the cells and interstitial substance. His recommends 
the foetuses of the cow and hog of about 5 ctm. 
The blood-vessels occupy only the peripheral portion of the 
organ in the adult, as we learn from artificial and natural in- 
jections. 
The magnificent transparency of the so accessible cornea 
renders it more than any other structure appropriate for artifi- 
cial inflammatory irritations, and the study of the tissue- 
metamorphoses which take place thereby. It is therefore 
frequently employed for such investigations, and the facts 
obtained interpreted in accordance with the prevailing patho- 
logical views. While years ago the profound work of His 
appeared to lend an important support to Virchow’s theory 
concerning the participation of the connective-tissue corpuscles 
in the inflammatory process, at the present time the case is 
entirely reversed, and the cornea has become a favorite object 
of study for demonstrating the correctness of the Waller- 
Cohnheim theory of the immigration of lymphoid cells. The 
doubters have also resorted to this field. 
To produce inflammation of the cornea, keratitis, our struc- 
ture may be irritated in several different ways, as by the in- ORGANS OF SENSE. 
sertion of threads and silver wires, the application of tincture 
of cantharides, chloride of zinc, or, still better, a pencil of nitrate 
of silver (Eberth). The latter should be pointed and further 
polished with pumice-stone. It is well to tinge such corneas 
with hsematoxyline or to subject them to a subsequent im- 
pregnation with gold. Here also the coloring matter mentioned 
may finally be allowed to act for a time (Eberth). Muller’s 
fluid and hsematoxyline are also recommended. 
The desired inflammation is obtained in rabbits after 
twenty-four hours, in summer frogs after two to three days, 
but only after double this time in hibernating frogs. 
If cinnabar, carmine, or, still better, aniline blue suspended 
in water has been injected with a Pravaz’ syringe into one of 
the lymph spaces of such a frog, no serious disturbance of the 
health of the animal is caused. The stuffed lymphoid cells 
now penetrate as pus-corpuscles from the periphery into the 
cornea, to adhere to the place of irritation. It is only a few of 
these cells, however, which bear the colored granules in their 
bodies as a mark of their origin. A considerably larger number 
of these can only be obtained when this coloring matter has 
been injected for several consecutive days into the various 
lymphatic spaces. 
However, even in a cauterized cornea, if it is only obtained 
living, lymphoid cells accumulate in such quantities around 
the point of irritation, that the migratory cells present in it at 
the moment of separation do not suffice to supply the demand 
(Hoffmann and Recklinghausen). An origin of these cellular 
elements from the stellate corneal corpuscles cannot, according 
to this, be denied, however earnestly it may and will be op- 
posed. 
The net-work of blood-vessels which may cover the anterior 
surface of the cornea, as a result of inflammation, requires, 
after the beautiful statements made by Thiersch concerning the 
vascularization of wounds (p. 398), a renewed investigation. 
Portions which have been removed are regenerated by newly 
formed corneal tissue. The yellowish margin which the cornea 
shows in the so-called arcus senilis, consists of a deposition of 
fat in the corneal cells, and also in their interstitial substance ; 
it is therefore one of those commencing fatty degenerations, 
such as likewise make their appearance at a more advanced age 
in other parts of the body. 584 
SECTION TWENTY-SECOND. 
Corneal preparations may be tinged, and, after extraction of 
tlieir water by means of absolute alcoliol, mounted in Canada 
balsam. A moist mounting in watery glycerine is, as a rule, 
employed. 
The tissue of the sclerotica, as is known, is continuous with 
that of the cornea, but consists, after the manner of the fibrous 
membranes, of a fibrillated intercellular substance, which is 
changed by boiling into ordinary gelatine, and not, like the 
cornea, into chondrin. The flattened bundles of these fibrillse 
cross each other nearly at right angles. Fine elastic elements 
and a reticulum of connective-tissue corpuscles stand out from 
the hyaline interstitial substance after the application of acetic 
acid. 
The fresh tissue teased out into fine pieces, and objects hard- 
ened or dried in the same manner as the cornea, serve for the 
examination. If the iris and choroid have been retained on 
them, the immediate transition of these tissues into that of the 
sclerotic may be finely observed ; likewise the transverse section 
of the canal of Schlemm, the origin of the musculus ciliaris 
and the prolongation of the membrane of Descemet into the 
so-called ligamentum iridis pectinatum. 
The system of the uvea consists of the choroid and iris, 
membranes which contain muscular fibres and 
are rich in pigment and vessels. They are cov- 
ered on their inner surfaces by a pigmented epi- 
thelium (fig. 371), the so-called polyhedral pig- 
ment-cells of an earlier epoch. For the demon- 
stration of these cells (which are, however, with 
Fig. 371. Profile 
view of two cells of the 
human retinal epithe- 
lium. 
much greater propriety to be included with the 
retina), the fresh eye may be used, or one which 
has been divided and hardened either by means 
of chromic acid, chromate of potash, or Muller’s fluid. Small 
portions of the black covering of the exposed inner surface 
may be removed with the scalpel or the cataract-needle. They 
are then to be spread out with needles or the brush, and cov- 
ered with a right thin covering glass. Strongly hardened eyes 
permit of transverse sections of the entire uvea, and hence pro- 
file views of the epithelial covering. 
Our cells send downwards, that is, towards the centre of the 
eyeball, either pigmented filaments or, occasionally, also, a 
kind of membranous tube (Schultze, Marano). These prolon- OKGANS OF SENSE. 
585 
gations ensheath the so-called rods of the retina, remarkable 
structures which we shall soon have to discuss. 
Interesting views are presented by an Albino eye, that of a 
white rabbit, or the nnpigmented covering on the so-called 
tapetnm of one of onr rnminantia. Viewed from the surface, 
a mosaic of polyhedral cells will be perceived, and, in the lat- 
ter locality, appearances will be at the same time obtained 
which show that on the peripheral portion 
of the tapetnm cells, with a scanty deposi- 
tion of melanine, form the transition into 
ordinary pigment-cells. 
The choroid proper consists, as is 
known, of a soft connective tissue, show- 
ing stellate cells united in a reticular man- 
ner, and which is permeated by an extraor- 
dinary quantity of blood-vessels. These 
cells characterize themselves by a great dis- 
position to develop pigment molecules in 
their bodies and to thus become stellate 
pigment-cells (fig. 372). 
Fig. 372. Stellate pigment- 
cells (pigmented connective- 
tissue corpuscles), from the 
mammalial eye. 
We distinguish several layers of the choroid. An external 
looser stratum of soft connective tissue, rich in pigmented cells 
(lamina fusca, supra-choroidea), serves for the connection with 
the inner surface of the sclerotic. Its structure may be readily 
recognized in fresh, picked preparations ; likewise its rela- 
tions with the neighboring tissues in sections through the 
sclerotic and uvea of an eye strongly hardened 
in chromic acid. 
Beneath the lamina fusca follows a middle 
layer of this connective-tissue substance, present- 
ing the larger arterial and venous ramifications. 
The fresh tissue, or an eye which has been in- 
jected with a transparent mixture, serves for the 
recognition of this slightly pigmented layer. 
Finally, as a third layer appears, a more homo- 
geneous unpigmented stratum, the so-called 
chorio-capillaris, which contains a remarkably 
rich, very narrow-meshed reticulum of delicate 
Fig. 3T3. Capillary 
arrangement from the 
chorio-capillaris of the 
cat. 
capillary vessels (fig. 378). Here also recourse may be had 
either to an injected organ (calf, sheep, cat), or a portion of 
choroid may be taken from a chromic-acid preparation and 586 
SECTION TWENTY-SECOND. 
freed as well as possible from the external layers and, by cau- 
tious brushing in glycerine, from the pigmented pavement epi- 
thelium which covers the inner surface. A sufficient quantity 
of blood-corpuscles will generally be found retained in the 
capillary net-work. 
The fine hyaline, more independent boundary layer of the 
chorio-capillaris, towards the pavement epithelium, has been 
designated as the elastic layer of the choroid. For its primary 
recognition a fold of the fresh choroid may be used ; acids and 
alkalies serve as media. A longer action of alO per cent, 
solution of common salt causes this to appear fibrillated. 
These lamellae undergo interesting senile metamorphoses, 
thickenings, spherical and druse-like concretions, frequently 
with deposits of lime-molecules, which may dislodge the pig- 
ment epithelium and compress the retina (Muller). Other 
hyaline membranes of the eye also increase in thickness with 
age. 
The injection preparations mentioned, deprived of their 
water with alcohol, may be beautifully mounted in cold Canada 
balsam (diluted with chloroform); the others are to be mounted 
moist. 
For the primary recognition of the ciliary muscle, sections 
from a dried eye may be used. Here the rows of fibres run- 
ning in a meridional direction may be perceived, and on good 
sections also the circularly arranged ones which Muller dis- 
covered. For further investigations, use the reagents custom- 
ary for the connective tissue and the contractile fibre-cells, 
the 30-40 per cent, potash solution, the chloride of palladium 
with a subsequent carmine tingeing, the double staining of 
Schwarz, etc. According to Flemming, the contractile fibre- 
cells may still be isolated, after hardening in chloride of pal- 
ladium, by means of the potash solution mentioned. A long, 
12 to 24 hours’ action of the latter is then necessary. 
The examination of the ciliary body is to be made on fine 
sections from an eye which has been injected with transparent 
gelatine fluids, and hardened in chromic acid or alcohol. The 
delicate rich reticulum of vessels may in this way be most 
accurately followed. Here, as with the iris, the eye of the 
white rabbit injected with carmine deserves the preference. 
For the primary recognition of the structure of the iris, 
avoid dark-eyed creatures, as the stellate pigment-cells which ORGANS OF SENSE. 
587 
occur in their tissue increase the difficulty of the examination 
very much. The eye of a new-born or of a bright-eyed child 
deserves to be recommended here. The methods consist, after 
the removal of any pigmented epithelial layer which may be 
present (and which may be previously macerated in acetic or 
oxalic acid) by means of the brush, firstly in tearing, then in 
the examination of whole pieces with the use of acetic acid 
for connective tissue, and of the dilute soda solution for the 
nerves. For the smooth muscular tissue use the reagents now 
generally employed for that tissue, and which have Just been 
mentioned. One may thus convince one’s self of the existence 
of a dilatator pupillse, concerning which numerous controversies 
have lately arisen, and which is, nevertheless, not so very 
difficult to recognize. The whole or half of the iris of a small 
white rabbit may be used for the study of the coarser arrange- 
ment of the muscles when treated with acetic acid, and also 
with the addition of soda for following the nerves of the iris 
with lower magnifying powers. Such objects, tinged with 
hsematoxyline or carmine, in the latter case washed out in weak 
acetic acid, become very handsome, as 
do also transparent injections of the 
blood-vessels. 
There is nothing especial to be re 
marked concerning the methods of pres- 
ervation. 
Concerning the refracting organs, the 
lens and the vitreous body, the tissue of 
the latter has already been mentioned in 
one of. the preceding sections of our 
book (p. 275); the crystalline lens, on 
the contrary, although in reality an 
epithelial structure, has not yet been 
discussed. 
The fresh eye of any somewhat large 
mammalial animal may be employed 
for the examination of the lens-capsule 
(fig. 374, a) and of the extremely delicate 
Fig. 374. Diagrammatic represen- 
tation of the human crystalline lens, 
a, the capsule; c, the lens-fibres with 
widened ends id), becoming inserted 
at the anterior layer of the epithelium 
(6), and also inserted posteriorly into 
the capsule (e); /, the so-called nu- 
clear zone. 
pavement epithelium (Jj) which occurs on the posterior surface 
of the anterior segment of the capsule. The capsule, isolated 
with the lens, is to be liberated by an incision and placed in 
fragments under the microscope, with the addition of vitreous 588 
SECTION TWENTY-SECOND. 
fluid. Weak powers, with a strongly shaded field, show the 
borders and folds of the hyaline membrane at once. Stronger 
objectives show the thoroughly homogeneous structure of the 
hyaline membrane, and with repeated considerable shading, the 
pavement-shaped epithelium may be recognized. The addition 
of aniline red is here very convenient, as the tingeing follows 
very rapidly and without any alteration of the tissue. Other 
tingeing methods also accomplish the object. 
For the capsular epithelium, one may resort to chromic 
acid, the bichromate of potash, nitrate of silver, and chloride 
of gold. 
On a fresh section of a lens, however, even with the use of 
these two accessories, one would be 
able to recognize the lens-fibres (fig. 
375) only very incompletely. 
Various accessories are to be rec- 
ommended here, as the maceration in 
highly diluted sulphuric acid (4-5 
drops of the acid of 1.838 sp. wt. to 
one ounce of water), which isolates 
the lens-fibres (v. Becker); in mu- 
riatic acid of 0.1-1 per cent. (Morig- 
gia); further, the preparatory hard- 
ening in chromic acid, bichromate of 
potash, or Muller’s fluid (Zernoif). 
The object may likewise be obtained 
with alcohol, though not so well; 
and also by peeling ofi thin scale- 
like portions from a dried lens. The 
organ being of itself quite transpar- 
ent, with many chromic-acid prepa- 
rations, the use of media which tend 
to increase the transparency, such 
as glycerine, is to be avoided. Such 
objects may occasionally be very suit- 
Fig. 3T5. Lens-fibres of the human em- 
bryo of eight months, a, Fibres with a 
nucleus; b. one which still presents the 
cellular character ; c, the flattened form 
of the side view ; d, fibres with two and 
three nuclei. 
ably tinged with aniline. Others, which are more opaque, can 
be again rendered transparent by means of glycerine or acetic 
acid. An immersion, lasting for 15 minutes, in a nitrate of 
silver solution of 0.125-0.1 per cent, has also been praised 
(Robinsky), likewise dilute solutions of osmic acid (Arnold). 
The leps-tubes and the nuclei of the equatorial zone readily ORGANS OF SENSE. 
589 
appear (fig. 374,/). To recognize the relations of origin of 
these fibres to the epithelium of the capsule, one may use a 
strongly hardened lens which is within its capsule, and the 
equatorial as well as meridional sections from that region. 
Equatorial sections may be obtained from the adequately 
hardened crystalline lens, and may thus permit of the recogni- 
tion of the delicate mosaic of the lens-tubes cut at right angles. 
A lens which has become considerably dried in the air, if em- 
ployed at tlie proper moment, has not unfre- 
quently acquired such a degree of consistence 
as to permit of convenient cutting without 
splintering. From it very handsome trans- 
verse sections may be obtained (fig. 376). A 
similar appearance may be obtained from 
ground sections of a strongly hardened lens. 
Pig. 876. Transverse 
section of the lens-fi- 
bres from the dried 
organ. 
The previous saturation with a mixture of gum mucilage and a 
little glycerine is also to be tried in drying. 
Opacities of the lens-capsule, in part, with depositions of 
elemental granules, likewise embedments of fat-molecules in 
the epithelial cells and lens-fibres, 
of granules between the latter, de- 
posits of lime, etc., are not unfre- 
quent occurrences. The methods of 
examination are the same. 
Human and mammalial embryos, 
hardened in absolute alcohol or chro- 
mic acid, serve for ascertaining the 
primary origin and the foetal structu- 
ral conditions of the lens (fig. 377) and 
the vitreous body. In embryos of the 
sheep of 6-7'", everything is still cel- 
lular ; in human foetuses of about 8-9 
weeks, the lens also seems to be consti- 
tuted of only delicate spindle-shaped 
cells (Kolliker). The condition of a 
Pig. 377. a-c. Lens-cells of a two- 
inch foetus of the pig. a, Original cells; 
5, oval elongated ; c, grown longer in the 
transition into lens-tubes; d, epitheli- 
um of the lens, from an eight months1 
human embryo; e, cells of the so-called 
humor Morgagni!. 
pig’s foetus of two inches is shown in our figure. Foetuses of 
this animal of 3i" have already a fibrous nucleus (Schwann). 
Preservation is to be attempted with strongly watered gly- 
cerine. 
The membrana hyaloidea is readily recognized in the hard- 
ened and also in the fresh organ. 590 
SECTION TWENTY-SECOND. 
In sncli conditions, after brushing off the epithelium, the 
fibres of the zonula Zinuii may be perceived with some difficul- 
ty, but they appear far more beautifully and sharper in the 
suitably hardened eye. 
If we now proceed to the nervous portion of the eyeball, 
the retina, there lies before us in the so difficult to compre- 
hend, extremely complicated structure of the most delicate 
and changeable membrane, one of the most troublesome, but 
likewise, also most attractive objects of microscopic investiga- 
tion. An infinite amount of work has already been done in 
older and more recent times in the investigation of the so 
wonderful retina ; and, though the knowledge concerning this 
membrane has made very great progress by the aid of the mod- 
ern accessories, there remains to the present hour unsolved 
many textural questions of physiological importance. 
To obtain the primary review preparations recourse will 
nowadays be generally had to an artificially hardened eye. 
An opened eyeball may be immersed in chromic acid of 0.5-0.2 
per cent, (if unopened the concentration may be increased), or 
the corresponding quantity of the bichromate of potash. At 
present we can recommend nothing more highly for the un- 
opened bulb than Muller’s fluid. It preserves the cones and 
rods very beautifully, which, with the other solutions, does not 
succeed or only very incompletely ; the examination may be 
made after 2-3 weeks (but also much later). Alcohol, which 
was formerly regarded as inappropriate, has more recently been 
highly recommended (Henle, Ritter); likewise, for the con- 
nective-tissue part at least, the mixture (mentioned at p. 137-8) 
of chloride of platinum and chromic acid (Merkel), 
Thin vertical sections, from the fundus of the bulb may 
also be readily made with a sharp knife with such retinas. 
Such a vertical section, examined in the hardening fluid with 
the addition of a little glycerine (according to circumstances it 
may very suitably be previously tinged with glycerine-carmine), 
and cautiously covered with a very thin covering glass, shows 
at once the numerous layers of the retina which were conquered 
for science with such difficulty, and of which the adjacent 
sketch (fig. 378) may recall the necessary conception to mind. 
The various localities of the retina, if treated in the same man- 
ner, will present their primary structural peculiarities. 
Assisted by the advanced knowledge of the connective sub- ORGAN'S OF SENSE. 
591 
stances, one may at present recognize in any retina a consider- 
ably developed connective-tissue framework substance, the 
perception of which is, however, considerably impeded by the 
extraordinary fineness of the elements. The best investigation 
of this framework substance was made 
by M. Schultze. 
This is permeated by the nervous 
elements, among which are to be enu- 
merated the layer of optic nerve-fibres 
(fig. 378, 7) and of the ganglion-cells 
of the inner portion (6); then the 
cones (and rods) of the outer layer (1), 
and likewise a part of the elements of 
the granular layers (2, 4); as also, 
finally, a system of radially arranged 
finest nerve-fibres, which have only re- 
cently been distinguished from the 
connective-tissue supporting fibres. 
The verification on the fresh eye 
will be necessary even for what has 
thus far been described. The eye is 
to be opened under iodine-serum in 
a dish, and a portion of the retina re- 
moved. A fold having been carefully 
made, and a piece of thin glass placed 
near it, to protect it from the pressure 
of the covering glass, the various lay- 
ers may be more or less distinctly 
Pig. 378. Vertical transverse sec- 
tion of the human retina (made about 
half an inch from the point of entrance 
of the optic nerve). 1, Layer of rods 
and cones; 2, external granular layer; 
3, inter-granular layer; 4, internal 
granular layer; 5, fine granular layer; 
6, layer of ganglion-cells; 7, expan- 
sion of the optic nerve-fibres; 8, radial 
fibres; 9, their insertion into the in- 
ner limiting membrane, the membrana 
limitans interna, 10. 
recognized. Fine vertical sections are, nevertheless, more 
suitable. Do not believe that immense skill is necessary for 
their preparation. The piece of retina carefully separated 
from a fresh ox-eye, is to be placed on the microscopic glass 
slide, or on a cork plate, and a little vitreous fluid or iodine- 
serum added. The attempt is then to be made with a sharp 
moistened blade, such as that of a cataract-knife, or the convex 
one of a small scalpel, by careful pressure and a rocking motion, 
to obtain as fine as possible sections. Many of these attempts 
will fail, but a few objects will possess sufficient thinness to 
permit of a successful examination, if treated with the same 
precautions as a fold. 
For further studies such sections (in which it is true one is 592 
SECTION TWENTY-SECOND. 
not protected from a displacement of the elements, and which 
therefore require a comparison with other methods) may be 
further picked. It is also suitable to employ with them a 
weak chromic acid, or the dilute Muller’s fluid. 
A portion of the above-mentioned connective-tissue frame- 
work of the retina may be recognized even by the aid of the 
previous methods; though even a half-way sufficient view is 
never obtained. As Schultze has shown, other methods are 
necessary for this purpose, the same as have already been men- 
tioned at the organs of smell. 
Among these are to be enumerated chromic acid in a con- 
dition of extreme dilution (p. 128), the very watery sulphuric 
acid (p. 124), and the concentrated oxalic acid solution (p. 
129). 
To obtain a primary view of the connective-tissue framework 
structure of the retina, that investigator says that the eye of a 
fish is to be used, as the arrangement is easier to understand 
here than in the mammalial animal. The bulb of a river perch 
which has just been killed is to be divided through the equator 
and placed for three days in the familiar highly diluted chromic 
acid solution, which contains grain of the acid (or \-2 grs. 
of bichromate of potash) to the ounce of water. The exami- 
nation is then to be made, cautiously picking, and using the 
high magnifying powers of a Hartnack’s immersion system. 
While the connective-tissue framework substance is thus ren- 
dered recognizable by the chromic-acid solution, the latter has 
likewise the already mentioned excellent property of causing 
varicosities on the finer nerve-fibres, and of rendering it possi- 
ble to distinguish the two systems of fibres in the retina as in 
the regio olfactoria. 
The concentrated watery solution of oxalic acid is also an 
excellent medium for this examination and discrimination, as 
it renders the connective-tissue framework paler and hardens 
the nervous elements somewhat, and thus renders them more 
distinct. One is not confined to a definite time by this means, 
as the examination may be made after a few hours, or even 
after several days. 
Sulphuric acid of 0.6 per cent, preserves the nervous elements 
very well, but also at the same time those of the connective- 
tissue framework. 
The scientist mentioned afterwards found in osmic acid an ORGANS OF SENSE. 
593 
important accessory for the investigation of the textural condi- 
tions under consideration. We shall return to the same. 
By such methods the connective-tissue framework substance 
has presented the following 
arrangement (fig. 379, A). 
The entire retina is per- 
meated by it, with the ex- 
ception of the bacillar layer. 
A system of radial or Mul- 
lerian supporting fibres (e) 
forms, with its innumerable 
fine processes, a delicate net- 
work which in two places, 
namely, in the intergranu- 
lar layer {d) as well as the 
fine granular layer (g), as- 
sumes an extraordinary 
fineness and compactness, 
and here becomes changed 
to a regular spongy tissue, 
related to that of the gray 
substance of the brain. 
Inwards, these supporting 
fibres, uniting together and 
spreading out in a peculiar 
manner, form a hyaline con- 
nective-tissue boundary lay- 
er, the membrana limitans 
interna {!) which, after treat- 
ment with a 0.25-0.5 per 
cent, solution of nitrate of 
silver, presents an irregu- 
lar, black bordered mosaic 
(Schwalbe). Externally, 
over the so-called external 
granular layer, a second, 
similar boundary layer, but 
finer and perforated in a 
Pig. 379. Diagrammatic representation of the retina of 
man and the vertebrafca, after M. Schultze. A, connective- 
tissue framework of the retina, a, membrana limitans ex- 
terna ; e, radial or Mullerian supporting fibres, with their 
nuclei e'; I, limitans interna ; d,framework substance of the 
intergranular, and g, of the fine granular layer. B, ner- 
vous elements of the retina; 6, rods with outer and inner 
portions, as well as the rod-granule (b'); c, cone with the 
rod and granule (o'); d, expansion and apparent termi- 
nation of the cone-fibres in the intergranular layer, with 
the transition into finest fibrillse; /, granules of the inner- 
granular layer; g, confused mass of finest fibrillse in the 
fine granular layer; h, ganglion-cells; h\ their axis-cylin- 
der processes; i, layer of nerve-fibres. 
sieve-like manner, may be seen. This is the limitans ex 
terna {a). 
If the finer textural conditions of the nervous elements of 
38 594 
SECTION TWENTY-SECOND. 
the retina, as well as finally the connection of the same, are to 
be investigated, the methods which have until recently been 
employed in this difficult domain have already been mentioned 
in the preceding. 
Maceration may be accomplished with the various acids 
mentioned for the connective-tissue framework, among which 
the highly diluted solutions of chromic acid have been most 
employed. Corresponding solutions of the bichromate of 
potash, as well as Muller’s fluid diluted with water, are also 
to be recommended as suitable. A careful picking naturally 
follows. 
For hardening, to subsequently obtain very fine sections, 
the stronger solutions of chromic acid and its potash salt, as 
well as, above all, the Muller’s fluid, are employed. A very 
conservative tingeing with carmine will render many things 
more distinct, although its value proves to be less here than 
for many other organs. 
We scarcely need to remark that for such infinitely delicate 
textural conditions the strongest objectives must be used. 
The rods and cones usually keep well in weak solutions of 
chromic acid and chromate of potash ; the extremely dilute 
solutions mentioned by Schultze are unserviceable. The Mul- 
ler’s eye-fluid preserves them well. Schultze found the rods 
excellently preserved in the concentrated oxalic acid ; the 
above-mentioned sulphuric acid of 0.6 percent, is also useful 
for the rods. The recognition of the latter with the external 
and internal portions is relatively easy in the quite fresh eye, 
with the addition of humor aqueus and vitreous or iodine-se- 
rum, whereby we meet at the same time with a quantity of 
fragments and in part strangely disfigured specimens. A por- 
tion of fresh retina, with the external surface turned upwards 
and placed under the microscope without a covering glass, 
forms the best object for the recognition from above of the 
mosaic of the rods and cones. 
The external and internal portions of the rods, the former 
(fig. 379, B, b, figs. 380, and 381) of stronger refractive power, 
the latter delicately contoured and becoming reddened in the 
carmine solution (Braun), are to be discovered with tolerable 
facility ; likewise the very fine and perishable filament which 
arises from the pointed end of the inner member. Schultze 
succeeded years ago, with his familiar highly diluted chromic ORGANS OF SENSE. 
595 
acid solutions, in demonstrating varicosities on these, and 
thereby their nervous nature in contradistinction to the con- 
nective-tissue supporting fibres. 
The impossibility of following these finest rod-fibres through 
the entire thickness of the retina was known even at that time, 
as their course is maintained in a radial direction over limited 
portions only. 
Pig. SSO. Structure of the rods (Schultze). 
1. Those of the guinea-pig in a fresh condi- 
tion, with inner and outer portions to the left, 
in connection with a transversely striated 
granule. 2. Those of the Macacus cynomol- 
gus, macerated in iodine-serum, with Ritter’s 
filament. 
Pig. 381. Structure of the rods (Schultze). 1, from 
the chicken; 2, from the frog (in a fresh condition); 
3, from the salamander (likewise fresh) ; 4, from the 
pike (also fresh); 5, the division into plates of a rod 
from the frog treated with acetic acid : a, lenticular 
body. 
The recognition of the cones (fig. 379, B, c, fig. 382, fig. 383, 
2) as well as their rod-shaped terminal portions (cone-rods) also 
succeeds with the older methods, although the extraordinary 
changeability of the cone-rod renders the perception of its true 
structure very difficult. 
The external granular layer, occurring under the limitans 
externa, shows with tolerable facility the varicose rod-fibres, 
as well as the small spindle-shaped and transversely striated 
cells (rod-granule) embedded in it, with a nucleus and nucle- 
olus. One likewise perceives, joined to the inner extremity of 
the cone, the analogous (but not as in the rod-granule, fig. 380, 
1, transversely striated) structure, the cone-granule. Years 
ago H. Muller correctly recognized differences in these rod and 
cone-granules. A difference could be recognized between the 
broader fibres passing from the cones and the finer varicose 
rod-fibrillm, and they seemed to terminate in a strange manner 
with conical, widened, terminal portions at the margin of the 596 
SECTION TWENTY-SECOND. 
intergranular layer (Muller, Henle), so that, for a time, even 
Schultze had doubts of their nervous nature. Against this, 
however, the macula lutea, formed entirely of more slender 
Fig. 382. Cones, a, from man, with a decom- 
posed external portion and fibrillary appearing in- 
ner portion; b, from the Macacus cynomolgus, 
after maceration in dilute nitric acid, with the 
lenticular body (Schultze). 
Fig. 383. Fibrillated covering of the rods 
and cones, after Schultze. 1. Rods, 2, cones 
of man; a, outer: b, inner portion; c, rod- 
filament ; d, limitans externa, ti. Rods of 
the sheep. The fibrillas project beyond the 
inner portion ; the outer portion is wanting. 
cones, with their obliquely arranged cone-fibres, formed an im- 
portant objection. 
The inner granular layer (fig. 379, B,f) likewise shows 
without difficulty a small cell with a nucleus and nucleolus, 
analogous to that which appeared to us as the rod-granule in 
the external granular layer of the retina. From both poles of 
a number of these so-called granules arise very fine radial fila- 
ments, in which, however, no connection with the varicose 
fibres of the rods can be recognized. Years ago Muller and 
Schultze succeeded in distinguishing the oval nuclei of the 
framework of supporting fibres {A, e) from these granules. 
By the aid of the older methods one may recognize with ORGANS OF SENSE. 
597 
relative facility, especially in large animals, the 
layer of the multipolar ganglion-cells (B, 7i) and its varying 
thickness in the various portions of the retina. Neither does 
the flattened extension of the (as a rule non-medullated) retinal 
fibres (i) in the inner layer of nervous elements present any 
great difficulties, either as surface views or their vertical sec- 
tions. An exquisite object is afforded by the retina of the 
rabbit and the hare, where our nerve-tubes, streaming in by 
way of exception, as two rows of medullated fibres, may be 
everywhere readily noticed. 
We have here mentioned, with the most concise brevity, the 
chief results of earlier investigations. The great differences 
which the retina presents in the various groups of vertebrate 
animals also become more and more apparent (Muller). The 
gigantic rods of the frog, the peculiar twin-cones of the osseous 
fishes, the often delicately colored fat-globules at the base of 
the cone-rods in birds and squamigerous reptiles, must capti- 
vate the interest of the observer. We can at present say that 
rods and cones are widely diffused among the vertebrate 
animals, but are by no means everywhere present. Most mam- 
malial animals (ape, ox, horse, dog, etc.) have them similar to 
those of man. The eye of the bat, the hedgehog, the mole, 
the mouse, and the guinea-pig has, however, only rods and no 
cones. The latter structures are quite scanty and undeveloped 
in the retina of the rabbit and the cat. Birds have an excess 
of cones (only in owls these elements recede entirely and 
colored fat-globules are wanting). Only cones, and no rods, 
appear in the retinas of lizards and serpents. Rays and sharks, 
in contradistinction to the osseous fishes, are entirely without 
cones (Schultze). We cannot here enter further into the im- 
portant physiological consequences of these remarkable con- 
ditions. It suffices for us to have made mention of them for 
practical purposes, for the selection of materials for investi- 
gation. 
As was mentioned, a further excellent accessory for the ex- 
amination of the retina has become known through M. Schultze 
in osmic acid (p. 165), and this reagent has been employed in 
superior investigations with the greatest success.* 
* Chloride of gold and chloride of gold and potassium deserve a more accurate 
trial for the retina. 598 
SECTION TWENTY-SECOND. 
For its application a 2 or 1 per cent, solution should be 
kept on hand, so that it may be diluted at pleasure in a meas- 
uring glass. One may go down to 0.1 per cent., or even lower. 
Stronger solutions of 1-0.25 per cent, cause rapid hardening 
(without inducing coagulations), so that after an immersion of 
even half an hour portions of the retina may be divided, in the 
direction of their radial fibres, into lamellae, and the nervous 
elements may be recognized, while the connective-tissue sup- 
porting apparatus is rendered but slightly prominent. Such 
preparations may be left for a day in the solution, and, washed 
out in water (which also serves as a medium for osmium pre- 
parations), they may be preserved for days for further examina- 
tion likewise in alcohol and acetate of potash. 
The blackening, which appears very rapidly, is more regu- 
lar at the commencement. Later, the nerve-fibres frequently 
become colored, the fine granular and intergranular layers 
more intensely than the other portions. The outer portion of 
the rod appears, as a rule, darker and sharply contrasted from 
the inner portion, quite especially and very remarkably so in 
the frog and in fishes. 
Weaker degrees of concentration of the osmic acid of 0.2 
per cent, and less, no longer cause hardening alone, but also 
exert, at the same time, a macerating effect. The preparation is 
now less brittle and permits of picking with needles. It is gen- 
erally sufficient to allow the action to continue for a half or a 
whole day. The nerve-fibres may assume varicosities in these 
watery solutions. 
The connective-tissue framework becomes hardened later 
than the nervous elements. 
To thoroughly preserve the rods and cones, take a vitally 
warm eye, remove the posterior segment of the sclerotic to be- 
yond the equator, and immerse in a solution which contains 
about two per cent, of the dry acid. The desired effect is ob- 
tained in a few hours. The fluid media and preservative fluids 
have already been mentioned. 
Schultze arrived at important results for the external por- 
tion of the retina. The rod-fibres arrive, as far as the inter- 
granular layer (fig. 379, B), to here ; with slight intumescences, 
withdraw from observation. The broader cone-fibres are quite 
similar to an axis-cylinder, permit of the recognition of delicate 
longitudinal striations (perhaps as an indication of a further ORGANS OF SENSE. 
composition), and form at the same locality the already men- 
tioned conical expansion (d). From the base of the latter 
arises a new system of extremely fine Abridge, which, with nu- 
merous divarications, assume another, and, indeed, horizontal 
course. Varicosities speak for the nervous nature of the latter 
fibrillse. 
The connection of the nervous elements in the inner layers 
of the retina still remains quite obscure. Whether the radial 
fibres of the inner granular layer (/), which are united to a 
granule, are connected with the confused mass of finest fibril- 
Ise which arise from the resolution of the cone-fibres, we are not 
yet able to say. 
The similar mass of fibres, perhaps arising from the radial 
fibres of the inner granular layer, also passes through the fine 
granular layer (g), to finally pass over into the fine or so-called 
protoplasma processes of the ganglion-cells {h) (comp. p. 351, 
fig. 198). Should this conjecture of Schultze’s prove to be 
true (whereby a parallel with the texture of the gray sub- 
stance of the central organ results), and should the system 
of processes of a cone-fibre hereby enter into different gan- 
glion-cells, complication of the nervous channels would indeed 
result which could not be mastered by our present acces- 
sories. 
Probably an inwardly directed broad process of the gan- 
glion-cells of the retina corresponds to the so-called axis-cylin- 
der process of the central cell, and simply assumes the form of 
a primitive fibre of the nervous layer (7i). 
It would lead us far beyond the narrow limits of this book, 
and the requirements of our circle of readers, were we to here 
make more complete mention of the most recent acquisitions 
in this domain. Thus a problematical axis-filament has been 
ascribed to the rods (fig. 380, 2) which is certainly wanting in 
the outer portion (Schultze). At the inner portion of the rod, 
where it joins the outer portion, a singular lenticular body of 
semispherical or piano-parabolic form has been met with (fig. 
381, a). Something of the kind also appears to occur in the 
cones (fig. 382, b). For the (certainly transitory) preservation 
of these structures the solution of the bichromate of potash 
may be tried. 
Of interest is furthermore a disk-like structure of the rods 
(fig. 381, 5), which was incompletely seen many years ago, 600 
SECTION TWENTY-SECOND. 
but which has been recently more accurately recognized and 
studied. On the fresh rod it is seldom that anything of it can 
be seen, only examinations with oblique light and a rotary 
stage show us a trace of the same, if one of the strongest im- 
mersion systems can be used. It becomes distinct only when 
distending reagents are resorted to, as, for example, dilute 
serum to which a little acetic acid may be added, dilute nitric 
acid, etc. Osmic acid (1-2 per cent.) also affords good prepa- 
rations and, with careful picking in water, presents transverse 
sections of these plates. The same foliaceous disintegration 
also occurs on the outer portions of the cone-rods (figs. 382, 
388, 2, a). 
Finally, M. Schultze (we have thus far quoted from his 
works) found an infinitely delicate longitudinal fibrillary struc- 
ture covering the rods and cones externally throughout their 
entire length (fig. 383). One may think of the primitive fibril- 
Ise of the axis-cylinders and ascribe the latter signification to 
the rod- and cone-fibres. Still the connective-tissue nature of 
this external striation is undoubted. It belongs to a very deli- 
cate envelope which is connected with the limitans externa. 
More recently the indefatigable investigator, now deceased, 
discovered in the interior of the inner members of the cones and 
rods a very fine filamentous apparatus. The latter is possibly 
of a nervous nature, and corresponds to the primitive fibrillse 
of the axis-cylinder formerly looked for on the outer sur- 
face. 
For this purpose, also, osmic acid constitutes the best ac- 
cessory. 
The macula lutea and fovea centralis require no new methods. 
Their structure must be ascertained from the text-books on 
histology. 
The usual hardening treatment with chromic acid and chro- 
mate of potash (and alcohol) also serves to show the relation of 
the blood-vessels to the retinal layers, and their advancement 
to near the intergranular layer; while the delicate vascular 
net-work in its extension (fig. 384) (for the demonstration of 
which we recommend the injection of the eye of the ox and the 
sheep) requires surface views. 
With regard to the pathological changes of the retina, we 
are at present acquainted with hypertrophies of the connective- 
tissue parts, with a corresponding degeneration of the nervous ORGANS OF SENSE. 
601 
elements, proliferations of the granular layers, amyloid bodies, 
fatty degeneration of the nervous (but also of the connective- 
tissue) parts, embolia of the retinal vessels, likewise pigmenta- 
tions coming partly from the extravasated blood, partly caused 
by the proliferated choroidal epithelium which has penetrated 
the retina, and which latter hereby frequently lies near the 
retinal blood-vessels, etc. Tumors of the retina are, as a rule, 
either sarcomata or glioma 
(p. 360), and only very rarely 
carcinomata. 
Preparations from more 
hardened retinas (after the 
use of Muller’s fluid) may be 
readily preserved in glycer- 
ine in the form of review 
specimens; for many views 
we would recommend tinge- 
ing them with carmine. The 
finest textural relations of the 
several layers and their ele- 
ments could not, on the con- 
trary, from the condition of 
the microscopical technique, 
be preserved for a long time. 
Attempts to mount them in 
their macerating fluids rapidly 
came to an end, as a rule, in 
Fig. 384. Vessels of the human retina, a, arterial; 
c, venous branches; 6, the capillary net-work. 
the destruction of the preparation. M. Schultze subsequently 
gladdened us with the important information that osmium 
preparations may be preserved for years in a solution of the 
acetate of potash (p. 217). This succeeds occasionally. 
Foetal eyes maybe studied on very small embryos immersed 
fresh in chromic acid. With older foetuses the eye is to be 
taken out and further treated in accordance with the directions 
given for the adult. The eyes of new-born kittens are to be 
recommended for injecting the magnificent vascular net-work 
of the membrana capsulo-pupillaris. 
5. With regard to the organs of hearing, the external parts 
of the same, such as the auricle and the external auditory canal, 
require no special directions. 
The ceruminous glands, with their coil-shaped bodies and 602 
SECTION TWENTY-SECOND. 
short excretory ducts, are to be examined in the same manner 
as the related sudoriparous glands. 
The membrana tympani is to be studied either in the fresh 
condition, with the aid of the knife and needles, and with the 
use of acetic acid as well as the alkaline solutions, or the pre- 
viously dried organ is employed for fine sections, whereby we 
would also urgently recommend the usual tingeing methods. 
Total views are obtained with resinous mounting media. 
The epithelium and the lymphatics are rendered distinct by 
nitrate of silver ; for the demonstration of the nerves use chlo- 
ride of gold (Kessel). 
The walls of the cavity of the tympanum and Eustachian 
tube, with the covering of ciliated cells, the ossicula auditus, 
with their porous bone substance and their transversely striated 
muscles, are to be examined by the methods customary for the 
tissues in question. 
The investigation of the labyrinth is far more difficult. 
Even the opening by means of saw and chisel must be accom- 
plished with caution ; and from the delicacy of many structural 
conditions, only quite fresh, just previously killed animals are 
to be used. For the primary examination the labyrinths of 
larger mammalial animals, such as the calf and ox, are to be 
selected. If a certain practice in such procedures has once 
been acquired, the exposure also succeeds later with smaller 
creatures—the dog, the cat, and the rabbit. The great alter- 
ability of the elements also renders it necessary, as with the 
retina, to use fluid media which are as indifferent as possible ; 
among these we would recommend blood- and iodine-serum, 
vitreous fluid, and dilute albumen. Dilute solutions of chromic 
acid may also be suitably applied to the fresh tissue. 
The decalcification of the bones with chromic acid, in order 
to make transverse sections, seems to be of the greatest impor- 
tance for the first views. For further studies we would also 
advise hardening and especially the immersion in solutions of 
chromic acid, bichromate of potash, and Muller’s fluid. The 
latter fluid, diluted with an equal volume of water, may be 
very highly recommended. 
The aggregations of ear-stones or otoliths (as the polariz- 
ing microscope teaches, columns crystallized in the arragonite 
form) may be perceived in the sacculi of the vestibule as white 
spots, surrounded by an especial thin membrane. They are 603 
ORGAN'S OF SENSE. 
generally small and, according to many statements, possess an 
organic basis. Their appearance may be represented by fig. 385. 
With regard to the distribution of the acoustic nerve on 
both saccnli of the vestibule, and 
on the membranous ampullae of 
the semicircular canals, the coars- 
er arrangement is not difficult to 
recognize. The nerve-fibres enter 
duplicatures of the walls, which 
are, especially in the ampullae, dis- 
tinctly recognized as prominences 
projecting into their cavity. This 
projection, called the septum ner- 
veum, contains the termination. 
An earlier epoch, without having 
Fig. 385. Otoliths. 
any presentiment of the difficulties of such investigations, 
would here convince itself of the presence of terminal loops. 
That conditions also occur here which are quite similar to 
those we have mentioned in connection with other organs of 
sense; that there are auditory cells as well as olfactory and 
gustatory cells, was first demonstrated 
by Reich and M. Schultze ; the former 
by the investigation of the lamprey, 
the latter by that of the ray and shark. 
Our fig. 386 may bring such conditions 
of the plagiostomy before the reader, 
and show the characteristic cells, c, 
with their rod-shaped projection, d, 
and their lower fine terminal filament, 
e. The latter is undoubtedly the ter- 
minal nerve-fibrilla, although even here 
a continuous connection could be rec- 
ognized by M. Schultze with as little 
certainty as in the olfactory organ. 
Strange long hairs also occur on the 
peculiar epithelium of this locality. 
Pig. 385. From the crista acustica oi 
the ampullae of Baja clavata. a, cylin- 
der cells; 6, basal cells; c, fibre cells, 
■with the upper rod-shaped processes d. 
and lower fine fibrillary ones e ; f, 
nerve-fibres, becoming at g pale rami- 
fying axis-cylinders. 
Here also chromic acid, with those 
dilute solutions which we have had to 
mention so frequently for the higher organs of sense, plays at the 
present time the role of the most important accessory. Osmic acid 
and chloride of gold will be tried by some subsequent observer. 604 
SECTION TWENTY-SECOND. 
According to the few observations which have at present 
been published, similar textural conditions appear to occur in 
the vestibulum of the mammalia! animal (ox). Although all 
of our knowledge of these subtile arrangements is still in em- 
bryo, a penetration of the nerve fibrillse into a peculiar epithe- 
lium and the existence of specific cells is nevertheless quite 
certain. 
Infinitely more difficult, and leading into a true chaos of 
the most intricate structural conditions, is the termination of 
the nervus cochlearis in the Reissnerian cochlear canal, or the 
so-called scala media. Since Corti undertook the first success- 
ful excursion into this domain full of w-onders, our knowledge 
has been enriched by each of the subsequent investigations by 
the discovery of new fragments. Within a period not long 
elapsed, Deiters especially has rendered the greatest service in 
connection with the structure of the cochlea ; and Kolliker, by 
the discovery and closer investigation of the almost forgotten 
Reissnerian cochlear canal, has established a new acceptation 
of the scala media. Among the numerous successors, we men- 
tion only the names of Hensen, Botcher, Waldeyer, and Gfott- 
stein. 
It would lead us far beyond the limits of this work were we 
to mention here the structural conditions which have thus far 
been investigated, especially the structure of the so-called 
Cortian organs (fig. 887). Notwithstanding all previous efforts, 
the knowledge of the nerve terminations is not as far advanced 
as in the other organs of sense. Probably, however, the ter- 
minal nervous structures of the nervus cochlearis (/) are pres- 
ent in certain ciliated cells {i and p, q, r). 
The exposure of the parts in question may be accomplished 
and learned on the quite fresh auditory apparatus of one of 
our larger cattle (the ox). After some practice this may also 
be gradually achieved with smaller creatures. Fragments 
which are obtained in this manner from the scala media are to 
be examined by means of indifferent media or strongly diluted 
chromic acid. The latter, or chromate of potash, also serves 
for the immersion and hardening of the opened cochlea. For 
many cellular conditions of the Cortian organs, high degrees 
of dilution, similar to those introduced into histology by 
Schultze, are to be tried ; and certainly also osmic acid, chlo- 
ride of gold, and chloride of gold and potassium. To obtain OEGANS OF SENSE. 
605 
transverse sections of the entire Reissnerian cochlear canal, the 
organ, previously hardened by means of chromic acid or Mul- 
ler’s fluid, is to be cautiously decalcified by adding a few drops 
Pis. 387. The Corti’s organ of the dog in perpendicular section ; a, b, homogeneous stratum of the mem- 
brana basilaris: u, vesicular stratum ; v, tympanic stratum with nuclei and protoplasma; a, labium tym- 
panicum of thecrysta spiralis; al, continuation of the tympanic periosteum of the lamina spiralis ossea :c, 
thickened commencing portion of the membrana basilaris, together with the place of section ; /i, of the 
nerve d, and e, blood-vessels ; f, the nerve ; ff, epithelium of the sulcus spiralis externus ; i, inner hair-cell 
with the basal process, *, surrounded by nuclei and protoplasma (of the “granule stratum”), into which 
the nerves radiate; n, base or foot of the inner pillar of the Corti’s organ; m, its “ head piece,” connected 
with the same part of the outer pillar, the lower part of which is wanting, while the next following pillar, 
o. pi’esents the middle part of the base; p, q, r, the three outer hair-cells; s, a so-called supporting cell of 
Hensen; I, lamina reticularis ; w, nerve-fibre terminating at the first of the outer hair-cells. 
of muriatic acid to these fluids and frequently changing the 
entire mixture. The lamina spiralis of the larger animals may 
be isolated and exposed to such a procedure. The nerve dis- 
tribution in the zona ossea may likewise be brought to view in 
this manner. Several years ago Hensen, to obtain the mem- 
brane of Corti in its position, made use of a three months’ 
immersion in Midler’s fluid, and injected tolerably concen- 
trated gelatine through a puncture in the tympanum secunda- 
rium, which then transuded into the cochlear canal. The ex- 
ternal wall of the cochlea was afterwards‘broken open, and 
the scala media with the gelatine cast isolated. Hensen also 
found carmine imbibition appropriate here. 
Waldeyer, one of the most excellent investigators in this 
difficult domain, recommends, besides the review of fresh ob- 
jects in humor aqueus, the osmic acid, to which he ascribes the 
same importance as for the retina of the eye. Degrees of con- 
centration of 0.1-1 per cent, are to be used ; the former for 
picking, the latter for hardening. A solution of chloride of 
sodium of 0.25-0.5 per cent, rendered him excellent service for 606 
SECTION TWENTY-SECOND. 
the former preparations. Chromic acid of 0.05 per cent, chlo- 
ride of gold, according to Cohnheim’s directions, and a 1 per 
cent, solution of nitrate of silver, are likewise useful for many 
purposes. 
To obtain good section preparations, remove as much bone 
as possible from large cochlese, and make two or three small 
openings into the capsule. Smaller organs, on the contrary, 
are to be left intact. The cochlese are then to be placed for a 
day in a liberal quantity of a solution of chloride of palladium 
(0.001 per cent.), or in one of osmic acid of 0.2 per cent, if the 
organs are small; while more voluminous ones require an 
increased concentration of 0.5-1 per cent. Such objects are 
then to be exposed to the action of absolute alcohol for twenty- 
four hours, and at once placed in the decalcifying fluid. 
Waldeyer found chloride of palladium (0,001 per cent.) 
with -jJ-jj- part muriatic acid, or chromic acid of 0.25-1 per cent, 
most serviceable for the latter purpose. After the decalcification, 
the preparations are to be washed out with absolute alcohol; 
it may then (for the subsequent preparation of sections) be 
embedded in a piece of fresh spinal cord or fresh liver, and the 
whole then replaced in the absolute alcohol. During the 
hardening the enveloping piece of organ shrinks so firmly 
around the cochlea that the latter remains immovable and 
permits the desired sections to be made. 
Before this embedding the cavity of the cochlea may be 
filled with gelatine glycerine (1:1), or (not so good) with a 
mixture of wax and oil. This filling, however, is not absolutely 
necessary. 
The primary views of the cochlear canal may be obtained 
without great difficulty from embryos, treated in a similar 
manner, by means of suitable transverse sections through the 
petrous bone. 
For cabinet preparations the same remarks apply which we 
have made (p. 601) concerning the retina. Preparations of the 
Cortian organ, however, I have preserved for years entirely 
unaltered in watery glycerine. Hensen recommends the 
watery solution of arsenious acid for mounting. Acetate of 
potash should also be tried. INDEX. INDEX 
Abbe’s theory of the microscope, 13, note; on curva- 
lure phenomena of the light, and microscopic de- 
ceptive images, 62, note 
Abdominal typhus, changes of the lymphatic glands 
in, 407 ; of their lymphatics, 407 ; of the Peyerian 
follicles, 452; of fiscal masses in, 455 ; changes of 
the spleen in, 483 
Aberration, chromatic, of the lenses, 9; chromatic, 
of the microscope, 55 ; spherical, of the lenses, 8; 
spherical, of the microscope, 54 
Abscess, 252 
Accessory apparatus for microscopic drawing, 38 
Accommodative power of the eye, 2 
Acetate of potash, 135, 217 
Acetic acid and alcohol mixture, 139 
Acetic acid, concentrated, 130 ; Moleschott’s diluted, 
180; Kolliker’s very dilute, 130; Prey’s, 130; 
swelling action on certain tissue elements, 131; 
for washing objects tinged with carmine, 149; i 
with glycerine, 149, 216 
Acetic acid, glacial, index of refraction of, 118 
Acetic acid hydrate, 129 
Achorion Sohcenleinii, 560 
Achromatic double lenses, 9; lens, 9 
Adenoid tissue, see Beticular Connective Substance ; j 
sarcoma of the mammary glands, 544 
Adjustment of focus, apparatus for, 20, 21 
Aeby employs concentrated muriatic acid for isolat- j 
ing muscles, 125, 324; finds the capillaries to con- i 
sist of cells, 382 j 
Aerial image of the compound microscope, 8; of the j 
improved, 13 
Air-bubbles, removal of, from Canada balsam, 209; ; 
occurrence of, in saliva, 429; in lung preparations, j 
486; in sputum, 494 
Aloannine solution, 582 _ ! 
t Ammonia liquor. 134 
Ammonia, molybdate of, 137 ; for the central organ 
of the nervous system, by Henle and Merkel, 357 ; 
for salivary glands, by Krause, 426 
Ammonio-phosphate of magnesia crystals in the 
fasces, 455 ; in the urine, 528 
Amyloid bodies, 361; degeneration, see various or- 
gans ; reactions, 124,132, 155, 474 
Amylon, see Starch 
Anacardium nuts, 582 
Analyzer, 49; over the ocular, 49; in the ocular, by 
Hartnack, 49 
Andrejevio on biliary capillaries, 465 
Aneurisms, 394 
Angle of vision determines the apparent size of an 
object, 1 
Anilin blue as a tingeing medium, 156 ; for gastric 
glands, 433 
; Anilin-iodine-violet, 155 
i Anilin red as a tingeing medium, 154; for the recog- 
j nition of the axis cylinder, 337 
I Anis oil, index of refraction of, 118 
j Anthracosis of the lungs, 491; of the lymphatic 
glands, 407 
j Aperture, angle of, of the lenses, 7; of objectives, 
| 14, importance and size of, 57; available portion 
j of, 59 ;of Hartnack’s systems, 60 ; other excellent 
■ modern objectives, 60 
i Aplanatic double lens, 10; eye-piece, 15; objec- 
tives, 14 
i Apolar ganglion cells, see Nervous System 
; Apophysis cerebri, 379 
Apparatus for drawing, 37, 38 
j Apparatus for injecting by constant pressure, 192- 
4; with a column of fluid, 192; with mercury 
193-4 
Alkalies, 133; their action on the epidermis, 267; | 
on the tissue of the nails. 269 ; dilute, their action 
on the ciliary motion, 264; on the movement of 
the spermatozoa, 552 
Alcohol, action of, 188; a constituent of other mix- 
tures, 189 
Alcohol mixtures, 139; with acetic acid (Clarke’s), 
139; Moleschott’s acetic acid mixture, strong, 139; 
Apparatus for measuring, 32; angles (goniometer), 
36 
Apparatus for micro-photography, Gerlach’s, 41; 
Moitessier’s, 42 
Appreciation of microscopic images, 94; of their 
conditions of relief, 95 
Arcus senilis, 583 
Argand lamp, 86 
weak, 140 ; with acetic and nitric acid, 140 ; with 
soda, 140 
Alum with corrosive sublimate and chloride of sodi- 
Arnold’s studies on smooth muscles, 317; their nerves, 
867 ; the new formation of vessels, 392; Arnold 
and Thoma on the bluing of the cement ledges of 
the epithelium, 259 
Arrangement and use of the Gerlach’s photographic 
apparatus, 41 : of Moitessier’s, 42 
Arsenious acid in watery solution, 220 ; with glyce- 
rine, by Fan-ants, 216 
Arteries, see Vessels 
Arteriolas recta- (kidneys), 516 
Ascaris lumbricoides (ova in fseces), 457 
Asphalt cement, 227; Bourgogne’s, 227 : making a 
border with, 227 
Atheroma of the skin, 558 
Atheromatous processes, 893 
Alveolar cancer, 289 
Alveolar epithelium of the lungs, 489 
Alveoli of the lungs, 488 
Amici shows the influence of the covering glass, 16 ; 
microscope of, 72; microscopical improvements of, 
11; on the muscular filaments of the house-fly, 
828-9; his prisms, 51 
Ammonia, bichromate of, 137; for the central or- 
gan of the nervous system, by Gerlach, 351; sim- 
ple chromate of, 137 ; for the gland-cells of the 
kidney, by Heidenhain, 511 
um, 217-8 610 
INDEX 
Atrophy, see the organs; acute yellow of the liver, ] 
471 
Auditory apparatus, 601; ceruminous glands, 601; i 
membraua tympani, cavity of the tympanum, i 
602; otoliths, 602; sacculi of the vestibula of 
fishes, 603 ; vestibulum of mammalial animals, | 
604 ; cochlea, 604 ; difficulty of the examination, [ 
604; cochlear canal, 604 ; Hensen and Waldeyer’s 
methods, 604 
Auditory cells, 604 
Auditory ossicles, 602 
Auerbach’s studies of the cell nucleus, 130 ; plexus 
myentericus, 846; finds the capillaries to consist 
of cells, 382 
Axis cylinder of the nerve-fibres, 336 
Axis flbrill® of the axis cylinders of the nerve-fibres, 
339, 600 
enumeration of both kinds of cells, 235; pathologi- 
cal changes, 236; leucaemia and melanaemia, 
236; embryonic blood, 237; formation from lym- 
phoid cells of the frog, according to Recklinghau- 
sen, 287; change of the colored blood corpuscles 
by heat, 238; reagents, 238; cabinet prepara- 
tions, 240; blood crystals, 241 ; haemoglobine, 
241; htemin and hasmatoidine, 241 ; examina- 
tion of the circulation, 245 : Schulze’s slide for 
frog and salamander larvae, 246; behavior of the 
blood-cells of the living mammalial animal, accord- 
ing to Rollett, 247; Cohnheim’s directions, 247 ; 
Strieker and Sanderson’s, 247; emigration, ac- 
cording to Waller and Cohnheim, 249; blood in 
vomit, 486 ; in sputum, 494; in urine, 523 
Blood cells, see Blood 
Blood corpuscles, see Blood 
Blood crystals, see Blood 
Blood lymph glands (spleen), 479 
Blood-vessels, 381; capillaries, 381; composed of 
cells, 382; adventitia, 383; objects and methods 
for examination, 383 ; value of artificial injections, 
383; natural injection, 384; “stigmata” and 
“ stomata,” 884; larger vessels, arteries, and veins, 
885; their examination, 386; drying and embed- 
ding, 386; pulling off the several layers, 387 ; new 
tingeing methods, 357; capillary net-work, 388; 
treatment of the injected capillary district, 388 ; 
straight and circular net-work, 389; loops, 390; 
first appearance in the embryo, 390 ; method of in- 
vestigation, 391; examination of the tail of the 
frog’s larva, according to Arnold, 392; further 
transformation of the foetal vessels, 392; patholo- 
gical conditions of the blood-vessels, 393; athero- 
matous processes, 393; aneurisms, 394; changes 
in the veins, 394; changes in smaller vessels, 395; 
smaller arteries of the cerebral substance, 395; 
calcareous, fatty, and pigment degenerations, 395- 
6; melanasmia, 896; emboli, 396; pathological 
new formation of vessels, 396 ; signification of the 
vascular cells in pathological transformations, ac- 
cording to Thiersch, Waldeyer, and Bnbnoff, 396 ; 
Arnold’s studies, 397; methods of examination, 
398 ; observations of Thiersch in healing wounds, 
398 
B. 
Bacteria, 263 ; their nature, 254; fine granular basis 
(zooglia of Cohn, micrococcus of Hallier, microspo- 
ron of Klebs), 254; bearer of putrefaction, 254; 
occurrence in diseases, 254 
Bailey recommends Hyaloidiscus subtilis as a test 
object, 63 ; Grammatophora subtilissima, 66 
Baryta, sulphate of, as an injection mass, 179, 188; 
directions for preparing, 179 
Baryta water, 134 
Bastian recommends carbolic acid and glycerine as 
a preservative fluid, 216 
Beale, works on the microscope, xi., xii.; treatise on ! 
micro-photography, 40 ; B. and Clarke’s alcohol 1 
mixtures, 139; mixture of alcohol, acetic acid, and j 
nitric acid, 140 ; alcohol and soda, 140 ; for calci- i 
fied cartilage, 292; on carmine tingeing, 151; j 
cold flowing injection mixtures, 186-7; with Prus- | 
sian blue, 187 ; with carmine, 188; mounting fluid, 
216 ; directions for preparing glass cells, 223; | 
on ganglion cells, 344 ; directions for hardening | 
livers, 462 
Becherzellen, 438 
Bell glass, for covering the microscope, 91; for cov- 
ering specimens, 93 
Benecke on micro-photography, 40 
Benzine, 142 
Berre’s injections, 173 
Bichromate of potash, 136 ; (see Chromate of Pot- 
ash) 
Bidder on the connective-tissue framework sub- 
Blood-vessels, injection of, 172, 190 ; of pathological 
objects, 199; with the syringe, 196 ; with constant 
pressure, 192; self-injection of the living animal, 
190 
Blood-vomiting, 436 
Boiling animal tissues (the smooth muscles), 317; 
in vinegar, 131 
Bone cartilage, see Bones 
Bone corpuscles, see Bones 
Bones, 296 ; preparatory treatment, 296; decalcifica- 
tion, 296 ; isolation of the cells with strong acids, 
297 ; recognition of the cells by tingeing with car- 
mine, haematoxylme and gold impregnation, 298 ; 
Sharpey’s fibres, 303 ; preparation of sections, 299; 
texture of bone, 299; lamellae, 299; bone-spaces 
and cells, 299; medullary canals, 299 ; mounting 
the sections, 300; injection of the blood-vessels, 
301; injection of the bone-spaces and canaliculi ac- 
cording to Gerlach, 301; behavior in polarized 
light, 301; fibrous nature of the basis substance 
according to von Ebner, 302; origin of bone, 305; 
endochondral bone, 305 ; absorption of the carti- 
lage, 805; ossification points, 305; cartilage me- 
dulla, 306 ; fate of the cartilage medulla cells, 307; 
Gegenbaur’s osteoblasts, 308; new formation of 
bone substance, 309 ; osteogenous and osteoid tis- 
sue, 310 ; absorption of the bone substance, 310 ; 
growth of bones, 310 ; development from a connec- 
tive tissue basis, 811; periosteal bone, 310 ; exami- 
nation of bone medulla, 311; origin of blood-cells 
according to Neumann and Bizzozero, 311; bones 
in rachitis, 311; method of examining foetal bones, 
310 ; new formation of bone substance under abnor- 
mal conditions, 312; callus, 313 ; regeneration of 
lost portions, 313; hyperostosis, 313; exostosis, 313; 
sclerosis, 314 ; osteo-sarcoma, 314 ; origin of bone 
substance in connective tissue parts, 314 ; absorp- 
tion processes, 314; Haversian spaces, 314; How- 
stance of the central organs of the nervous sys- 
tem, 359 
Bile, 468 ; coloring matter of, red, bilirubin, 469; 
relation to, and difference from hmmatoidin, 469 
Biliary passages, finest, 464; capillaries, injection of, 
by Budge, Andrejevic, MacG-illavry, Prey, Be- 
ring and Eberth, 465; procedure and selection of 
objects, 465;,fi11ed by pathological concretions, 
469; sediments, 469 
Bilifulvin, 469 
Biliphaein, 469 
Bilirubin of Staedeler, 469 
Billroth recommends chloride of iron, 137; describes 
the reticulum of the spleen pulp, 480; shows the 
connection of the muscular filaments of the tongue 
with connective-tissue corpuscles, 424 ; on the ex- 
amination of the kidneys, 507; on the typhoid 
spleen, 483 
Binocular microscopes, 46 ; of Nachet, 47; stereo- 
scopic, 47; arrangement of Wenham, Riddell, Ross, 
and Crouch, 47-8 
Binocular stereoscopic eye-piece of Hartnack, 48; of 
Tolies, 80 
Bipolar ganglion cells, see Nervous System 
Bizzozero, on the formation of colored blood corpus- 
cles from the lymphoid cells of the bone marrow, 
311 
Bladder, urinary, 522; epithelium of, 522; changes 
in catarrh, 523 
Blood, 233; to obtain, 233; colored cells of, 233; 
colorless cells of, 234; their vital changes of form, 
234; locomotion and reception of granules, 235 ; INDEX 
611 
ship’s lacunas, 314; Kiilliker’s osteoclasts, 314; os- 
teoporosis, 314 ; osteomalacia, 314 ; caries, 315 ; 
process of deoalcification, 315; method of examin- 
ing decalcified bones, 315 
Bone tissue, see Bones 
Bothriocephalus latus, ova in faeces, 457 
Bourgogne’s microscopic preparations, 232; Bruns- 
wick black, 227 
Bowman’s directions for making chrome yellow, 
176 ; theory of the muscles, 328 ; work on the kid- 
ney, 503 ; capsule of the glomerulus of the kidney. 
503; glands of the regio olfactoria in the higher 
animals, 568 
Brain, 348; membranes of, 378; sand, 379 
Bright’s disease of the kidneys, 520 
Bronchi, 485 
Bronchial glands, see Lymph Glands 
Brooke’s revolving nose-piece, 89 
Briicke defines the optical condition of the muscular 
filament, 331; his soluble Prussian blue, 183 
Brunner’s gland, 239 
Brunonian molecular motion, 97; in cells, 97; of 
small crystals, 97; their rapidity, 97 ; in salivary 
corpuscles, 429 
Brushing method of His, 115 
Brushing out microscopic preparations, 115 
' the moist chamber and the warm stage, 99-101; 
i locomotion of, 98; of pus-cells through the spaces 
| of the cornea, 252 
j Cells for microscopic preparations, 222-3 
1 Cements, 227; asphalt. 227; Bourgogne’s, 227; gold 
j size, 228; masklac, 229 
j Cementum, see Teeth 
[ Central light for illumination, 222; for examining 
; test objects (Nobert’s plates), 68 
| Central organ of the nervous system, see Nervous 
| System 
i Central rays, refraction of, 8 
| Cercomonas intestinalis of Lambl, 456 
: Ceruminous glands of the ear, 601 
| Chamber, moist, of Eecklinghausen, 99; combined 
with the warm stage, 100 ; ordinary moist cham- 
ber, 99; gas, of Strieker, 100 
Charriere’s injection-syringe, 196 
Chevalier and Selligue produce achromatic objec- 
tives, 11; construct camera lucida, 38; micro- 
scopes, 25, 77 
Chinolin blue (cyanin), 158 
Chloral hydrate, 141 
Chlorate of potash, 135 
Chloride of calcium, 135; constituent of preservative 
fluids, 219 
Budge (and TJechtritz) recommend chlorate of pot- 
ash and nitric acid for the axis cylinder, 337; on 
the finest biliary passages, 465 
Burette, 142; for examining urinary sediments, 530 
Chloride of palladium, recommended by Schulze, 137, 
168 
Chloride of platinum, used by Merkel, 137 
Chloride of silver, Teichmann’s, ISO 
Chloride of sodium, 134; in impregnations with sil- 
ver, 135, 164; with alum and sublimate, 217; a 
constituent of preservative fluids, 217-19; in ten 
per cent, solution for smooth muscles, 319; for the 
cornea, 579 
Chloride of sodium crystals from the urine, 527 
Chloroform, 141; for recognizing the axis-cylinder, 
337 
Calcification, see Cartilage 
Callus, 313 
Camera lucida of Chevalier and Oberhauser, 38; ob- 
scura, eye compared to a, 1 
Canada balsam, its index of refraction, 118; for 
mounting cabinet preparations, 208; varieties, 
208, cold-flowing, 210; dissolved in chloroform 
and ether, 141, 211; removal of the excess from 
the slide, 210; removal of the air bubbles, 210; 
artificially hardened for mounting bones, 211 
Cancerous tumors, 289 
Cancroid, see Epithelial Cancer 
Caoutchouc, 225; cement, 225; ceils, 223 
Capillaries, see Blood-vessels; their composition of 
cells according to Hoyer, Auerbach, Eberth, and 
Aeby, 381 
Carbolic acid, 142; with glycerine according to Bas- 
tian, 216 
Carbonate of lead, 179 
Carcinoma, 289 
Caries, 315 
Carmine, 147; solution in ammonia, 148, 183, 188; 
injection mass of Gerlach, 183-4; of Beale, 151; of 
Kollmann, 189, note; with glycerine, 149; for self- 
injection, 190 
Carmine tingeing, invented by Gerlach, 147; wash- 
ing in acetic acid, 149; Beale’s, 151; Heidenhain’s, 
152 ; Thiersch’s with oxalic acid, 150; with borax, 
151; acid carmine fluid, 152 
Carpenter’s work on the microscope, xi, xii 
Cartilage, 290 ; various forms, 291; hyaline, fibrous, 
or reticular and connective-tissue cartilage, 291; 
method of examining the hyaline cartilage, 291; 
costal cartilage, 291; large primary and secon- 
dary cells, 292; decalcified cartilage, 292; exami- 
nation of reticular cartilage, 293 ; behavior of car- 
tilage in polarized light, 293 ; cartilage capsules, 
295; destruction of the intermediate substance by 
chemical means, 294; pathological cartilage tissue, 
295 ; methods of preservation, 295 
Cartilage cells, see Cartilage 
Cartilage medulla cells, see. Bones 
Cartilage, ossification of, 291 
Cataract needle, 105 
Catarrh of the bladder, 523 
Cavernous body of the male generative organ, 550 
Cell, recognized by Schwann as the elementary form 
of the body, ix.; change of form of the lining, 
98, 100, 247, 249, 262 ; method of examining with 
c. 
Cholepyrrhin, 469 
Cholera vomit, 436; stools, 454 
Cholesterine, properties of and occurrence of in 
nerve-tissue, 361; in meconium, 454; in the bile, 
469 
Chorio-capillaris, 485 
Choroid, 584 
Chromate of ammonia, 137 
Chromate of potash, 136; action, 136; constituent 
of Muller’s fluid, 136 
Chromatic aberration, 9 
Chrome yellow precipitated in the blood-vessels by 
Bowman, 176; Hunting’s method of preparation, 
178; Hoyer’s transparent, 185 ; Thiersch’s, 185 
Chromic acid, 126; recommended by Hanover, 126; 
its action, 126; degree of concentration, 127; very 
dilute solutions, according to Schultze, 128 
Chrzonszczewsky’s self-injection of living animals, 
190; of the liver, 466; of the kidney, 514 
Chyle, 249; obtaining, 249; cells, 250; chyle-dust, 
250 ; preservation, 250 
Chyle-fat in cylinder epithelium, 438 
Chyle-passages, 444 
Chyle-vessels, see Lymphatics 
Cicatricial tissue, 288 
Ciliary body, 586; muscle, 586 
Ciliary epithelium, see Epithelium 
Ciliary movement, 262 
Cinnabar, as an injection mass, 177 
Circulation, investigation of, 245 ; in amphibia, 246; 
in mammalia, 247; in inflammation, 247; in im- 
peded circulation, 248 
Cirrhosis of the liver, 476 
Clarke’s (and Beale’s) alcohol mixture, 139; method 
of examining the central organ of the nervous sys- 
tem, 356 
Cleaning the glasses of the microscope, 92 
Clove oil, recommended by Bindfleisoh, 142 
Coagulation of the blood, 239; of the nerve medulla, 
335 
Cochlea, 604 
Cochlear canal, 604 ; nerve, 604 
Cohnheim employs chloride of gold, 137, 166; con- 
firms Waller’s observations on the passage of lym- 
phoid-cells through the uninjured walls of vessels, 612 
INDEX 
249 ; immigration of tho latter cells in the inflamed 
cornea, 583; studies of blood-stasis, 248; exam- 
ines sections of frozen striated muscles, 322; C. 
and Hoyer discover the penetration of corneal 
nerves into the epithelium, 370 
Cold-flowing injection masses, 186 
Collective lens of the compound microscope, 11; its 
action, 11 * 
Collective lens, renders small bodies visible, 5; 
shows them enlarged, 5 ; for opaque objects, 21; 
inserted into the stage, 23; on the photographic 
microscope, 23 ; on the polarizer, 49 
Collective tubes of the uriniferous canals of the kid- 
correction for thickness, 17,104 ; supporting for 
very delicate objects, 104 
Cowper’s glands, 550 
Crabs, river, for the demonstration of the sarcoua 
elements of muscles, recommended by Haokel, 
329 
Creosote, 141; and methyl-alcohol, 220 ; recommend- 
ed by Stieda for rendering tissues transparent, 
141 ; used by Schwarz, 159 
Crouch’s stereoscopic microscope, 48 
Crown-glass, refraction and color dispersion of, 9- 
10 ; lenses, 9 
Cryptoooccus cerevisim in the digestive apparatus, 
437 ; in the urine, 529 
Crystalline lens, see Lens of the Eye 
Crystalloid substances of Graham, 119 
Curtis, Dr. E., improvement of illumination, 87 ; 
improved section-cutter, 108-113 ; substitute for 
simple microscope, 100 
Curvature of the microscopic image, 7, 8 
Cutaneous nerves, 872, 375, 376 
Cutaneous warts, 558 ; dry, 269 
Cutter, G. R., on American microscopes, 77-82 
Cyanin, 158 
Cylinder cells of the regio olfactoria, 567 
Cylinder diaphragms, 22 ; their application, 22 
Cylinder epithelium, see Epithelium 
Cylinder glasses for reagents. 123 
Cystic tumors of the skin, 558 
Cystine in the liver, 473 ; in the urine, 529 
Cysts, formation of, in the kidney, 521; in the 
ovary, 53!); in the mammary glands, 544; in the 
skin, 558 
Cytogenic tissue, see Connective Substance (reticu- 
lar) 
Cytogenous tissue, 275 
ney, 509 
Collodium, 141 
Colloid (alveolar) cancer, 289 
Colloid degeneration, 289; of the glands, 420; of 
the thyroid, 497 
Colloid substances of Graham, 119 
Colophony dissolved in absolute alcohol as a substi- 
tute for Canada balsam, 214 
Colors, covering, 38 ; transparent, 38; granular for 
injections, 177; transparent, 177; colors in tubes 
for injections, recommended by Hyrtl, 177 
Colostrum corpuscles, 545 
Column® Bertini, 502 
Comedones, 559 
Compression apparatus of Frey, 212 
Concentric bodies of the thymus, 270, 500 
Condensers, 23 ; their action, 23 ; achromatic of the 
English, 23; of Dnjardin, 23; of Hartnack, 23 
Cones of the retina, 595-7 
Connective substance, 274; reticular, 275; method 
of demonstration, 276; hardening, 276; varying 
condition in certain parts, 277; preservation of 
preparations, 277 ; myxomata, 289 
Connective tissue, 274, 279; ordinary, 279; living, 
according to Kiihne, 279 ; different cell forms, 280 ; 
fixed and migratory cells, 280-1 ; elastic elements, 
281; demonstration of the intermediate substance, 
282 ; pre-existence of the fibrill®, 282; demonstra- 
tion of the same by chemical means, by Eollett, 
282; double refracting, 282; in polarized light, 
282; demonstration of the connective-tissue cor- 
D. 
Damar varnish, 213 
Daughter (secondary) cells of cartilage, see Carti- 
lage 
puscles, 280 ; methods of Kanvier and Flemming, i 
284; elastic sheaths around bundles, 283; trans- 
formation of the interstitial substance into gelatine, I 
285; impregnation with gold, 286; elastic fibres, I 
Deane’s mounting fluid, 216; preservative fluid, 
221 
Dean, J., method for examining the central organs, 
356 
286; objects for examination, 286 ; embryonic con- 
nective tissue, 287; pathological connective tissue 
and its signification, 287; Waller and Cohnheim’s 
investigations, 288; hypertrophic connective tis- 
sue, 288; cicatricial tissue, 288; basis of benign 
and malignant tumors, 288-9; methods of examin- 
ing the pathological forms, 290; cabinet prepara- 
tions, 290 
Construction of the modern microscope, 18 
Constriction rings of the nerve-fibres (Ranvier’s), 
338 
Convoluted glands, see Glands; of the skin, see 
Sudoriparous Glands ; of tho conjunctiva, 573 ; of 
the organ of audition, 601 
Copal lac, 213 
Copper, chromate of, 189, note ; sulphate, 189, note 
Corium, see Skin 
Cornea (organ of vision), 577; corneal nerves, 369; 
by Hoyer and Cohnheim, 370; by Engelmann, 
871 ; statements of Saemisch and Muller, 370 
Corneal corpuscles, 578 ; their pathological changes, 
583 
I Decalcifying method for cartilage, bone and dental 
! tissues, 293, 296, 297 
Decidua of the ovum, 540 ; spuria of menstruation, 
542 
Defects of the older compound microscopes, 7 
Defining powers of a microscope, 56 
Deiters on the cochlea, 604; directions for examin- 
ing central organs of nervous system, 353 
Delomorphous cells, 431 
Demodex folliculorum, 560 
Dentine, 298; ceils and their processes, 298 
Dermoid cysts of the ovary, 539 
Descemet’s (Demour’s) membrane of the cornea, 577 
Deyl, H. Van, made the first achromatic micro- 
scope, 11 
Dialyser of Graham, 120 
Diaphragms, 22; their effect on a lens, 8, of the 
compound microscope, 22; their use protects the 
eyes, 84 
Diatomacem as test objects, 61 ; various sorts and 
their resolution, 61-67 
Diatom test-plate of Mdller and Rodig, 63, note 
Digestive apparatus, 422; material for examination, 
422; lips with their glands, 422; mucous mem- 
brane of the oral and pharyngeal cavities, 422; 
papillae, 428 ; glands, 423 ; nerves, 423 ; tongue, 
424; divisions of its muscular filaments, and 
Corneal nerves, see Cornea 
Corneous layer of Remak, 414 
Cornil communicates the composition of preserva- 
tive fluids, 218 
Corpus Highmori, 546 
Corpus luteum, 539 
Correction of the aberration of a lens, 13,14 ; appar- 
atus for objectives, 18, 58 
Corrosion method for tho lungs, 487 
Corti’s organ, 604 
Cortical pyramids of the kidney, 506 
Costal cartilages, see Cartilage 
Covering glass, thickness and optical effect of, 16-7; 
methods of examination, 424 ; blood-vessels and 
lymphatics, 424: tonsils and lingual follicles, 425 ; 
salivary corpuscles, originating in part in the ton- 
sils, 425; salivary glands, 426; methods of Pfluger 
Heidenhain, Krause, and Ranvier, 426-27 ; sub- 
maxillary gland in a quiet and in an irritated con- 
dition, 427 ; oral cavity. 428 ; Leptothrix buccalis, 
428; Oidium albicans, 429; saliva, 429; its consti- INDEX 
tuents, 429 ; salivary corpuscles, 429 ; granular 
movements within them, 429; oesophagus, 430 ; 
stomach, 430; methods of examining, 430; gas- 
tric glands, 430 ; double cell forms, 431 ; active 
and inactive condition, 432; covering of the gas- 
tric surfaces, 432; gastric mucous glands, 432; 
tissue of the mucous membrane, 433; lenticular 
Eberth finds the capillaries composed of cells, 382; 
investigation of the biliary capillaries, 465 
Ebner, von, fibrous nature of bone substance, 802 
Ebstein on gastric mucous glands, 433 
Elastic fibres in sputum, 496 
Elastic tissue, see Connective Tissue 
E. 
glands, 433; muscles and nerves of the mucous 
membrane, 433 ; Loven discovers the lymphatics j 
Electric apparatus of Harting, 102 
Elementary organisms (cells), ix 
Elephantiasis, 558 
Embedding methods, 118 ; in gum, wax and oil, 
paraffine, glycerine and gelatine, transparent soap, 
albumen and tallow, 113-115 
Emboli of the finest vessels, 395 ; from fluid fat, 396 ; 
from pigment flakes, 395 
Emigration of lymphoid cells from the blood-vessels, 
249; of the red blood-corpuscles, 248 
Enamel organ, see Gelatinous Tissue 
Enamel, see Teeth 
Bnchondromata, 295 
Endosteum, see Bone 
Endothelium, see Epithelium 
Engelmann on the termination of the nerves of the 
voluntary muscles, 364; on the termination of the 
gustatory nerve of the rabbit, 563 
Eosin tingeing, 155 
Epidermis (see Epithelium), 256, 266 
Epididymis, 547 ; its ciliated cells, 547 
Epiphytes, 559; their examination, 559 
Epithelial cancer, 270, 289 
Epithelium (and endothelium), 256; pavement cylin- 
der, ciliated and pigment, 256 ; endothelium, 256 ; 
method of demonstration, 257; simple pavement 
(endothelium), 258; silver impregnation, 258; 
bluing of the cement ledges, according to Arnold 
and Thoma, 259; examination of pigment-cells, 
260; molecular movement of the pigment granules, 
260; cylinder epithelium, 260 ; porous canals on 
cylinder-cells, 261; methods of preserving, 262; 
ciliary movement, 262; choice of suitable mate- 
rial, 262; fluid media. 263; microscopic image of 
the ciliary motion, 263 ; movement reproduced by 
dilute alkalies, according to Virchow, 264; forms 
of the movement, according to Burkin)e and Val- 
entine, 265; statements of Engelmann, 265 ; diffi- 
culty of the examination in warm-blooded verte- 
brates and man, 265; obtaining ciliated cells in 
acute catarrh of the nose and respiratory passages, 
265 ; stratified pavement-epithelium and epider- 
mis, 266; stachel and riff-cells of the deeper layers, 
266 : method of examination, 266 ; action of potash 
solutions, 267; chloride of gold, 268; method of 
preservation, 269; epithelial new formations 
of a pathological nature, 269; indurations and 
warts, 269 ; pearl-like tumors and concentric bod- 
ies of the thymus, 270; epithelial cancer (can- 
croid), 270 ; epithelial cells of the organs of sense 
—see these 
of the mucous membrane, 434; pathological 
changes, 434; mammiliated condition, 434; hy- 
pertrophy of the muscular tissue, 435 ; vomited 
matters, 435; constituents, 435; acid matters in 
pyrosis, 436; green substances. 436; rice-water- 
like matters in cholera, 436; bloody matters, 436 ; 
cryptococcus cerevisias, 437 ; sarcena ventriculi, 
437; Oidium albicans, 437 ; intestinal canal, 437 ; 
cylindrical epithelium, 437 ; Becher cells, 438 ; 
probable penetration of mucous and pus corpus- 
cles into these cells, 438 ; immigration of psoro- 
sperms, 438; chyle-fat passing the cylinder cells, 
438: method of examining the intestine, 438 ; 
Brunner’s glands, 438-9; nature of the mucous 
membrane, 439; process of examination, 440; 
Lieberkuhn’s glands, 441 ; muscular tunic of the 
mucous membrane, 441; intestinal villi, 441 ; 
method of examining, 442 ; muscular tissue of the 
intestine and submucous tissue, 442 ; injection of 
the blood-vessels, 442 ; natural injection, 444; 
chyle-vessels, 444 ; their natural and artificial in- 
jection, 444; injection of the lymphatics of the 
small intestine, 445 ; lymphatic vessels and pas- 
sages, 446; lymphatic follicles, solitary and Peye- 
rian glands, 447; structure and methods of ex- 
amination, 448 ; parts of the Peyerian follicle, 
449 ; blood-vessels, 450 ; lymphatics, 450 ; Peyerian 
follicles in the vermiform process, 451 ; changes 
of the intestinal mucous membrane, 451; of the 
Peyerian follicles in disease, 451; in abdominal 
typhus, 452; methods of preservation, 452; con- 
tents of the intestine, 453; chyme, 453; con- 
tents of the large intestine, 454; faeces, 454 ; 
meconium, 454; ftecal matters in disease, 454 ; 
dysenteric stools, 455; cholera stools, 454; mat- 
ters passed in abdominal typhus, 455 ; crystals of 
the ammonia-phosphate of magnesia, and their 
significance in faeces, 455 ; crystals of taurine, 
455; animal parasites, 456 ; Paramsecium coli, 456; 
Cercomonas intestinalis, 456; ova of helminths, 
456 ; trichina spiralis, 456 : methods of examining 
the helminthian ova, 456; ova of Tricocephalus 
dispar, 457 ; Ascaris lumbricoides, 457: Oxyuris 
vermicularis, 457; Distoma hepaticum, 407 , Lan- 
ceolatum, 457 ; Bothriocephalus latus, 457 ; Taenia 
solium, 458 ; mediocanellata, 458; booklets of the 
taenia, 458 
Dippel’s work on the microscope, xii 
Distoma, ova of in faeces (D. hepaticum and lanceola- 
tum), 457 
Dellinger’s injections, 173 
Donders explains the action of potash solutions, 
133; recommends costal cartilage, 292 
Donn6 publishes an atlas of daguerreotypes, 40 ; dis- 
covers the Trichomonas vaginalis, 542 
Double injection, see Injection. 
Double knife of Valentin, 107; improved form of the 
English, 107 
Double lens, see Dens. 
Double refraction, weak, its recognition, 50 
Double tingeing with carmine and picric acid, 159; 
with carmine and indigo-carmine, 160: with in- 
digo-carmine and picric acid, 160; with hsema- 
toxyline and carmine, 160; with haematoxyline 
and picric acid, 161; Gerlach’s complicated, 161 
Drawing microscopic objects, 36; its value, 36; 
directions for, 37 ; apparatus for, 38 
Drebbel, Cornelius, as a discoverer of the compound 
microscope, 7 
Drying method, 169 
Ductus ejaculatorii, 549 
Dujardin, see Illuminating Apparatus 
Dumb-bells of uric acid, 527 
Dysenteric stools, 455 
Epizoa, 560 ; their examination, 561 
Ether dissolves fat and Canada balsam, 141 
Eustachian tube, 602 
Examination with the microscope, 83; with magni- 
fying powers of increasing strength, 94 
Exostosis, 313 
Exudation-cylinders of the uriniferous canals in 
Bright’s disease, 530 ; in the urine, 523 
Exudations, asserted organization of, 288 
Eye-ball, see Organ of Vision, 572 
Eye-lids, 572 
Bye-piece micrometer, 82; its action, 34; valuation 
of its divisions, 34; dependence of the same on the 
I objectives, 34; with screw, 32; improved by 
Mohl, 83 
Eye-pieces of the oldest compound microscopes, 6; 
of the improved instruments, 11; designation ac- 
cording to their strength, 14 ; shortening with the 
increase in strength, 14; ordinary (negative) of 
Huygens, 14 ; positive of liamsden, 15 ; orthoscopic 
of Kellner, 15; holosteric, 15 ; aplanatic, 15; under 
corrected, 16; position of the lenses in an eye- 
piece, 16; use of weak eye-pieces, 89, 90 ; limits 
of the use of strong eye-pieces, 90; uselessness 614 
INDEX 
of very strong ones, 90; image-inverting ocu- 
lar of Hartnaok, 96; spectroscopic of Hartnack, 
Zeiss, and Merz, 51, 53 
Bye, see Organ of Vision, 573; hypermetropic, 3 ; 
myopic, 3; as a camera obscura, 1; protecting the, 
in microscopic work, 84, 93 
Fungus, filamentous, of the mouth (Leptothrix buo- 
calis), 428 
G. 
F. 
Galilei, asserted inventor of the microscope, 7 
Ganglion cells, see Nervous System; layer of tho 
retina, 596 
Gas chamber of Stricter, 100 
Gastric carcinoma (false), 435 
Gastric glands, 430 
Gastric mucous glands, 433 
\ Gastric mucus, 433 
Gegenbaur’s osteoblasts, 308 
Gelatine as an injection mass, 174; varieties, 175 
Gelatine with glycerine, 175 
Gelatinous tissue, 374 ; varieties, 374: vitreous body, 
375; enamel organ, 375 ; methods of examination 
and preservation, 375; new formations, myxoma, 
389 
Farrant’s mounting fluid, 216 
Fat cells, see Fat Tissue 
Fat emboli in the capillaries, 396 
Fat tissue, 378; demonstration, 378; crystallization 
of contents of cell, 279; blood-vessels, 379; mount- 
ing, 279; new formation as lipoma, 278 
Fatty acids, crystals of in pus, 253; in fat cells, 279 
Fatty degeneration, see the several organs 
Fatty liver, 470 
Favus crusts, 560 ; fungus, 560 
Fermentation of pus, 253 ; of urine, acid, 526 ; alka- 
line, 529 
Fermentative fungus in the stomach, 437; in acid 
urine, 526 ; in alkaline, 529 
Ferrooyanide of copper, 189, note 
Fibre-cells, contractile, see Muscles 
Fibrin, 239; coagulation of, 239; cylinder, see Exu- 
dation-cylinder 
Fibroid, consisting of connective tissue, 289; of the 
uterus, 541 
Field, flattening of, by the collective lens, 12 
Field of vision, rendering the same plain, and correc- 
tion of the image by the collective lens, 12 
Finder (indicator), 230, note 
Flakes, containing blood-corpuscles, of the spleen, 
481 
Generation, female organs of, 583; structure of the 
ovary, its stroma and follicles, 533; the ovum, 
533; its constituents and the methods for its in- 
vestigation, 534 ; the germ, 585 ; development of 
the follicle, 536 ; Pfliiger’s observations, 537; rup- 
ture of the follicle, 538; formation of the corpus 
luteum, 538; its ultimate fate, 589; crystals of 
haunatoidine in it, 539; pathological conditions 
of the ovary, 539; ovarial cysts, 539; with the 
structure of the skin, 539; oviducts, 540 ; uterus, 
540 ; mucous membrane and glands, 540 ; muscu- 
lar portion, 540; pathological conditions of the 
uterus, 541; fibroid tumors, polypi and carcino- 
mata, 541; vagina and external genitals, 541; 
secretion of the cervix uteri, 541; vaginal mucus, 
542; trichomonas vaginalis, 542 ; menstrual blood, 
542 ; lochial secretion, 543 ; lacteal glands, 543; 
development, 548 ; of the male and female, 544; 
pathological conditions, 544; cysts and adenoid 
tumors, 544; methods of examining the organ, 
544; milk, 545 ; milk-globules, 545; colostrum 
corpuscles, 545; methods of examining the milk, 
546 
Flattening the field by the collective lens, 12 
Flemming’s transparent soap, 114; on connective- 
tissue cells, 284 
Flint glass, refraction and color dispersion of, 9; 
lenses, 10, 49 
Fluid media for microscopic preparations, 117 ; in- 
different, 118; more active ones, 121; their opti- 
cal effects, 121 ; action on certain elementary 
forms, 117; importance of truly indifferent ones, 
117; requirements of such, 118; crystalloid mat- 
ters, 119; colloid substances, 119; combination of 
both, 120 ; iodine serum, 121 
Follicular chains of the ovary, of Ffliiger, 537 
Follicular tumors of the skin, 458 
Fontana, asserted inventor of the microscope, 7 
Food, remains of, in the saliva, 429; in vomited 
matters, 435 ; in the small intestines, 453 ; in the 
faeces, 454 
Forceps, 105 
Forked cells of the lingual papilla;, according to 
Engelmann, 564 
Formic acid in combination with glycerine, recom- 
mended by Ranvier as a mounting fluid, 216 
Forster isolates bone corpuscles with strong mineral 
acids, 297 
Fovea centralis of the retina, 600 
Freezing method for obtaining fine sections, 171 
Frerichs on liver diseases, 469 
Prey, testing lenses, 68; recommends anilin red for 
tingeing, 154; and for the axis-cylinder, 337; on 
purpurin, 155; on eosin, 155; anilin blue, 157 ; 
parme soluble, 157; hsematoxyline solution, 158 ; 
cold-flowing injection masses, 186, 189; carmine 
for injections, 184; sulphate of baryta, 179, 188; 
recipe for chloride of silver, 180; for a watery 
Prussian blue for injecting glandular canals, 189, 
note ; improved turn table, 212 ; very dilute acetic 
acid1 for muscular nerves, 130, 365; on biliary 
capillaries, 465; on lymphatics of the thyroid 
gland, 497; on absence of lymphatics in the thy- 
mus, 501; on lymphatics of the trachoma glands, 
574 ; on injections of the uriniferous canals, 513 
Frustulia Saxonica as a test object, 63 
Fuchsin, see Anilin Red 
Fiihrer recommended chloride of iron for hardening 
spleen, 187 
Generation, male organs of, 546; testicles, 546 ; semi- 
niferous canals, corpus Highmori, 546; epididymis, 
547; blood-vessels, 547; lymphatics, 548; patholo- 
gical new formation of the testicle, 549; methods of 
injection and examination, 548; ductus ejaculatorii, 
549 ; prostate, 549 ; its concretions, 549 ; Cowper’s 
glands, 550 ; cavernous organs, 550; seminal fila- 
ments, 550; movements, action under reagents, 
551; development, 552; preserving the filaments, 
553; recognition of the same in seminal stains, 
553 
Gerlach, photographing apparatus of, 41; increase 
of magnifying power by means of photography, 
45; inventor of carmine tingeing, 147 ; studies on 
nerve terminations in transversely striated muscles, 
366; application of chloride of gold and potash, 
357 ; complicated tingeing, 161; carmine injection,. 
183 ; injections of bones, 801; method of examin- 
ing the tactile bodies, 376; of injecting the semi- 
nal canals, 548 
Germinal spot and vesicle, see Ovum 
Gianuzzi on the submaxillary gland, 427 
Gillavry, Mac, on biliary capillaries, 465 
Gingival papilla;, 423 
Gland capillaries, see Glands 
Glands. 410 ; structure, membrana propria, cells and 
vessels, 410 : tubular glands, 411; coil-shaped, 411; 
racemose, 412; their vascular net-work, 412; closed 
gland capsules, 413; capsules of the ovary, 413; 
blood vascular glands, 414; thyroid gland, 414; 
lymphatic glands, 414; gland-cells, 414; their ori- 
gin in the corneous and intestinal gland layers, 
414; arrangement, 416; in mucous and serous 
glands, 416 ; perishable nature, 416 ; formation of 
the secretion, 410; physiological destruction of the 
cells in many secretory processes, 416; method of 
examination, 417; injections, 419; finest gland 
oanalicules or gland capillaries, 419 ; examination 
of foetal glands, 420 ; pathological changes, 420 ;. INDEX, 
615 
participation of the frame-work, 420 : of the cells, 
420 ; new formation of gland tissue, 421 
Gland tissue, see Glands 
Glass boxes, 104; quadratic, 103 ; larger, for cover- 
ing the specimen, 93 
Ol&ss cells 223 
Glass micrometer, 33; its divisions, 33 ; as an object 
slide (objective micrometer), 33: in the eye-piece, 
33-84 
Glass prisms, 88. 46-47 
Glass rod, its appearance in various fluid media, 118 
Glioma of the brain, 360; of the retina, 601 
Glycerine as a medium for rendering tissues trans- 
parent, 118; index of refraction, 118; for wet 
mounting, 215; with water and muriatic acid, 
215 ; with acetic acid, 216 ; with formic acid, 216; 
with carbolic acid, 216 ‘ with gelatine, 114, 216, 
284: with tannin, 216 ; gum-arabic and arsenious 
acid, 216; carmine, 149, 151 
Goadby’s fluid, 217 
Goitre, 499 
Gold, chloride of, 137,166; and potash, 187, 168; 
and soda, 137, 108 
Gold size, 228 
Goniometer of C. Schmidt, 36 
Goodsir, J., discovers Sarcina ventriculi, 437 
Graafian follicle of the ovary, 533 
Graham on colloid and crystalloid substances, 119 
Grammatophora subtillissima, 62, 66 
Grandry, composition of the axis cylinder of the 
Pacinian corpuscle, 377 
Granulations, 288; in Bright’s disease, 521 
Granule cells, 495 
Granule layer of the retina, 596 
Growths, homy, of the skin, 269 
Grunow, J., sketch of, 79 
Gum with glycerine, 216; for embedding, 113; as 
an addition to chromic acid, 129 
Gustatory cells, see Gustatory Organ 
Gustatory organ, 562 ; nerve distribution, 562; dis- 
covery of the nerve distribution In the gustatory 
buds, 563 ; in the papilla? of the frog’s tongue, by 
Schultze, Key, Bngelmann and Wyss, 563; gusta- 
tory cells, 563 ; forked cells of Bngelmann, 564 
Gustatory papilla of the frog’s tongue, 564 
Gutta-percha cement, 224; cells, 222 
tin case for injecting, 196; gutta-percha cement, 
224; india-rubber cement, 225 
Hartnack, his holosteric eye-piece, 15 ; stereoscopic, 
48 ; image inverting, 96; spectral apparatus, 51: 
flint-glass lens over the polarizer, 49; improves 
the analyzer, 49; his lenses and their angles of 
aperture, 60; immersion systems, 60 ; their angles 
of aperture tested by Harting, 59; action with 
test objects, 65-68 ; resolve the lines of the suri- 
rella gemma into hexagonal area, 66; large horse- 
shoe stand, 27-28, 69, 85 ; the smaller stand, 30, 
70 ; other instruments, 71; his lamp, 86 
Hassal’s concentric bodies of the thymus, 270, 500 
Haversian canals and spaces, see Bones 
Heart, branched muscular fibres of, 822; position of 
the nuclei in the sarcous substance, 322; nerves of 
the heart, 368 
Heidenhain, his method of tingeing with carmine, 
152; with aniline blue, 157 ; on cartilage capsules, 
294; on salivary glands, 427; on gastric glands, 
430-131 ; on the pancreas, 459 ; on the structure of 
the kidney, 511, 514 
Helminthian ova in the faces, 456 
Henle recommends strong muriatic acid for the 
uriniferous canals of the kidney, 125 : investigates 
the course of the uriniferous canals, 503 
Henocque’s method of impregnation with gold, 167 
Henson on the structure of the muscular filament, 
330 ; examination of the nerve termination in the 
tail of the frog’s larva, 372; method with the coch- 
lear canal, 605 
Bering's apparatus for injecting by constant pres- 
sure, 196; examination of the biliary capillaries, 
465 
Herpes tonsurans, 559 
His, brushing method, 115 ; silver impregnation, 137, 
164 ; adenoid tissue, 275; work on the cornea, 
577 ; on the thymus, 499 
Histology of the normal and abnormal body, and its 
significance, xi 
Hoffmann’s indicator, 230, note 
Holosteric eye-piece, 15 
Hornlayer of llemak, 414 
Howship’s lacunae of the bones, 314 
Hoyer, his yellow transparent coloring matter, 185 ; 
discovers the structure of the capillaries, 382; and 
Cohnheim discovered the penetration of corneal 
nerves into the epithelium, 370-871 
Huyghen’s negative eye-piece, 14 
Hyaloidiscus subtilis, recommended by Bailey as a 
test object, 63 
Hyperosmic acid, see Osmic Acid 
Hypertrophies, see The several organs 
Hypophysis cerebri, 379 
Hypoxanthine (sarcine) in the liver, 472; in the- 
urine, 530 
Hyrtl, history of injections, 173; resinous masses 
and their use, 174; gelatine masses, 174; cold- 
flowing masses dissolved in ether, 176; recom- 
mends colors in tubes for injections, 177 ; punc- 
turing method, 201; examines the kidneys, 502, 
514 
H. 
Hackel recommends crabs for the demonstration of 
the sarcous elements of striated muscles, 329 
Hsematine crystals, 243 
Hmmato-crystalline, 241-242 _ 
Hieraatoidine crystals, 244; in ruptured Graafian 
follicles, 539 
Hsematoxyline, 158; with carmine, 160 
Hmmatoxyline solution, 158 
Htemoglobine crystals, 241 
Hagen on American microscopes, 77 
Hair, 270; method of examining, 270 ; hair sac, 
271; shaft and bulb, 271; root sheath, 271; epi- 
dermic covering of the hair, 272; transverse sec- 
tion through the hair, 272; cells of the external 
root-sheath. 271; foetal hairs, 273; mounting 
methods, 273; in dermoid cysts of the ovary, 539; 
their origin, 539; diseases, see Skin ; fungi, 559 ; 
hair sac mite, 560 
Hannover recommends chromic acid, 126 
Hardening by chromic acid, 126; directions for, 
127; chromate of potash, 135; picric acid, 132; 
alcohol, 138; freezing, 171 _ .. . • 
Harting, his work on the microscope, xi., xn.; in- 
vestigates the question of the invention of the 
compound microscope, 7; explains the action of 
the immersion system, 59; electric apparatus, 102; 
recommends weak solutions of sublimate for pre- 
serving, 219: chloride of calcium, carbonate of 
potash and aqueous solution of creosote, 219, 220; 
on the refractive power of fluid media, 117 ; direc- 
tions for making chrome-yellow and carbonate of 
lead, 179 ; Prussian blue in oxalic acid, 182; from 
sulphate of iron and ferro-cyanide of potash, 182 ; 
I. 
Illuminating apparatus of Dujardin, 23 ; of Lieber- 
kuhn, 87 
Illuminating lens for opaque objects, 21 
Illumination by incident light, 21, 87; by trans- 
mitted, 21, 83 ; by artificial, 86 ; by central, 22; by 
oblique, 22; employment of central illumination, 
84; with cylindrical and rotary diaphragms, 22 ; 
with a condenser, 23 ; of the field depends on the 
condition of the sky, 84; method of improving, 
used by Dr. Curtis, 87 
Image, aerial, of the compound microscope, 6; of 
the improved, 13 
Image distortion, 8 
Image inverting microscope, 96; eye-piece, 96 
Image of the compound microscope, 6, 7 ; clearness 
of the same increased by the field glass, 11-13; 
curved, of the simple compound microscope, 7; 616 
INDEX 
enlarged, 7; inversion of the same by the micro- 
scope, 6, 94 
Images, microscopical, peculiarities of, 94 ; their re- 
lations of height and depth, 94; judging of the 
form from these, 94; value of weak objectives 
thereby, 95 ; increased difficulty of their apprecia- 
tion from extreme diminutiveness of the bodies, 
95 ; appreciation of their relations of relief, 95 ; 
Welcker’s directions for this purpose, 95 
Immersion lenses, 58 ; of Hartnack, 58 ; of Powell 
and Leland, 60 ; their action explained and tested 
by Harting, 59 
Increase of the magnifying power by photographic 
means, 45 
Indicator (object-finder), 230; Hoffmann’s arrange- 
ment, 230, note 
Indigo carmine, 156 
Indurations, 269 
Infarction, hemorrhagic, of the spleen, 483; uric 
acid, of the kidney, 521 
Inflammatory globules, 495 
Infundibula of the lungs, 487 
Injection clamps (serres fines), 198 
Injection masses for glandular canals, 189, note 
Injection material for the blood-vessels, 198; organs 
which are fresh, and those which are older and 
have been in alcohol, 198; for lymphatics, 199; 
for glandular canals, 199 
Injection methods, 173; with hardening, 174; and 
cold-flowing masses, 174; resinous masses, 174; 
their preparation according to Hyrtl, 174; gelati- 
nous masses, 174; their superiority, 174; their 
preparation, 175; treatment of preparations in- 
jected with gelatine, 176; cold-flowing mixtures 
containing glycerine, alcohol, and water, 176; 
their superiority, 177 
Injection mixtures, cold-flowing, with Beale’s Prus- 
sian blue, 186; with Richardson’s blue, 187; with 
Muller's blue, 188; with Beale’s carmine, 188; 
with sulphate of baryta, according to Frey, 188 
Injection of the brain and spinal cord, 358 
Injection of the several organs, see these 
Injection procedure with blood-vessels, 198; with 
lymphatics, 199; with lymphatics by the punctur- 
ing method of Hyrtl and Teichmann, 201; with 
thin-walled parts, 201; with glandular passages, 
199 ; filling the syringe during the injection, 200 ; 
forcing in the mass, 202; ligation of the vessel, 
200; closing the canule, 200 ; completion of the 
injection, 203 ; double injection of the blood-ves- 
sels, 203; injection of the blood-vessels and lym- 
phatics, 204 ; after-treatment of the injected ves- 
sels, 205; hardening the preparations, 205; mount- 
ing methods, dry and wet, 206 
Injections double, see Injection Methods 
Injection, spontaneous, of the living animal, accord- 
ing to Chrzouszczewsky, 190; with carmine and 
indigo carmine, 191; of the lymphatic glands with 
aniline blue, according to Toldt, 405 
Injection syringes, 196; their canules, 196; their 
management, 197 ; tying in the, canule, 200 ; fill- 
ing the syringe, 202 ; management of the piston, 
202; closing the canule, 203 
Injections, their importance for histological work, 
172; the art in its infancy, 173; in its present con- 
dition, 173 ; colors for, 177-188; the granular pro- 
duced by precipitations in the vessels, 178 ; colors 
in tubes, 177; red, cinnabar, 177; yellow, chrome 
yellow, 178; white, lead and zinc white, sulphate 
of baryta, 179; chloride of silver, 180; transparent, 
180 ; Thiersch’s Prussian bhxe, 181; Prussian blue 
in oxalic acid, 181; Prussian blue from sulphate of 
iron and cyanide of iron and potash, 182,; soluble 
Prussian blue, 183 ; Gerlach’s carmine mass, 183 ; 
Frey’s method, 184 ; Thiersch’s transparent yellow, 
185; Hoyer’s, 185 ; Robin’s yellow, 186 ; Thiersch’s 
transparent green, 186 ; Beale’s ordinary blue for 
cold-flowing masses, 186: Beale’s best blue, 187 ; 
Richardson’s blue, 187 ; Muller’s, 188; Beale’s car- 
mine, 188; Frey’s baryta mass, 188 ; Hyrtl’s colors 
with resinous masses, 174 
Injection with constant pressure, 192; with the 
glass tube and column of fluid, 192; with mercu- 
rial pressure, 193; with compressed air, 195; 
Harting’s injection chest, 196; Her mg’s appara- 
tus, 196 
Intercalary piece in the cortex of the kidney, 509 
Intergranular layer of the retina, 593 
Intestinal contents, 458 ; ganglia, 345 ; glands, 441; 
villi, 441 
Intestinal gland-layer, 414 
Intestines, 437 (see Digestive Apparatus) 
Inversion of the microscopic image, 6 
lodine, 132; with sulphuric acid, its action on amy- 
lon, amyloid, cellulose and cholesterine, 124; va- 
por, according to Rollett, 132 
lodine-serum of Schultze, 121 
Iris, 584, 586 
Iron, chloride of, 137, 183, 186, 187; sulphate of, for 
making Prussian blue, 182; tincture of chloride 
of, 186, 187 
Itch, the, 560 ; mite, 561 
J. 
Janssen, inventor of the compound microscope, 7 
Javelle water (hypochlorate of soda), 135 
Juice canals of Recklinghausen, 400 
J nice clefts of Waldeyer, 400 
Jurgen’s reagent for amyloid, 155 
K. 
Kellner’s microscope, 76; orthoscopic eye-piece, 15 
Key confirms the connection of the muscular fila- 
ments of the tongue with connective tissue cor- 
puscles, 424; with Schultze discovers the termina- 
tion of the gustatory nerves, 564 
Kidney (urinary apparatus), 502 
Kidneys, Bright’s disease of the, 520 
Klein’s method of gold impregnation, 371, 581; 
method of examining the spleen, 478 
Knives, 105 
Kolliker describes the osteoclasts, 314; recommends 
very dilute acetic acid for muscular nerves, 130, 
865; very dilute muriatic acid, 365; very dilute 
nitric acid, 365; on cytogenous tissue, 275; re- 
commends boiling the thymus, 501; follows the 
lymphatics in the tail of the frog’s larva, 409; ex- 
amines with Scanzoni the mucus of the female 
genital organs, 542 
Kollmann’s carmine mass, 189, note 
Krause, W., examination of the nerve terminations 
in muscles, 364; recommends dilute acetic acid 
for muscular nerves, 365 ; discovers the terminal 
knobs, 372; recommends dilute acetic acid for the 
latter, 373; uses molybdenate of ammonia for the 
salivary glands, 426 
Kuhne recommends very dilute sulphuric acid for 
muscular nerves, 365 ; nitric acid and chlorate of 
potash for isolating muscular fibres, 323; investi- 
gation of the cornea, 369, 578 
Kutschin recommends creosote, 141; his double 
tingeing, 161 
L. 
Labels, placing them on the object slides, 231 
Lambl’s ceroomonas intestinalis, 456 
Lamina elastica anterior of the cornea, 577; of the 
choroid, 586; spiralis of the cochlea, 605 
Landois uses fuchsine for cartilage, 294 
Lardaceous liver, 474 
Larynx, 485 
Lead, carbonate of, 179 
Leber’s impregnation with Prussian blue, 169 
Legros uses hyposulphite of soda for objects im- 
pregnated with silver, 162 
Lehmann on crystals of muriate of haematine, 242 INDEX. 
617 
Lons combination, inserted in the stage, 23 
Lens (double) achromatic, of crown and flint glass, 
9; applied to the microscope by Van Deyl and 
Fraunhofer, 11; aplanatic, 10; over and under 
corrected, 10 
Lens of the eye, 587; its capsule, 687; fibres, 588 ; 
changes in disease, 589; development, 589 
Lenticular glands, 433 
Leptothrix buccalis, 428; in faeces, 454 
Leucaemia, 236 
Leucine from the liver, 472; in urine, 529 
Lieberkiihn’s injections, 173 ; arrangement for illu- 
mination, 87; glands, 441 
Light, central and oblique, 22, 85 ; polarized, 48 
Lime, carbonate of, its crystals suitable objects for 
the study of the molecular motion, 97 ; in the 
organ of hearing, 602 ; oxalate of, in urine, 527; 
in the exudation cylinders of Bright’s disease, 
524; infarctions of the kidney, 522; lime-water 
used by Rollett for connective tissue, 184 
Line, Paris, reduced to millimetres, etc., 35 
Lingual follicles, 425 
Lipoma, 278 
Lips and their sebaceous follicles, 422 
Liquid stove-polish, a substitute for Brunswick 
black, 227 
Lister and Turner on the inner circle of the trans- 
111. 
Maceration in acids, of connective tissue, 283; of 
bones and teeth, 296; of the muscles, 318; of the 
kidneys, 507 
Macula lutea of the retina, 600 
Magnifying glasses known even in the middle ages, 
7 
Malmsten’s paramaacium coli, 456 
Malpighian vascular coil of the kidney, 504 ; cor- 
puscles of the spleen, 479; pyramids of the kid- 
ney, 502; rete mucosum of the skin, 554 
Mammillated condition of the gastric mucous mem- 
brane, 484 
Margo examines the nerve termination in the mus- 
cles, 364 
Marine glue, 224 
Masklack, black, 229 
Mastic in chloroform, 213 
McAllister on American microscopes, 77 
Measure, units of, for microscopic determinations of 
size, 35 
Measures, microscopic, 33-86 
Measuring apparatus, microscopic, 32-35 
Measuring cylinder, 142 
Meconium, 454 
Medullary rays of the kidney, 506 
Meibomian glands, 572 
Meissner discovers the ganglionic plexus in the sub- 
mucous tissue of the digestive canal, 345 
Melansemia, 236; condition of the liver and spleen 
in, 484; condition of the cerebral vessels in, 396; 
emboli of the hepatic vessels, 474; of the kidneys, 
519 
verse section of the nerve tube, 339 
Liver, 460 ; cells, 460 ; lobules, 461; methods of de- 
monstration, 461; transverse section of a lobule, 
461; blood-vessels and injections, 462; capillary 
net-worksand their cells, 462; membrana propria, 
464; finest biliary passages, 464 ; their injection, 
464; lymphatics, 467; nerves, 468; Pfliiger’s latest 
process, 468; bile, 468; its normal constitution, 
468; sediments, 469 ; cholesterin, 469; bilirubin, 
469; pathological changes of the liver-, 469; hy- 
pertrophy, 469; brown molecules of the hepatic 
cells, 470 ; deposits of fat in the hepatic cells, 470 ; 
method of examining fatty liver, 470; fatty de- 
generation, 471; destruction of the liver in acute 
yellow atrophy, 471 ; chemical constituents of the 
diseased liver, 472; tyrosine, 472; leucine, 472 ; 
hypoxanthine (sarcine), 472; xanthine, 473 ; cys- 
tine, 473; emboli of the hepatic vessels by pig- 
ment flakes in melanaemia, 474; amyloid degenera- 
tion (waxy or lardaceous liver), 474; examination 
of the amyloid substance, 474; tubercles, 475; 
cirrhosis, 476; carcinoma, 476 
Lochial secretion, 542 
Loupe, 4; stand, 4 
Lovdn’s discovery of lymphatics in the gastric mu- 
cous membrane, 434; the gustatory buds of the 
tongue, 563 
Ludwig and Tomsa on the lymphatics of the testicle, 
548 ; L. and Zawarykin on the kidneys, 504 
Luer’s injection syringes, 196 
Lungs (respiratory apparatus), 485; vesicles of, 487 ; 
epithelium, 486; fibres of in sputum, 496; capil- 
lary loops, 489 
Lymph, 249; how to obtain it, 249; cells (corpus- 
cles), 250 ; mounting, 250 
Lymph corpuscles in lymphoid organs, 402; in the 
mucous membrane of the intestines, 439 ; in the 
spleen, 480 ; in the thymus, 499 
Lymphatic glands, 402 ; methods of examination, 
402 ; Toldt’s method, 408; framework, 403; in- 
jections, 404; puncturing method, 404; natural 
injection, 405; treatment of chyle glands filled 
with fat, 405 ; pathological and other changes, 406 ; 
fat-cell tissue, 406; pigmentations, 406; melanosis, 
406; anthracosis, 407; bronchial glands, 407; 
connective-tissue metamorphosis, 407; anatomical 
conditions in abdominal typhus, 407; in tubercu- 
losis and scrofula, 408; inflammatory conditions 
and hypertrophies, 408; value of injections in 
these cases, 409; development in the foetus, 409 
Lymphatics, 398 ; structure and examination of the 
larger and smaller trunks and lacunse, 399: silver 
impregnation, 399; injection, 399; lacteals, 400 ; 
new formation of lymphatics in neoplasms, ac- 
cording to Krause and Neumann, 401 
Melanine, 256, 585 
Melanosis (and anthracosis) of the bronchial glands, 
406-407; of the lungs, 490, 491 
Membrana limitans interna of the retina, 593 ; ex- 
terna, 593 
Membrana propria, see Glands 
Membrana tympani, 602 
Menstrual blood, 542 
Mentagra, 559 
Mercnrj', chloride of, 187, 219; with alum and chlo- 
ride of sodium, 217 
Mercury, column of, for injecting, 198-194 
Merz microscopes, 25, 77 v 
Metallic impregnations, 162 ; nitrate of silver, 162; 
other silver salts, 164 ; osmic acid, 164 ; osmiamide, 
166; chloride of gold, 166; chloride of gold, potash, 
and soda, 168; chloride of palladium, 168; Prus- 
sian blue, 169 
Methyl alcohol, 140 ; as a constituent of cold-flowing 
injection mixtures, 187; of preservative fluids, 
220 
Meyer, H., recommends sulphuric acid for separating 
the epidermoid covering of the hair, 271 
Mica scales, 51 
Micrococcus of Hallier, 254 
Micrometer eye-piece, 32-34 
Micrometers, 32-33 
Micrometer screw, 21 
Micromillimetre, 35 
Microscope, compound, selection of, 69; arrangement 
of, 11; simplest form of, 6, 7; improved form 11,18; 
tube, 20; objectives, 13, .14,18; eye-pieces, 14,15,16, 
18; mirror, 21; diaphragms, 22; condensers, 23; 
use of the instrument, 83; illumination, 83 ; posi- 
tion in the room, 83; cutting off incident light by 
a dark screen, 83; illumination dependent on the 
condition of the sky, 84; oblique and artificial 
illumination, 85-86; lamps, 86; illumination with 
incident light, 87; adjustment, 88; caution in the 
use of reagents, 91; cleaning the glasses, 92 ; test- 
ing, 53 ; the magnifying power, 53; the spherical 
and chromatic aberration, 545 ; the flatness of the 
field, 55; defining power, 66 ; penetrating power, 
57; value of the optical portion, 70; of the me- 
chanical portion, 70 
Microscope, invention of the compound, by Janssen, 
7; claimed by Drebbel, Fontana, and Galilei, 7 
Microscope, its importance for the physician, ix.; lit- 
Lymphoid cells, 234 
erature of, xii 618 
INDEX, 
Microscope lamps, 86 
Microscope makers, price lists of, see Appendix 
Microscope, oldest compound, its invention, 17 ; its 
incompleteness, 17 
Microscope, simple. 5 ; its arrangement (stand, stage, 
mirror, etc.), 5 ; of importance only for making 
preparations^: instruments of Plossel and Nachet, 
5; Dr. Curtis’ substitute for, 106 
Microscopes, American, 77-82 
Microscopes, compound binocular, 47; of Nachet, 
47 ; multocular, 47 ; photographic, 41; polarizing, 
49; stereoscopic, 47; of Crouch, 48; Riddell, 47 ; 
Wenham’s arrangement, 47; of Nachet, 48; Hart- 
nack’s arrangement, 48 
Microscopes, improvements of, by van Deyl, Fraun- 
hofer. Selligue, Chevalier, Amici, 11 
Microscopes of various makers, 71-77; American, 
77-82 
Microscopic vision, x, 84, 94 
Microsoopist, qualifications of the, 93 
Microsporon of Klebs, 254; Audouini, 559; menta- 
grophytes, 559; furfur, 560 
Microtomes, 108; Schieiferdecker’s, 108; Curtis, 
108; Seiler’s, 113 
Miliary tubercle of the cerebral vessels, 378; of the 
spleen, 483 ; of the lungs, 492 
Milium, 559 
Milk, 545; globules, 545; glands, 543; new forma- 
tions of, 544 
Miller, L., notice of, 81 
Millimetre reduced to Paris lines, etc., 35 
Mineral acids, 123 
Mirror of the simple microscope, 5 ; of the compound 
microscope, with a plane surface, 21, 84; with a 
concave surface, 21, 84 
Mixture of Muller, 136 ; of Goadby, 217; of Pacini, 
217; of others, 216-221; cold-flowing for injec- 
tions, 174-180, 186 ; hardening, 174 
Moderation of the light, 84, 94; moderation of the 
lamp-light by blue glasses, 86 
Moderator lamp, 86 
Mold, work on the microscope, xi., xii. ; recom- 
mends the condenser for the polarizing micro- 
scope, 50 ; an improved screw micrometer for the 
eye-piece, 33 ; the scales of the Papilla Janira as a 
test object, 61 
Moitesaier on micro-photography, 40; his photo- 
graphic apparatus, 42, 43 
Molecular movement of small bodies, see Brunonian 
Movement 
Muller’s fluid, 136 
Multipolar ganglion-cells, see Nervous System 
Muriatic acid, concentrated, 125; strong, 125; di- 
lute, 126 ; use of the strong acid for the urinifer- 
ous canals, according to Henle and others, 125; 
in extreme degrees of dilution, 126 
Muscles, 316; smooth and striated, 316; form and 
physiological condition, 316 ; methodj of examin- 
ing the smooth, 316; contractile fibre-cells, 317; 
their isolation, 317; with nitric and muriatic 
acids, 318; dilute acetic acid and acetic acid mix- 
ture, 318; potash solutions, 318; solutions of 
common salt, 819; degeneration and new forma- 
tion, 319; striated, 319; methods of examination, 
319; recognition of the sarcous substance, 326; of 
the nucleus, 320 ; of the saroolemraa, 321; rela- 
tions, 321; transverse sections of the muscular 
filaments, 821; their isolation, 322-324; chemical 
accessories, chlorate of potash with nitric acid, 
according to Kiihne and von Wittich, 328; very 
dilute sulphuric acid, 323; by heating in hermeti- 
cally sealed glass tubes, according to Rollett, 324 ; 
by concentrated muriatic acid, according to Aeby, 
324; by potash solutions, 324; relation to the ten- 
dons, 324; method of demonstration, by Weiamann, 
with potash solutions, 324 ; pointed muscular fila- 
ments, 325 ; capillary vessels, 326; nerve termina- 
tions, see Nervous System; explanation of the 
longitudinal and transverse markings, 827 ; fibrilla 
theory, 327; Bowman’s theory, 328; sarcous ele- 
ments, 328; studies with reagents, 329; sarcous 
elements of the fly. according to Amici and Prey, 
328; new investigations of Krause and Hensen, 
330 ; double and single refracting strata, accord- 
ing to Briicke, 331; origin of the striated muscle, 
831; fatty degeneration, 331; pathological changes, 
332 ; trichina, 332 ; their capsules, 333; examina- 
tion of trichinized muscles, 333 ; typhus metamor- 
phosis, according to Zenker, 332; mounting pre- 
parations, 334 
Muscular fibres in vomited matters, 435 ; in fasces, 
454 
Myeline, 861 
Myxoma, 28'.) 
N. 
Moleschott recommends a strong and a weak mix- 
ture of acetic acid and alcohol, 139-140; potash 
solutions, 133; investigates the action of potash so- 
lutions on epithelium, 267 ; on smooth muscles, 318 
Holler’s preparations, 232; diatomic test-plate, 63, 
note 
Nachet’s microscopes, 25, 31, 74 
Nsevi, vascular, 558 
Nail fungus, 559 
Nails, 269; human nails without reagents, 269; with 
alkalies and sulphuric acid, 269 
Nasal catarrh, 565 
Nasal mucous membrane, 565 
Nathusius reduces gold preparations with sulphate 
of iron, 167, 268 
Navicula affinis, 63, note; Amicii, 62, 66, note; rhom- 
boides (sporangial form), 66 
Near point, 8 
Negative (Huyghenian) eye-piece, 14 
Negative, photographic, 45 
Nerve ceils, see Nervous System 
Nerve corpuscles of the genitals, 557 
Nerve fibres, see Nervous System 
Nervous system, 334 ; elements of, 334 ; nerve-fibres, 
334; ganglionic or nerve cells, 334: constituents of 
the nerve-fibres: axis cylinder, medulla, primitive 
sheath, 334; suitable localities for examination, 834; 
homogeneous nerve-fibres, 835 ; coagulation of the 
medulla, 335; its nature, 835 ; action of reagents, 
336 ; axis cylinder, 336 ; chemical accessories for its 
demonstration, 337-338; nitric acid and chlorate of 
potash, according to Budge and Uechtritz, 337; col- 
lodium, according to Pfliiger, 837 ; chloroform, ac- 
cording to Waldeyer, 337 ; aniline red, 337 ; metal- 
lic impregnations, 338; Ranvier’s constriction 
rings, 838 ; transverse sections of hardened nerves, 
388; concentric circles according to Lister and Tur- 
ner, 339; composition of the axis cylinder of the 
finest filaments, axis or primitive flbrillEe, 339; non- 
medullated fibres of the olfactory nerve, 339; Re- 
mak’s fibres, 340; embryonic nerve-fibres, 340; 
Molybdate of ammonia, 137 
Mother (primary) cells in cartilage, 292 
Mould formation in urine, 529 
Mounting media, 206; resinous, 208-214 ; fluid, 215 ; 
simple, 215 ; complicated, 216-221 
Movement phenomena, vital, 97; amoeboid of the 
cells, 98; of small bodies, 97; molecular, 97 
Mucous corpuscles (lymphoid cells), 250 ; origin, etc., 
250: their preservation, 251; of the oral cavity 
(salivary corpuscles), 425; in vomited matters, 
436; in the small intestine, 439: in the evacua- 
tions of pyrosis and cholera, 436. 455; in sputum, 
495 ; in fseces, 453; in urine, 523 ; in the vaginal 
mucus, 542; in the nasal mucus, 666 
Mucous glands of the mouth and pharynx, 422 ; of 
the small intestines, see Brunner’s Glands; sub- 
maxillary as a mucous gland, 427 
Mucous membrane of the digestive organs, 423, 430, 
439; of the respiratory organs, 485; of the blad- 
der, 522; of the nose, 565 
Mucus, 250 
Muguet (thrush), 429 
Muller, H., recommends chromic acid with muriatic 
acid for decalcifying, 293 ; on the retina, 597 ; M. 
and Siimisch examine the corneal nerves, 370 
Muller, W., his Prussian blue, 188 ; brown injection 
fluid, 189, note ; studies on the spleen, 482 INDEX. 
619 
method of examining the non-medullated tubes, 
340; by polarized light, according to Valentin,"34l; 
ganglion-cells, 341; appearance, 341 ; processes, 
341; apolar cells, 342; methods, 342; origin of 
the fibres, 342; suitable objects, 342; methods of 
demonstration, 343; ganglion-cells, according to 
Beale and Arnold, 344 ; ganglionic reticules; intes- 
tinal ganglia in the submucous tissue of the diges- 
tive organ, discovered by Meissner, 345; methods 
of demonstration, 845 ; pyroligneous acid, 345; Au- 
erbach’s plexus myentericus, 346; methods, 346- 
348; central organs of the nervous system, brain 
and spinal cord, 348; examination of, in a fresh 
condition, 348; nerve-fibres, 349; multipolar gan- 
glion-cells, 350 ; maceration methods, 349; accord- 
ing to Deiters, 349; multipolar g.nglion-cells ac- 
cording to this investigator, 350 ; axis cylinder pro- 
cess and protoplasma processes, 350 ; complicated 
structure of the ganglion-cell, according to Remak 
and Schultze, 351; G-erlach and Frohmann’s meth- 
od of procedure, 851-352; hardening methods, 
353 ; with alcohol, 353 ; chromic acid and chromate 
of potash, 353 ; more accurate directions for chro- 
mic acid, 853 ; chromate of ammonia, 354; prepara- 
tion of sections, 354; their treatment for moist pre- 
parations, 355 ; for dry, 356; Clarke’s method, 
356; Deane’s, 356 ; later statements, 357; difficulty 
of the investigation of the brain and spinal cord, 
358; statements of Schiefferdeckcr, 358; direc- 
tions for injecting the blood-vessels in the central 
organs, 358 ; connective-tissue framework (neuro- 
glia), 359; Bidder’s investigations, 359; occur- 
rence in the white substance of the spinal cord and 
brain, 359 ; amyloid corpuscles, 361; myeline, 361; 
cholesterine, 361 ; nerve terminations, 362 ; of mo- | 
tor nerves in striated muscles, 362; suitable objects. | 
362-363 ; new investigations of Kiihne, Margo, Kill- [ 
liker, Rouget, Krause, Engelmarm, 564 ; methods, ! 
864 ; very dilute acetic acid, according to Kolliker, j 
Engelmann, and Frey, 365 ; diluted, according to I 
Krause, 365; dilute muriatic acid, 365; isolation | 
of the muscular filaments with the nerves, 365; in 
the smooth muscles, 367; in the heart, 868; in 
the cornea, 369; termination in the epithelium, 
370 ; methods, 871 ; Muller and Saemisch’s direc- 
tions, 370 ; Hoyer’s, 371; cutaneous nerves of the 
frog’s larva, 372; tooth-pulp, 372; terminal bulbs 
of Krause, 372; methods, 373 ; tactile cells, 374; 
tactile bodies, 375; methods, 375; Gerlaoh’s, 876; j 
Pacinian or Vaterian corpuscles, 376; methods, 
377; development of the nerve-fibres, 377; mem- j 
branes, 378; pineal gland and brain sand, 879; 
pathological conditions, 379; methods, 379 
ETervus acnsticus, 603 ; cochlearis, 604 ; olfactorius, 
lenses, 14; with connecting apparatus, 18, 58 ; 
with apparatus for correction and immersion, 58; 
angles of aperture, 14, 59; weak, in combination 
with strong eye-pieces, 19; strong, with weak 
eye-pieces, 20 ; value of weak objectives in con- 
tradistinction to strong ones, 89, 95; for the 
recognition of the relations of relief of micro- 
scopic objects, 95; over-corrected, 16 
Objectives of the oldest compound microscope, 9; of 
the modern, 11 
Odontoblasts, 298 
Oidium albicans (thrush) in the oral cavity, 429; in 
the stomach, 437 
Oils, ethereal, 142 
Olfactory cells, 567; rods, naked or with cilia, 668; 
connection with the axis cylinders of the olfactory 
nerve, 569, 571; Schultze’s directions for their 
investigation, 569 
Olfactory organs, 565; structure of the ordinary 
mucous membrane, 565; catarrhal processes in 
this, and the formation thereby of mucous and 
pus corpuscles, 565; regio olfactoria, 566; its 
structure, 566; the epithelial covering, 566; ol- 
factory cells, 567; their connection with axis 
cylinders of the olfactory nerve, 669, 571; Bow- 
man’s and mucous glands, 568; methods of ex- 
amination, 570, 571 
Olfactory nerve, pale fibres of, 569 
Ollier’s experiments with the periosteum, 813 
Oral cavity, 422 ; condition of, 428 
Orthoscopic eye-piece, 15, 90 
Osrniamide, 166 
Osmic acid (hypcrosmic acid), 132, 164; acetate of 
potash for mounting, 217; its use in investigations 
of the retina, and Schultze’s directions for this 
purpose, 592, 597 
Ossicula auditus, 602 
Ossification of cartilage, 292 
Ossification point of bones, 205 
Ossification, process of, see Bones 
Ossification, see Bones 
Osteoblasts, 308 
Osteoclasts of Kolliker, 814 
Osteogenesis, 305 
Osteogenous tisstie, 310, 314 
Osteoid tissue, 310 
Osteomalacia, 314 
Osteophytes, 314 
Osteoporosis, 314 
Osteosarcoma, 314 
Otoliths, 002 
Ovary (sexual organ), 683 ; cysts of, 539 
Over-corrected objectives in combination with 
under-corrected eye-pieces, 16 
Oviducts, 540 
Ovum, 534; zona pellucida, yolk, germinal vesicle, 
and germinal spot, 534 
Owsjannikow employs osrniamide, 166 
Oxalate of lime, see Lime, Oxalate of 
Oxalic acid in watery solution, 129; in alcohol, 129; 
constituent of Thiersch’s tingeing fluids, 150, 
156; dissolving medium for Prussian blue, 181; 
its action on the regio olfactoria, 571; on the 
retina, 592 
Oxyuris vermicularis, ova of, in fajces, 457 
569; opticus, 591 
Neumann’s treatment of the vitreous body, 275; of 
bones and teeth, 297 ; on carious teeth, 303; on 
the formation of colored blood corpuscles from the 
lymphoid cells of the bone medulla, 311 
New formation of connective tissue, 288-289; varie- 
ties of, see the several organs and tissues 
Nicol’s prisms, 49 
Nitric acid, concentrated, 124; with chlorate of pot- 
ash, 124, 135; of 20 per cent., according to Reich- 
ert and Paulsen, 125, 318; dilute, 125 ; very dilute, 
according to Kolliker, 125 
Nitzchia sigmoidea as a test object, 62, 65 
Nobert’s test-plate, 67; as a test-object, 67, 68; used 
by Schultze, 68 
Normal solutions (titrition), 143-146 
p. 
Pacinian bodies, 376 
Pacini’s preserving fluids, 217, 218 
Paddle-wheel cells of the connective-tissue of Wal- 
o. 
deyer, 280 
Palladium, see Chloride of Palladium 
Pancreas, 459 ; methods, 459 ; gland-cells, 459; 
| blood-passages, 460 
j Paper strips, 222 
Papilio janira, scales of, as a test-object, 61; their 
i resolution with Hartnack’s and other microscopes, 
61, 62 
! Papilla foliata of the tongue, 564 
Oberhauser, his older microscopes, 11; camera 
lucida, 38 ; horse-shoe microscope, 27, 28 
Object-finder, 230; Hoffman’s arrangement, 230, 
note 
Object glass micrometer, 34 
Object slides, form of the, 230 
Objectives, achromatic, made by Chevalier and Sel- | 
ligue, 11 ; their action, 11; aplanatic, 16 ; desig-! 
nation of, 14; with movable and immovable j 
Paraffine, 114 620 
INDEX, 
Parasites, animal, in the feces, 456; in vaginal 
mucus, 542; ova of, in the faeces, 456; of the 
skin, 560 
Parasites, vegetable, in the oral cavity, 428; in the 
stomach, 487; in the feces, 454; in the urine, 525, 
628; of the skin, 559, 560 
Parme, soluble, 157 
Paulsen, see Reichert 
Pavement epithelium, see Epithelium 
Pearl tumors, 270 
Pencils for drawing, 87 ; how to point them, 37 
Penetrating power of the microscope, 57; nature 
of, and testing the, 57 
Pepsine granules, 431, 432 
Peptic gastric glands, 481; cells (covering or delo- 
morphous cells), 431 
Pericardium, 493 
Periosteum, see Bones 
Peripheral rays, refraction of, by a lens, 8 
Peritoneum, 498 
Peyerian glands (see Digestive Apparatus), 447 
Pfliiger recommends collodium for the axis cylinders, 
141, 837; his investigation of the salivary glands, 
426; of the hepatic nerves, 468; of the ovary, 
537' 
dissolved in ether or chloroform, 211; depriving 
the tissues of their water, 212; immersion in tur- 
pentine, 213; from turpentine into Canada bal- 
sam, 212; other mounting media: gum dammar in 
turpentine, 213 ; mastic in chloroform, 213 ; colo- 
phony, 214; sandarac in alcohol, 214; moist pre- 
parations, 215; with glycerine, 215; glycerine 
and water, 215; acidulated glycerine, 215; glyce- 
rine and gelatine, 216; and tannin, 216 ; and for- 
mic acid, 216; and carbolic acid, 216 ; with gum, 
glycei-ine, and arsenious acid, 216; acetate of pot- 
ash, 217; Goadby’s fluid, 217; Pacini’s fluids, 
217; mixtures of the Berlin Pathological Institute, 
218; corrosive sublimate, 219; chromic acid and 
chromate of potash, 219 ; chloride of calcium, 219; 
creosote, 220 ; arsenious acid, 220; methyl alcohol, 
220; and creosote, 220; Topping's fluid, 220; 
Deane’s fluid, 221 
Preparations, microscopic, 87, 103; directions for 
making: covering and moistening them, 104; 
mounting by simply laying on the covering glass, 
104 ; strips of paper or silver wire between slide 
and cover, 222; with a cell, 222; of gutta-percha, 
india-rubber, or glass, 222, 223; tin-foil, 225; ce- 
ment, 225; rotary table, 226; size and form of the 
slides,[23o ; indicator, 230, note; slides with ledges, 
231; labels, 231; cases for preparations, 231; com- 
mercial preparations, 232; collections, 232 
Preparing microscope, new, of Zeiss, 106; Curtis’ 
substitute for, 106 
Preserving fluids, 215 ; of glycerine, 215 ; with mu- 
riatic, acetic, or formic acid, 215, 216; tannin in 
glycerine, 216 ; glycerine and gelatine, 216 ; glyce- 
rine and gum arabic, 216; glycerine and carbolic 
acid, 216; with acetate of potash, according to 
Schultze, 217 ; Goadby’s fluid, 217; Pacini’s, 217 ; 
of the Berlin Pathological Institute, 218; with cor- 
rosive sublimate, 219; with chromic acid and chro- 
mate of potash, 219; chloride of calcium, 219 ; car- 
bonate of potash, 219; arsenious acid, 220; creosote; 
220; methyl alcohol, 220 ; Topping’s fluid, 220; 
Deane’s fluid, 221 
Pressure cock, 143, 194 
Price lists of microscope makers, see Appendix 
Prices, differences of, of Continental and English 
microscopes, 72 
Primary cells in cartilage, 292 
Primitive fibrillae of the axis cylinders in the nerve- 
fibres, 339 
Prisms for drawing, 38 ; in the binocular and mul- 
tocular microscopes, 46-48 
Processus vermiformis, 451; facility of injecting the 
lymphatics of, in the rabbit, 201, 451 
Procuring a microscope, 69 
Prostate, 549 
Prostatic calculus, 549 
Protoplasma, 98; its changes, 98; processes of the 
central ganglion-cells, 350, 351; those of the reti- 
na, 399 
Prussian blue, 181-183 ; as a medium for impregna- 
tions, recommended by Leber, 169; soluble, 183 
Psorosperms of the rabbit, 438 
Pulp of the spleen, see Spleen 
Pulp of the teeth, see Teeth 
Punch, 222 
Purkinje, with Valentine, investigates the ciliary 
movement, 265 
Purpurine tingeing, 155 
Pus, 251; cells or corpuscles, 251; emigration from 
the blood-vessels, 248, 261; assumed formation 
in their epithelial cells and connective-tissue cor- 
puscles. 252; amoeboid transformations of the 
cells, 252; their migrations, 252; method of ex- 
amining, 253; acid and alkaline fermentation, 
253; method of preserving, 253; corpuscles in 
small intestines, 465; in sputum, 494; in urine, 
523; in vesical catarrh, 623; in vaginal mucus, 
552; in nasal catarrh, 566 ; occurrence in corneal 
spaces, 583 
Pyramidal processes of the kidney, 502 
Pyrogallic acid, 159 
Pyroligneous acid, its use in histology, 131 
Pyrosis, vomiting in, 486 
Pharyngeal mucous membrane, 423 
Photogenic lamp, 43 
Photographic microscopes, 41-42; their arrangement, 
according to Gerlach, 41; according to Moitessier, 
42 ; manipulation, 43, 44 
Photography, microscopic, 40; observations on, by 
Gerlach, Beale, and Moitessier, 40 ; its application, 
44; used by Gerlach for increasing the enlarge- 
ment, 45 
Picking preparations, 105 
Picric acid, recommended by Schwarz for tingeing, 
132; by Ranvier for hardening tissues, 132 
Picro-carmine of Ranvier, 153 
Pigment-cells, polyhedral, see Epithelium; stellate, 
585 
Pigmentation, abnormal, see The Several Organs 
Pigmented epithelium (polyhedric pigment-cells), 
see Epithelium of the uvea, 584 
Pipette, 116; for titrition, 142 
Pityriasis versicolor, 560 
Plaques, Peyerian, 451 
Plasma-cells of the connective tissue, by Waldeyer, 
281 
Pleura, 493 
Pleurosigma angulatum as a test-object, 63; its res- 
olution by Hartnack’s microscope, 65 
Plexus myentericus of Auerbach, 846 
Plossl’s microscopes, the older, 11; modern instru- 
ments, 76 
Polarizer, 49 ; its position, 49 
Polarizing microscope, 49 
Polishing sections of bones and teeth, 299 
Porrigo decalvans, 559; favosa, 560 
Positive eye-piece of Ramsden, 15 
Potash, 133; chlorate of, in combination with nitric 
acid, 135; acetate of 135, 217; caustic, 183; car- 
bonate, 219; potash solutions, weak and strong, 
138, 134; Moleschott’s solutions, 133 ; Schultze’s, 
133 ; and iron, cyanide of, 182 
Powell and Lealand, their immersion objectives 
tested by Harting, 60; their microscopes, 76 
Preparation instruments for microscopical investiga- 
tions, 105 ; their simplicity, 105 
Preparation of microscopical objects, 103; avoiding 
too large pieces, 88, 105 
Preparations, cementing of, 221; fastening the cells 
with marine glue, 224; process, 224; with gutta- 
percha cement, 224 ; with india-rubber, dissolved 
in chloroform, 225 ; cement frames, 225 ; laying on 
the covering glass, 226; the rotary table, 226; 
cementing with asphalt lac, 227; Bourgogne’s do., 
227; gold size, 228; Ziegler’s white cement, 228; 
black mask lac, 229; cementing Canada balsam 
preparations with shellac varnish, 329 
Preparations for a cabinet, how to make them, 207; 
preserving in weak alcohol, 207 ; dry preparations, 
208; dry, in Canada balsam, 208; with heating, 
209; without heating, 210; with Canada balsam INDEX, 
621 
Quekett’s injections, 173; recommends dilute me- 
thyl alcohol as a preserving fluid, 220 ; designation 
of the proper variety of marine glue for cement- 
ing, 224 
Q. 
Rod-cells of the kidney, according to Heidenhain, 
511 
Bods of the retina, 594 
Rollett recommends lime and baryta water for con- 
nective tissue, 134; on blood-crystals, 242; dis- 
solves the connective tissue of muscles in hermeti- 
cally sealed tubes by slight warming, 324; demon- 
stration of the connective-tissue fibriihe, and their 
double arrangement, 282; on gastric glands, 431; 
on the cornea, 577 
Boot-sheath, see Hairs 
Boss, A., increases the angle of aperture of objec- 
tives, 57; his microscopes, 76; his binocular ste- 
reoscopic microscope, 47 
Rotary disk, 22 
Rouget on the termination of the nerves in the vol- 
untary muscles, 864 
Rubber, its use in microscopic drawing, 37 
Ruysch’s injections, 173 
E. 
Rachitis, 811 
Radial fibres of the retina, 593 
Ramsden’s eye-piece, 15 
Ranvier, his work, xi., xii.; recommends picric 
acid, 132; picro-carminc, 153; glycerine with 
formic acid, 216 ; studies of connective-tissue cells, 
280; method for examining the tendons, 286; 
constriction rings of the nerve-fibres, 338 
Razors, 107; English, 107; Swiss, 108; form of the 
blade, 107 ; grinding and sharpening, 107 
Reagents, chemical, 122; their use, 122; method of 
application to the microscopic preparations, 122; 
their more prolonged action, 123; accurate deter- 
mination of their strength, 123 
Recklinghausen, Yon, recommends nitrate of silver, 
137, 162; his moist chamber, 99; investigates the 
amoeboid cell movements, 98, 252; discovers the 
formation of red blood-corpuscles from the lym- 
phoid cells in the frog, 237 
Reduction table of the millimetre and the Paris 
s. 
Sago spleen, 484 
Saliva, 429 
Salivary corpuscles, 429; of the tonsils, 425 ; move- 
ments of their granules, 429 
Salivary glands, 426 
Saemisch, with Muller, examines the corneal nerves, 
370 
line, 35, 36 
Reichert’s connective-tissue theory, 281; R. and 
Paulsen’s use of nitric acid for the study of the 
smooth muscles, 125, 318 
Beinicke recommends frustulia Saxonica as a test- 
object, 63 
Reissner on the cochlear canal, 604 
Refraction, index of, of anis oil, acetic acid, glyce- 
rine, Canada balsam, oil of turpentine and water, 
118 
Refractive power of the fluid medium and of the 
object, 118 ; of the fluid media changes the micro- 
scopic image, 118 
Regio olfactoria, 566 
Relief, relations of, of microscopic images—see Mi- 
croscopic Images 
Bemak discovers the pale fibres of the sympathetic 
nerve, 340 ; demonstrates the corneous and intes- 
tinal gland layer, 414; investigates the develop- 
ment of the liver, 464 
Resolving power of the microscope, 57; its relations 
to the angle of aperture, 57 
Respiratory apparatus, 485; larynx, trachea, and 
bronchi, 485; lungs, 485; methods of examination, 
486; drying, 486; hardening, 486; infundibula, 
and alveoli, 487; method of demonstration, 487; 
corrosion method, 487; closer examination of the 
pulmonary vesicles or alveoli, 487; pulmonary 
epithelium, 489; injection of the blood-vessels, 
489 ; lymphatics, 490; nerves, 490 ; fcetal lungs, 
490 ; changes in disease, 490 ; pigmentations and 
their signification, 490; anthracosis, 491; pus- 
corpuscles, 491 ; inflammation, 491; tuberculosis, 
492; origin of the tubercular elements, 492; soft- 
ening, 493; caverns and the nature of their walls, 
493; pleura (pericardium and peritonaeum), 493; 
sputum, 493; constituents of the latter, 494; mu- 
cus and pus corpuscles, 495; granule-cells (in- 
flammatory globules), 495 ; pigment-cells, 495 ; 
blood, 496 ; elastic fibres, 496 ; crystals of ammo- 
nio-phosphate of magnesia, 497; method of exam- 
ination, 496 
Retina (visual apparatus), 590 
Richardson, his bine injection mass, 187; on lym- 
phoid cells, 251 
Riddell’s binocular stereoscopic microscope, 47, 80 
Riff cells of Schultze, 266 
Rindfleisch uses oil of cloves, 142 ; directions for the 
treatment of the lungs, 486 
Ripmann n§es strong muriatic acid for the division 
of the tongue muscles, 424 
Robin’s leptothrix buccalis, 428 
Rodig’s diatome test-plate, 63, note; his preparations, 
232 
Sandarac resin in alcoholic solution, 214 
Sarcina ventriculi in the contents of the stomach, 
487 ; in the urine, 525 
Sarcine or hypoxanthine in the liver, 472; in the 
urine, 530 
Sarcolemma, see Muscles 
Sarcoma, 259; adenoid, of the lacteal glands, 544 
Sarcoptes hominis, 560 ; method of examining, 561 
Sarcous elements, see Muscles 
Saws for fine sections of hard tissues, 115 
Scabies, 560 
Scala media of the cochlea, 604 
Scales of the papiiio janira, 61 
Scall (porrigo favosa), 560 
Scanzoni, with Iviilliker, examines the mucus of the 
female genitals, 542 
Schaoht recommends black mask lac, 229 
Schiek’s older microscopes, 11: later instruments 
76 
Schicfferdecker, his microtome, 108; on the spinal 
cord, 358 
Schlemm’s canal, 584 
Schmidt, C., goniometer, 36 
Schonn on the sarcous elements of muscles, 329 
Schriin’s investigations of the ovary, 537 
Schulze, E. E., employs chloride of palladium, 137 
168 ; examines the Becher cells of the epithelium’ 
437, 438 
Schulze’s reagent, 125, 135 
Schultze recommends iodine-serum as an indifferent 
fluid, 121; his warm stage, 101; compares objec- 
tives by central illumination with Robert's latest 
test-plate, 68; recommends very dilute solutions 
of chromic acid, 128; of bichromate of potash, 
136 ; of sulphuric acid, 124, note ; oxalic acid, 129 ; 
potash solutions, 133; osmic acid, 182, 164; solu- 
tion of acetate of potash for mounting, 217; on 
stachel and riff-cells, 266 ; on primitive fibrill® in 
the axis cylinder, 389; on the complex structure 
of the ganglion-cell, 351; examines, with Key. the 
termination of the gustatory nerve in the frog’s 
tongue, 564; investigations of the olfactory mucous 
membrane, 567; follows the olfactory nerve to its 
termination, 569; on the retina, 591-601; on the 
terminations of the auditory nerve, 603 
Schwalbe on gustatory buds, 568 ; on the lymphatics 
of the eye, 575 
Schwan teaches that the cell is the elementary struc- 
ture of the animal body, ix 
Schwarz invents double tingeing with picric acid and 
carmine, 159 
Schweigger-Seidel recommends glycerine and water, 622 
INDEX, 
121; acid carmine mixture, 152; on the kidneys, 
504 
Scioptioon, 44, note 
Scissors, 105 
Sclerotic, 584 
Screw for moving the microscope, 21; fine (micro- 
meter screw), 21 
Screw micrometer, 32 ; divisions of that of Schiek 
and Plossl, 82 ; in the eye-piece, 32 
Sebaceous glands of the skin, 555, 556; development 
in the foetus, 558; their cells, 416, 417; formation 
of these glands in cysts of the ovaries, 539 
Sections through hard objects, method of making, 
115, 299 ; through very small objects, 113 
Seibert’s microscopes, 25, 31, 77 
Seiler, 0., his section-cutter, 113 
Selenite plates, 51 
Self-injection of the living animal, 190 
Selligue, see Chevalier 
Semen, 550 
Seminal canaliculi, 545; filaments. '550; stains, 
their investigation, 553; vesicles, 549 
Sense, organa of, 554 
Serous glands, 416, 423 
Serres fines, 198 
Shading microscopic drawings, 37 
Sharpey’s fibres of bones, 303 
Shellac varnish, with anilin blue or gamboge, for 
cementing Canada balsam preparations, accord- 
ing to Thiersch, 229 
Silver, acetate of, 164 
Silver, citrate of, 164 
Silver impregnation, 162; Kecklinghausen’s method, 
162 ; duration of the action, 162; with the subse- 
quent action of common salt, 1.64; His’ method, 
164 ; Legros’, 162; Thiersch’s, 164; with other 
salts of silver, 164 
Silver, lactate of, 164 
Silver mosaic in the blood-vessels and lymphatics, 
163, 382, 399 
Silver, nitrate of, 137, 162 
Silver, piorate of, 164 
Silver wire for supporting the covering glass, 222 
Size, apparent, of an object determined by the an- 
gle of vision, 1 
Skin, 554; its structure, 554 ; epidermis, 654; Mal- 
pighian rete mucosum, 554; corium, 554 ; sudori- 
parous glands. 555 ; sebaceous follicles, 556 ; blood- 
vessels, 556 ; lymphatics, 556; cutaneous nerves, 
557 ; fcetal skin, 558 ; cabinet objects, 562; path- 
•. ological changes of the skin, 558; inflammatory 
conditions, 558; hypertrophies, 658; elephantia- 
sis, 558; warts and condylomata, 558; vascular 
nasvi, and teleangiectasia, 558; cysts, 553; athe- 
romata, 558; comedones, 559; milium, 559; vege- 
table parasites, 559; tricophyton tonsurans, 559 ; 
miorosporon Audouini, 559; miorosporon menta- 
grophytes and furfur, 559, 560 ; achorion Schon- 
leinii, 560; animal parasites, 560 ; demodex folli- 
culorum, 560 ; sarcoptes hominis, 660 
Slides, 103 ; various forms, 103, 280; with protec- 
tion ledges, 231 
Sliding arrangement on objectives with correcting 
apparatus, 18 
Smith and Beck’s microscopes, 31, 76 
Soda solutions, 134; phosphate of, 136; nitrate of, 
136 ; hypoohlbrate of (eau de Javelle), l3s 
Soemmering’s injections, 173 
Softening dried sections, 130, 170 
Solitary glands, 447 
Spectral apparatus of Merz, 51; of Hartnack and 
Prazmowsky, 51, 52 
Spencer, Charles A., notice of, 77 
Spherical aberration of lenses, 8 
Spinal cord (see Nervous System), 348 
Spleen, 476; difficulty of the examination, 476; the 
fresh organ, 477: hardening methods, with alco- 
hol, chromic acid, and chromate of potash, 477- 
478; sections, 478; hardening pathological organs, 
478; mounting, 479; results of investigations, 
479; Malpighian corpuscles, 479; pulp and its 
canals, 480; blood-passages, 481; flakes contain- 
ing blood-corpuscles, 481 ; lymphatics, 482; 
Tomsa’s statements, 482; trabecula?, 482; nerves, 
482; changes in disease, 482; in leucaemia, 483; 
in abdominal typhus, 483; miliary tubercle, 483 ; 
hemorrhagic infarction, 488 ; hypertrophy, 488; 
pigmentation, 484; amyloid degeneration, 484; its 
two varieties, 484; mounting diseased spleens, 
484 
Sputum, 493-497 
Stachel (and riff) cells of Schultze, 266 
Stage of the simple microscope, 5 ; of the compound, 
20 ; rotary of the horseshoe stand, 29 
Stage, warm, of Schultze, 101; its defects according 
to Bngelmann, 101 
Starch granules in the saliva, 429; in vomited mat- 
ters, 435 ; in the small intestine, 453; in the feces, 
454 
Starch, reactions of, 182, 435 
Steel needles, 105 
Stein on micro-photography, 44 
Stereoscopic microscope, 47 
Stieda recommends creosote for rendering prepara- 
tions transparent, 141 
Stigmata of the vessels, 384 
Stomach, 430 
Stomata of the vessels, 384 
Strelzoff’s double tingeing, 160 
Sublingual gland, see Salivary Glands 
Submaxillary gland, see Salivary Glands 
Sudoriparous glands, 411, 555; development, 558; in 
cysts of the ovary, 589 
Sulphate of baryta, 179 
Sulphate of iron, 181 
Sulphuric acid, concentrated, 123 ; with iodine, 132; 
dilute, 124 ; very dilute, according to Kuhne, 124; 
action on the tissue of the hair, 271; on the nails, 
269; on the crystalline lens, 588 
Supra-renal glands, 580 ; structure of, 530 ; nerves, 
blood-vessels and lymphatics, 532; methods of in- 
vestigation, 532 
Surirella gemma, as a test-object, 62, 65; its trans- 
verse lines resolved into areolations by Hartnack, 
66 
Sympathetic nerve-fibres, 389; ganglia, 342-348 
Syphilis corpuscles of Lostorfer, 255 
T. 
Tactile bodies, 372 
Tactile cells of Merkel, 374-375 
Taenia booklets in the feces, 458 
Taenia mediocanellata, ova of, in feces, 458 ; solium, 
ova of, in faeces, 458 
Tannic acid, 159 
Taurine in the feces, 455 
Teeth, 296; decalcifying, 296-297; decalcified en- 
amel, 303; chemical isolation of the dentinal 
tubes, 298 ; sections, and the method of preparing 
them, 298-299; mounting, 300 ; carious teeth, 303 ; 
enamel, 303; sections, 304; isolation of the prisms, 
304; tooth-pulp, 304; development of the teeth, 
804; methods, 305 ; formation of teeth in the em- 
bryo, 305 ; in cysts of the ovaries, 539 
Teichmann recommends .chloride of silver for injec- 
tions, 180 ; employs the puncturing method for in- 
jecting the lymphatics, 201; shows how to make 
crystals of haemine, 243 ; on blood-crystals, 241 
Telangiectasia, 558 
Tendons, Eanvier’s method of examining, 286 ; rela- 
tion to the muscle. 324-325 
Terminal knobs, 372, 573; plates of the voluntary 
muscles, 364 
Termination of the nerves, see Nerves. 
Test acid, 143 
Test alkali, 143 
Test-objects, 60; their value, 60 ; enumeration of 
the most important ones, 61-68 
Test-plate of Nobert. 33; as a test object, 67-68 
Testicle {see Sexual Organs), 545 
Testing the microscope, 53; its magnifying power, 
53; the correction of spherical and chromatic 
aberration, 54-55; the plane field of vision, 55; 
the latest immersion systems, by Harting, 59 INDEX, 
623 
Theory of the microscope, 1 
Thiersch’s injections, 173; various injection masses: 
red, 185; blue, 181; yellow and green, 185-186; 
tingeing methods, 150; with carmine and oxalic 
acid, 150; and borax, 151; with indigo-carmine, 
156 ; method of impregnating alcohol prepara- 
tions with silver, 164; mounting for Canada bal- 
sam preparations, 229 
Thrush (oidium albicans) in the oral cavity, 429; in 
the stomach, 437 
Thymus gland, 499; its structure, 499; canal sys- 
tem, 499; vascular arrangement, 319 ; concentric 
bodies, 169, 320; methods of examining, 500; 
lymphatics of, cannot be injected, 500 
Thyroid gland, 497 ; relationship with other organs, 
497; blood- and lymph-passages, 498; structure, 
497-498; method of investigation, 498; colloid de- 
generation and goitre, 498-499 
Tin chest for injections, 195 
Tin-foil cells, 225 
Tingeing, 147 
Tingeing methods, 147; with red coloring matters, 
147; blue, 156; with carmine, invented by Ger- 
lach, 147; directions for carmine tingeing, 148; 
for injected tissues, 150 ; with glycerine-carmine, 
according to Frey, 149; with Thiersch’s carmine, 
150 ; lilac, according to Thiersch, 151; according 
to Beale, 151: Heidenhain’s modification, 152 ; 
Schweigger-Seidel’s acid carmine tingeing, 152; 
with picro-carmine, according to Kanvier and 
Flemming, 153; with aniline red, according to 
Frey, 154; purpurine tingeing, 155 ; eosine tinge- 
ing, 155; with aniline-iodine violet, 155 ; with 
blue coloring matters, 156; with indigo-carmine, 
156; with aniline blue, according to Frey, 167 ; 
Heidenhain’s and Kollett’s modification, 157 ; with 
Parme soluble, 157; with chinoline blue (cyan- 
ine), 158 ; with violet, hsematoxyline, 158; bluish, 
with the molybdate of ammonia, according to 
Krause, 159 ; double tingeing with picric acid and 
carmine, by Schwarz, 159; with carmine and in- 
digo-carmine, 160 ; with indigo-carmine and pic- 
ric acid, 160 ; with htematoxyline and carmine, by 
Strelzoff, with hmmatoxyline and picric acid, 161; 
Gerlach’s complicated tingeing, 161 
Tissue cement of the epithelium, 259; of the mus- 
cles, 825 
Titrition apparatus, 142 ; method, 143 ; examples, 
145-146 
TT. 
Ulcers, 252 
Urate of ammonia, 525, 528 ; of soda, 525 
Urea, nitrate and oxalate of. 530 
Ureter, 522 
Urethra, 522 
Uric acid, 526 ; infarctions, 621; salts 525 
Urinary fermentation, acid, 526; alkaline 529 
?5galls’ 502 ; importance for the ’physician, 
• ’ kld>ieys with medulla and cortex, 502; earlier 
views, 503 ; Henle’s newer observations, 503 • later 
investigations, 504; method of examining 504- 
hardening, 505; longitudinal and transverse sec- 
tions, 500-506; chemical isolation. 507; injection 
of the uriniferous canals, 612; Heidenhain’s more 
recent investigations, discovery of the rod-cells 
511; self-injection, 514; diagram of the course of 
the canalicules, 513; arrangement of the vessels 
514; vasa recta, 515 ; double injection, 517 ; selec- 
tion of material, 517 ; framework substance 517 - 
lymphatics, 517; pathological changes, 518; im- 
portance of the gland-cells and framework, 518 * 
hypertrophy, tubercle, fatty, pigment, and amy- 
loid degeneration, 518, 519; Bright’s disease, 520 ; 
precipitates in the uriniferous canals, 521; uric 
acid and lime infarctions, 621, 522; calices and pel- 
vis of the kidney, ureters, and bladder, 522 ; epi- 
thelium of the bladder, 522; urine, see this 
Urinary sediments, 525; method of examination, 
530 
Urine, 523 ; fresh, normal, 523; constituents, 523; 
abnormal constituents in disease: epithelium, mu- 
cous, and pus-cells, blood corpuscles, 523; fibrin or 
exudation cylinders, 523 ; sarcjna ventriculi. 525 ; 
sediments of crystalline and amorphous substances, 
525; urate of soda, 525 ; acid fermentation, 526 ; 
uric acid of various crystalline forms, 526; oxalate 
of lime, 527; fermentative fungi, 529 ; ammonio- 
phosphate of magnesia, 528; urate of ammonia, 
528 ; formation of mould and vibrion® in alkaline 
urine, 529; crystals of cystine, 529; leucine and 
tyrosine, 529 ; urea combined with nitric and oxa- 
lic acid, 530 ; sarcine and xanthine, guanine, 530 : 
method of examining the precipitates, 530 
Uriniferous canalicules, 502; loop shaped of the kid- 
ney, according to Heule and others, 503-507 
Uterine cancer, 541 
Uterine fibroids, 541 
Uterine glands, 540 
Uterine polypi, 541 
Uterus (see Sexual Apparatus), 540 
Uvea, 584 
Toldt’s recommendation of benzine, 278; self-injec- 
tion of the lymphatic glands, 405 
Tolies, 8,. 8., notice of, 80 
Tomsa, see Ludwig; T. on the spleen, 482 
Tongue (see Digestive Apparatus), 424 ; muscular 
tissue, 424; division of the muscular filaments, 
424; connection with connective-tissue corpus- 
cles, 424; nerves, 424, 562; their terminations 
examined by Schultze and Key, 564 ; modified by 
Engelmann, 564; follicular glands, 425 
Tonsils, 425 
Topping’s fluid, 220 
Trachoma glands of the conjunctiva, 574; their 
lymphatics, 574: method of injection, 574 
Transparent, reagents for rendering tissues, 118 
Transparent soap, as an embedding medium, ac- 
cording to Flemming, 114 
Trichina spiralis in muscles, 332; examination of 
the trichinized muscles, 833; trichina in the 
fasces, 456; microscopes for examining, 833, note 
Tricocephalus dispar, ova of, in the fasces, 456 
Trichomonas vaginalis, 542 
Trichophyton tonsurans, 559 
Tube of the microscope, 20 
Tubercle, 289 
Tubular glands, see Glands 
Turn-table, Prey’s improved, 226 
Turpentine, oil of, its property of rendering tissues I 
transparent, 141; index of refraction, 118; me- j 
dinm for dissolving Canada balsam, 141; removal ! 
of the preparation from alcohol to oil of turpentine, 
and from this to Canada balsam, 212 
Tympanic cavity, 602 
Tyrosine in the liver, 472; in the urine, 529 
Y. 
Vagina, 541 
Vaginal mucus, 542 
Valentine, his double knife, 107; the older form and 
the English improvement, 107; his and Furkinje’s 
examination of the ciliary movement, 265 ; exam- 
ines the behavior of muscles in polarized light 
331; the nerves, 341 
Vas deferens, 647 
Vascular new formations, 396 
Vaterian bodies, 376 
Veins, see Blood-vessels 
Vestibule of the fish, sacculi of the, 603 
Vessels, see Blood- and Lymph-vessels; for titrition, 
see Titrition Method 
Vibrionse, see Bacteria; formation of, in alkaline 
urine, 529 
Vinegar, 131; boiling the kidney in, recommended 
by Billroth, 507 
Vision, angle of, determines the apparent size of an 
object, 1 
Vision, distance of, medium, 3 
Vision, field of, levelling the same, and correction of 
the image by the collective lens, 12 
Visual apparatus. 672; eye-lids, 672; Meibomian 
and lachrymal glands, 572. 573 ; conjunctiva, 573; 
coil-shaped glands, terminal knobs, 573 ; blood- 624 
INDEX, 
vessels, lymphatics and trachoma glands, 573-574 ; 
eye-ball, 575 ; method of injecting and examining, 
575-576, cornea, 577; methods of examining, 577- 
578; pathological changes, 582; development and 
immigration of pus corpuscles, 683 ; sclerotic, 584; 
uvea, 584; pigment epithelium, 584; choroid 
with its layers, 585-586; chorio-capillaris, 585 ; 
senile metamorphoses of the elastic lamellae, 586 ; 
ins, 586 ; vitreous body, 587; lens, 587 ; its meta- 
morphoses, 589; its development, 589; rnembrana 
hyaloidea, 589; zonula Zinnii, 590; retina, 590; 
its structure, 591; various layers, 591 ; connec- 
tive-tissue framework, 592; method of investiga- 
tion, 592; rods and cones. 594; intergranular 
layer, 593; rnembrana limitans, 593; granular 
layer, 596 ; layer of ganglion cells, 597; nerve 
fibres, 597; conjectured arrangement of the ele- 
ments, 597 ; latest discoveries concerning the rods 
and cones, 599; vessels, 600; pathological condi- 
tions, 600 ; fcetal eyes, 601 
Virchow’s discovery of haematoidine, 244; direc- 
tions for isolating bone cells, 297 ; for reproducing 
the ciliary movements, 264 
Vitreous body of the eye, 275, 587 
Vix gives directions for the examination of helmin- 
thian ova in the human faeces, 456 
Vomited substances (comp. Digestive Apparatus), 
435 
| Water, its use, 118 ; index of refraction, 118; is 
| not an indifferent fluid, 118, 120 
' Water, removal of, from the tissues by means of 
I alcohol, 188, 141, 212 
Wax as an injection mass, 173-176 
, Waxy liver, 474 
| Weismann shows how to ascertain tne relation of the 
muscular fibres to the tendon by means of potash 
solutions, 824 
Welcker’s method of distinguishing between ele- 
vated and depressed surfaces, 95; shows how 
microscopic images are changed by the refractive 
power of the fluid media, 118 
Wenham’s arrangement of the binocular stereoscopic 
microscope, 47 
Whetstone, rotary, 115 
Wittich’s method of isolating striated muscles, 323 
Work-room of the microscopist, 83 
Work-table of the microscopist, 92 
X. 
Xanthine in the liver, 473 ; in the urine, 580 
Y. 
w. 
Yolk, see Ovum 
/. 
Wagner, E., on the liver, 469; on fat embolia of the 
capillaries, 396 
Wakleyer’s paddle-wheel cells and plasma cells of the 
connective tissue, 280 ; studies on carcinoma, 289, 
290 ; axis fibrilhe of the nerves, 339; investigation 
of the cochlear canals, 605, 606 
Wales, Wm, notice of, 80 
Warming the gelatine masses for injections, 175, 
196, 198 
Warts, 558; dry, 269 
Watch-glasses, 103 
Water-bath for gelatine injections, 198 
Water-colors for microscopic drawings, 37 
Zawarykin and Ludwig on the kidney, 504 
Zeiss’ microscopes, 25, 75; new dissecting micro- 
scope, 106 
Zenker describes the changes of the muscles in 
typhus, 332 
Zentmayer, J., notice of, 80 
Ziegler’s cement, 225, 228 
Zinc white, as an injection mass, 179 
Zona pellucida, see Ovum 
Zonula Zinnii, 590 
Zooglcea (Cohn), 254 
Zoosperms, see Seminal Filaments. PRICE-LISTS. PRICE-LISTS OF MICROSCOPE FIRMS. 
No. 1 •ice-List of the Achromatic Microscopes of Dr. E. Hartnack, 
JVo. 39 Waisen Strasse, Potsdam (1879). 
Price in Francs and Marks. 
Remarks.—All microscopes are contained in a mahogany case, furnished with a lock and key. 
The microscopes 1, 2A, 8, and 3A, are furnished with lens systems of older construction ; the remainder 
have new lens systems, with large angles of aperture. 
The polarizing apparatus may be used most advantageously on microscopes Nos. 7, 7A, and 8. 
From the following tables other systems and eye-pieces, which are required in the place of the custom- 
ary ones, as, indeed, any desired outfit, may be readily reckoned. 
A. Prices of the Microscopes. 
No. I.—Small microscope (d’hospice), with a lens system No. 7, and an eye-piece No. 3; magnify- 
ing power, 300; with a dozen slides and thin covers, brass forceps, scalpel, and preparing 
needles 75 fr. 60 marks. 
No. lIA.—Microscope with firm stage, micrometer screw over the stem; mirror freely movable for 
oblique illumination; with the lens systems 4, 7, and the eye-pieces 2 and 3; magnifying 
power from 50, 65, 220, and 300, and an illuminating lens for opaque bodies.. 136 fr. = 108 marks. 
The same instrument, with the addition of objective No. 8 and eye-piece No. 4; magnifying power, 
50-600 185 fr. 148 marks. 
No. 111.—Microscope, with the upper portion of the stand similar to the previous one; with horse- 
shoe foot; freely movable mirror for oblique illumination ; optical apparatus the same, 
155 fr. 124 marks. 
To obtain a magnifying power up to 600 205 fr. = 164 marks. 
No. lIIA. Microscope similar to the previous one, but with a joint on the stem for obtaining an 
oblique position ; optical apparatus the same 170 fr. zz 136 marks. 
To obtain a magnifying power up to 600 220 fr. z: 176 marks. 
No. Vl.—Dissecting microscope, with long focal distance and inversion of the image ; magnifying 
power (without changing the lenses or eye-pieces) from 10-100, rotary stage, with glass 
plate 250 fr. = 200 marks. 
No. Vll.—New, large microscope, the mechanical and optical construction of which differ essen- 
tially from the older large stand. It consists of 5 lenses, systems 2, 4, 5, 7, and the immer- 
sion and correction system 9, and 5 eye-pieces (one of which has a micrometer) ; magnifying 
power from 25-1,300 (each succeeding enlargement twice as great as the previous one). 
Coarse movement by an adjusting screw, the fine one by a micrometer screw. Large illumi- 
nating lens for opaque objects; all the necessary accessory apparatus 750 fr. zr 600 marks. 
The same instrument, with a joint for inclining 800 fr. = 640 marks. 
No. VllA.—Microscope similar to the previous one, but smaller, and with a lower stage; optical 
arrangement the same 650 fr. = 520 marks. 
The same instrument, with a joint for inclining 680 fr. = 544 marks. 
No. VIII.—New small stand, the arrangement of which, with the exception of the rotation of the 
stage and the coarse movement by means of a rack, presents the same advantages as No. 7, 
with the objectives Nos. 4, 7, 8, and eye-pieces 2, 3, and 4; magnifying power, 50-650, 
275 fr. = 220 marks. 
The same instrument, with the systems 4, 7, and 9, the latter with immersion and correction; 
3 eye-pieces, one of which is provided with a micrometer, magnifying 50-1,000, 390 fr. = 312 marks. 
The same, with a joint for inclining 405 fr. zr 324 marks. 628 
PRICE-LISTS OF MICROSCOPE FIRMS. 
B. Brices of the Individual I<ens Systems, and of the other Accessory 
Apparatuses. 
LENS SYSTEMS OP OLDER CONSTRUCTION. MAGNIFYING POWER WITH THE 
EYE-PIECES. 
System. 
Eye-piece 
No. 1. 
No. 2. 
No. 3. 
No. 4. 
No. 5. 
No. 6. 
Price. 
No. 1 
12 
15 
25 
20 francs 
20 “ 
20 “ 
16 marks. 
16 “ 
16 “ 
10 “ 
24 “ 
28 “ 
28 “ 
32 “ 
48 “ 
2 
20 
30 
40 
3 
SO 
40 
50 
4 
40 
50 
65 
150 
100 
200 
20 “ 
30 “ 
5 
75 
100 
6 
no 
150 
220 
300 
35 “ 
7 
150 
220 
300 
450 
600 
850 
35 “ 
40 “ 
8 
250 
300 
400 
800 
1000 
9 
360 
430 
520 
60 « 
NEW LENS SYSTEMS, WITH LARGE ANGLES OP APERTURE, 
System. 
Equivalent 
focus in 
inches. 
Eye-piece 
No. 1. 
No. 2. 
No. 3. 
No. 4. 
No, 5. 
No. 6. 
Price. 
No. 1 
2 
15 
20 
25 
20 francs. 
16 marks. 
2 
1 
25 
30 
45 
20 
16 
3 
X 
50 
CO 
80 
120 
30 
24 
4 
X 
CO 
70 
90 
140 
30 “ 
24 
5 
X 
100 
125 
160 
240 
35 
28 
6 
X 
150 
180 
240 
350 
40 
32 
7 
1-C 
200 
240 
300 
450 
COO 
750 
40 
32 
8 
1-9 
250 
300 
400 
COO 
800 
1000 
50 “ 
40 
9 
1-11 
850 
400 
550 
860 
1100 
1400 
75 “ 
60 
NEW SYSTEMS WITH IMMERSION AND CORRECTION. 
System. 
Equivalent 
focus in 
inches. 
Eye-piece 
No. 1. 
No. 2. 
No. 3. 
No. 4. 
No. 5. 
No. 6. 
Price. 
No. 9.... 
1-12 
410 
480 
630 
950 
1300 
1500 
150 francs. 
120 marks. 
10.... 
1-16 
520 
600 
750 
1100 
1500 
1800 
200 “ 
160 
11.... 
1-18 
600 
690 
850 
1250 
1750 
2500 
250 “ 
200 
12.... 
1-21 
710 
820 
1010 
1490 
2060 
2800 
300 “ 
240 
13.... 
1-25 
820 
950 
1170 
1730 
2370 
3100 
350 “ 
280 
14.... 
1-30 
930 
1080 
1340 
2000 
2680 
8850 
400 “ 
320 
15.... 
1-33 
1040 
1200 
1500 
2200 
3000 
3600 
450 “ 
360 
16.... 
1-40 
1200 
1400 
1750 
2570 
3500 
4200 
500 “ 
400 
u 
17.... 
1-45 
1400 
1600 
2000 
2940 
4000 
4800 
600 “ 
400 
(( 
18.... 
1-50 
1560 
1800 
2250 
3300 
4500 
5400 
500 “ 
400 
u 
Plain eye-piece, Nos. 1, 2, 3, 4, and 5 10 fr. = 8 marks. 
Holosteric eye-piece 15 fr. =l2 “ 
Spitzen eye-piece 25 fr. =2O “ 
Micrometer eye-piece 25 fr. =2O “ 
Binocular stereoscopic eye-piece, which shows the objects erect 180 fr. = 144 “ 
Movable stage 60 fr. =4B “ 
New compressorium 80 fr. =24 “ 
Stage micrometer, mounted in brass, the millimetre divided into 100 equal parts 20 fr. =l6 “ 
New movable micrometer (gives accurately 0.0001 millimetre) 50 fr. =4O “ 
Improved patent polarizing eye-piece, a prism with a large field, and a graduated circle, 60 fr. =4B “ PRICE-LISTS OF MICROSCOPE FIRMS. 
Goniometer fiO fr. = 48 marks. 
Universal goniometer 150 fr. = 120 “ 
Spectral apparatus for microscopical studies, with prisms in rectilinear arrangement, tubes for the 
fluids for comparison of the absorptions 120 fr. = 96 marks. 
Dujardin’s illuminating apparatus (improved construction) 50 fr. =4O “ 
Camera lucida of Oberhiiuser; also serving for the conversion of the vertical into the horizontal 
microscope 50 fr. = 40 marks. 
Camera lucida of Milne-Edwards and Doyere 35 fr. = 28 marks. 
Brucke’s loup (improved construction) 20 fr =l6 marks. 
Stand for this loup 80 fr. = 24 marks. 
Lamp for microscopic examinations, with a large lens for obtaining parallel rays ; to use with gas 
or petroleum 85 fr. = 28 marks. 
Loup for ophthalmologists 10 fr. = 8 marks. 
Loups 5-15 fr = 4-12 marks. 
Object slides, first quality, per dozen 2 fr. 50 cts. = 2 marks. 
“ “ second “ “ 1 fr. 25 cts. = 1 mark. 
Covering glasses, per dozen 1 fr. 25 cts. = 1 mark. 
“ “ per hundred 6 fr. 25 cts. = 5 marks. 
No. 2.—Nachet & Son, 17 Hue Saint Severing Paris (1879). 
Prices in Francs. 
1. Microscope, large model, improved, complete and binocular, suspended on the axis in such a 
manner that it may be inclined and remain fixed in any position between the horizontal and 
vertical. Coarse adjustment by rack-work; two movements for fine adjustment, one acting 
on the column supporting the body, the other very delicate and belonging especially to the 
tube carrying the objectives, and so disposed as to establish a constant elasticity for the pro- 
tection of the objectives in case of contact with the preparation. The stage is rotable, and 
is furnished with a double plate, and so arranged that the objects may be moved without 
touching them. The stage is furnished with a glass plate to resist the destructive effects of 
reagents. Illumination by a double mirror movable in all directions. A sliding arrangement, 
placed between the mirror and the stage, permits of the removal of the diaphragms" and of 
focussing the condensers with the greatest precision. Micrometric apparatus for introducing 
the micrometer into the eye-pieces without deranging them, and for accurately adjusting it 
to the focus of the eye, and for placing it in all parts of the field of vision. Eight objec- 
tives with correcting apparatus, from No. 0 to No. 7, magnifying from 30-1,400 diameters; 
four eye-pieces, binocular apparatus, goniometer, camera lucida, polarizing apparatus with 
selenite plates, condenser, eye-piece, and stage micrometers. Condensing lens on a stand. 
Accessories for preparing. Strong mahogany case with brass corners, lined with velvet; 
objectives ; in a separate case 1,400 fr. 
2. Microscope, large model, mounted like No. 1. Rotary stage with a black glass plate for use with 
acids. Rack-work for coarse adjustment, slider for diaphragms and condenser, double mir- 
ror, 3 eye-pieces, 6 objectives, Nos. 0, 1, 2, 3, 5, 7, for immersion and correction, magnifying 
from 30-1,400 diameters. Camera lucida, eye-piece, and stage micrometers, condensing lens, 
accessories for dissections, etc. Mahogany case, brass corners, etc .'6BO fr. 
3. Vertical, large model, rotary stage, coarse and fine adjustment, arrangement for introducing the 
diaphragms and condenser without deranging the object; eye-piece and stage micrometer; 
5 objectives, Nos. 1, 2, 3, 5, 7, immersion and correction, magnifying from 30-1,400 diameters. 
3 eye-pieces, camera lucida, condensing lens, accessories for dissecting, etc. Mahogany 
case, etc 550 fr. 
4. “ Microscope (i disposition particuliere," to reduce the height as much as possible, model of 
Prof. H. de Lacaze-Duthiers—same objectives as in the model No. 8 650 fr. 
5. Microscope, medium model for inclining. Coarse and fine adjustment, rotary stage and glass 
plate, double mirror, apparatus for adjusting diaphragms beneath the object, etc.; 5 objec- 
tives, No. 1, 2, 3, 5, 7, immersion and correction, magnifying, with three eye-pieces, from 80- 
1,400 diameters; condensing lens, accessories, eye-piece, micrometer, etc. Mahogany case, .500 fr. 
6. Vertical, medium model, similar to No. 3; rotary stage, black glass plate, 5 objectives. Nos. 1, 
2, 3, 5, 7; immersion and correction, 3 eye-pieces, eye-piece micrometer, condensing lens, 
accessories 450 fr. 
7. New model for inclining. Immovable stage, black glass plate, coarse and fine adjustment, dia- 
phragm arrangement as in medium models ; condensing lens, 3 eye-pieces, 4 objectives, Nos. 
1, 3, 5, 7; immersion and correction, magnifying from 25-1,400 diameters; condensing lens, 
accessories 430 fr. 
8. Same microscope with 3 objectives, Nos. 1, 3, 5; magnifying 80-700 diameters 280 fr. 
9. Small model for inclining : mirror freely movable, movable diaphragm, coarse and fine adjust- 
ment, draw tube, 2 objectives, Nos. 1, 3; 2 eye-pieces, magnifying from 30-700 diameters; 
condensing lens, accessories 150 fr-. 
10. Small model, vertical. Mirror freely movable; 2 objectives, Nos. 1, 3; 2 eye-pieces, condensing 
lens, accessories. Mahogany case 125 fr. 630 
PRICE-LISTS OP MICROSCOPE FIRMS. 
11. More simple microscope. Cast-iron base, 1 eye-piece, 1 objective, No. 8 ; maximum 380 diam- 
eters, accessories. Mahogany case 80 fr. 
12. Large model, binocular microscope. Constructed in such a manner as that the prismatic appa- 
ratus gives at pleasure stereoscopic or pseudoscopic images. The eye-pieces may be approxi- 
mated or separated according to the distance between the eyes of the observer ; coarse and 
fine adjustment, may be inclined horizontally, 3 objectives, Nos. 0, 1, 3 ; movable stage, con- 
densing lens. Mahogany case 500 fr. 
13. Small model, binocular, for inclining; coarse and fine adjustment, 3 objectives, Nos. 0, 1, 3; 2 
eye-pieces, condensing lens 350 fr. 
14. Binocular apparatus, applicable to all microscopes, with arrangement for adjusting to distance 
between the eyes; 2 eye-pieces, no objectives 150 fr. 
15. Binocular, stereoscopic and pseudoscopic apparatus, applicable to all microscopes 175 fr. 
16. Microscope for two persons, to observe simultaneously the same object. Objectives, Nos. 0, 1, 
3; condensing lens, accessories, etc. ; case 300 fr 
17. Double body to apply to ordinary instruments 2 eye-pieces, no objectives 80 fr. 
18. Microscope for three persons to observe simultaneously; coarse and fine adjustment; each ob- 
server may adjust the focus separately; 3 objectives, Nos. 0, 1, 8; case 400 fr. 
19. New large model, inverted, with a silvered mirror at the crossing of the rays. In this micro- 
scope the distance between the objective and the eye-piece may be increased to 90 centimetres 
or a metre without inconvenience. This combination requires a very delicate construction 
of the mounting. The strongest objectives may be used in this form of instrument, the loss 
of light produced by the silvered mirror (Foucault’s method) being insignificant. Achromatic 
condenser, mirrors, 2 eye-pieces, no objectives 800 fr. 
20. Inverted microscope for chemical studies. The objectives being placed under the object, there 
is no liability of clear vision being impaired by the accumulation of vapors. The stage is 
gilded ; 4 objectives. Nos. 0, 1, 3, 5 ; 1 movable eye-piece, accessories, alcohol lamp on an ar- 
ticulated support, excavated slips of glass, thin covers. Mahogany case 35U fr. 
21. New inverted microscope for the study of anatomical elements in gases at a steady temperature, 
with numerous accessories; 3 objectives, Nos. 1, 3, 5: 2 eye-pieces ; case 500 fr. 
22. Pocket microscope. The instrument is 90 millimetres long by 50 millimetres broad, can be used 
with high powers; objectives Nos. 1, 3, 5 are usually added ; one eye-piece, slides and covers, 
all in a compact leather case 200 fr. 
23. New portable microscope, larger than the preceding one, enclosed in a case, 14 centimetres long 
by 8 broad ; movable mirror; all objectives may be used ; with 8 objectives, Nos. 1,3, 5, and 
1 eye-piece 180 fr. 
24. Dissecting microscope, model of Dr. Cosson. This instrument has on one side an arm for 
carrying the doublets for dissections, and on the other a column with a horizontal support for 
the body of the microscope. It may be used either as a simple or compound microscope at 
pleasure. Coarse adjustment for the doublets, fine for the compound microscope. Two ob- 
jectives, Nos. 1 and 3; eye-piece, 3 doublets, of varying powers; condensing lens; case 140 fr 
25. Stage of this microscope alone, as a simple microscope with 3 doublets, and base, with articula- 
tions for supporting the doublets; accessories; case 50 fr. 
26. Dissecting microscope for laboratories, model of Prof. C. H. Robin. May be used with glass 
dishes or plates of cork on which opaque objects are fixed. It gives erect images and magni- 
fies from 8-70 diameters 120 fr, 
A stage with a mirror may be added for dissecting very small objects 20 fr, 
27. Hand microscope for demonstrations. The instrument may be placed on a stand till the object 
is permanently adjusted, and then passed among the audience. All kinds of illumination 
may be used ; coarse and fine movement; without objective 80 fr. 
28. Microscope on a support, for aquaria, without objective 120 fr, 
29. Photographic microscope, with accessories and a series of objectives 300 fr 
30. Dark chamber, etc 80 fr 
Moitessier’s photographic frames 45 fr. 
MOUNTED IMMOVABLE. 
OBJECTIVES. 
No. 0 15 fr. 1 No. 4 i 36 fr 
1 20 fr. 5 40 fr, 
2 25 fr. I 6 50 fr, 
3...'.'.'.'.'".'.'.’.'.'.’.'.V.so'fr. ! 7.V. .. so fr. 
OBJECTIVES WITH CORRECTION. 
No. 3 50 fr. I No.fi 100 fr, 
4 ..... .... ,60 fr. 7 125 fr. 
5 15 fr. PRICE-LISTS OF MICROSCOPE FIRMS. 
IMMERSION OBJECTIVES. 
MOUNTED IMMOVABLE. 
No. 6 70fr. I No. 7 100 fr. 
No. 6 120 fr. 1 No. 10 800 fr. 
7 150 fr. I 11 350 fr. 
8 200 fr. 12 400 fr. 
9 250 fr. 
IMMERSION OBJECTIVES WITH CORRECTION APPARATUS. 
LINEAR MAGNIFYING POWER OBTAINED BY THE COMBINATION OP THE OBJECTIVES 
WITH THE EYE-PIECES. 
ORDINARY OBJECTIVES, 
0 
1 
2 
3 
4 
5 
11 
SO 
80 
180 
260 
300 
850 
Eye-pieces-; 2 
40 
100 
260 
380 
420 
480 
(3 
60 
140 
S50 
500 
590 
080 
Corresponding focus in inches 
2 
1 
X 
H 
1-5 
Angle of aperture—degrees 
10 
15 
40 
90 
90 
130 
6 
7 
8 
9 
10 
11 
12 
n 
460 
580 
775 
900 
1150 
1320 
1700 
600 
900 
1100 
1300 
1560 
1800 
2400 
Eye-pieces 4 ,> 
900 
1400 
1600 
2000 
2200 
2680 
3260 
( 4 
1200 
1750 
2000 
2500 
2750 
3150 
4500 
Corresponding focus in inches 
1-10 
1-14 
1-15 
1-20 
1-30 
1-40 
1-50 
Angles of aperture—degrees 
140 
160 
175 
175 
175 
175 
175 
IMMERSION AND CORRECTION OBJECTIVES. 
31. Simple microscope for dissections, with doublets, rack-work for coarse adjustment, two wings 
at the sides of the stage for the support ot the hands in fine dissections, with two doublets 
and case 60 fr. 
32. Binocular microscope for dissections, magnifying 10-150 diameters 150 fr. 
33. Section-cutter 60 fr. 
34. “ simplified 35 fr. 
35. Microtome for holding the objects to make sections by hand with glass plate, model of Dr. 
Hayem 18 fr. 
36. Compressor 30 fr. 
37. Eye-pieces, each 10 fr. 
38. Eye-piece micrometer 15 fr. 
]STo. 3. C. Yebick (Pupil of Hartnack), liuede la IJarcheminerie, No. 2, 
Paris (1877). 
Price in Francs. 
No. 1. microscope, with complete stand ; movable binocular arrangement to fit on any other 
"instrument. Coarse movement by a rack, finer by a micrometer screw. Rotary stage covered 
with black glass. The mirror is movable vertically, horizontally, forwards and backwards, to 
permit of oblique illumination in all directions. The vertical movement is very important to 
increase or diminish the intensity of the light, without changing the distance of the 
diaphragm; perpendicular diaphragm carrier with vertical movement; joint with arrange- 
ment for securing in any position ; revolver arrangement for changing the lenses of newest 
construction, 6 objectives, Nos. 0, 2, 3, 6, 8 (dry system) and No. 10 (with immersion and cor- 632 
PRICE-LISTS OF MICROSCOPE FIRMS. 
rection) ; 3 eye-pieces, Nos. 3, 2, 3 (No. 2 with micrometer and screw for changing position). 
These optical combinations furnish magnifying powers from 18-1,200. Large illuminating 
lens on a stand. Accessory apparatus, slides and covers ; mahogany box with handle 980 fr. 
No. 2. Large microscope, but of simpler construction. Coarse and fine adjustment as in No. 1. 
The upper portion of the tube can be drawn out to obtain the proper position for the objec- 
tive and eye-piece. Rotary stage, covered with black glass; movable mirror as in No. 1; 
movable diaphragm carrier. Arrangement for oblique position as in No. 1. Five objectives. 
Nos. 0, 2, 6, 7 (dry system), and 10 (with immersion and correction) ; 3 eye-pieces. Nos. 1, 2, 
8 (No. 2 with micrometer and screw for changing position). Magnifying power from 18-1,200. 
Illuminating lens as in No. 1; the same accessories and same box 750 fr. 
No. 3. Medium microscope. The same double adjusting arrangement, tube to draw out, rotary 
stage with black glass plate; oblique illumination as in the larger stands; the diaphragm 
movable vertically; oblique position with checking arrangement; objectives Nos. 0, 2, 6, 8 
(dry system); 3 eye-pieces, Nos. 1, 2, 3 (No. 2 with micrometer). Illuminating lens, acces- 
sory apparatus, box as above 550 fr. 
The same stand without the rack 500 fr. 
No. 4. Smallest instrument; rotary stage covered with black glass; coarse adjustment through 
the neck, fine by micrometer screw, with oblique illumination and inclining position. Objec- 
tives Nos. 0, 2, 6, 7; eye-pieces Nos. 1, 2, 3 (No. 2 with micrometer) ; illuminating lens, etc.. 390 fr, 
The same instrument, with screw for changing position and the same optical constituents 440 fr, 
No. 5. Stand with non-rotary black glass stage ; double motion, oblique illumination, objectives 
Nos. 2, 6, 7 ; eye-pieces 1 and 3. Magnifying power from 60-780 ; inclining position, smaller 
illuminating lens, etc 260 fr. 
Same instrument, with screw for changing position 310 fr. 
No. 6. Instrument with two columns for laboratories 165 fr. 
No. 7. Horse-shoe student’s stand without inclining; double motion ; oblique illumination; objec- 
tive No. 2 ; eye-piece No. 1; magnifying power from 60-100 95 fr. 
With objective 6 105 fr, 
No. 8. Travelling and pocket microscope without optical apparatus. 
(The magnifying power obtained with the tube elongated or shortened is here separated.) 
Price of the Objectives, with tbeir Magnifying Power, 
Objective. 
Bye-piece 
1 
2 
3 
4 
Price. 
Equivalent 
focus in 
English 
inches. 
No. 00 
12 
16 
20 francs. 
2^ 
(( 
0 
18 
25 
30 
50 
40 
75 
45 
85 
20 “ 
2 
a 
1 
30 
35 
60 
100 
90 
140 
100 
170 
25 “ 
1 
a 
2 
60 
100 
80 
150 
120 
220 
130 
250 
25 “ 
% 
(C 
3 
80 
160 
110 
210 
170 
290 
200 
350 
35 “ 
K 
it 
4 
130 
210 
170 
300 
250 
430 
290 
520 
35 “ 
% 
u 
6 
170 
290 
220 
400 
330 
570 
550 
650 
85 “ 
1-6 
(( 
7 
250 
400 
300 
550 
480 
780 
550 
800 
40 “ 
1-9 
l( 
7 (new) 
75 “ 
1-9 
u 
8 
3i6 
500 
420 
720 
570 
880 
600 
i050 
60 “ 
1-11 
NEW OBJECTIVES, WITH IMMERSION AND CORRECTION. 
Objective. 
Eye-piece 
1 
2 
3 
4 
Price. 
Equivalent 
focus iu 
English 
inches. 
No. 8 
260 440 
350 
620 
500 
880 
610 
950 
90 francs. 
1-11 
“ 9 
810 580 
400 
070 
550 
950 
670 
1200 
120 “ 
1-12 
“ 10 
330 600 
450 
760 
620 
1120 
800 
1300 
150 “ 
1-16 
“ 11 
380 TOO 
500 
880 
690 
1200 
900 
1500 
200 “ 
1-18 
“ 12 
450 800 
550 
950 
750 
1300 
1070 
1690 
250 “ 
1-21 PRICE-LISTS OE MICROSCOPE FIRMS. 
Ranvier’s microtome for animal objects 12 fr. 
Rivet’s microtome for vegetable objects 30 fr. 
Kiinokel’s loup stand 40 fr. 
Malassez’s apparatus for counting blood-cells, vvitb quadratic eye-piece micrometer. 60 fr. 
Image inverting binocular arrangement fr. 
Eye-piece 10 fr. 
Holosteric eye-piece 18 fr. 
Micrometer eye-piece 20 fr. 
Photographic arrangement 50 fr. 
Stage micrometer in 100 15 fr. 
500 20 fr. 
Improved rotary stage 60 fr. 
1000 30 fr. 
New compressorium 85 fr. 
Polarizing apparatus 45 fr. 
Horizontal movable micrometer 50 fr. 
Improved Dujardin illuminating apparatus 45 fr. 
“ with a polarizing eye-piece having a graduated circle 60 fr. 
Goniometer 50 fr. 
Camera lucida of Oberhiiuser 50 fr. 
“ “ Milne-Edwards and Doyero 35 fr. 
“ -l Mathissen 20 fr. 
Roups 8-25 fr. 
No. 4.—Carl Zeiss, Jena (1877). 
Prices in Marks. 
No. 
System. 
Angle 
of 
Aperture. 
Equivalent 
focus. 
Magnifying Power at 155 millimetres. 
Length of Tube for 250 millimetres. 
Visual distance with Eye-piece. 
Price in 
Marks. 
1 
2 
3 
4 
5 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
11 
12 
I 
O 
■M 
- 
U1 
>> 
’ 
a 
aa 
A 
AA 
B 
BB 
C 
CC 
D 
DD 
E 
F 
20° 
20° 1 
33° ] 
40° [ 
00° f 
48° ( 
90° f 
72° I 
100° f 
105° 
105° 
30, 45, 60 mm. 
82 mm. 
16 mm., %" Eng. 
10 mm., 2-5" 
6.4 mm., 
4.2 mm., 1-6" 
2.8 mm., 1-9" 
1.8 mm., 1-14" 
5 to 
18 
45 
70 
110 
180 
240 
380 
20 
25 
60 
95 
140 
220 
330 
500 
”40 
85 
125 
200 
300 
450 
720 
“50 
110 
160 
260 
400 
600 
950 
“70 
150 
220 
350 
550 
840 
1400 
■ 
• 
12 
27 
24 
30 
30 
42 
36 
48 
42 
54 
66 
84 
13 
G 
fNo. 1 
180° 
3.0 mm., 1-8" 
220 
300 
420 
560 
790 
90 
14 
® 
“ 2 
180° 
1.7 mm., 1-15" 
400 
530 
760 
1020 
1500 
144 
G m 
§ >» 
G CQ 
M 
. “ 3 
180° 
1.0 mm., 1-25" 
680 
900 
1300 
1700 
2300 
277 
Objectives and Eye-pieces 634 
PRICE-LISTS OF MICROSCOPE FIRMS. 
No. s.—Seibert & Krafft, successors to E. Gundlaoh, Wetzlar (1876). 
Prices in Marks. 
Objectives. 
Objective. 
Focus of the Equivalent 
Lenses. 
Angle of 
Aperture. 
Marks. 
Eng. in. 
Mm. 
Degrees. 
No. 00 
2 1-2 
63.5 
10 
24 
0 
13-4 
44.4 
15 
21 
I 
1 
25.5 
20 
18 
II 
1-2 
12.7 
38 
IS 
Ill 
1-3 
8.7 
50 
18 
IV 
1-4 
6.4 
80 
27 
V. a 
1-8 
3.2 
86 
v. b 
1-8 
3.2 
150 
With “ “ 
48 
VI. a 
1-12 
2.1 
165 
60 
VI. 6 
1-12 
2.1 
165 
With “ “ 
75 
VII. a.... 
1-16 
1.6 
175 
Immersion without correction 
60 
VII. ?>.... 
1-16 
1.6 
175 
“ with “ 
75 
VIII 
1-24 
1.1 
175 
k. *k 
120 
IX 
1-32 
0.8 
175 
k. U ik 
180 
X 
1-50 
0.5 
175 
300 
Magnifying Power. 
Objective No. 
00. 
0. 
I. 
II. 
III. 
IV. 
v. 
VI. 
VII. 
VIII. 
IX. 
X. 
With Eye-piece No. 0 
10 
18 
SO 
45 
66 
100 
200 
305 
460 
650 
950 
1450 
“ “ I.... 
16 
26 
45 
70 
100 
150 
305 
460 
690 
1000 
1430 
2200 
“ “ IT.... 
24 
40 
68 
100 
150 
220 
450 
609 
1000 
1360 
2170 
3300 
“ “ III... 
32 
54 
90 
140 
200 
300 
610 
930 
1375 
2000 
2880 
4400 
Bye-piece No. 0, L, 11., 11l 'l% marks. 
Bye-piece No. 111., with arrangement for micrometer, and micrometer 12 marks. 
Microphotographic objective, 1 in 36 marks. 
“ “ in 30 marks. 
“ “ % in 45 marks. 
No. 6.—G. & S. Merz (formerly Utzschneider & Fraunhofer), Munich 
(1872). 
Price in Thalers. 
Objectives. 
Focus of the Equivalent Lenses. 
Angle of Aperture. 
Price. 
1", 1-2", 1-8" 
20°-40° 
10 Thalers. 
16 
20 “ 
24 
32 
44 
60 
1-6", 1-9" 
100°-120° 
1-12" 
140° 
1-15" I 
i-is" r 
1-21" ( 
1-24" ) PRICE-LISTS OF MICROSCOPE FIRMS. 
No. 7.—Powell & Lealand, 170 Euston Road, London (1879). 
Price in £,. s. d. 
Compound Microscopes. 
£ a. d. 
1. Large compound microscope, on an improved construction, with 1 inch of motion to the 
stage in rectangular directions by screw and pinion; slide holder and spring clip ; also 
wheel and pinion which rotates the whole concentric with the optical tube, combined 
with very thin stage for the oblique illumination of objects, either by the mirror or 
achromatic prism, with graduated silver circle, which can be used as a goniometer; 
coarse and fine adjustments to the body, with graduated sliding tube; substage, with 
rotary, rectangular, and vertical motions, for the adaptation of the achromatic condenser, 
paraboloid, etc.; graduated stage plates and clamp, to act as finder; large plane and 
concave mirrors, with double arm, and 2 eye-pieces 38 0 0 
Wenham’s binocular arrangement for low powers, with 3 eye-pieces 8 10 0 
Powell & Lealand’s patent ditto, which allows the highest powers to be used with it 3 3 0 
No. 4 and 5 eye-pieces 2 0 0 
Improved condenser, with revolving diaphragm and central stops, by which arrangement the 
relative sizes of the apertures and stops can be varied at pleasure,—achromatic combina- 
tion, with 170 degrees of aperture 8 8 0 
One pair of Kelner’s orthoscopic eye-pieces 2 8 0 
Two animalcule cages 0 14 0 
Stage forceps 0 10 0 
Wollaston’s camera lucida 1 1 0 
Silver side reflector 1 1 0 
Erector for dissecting with compound body 1 0 0 
Polarizing apparatus, with series of revolving selenites 5 0 0 
Indicator to eye-piece 0 5 0 
Annular condenser , 1 10 0 
Compressorium 1 10 0 
Frog plate 0 8 0 
Rectangular achromatic prism for oblique illumination, to fit into stand of bull’s-eye condenser. 115 0 
Lister’s dark wells, with fittings 0 13 0 
Large bull’s-eye condenser on stand 13 0 
Small ditto, with joints to fit into microscope stand 0 19 0 
Diaphragm, with Rainey’s light modifier 0 10 0 
Screw micrometer 410 0 
Spotted lens 0 10 0 
Brooke’s double arm, angular form (first made by P. & L.) 1 10 0 
Pliers 0 4 0 
Stage micrometer.., 0 5 0 
1-50 inch object glass. 31 10 0 
1-25 “ “ “ 21 0 0 
1-16 “ “ “ 16 16 0 
H “ “ " 9 9 0 
X “ “ “ 55 0 
1“““ 3 3 0 
X “ “ “ 5 0 0 
IX “ “ “ 3 0 0 
2 “ “ “ 215 0 
3 “ “ 2 15 0 
4 “ li “ 1 10 0 
Lieberkuhn’s 2 inch 14/-, IX inch 12/-, 1 inch 10/-, X inch, 7/-, X inch 6/- 2 9 0 
Immersion arrangement to the X inch and 1-16 inch 4 4 0 
Spanish mahogany case 4 12 0 
£2OO 15 0 
2. Large compound microscope, on an improved construction, with %-inch of motion to the stage 
in rectangular directions by screw and pinion; sliding and revolving slide holder and 
spring clip, coarse and fine adjustments to the body, with graduated sliding tube ; sub- 
stage, with rotary, rectangular, and vertical motions, for the adaptation of the achromatic 
condenser, paraboloid, etc.; plane and concave mirrors, with double arm, by which 
means a very oblique light can be thrown upon the object; and 2 eye-pieces 26 0 0 
3. Compound microscope, on an improved construction, with %-inch of motion to the stage in 
rectangular directions by screw and pinion; sliding and revolving slide holder and spring 636 
PEICE-LISTS OF MICROSCOPE FIRMS. 
clip, coarse and fine adjustments to the body, with graduated sliding tube; substage, 
with rectangular and vertical motions, for the adaptation of the achromatic condenser, 
paraboloid, etc.; plane and concave mirrors, and 2 eye-pieces . 18 10 0 
£ s. d. 
4. Portable compotind microscope stand, having % -inch motion to stage in rectangular direc- 
tions by screw and pinion; sliding and revolving slide holder and spring clip, coarse and 
fine adjustments to the body; substage, with rectangular and vertical motions, for the 
adaptation of the achromatic condenser, etc.; plane and concave mirrors, with double 
arm, by which means a very oblique light can be thrown upon the object; and 2 eye-pieces. 18 0 0 
5. Compound microscope stand, with %-inch of motion to the stage by means of a lever; 
coarse and fine adjustments to body, plane and concave mirrors, and 2 eye-pieces 11 0 0 
Ditto, the stand, pillar, and limb in bronze 9 0 0 
6. Compound microscope, with 1 inch and inch achromatic object glasses, with apertures 
of 28 and 95 degrees respectively, 2 eye-pieces, plane and concave mirrors, revolving 
diaphragm 13 0 0 
Student's microscope, with Wenham’s binocular arrangement, with % inch motion to stage by 
screw and pinion; coarse and fine adjustments to body 14 0 0 
Dissecting stand, with rack and pinion movements; compound body, made to receive the object 
glasses and eye-glasses of the above microscopes, and elongating arm 3 10 0 
Spanish mahogany case for No. 1 microscope, with box for apparatus 4 12 0 
Spanish mahogany case for No. 2 or No. 3 microscopes, with box for apparatus, and drawers for 
objects 5 0 0 
Honduras ditto, with box for apparatus 3 IQ 0 
Spanish mahogany case for portable microscope 1 16 0 
Case for No. sor 6, with packing for apparatus 1 15 0 
Honduras case for dissecting stand 1 5 0 
Achromatic Object Glasses for Microscopes 
Object Glasses. 
Angular 
Aperture. 
Magnifying Power with the various 
Bye-pieces. 
Price. 
Lieber- 
kiihn’s. 
No. 1 
2 
3 
4 
5 
4 inch 
9 degrees 
12 
12 
18 
25 
50 
75 
£ 
1 
s. 
10 
s. 
3 “ 
16 
24 
32 
64 
96 
2 
15 
2 *• 
14 
25 
37 
50 
100 
150 
2 
15 
14 
IX “ 
20 
37 
56 
74 
150 
220 
3 
0 
12 
1 “ 
30 
50 
74 
100 
200 
300 
3 
3 
10 
% “ 
32 
75 
111 
150 
800 
450 
3 
10 
10 
X “ 
70 
100 
148 
200 
400 
600 
5 
0 
7 
X “ 
40 
4 
4 
4-10 “ 
80 
125 
187 
250 
500 
750 
5 
5 
7 
X “ 
95 
200 
296 
400 
800 
1200 
5 
5 
6 
X “ 
130 “ 
7 
7 
X “ 
140 
On a new formula .... 
9 
9 
1-5 “ 
100 
250 
370 
500 
1000 
1500 
6 
6 
X “ 
140 
On a new formula 
9 
9 
X “ 
100 “ 
7 
7 
X “ 
140 
400 
592 
800 
1600 
2400 
8 
8 
1-12 “ 
145 
600 
888 
1200 
2400 
3600 
12 
12 
1-16 “ 
175 
800 
1184 
1600 
8200 
4800 
16 
16 
1-25 “ 
160 
1250 
1850 
2500 
5000 
7500 
21 
0 
1-50 “ 
150 
2500 
3700 
5000 
10000 
15000 
31 
10 
V 
Immersion arrangement to %, %, 1-12, or 1-16 £2 2s. extra. 
£ s. d. 
No. 1. Improved Monocular Microscope Stand, Ross model, with coarse and fine adjustments 
for focusing, one eye-piece, graduated concentric rotating stage, having one inch of rec- 
tangular motion, rack and screw movements, clamping lever for fixing the instrument at 
any angle, graduated sub-stage for holding and adjusting illuminating and polarizing ap- 
paratus, diaphragm plate, plane, and concave mirrors 33 0 0 
No. B.—Boss & Co., 164 New JBond Street, London (1879), 
No. IA. Monocular Microscope Stand, with one eye-piece, coarse and fine adjustment, for fo- 
cusing, graduated concentric rotating stage, having one inch of rectangular motion, rack 
and screw movements, clamping lever for fixing instrument at any angle, graduated sub- 
stage for holding and adjusting illuminating and polarizing apparatus, diaphragm plate, 
plane and concave mirrors 35 0 0 
No. 2A. Monocular Microscope Stand, with one eye-piece, coarse and fine adjustment for fo- 
cusing, mechanical stage with rotating movement, having %-inch of rectangular motion, PEICE-LISTS OF MICEOSCOPE FIEMS. 
£ s. a. 
mechanical sub-stage for holding and adjusting illuminating and polarizing apparatus, 
clamping lever for fixing the instrument at any angle, plane and concave mirrors with 
jointed arm 25 0 0 
No. 3A. Monocular Microscope Stand, with one eye-piece, coarse and fine adjustments for 
focusing, mechanical stage with rotating movement, mechanical sub-stage for holding 
and adjusting illuminating and polarizing apparatus, clamping lever, plane and concave 
mirrors with jointed arm 20 0 0 
No. 2. Monocular Microscope Stand, with one eye-piece, coarse and fine adjustments for focus- 
ing. mechanical stage with rotating movement, having %-inch of rectangular motion, 
mechanical sub-stage for holding and adjusting, illuminating and polarizing apparatus, 
plane and concave mirrors with jointed arm 23 0 0 
No. 3. Monocular Microscope Stand, with one eye-piece, coarse and fine adjustments for fo- 
cusing, mechanical stage with rotating movement, having >4-inch of rectangular mo- 
tion. mechanical sub-stage for holding and adjusting illuminating and polarizing appa- 
ratus, plane and concave mirrors with jointed arm 18 0 0 
No. IA. Binocular Microscope Stand, with two mye-pieces, coarse and fine adjustments for 
focusing, graduated concentric rotating stage, having one inch of rectangular motion, 
rack and screw movements, clamping lever, graduated sub-stage for holding and adjust- 
ing illuminating and polarizing apparatus, diaphragm plate, plane and concave mirrors, 
and Wenham’s binocular arrangement 42 0 0 
No. 2. Binocular Microscope Stand, with two eye-pieces, rack and pinion adjustment for focus- 
ing, sliding and rotating stage, plane and concave mirrors with jointed arm, and Wen- 
ham's Binocular arrangement 17 0 0 
No. 3. Binocular Microscope Stand, with two eye-pieces, coarse and fine adjustments forfocus- 
ing, mechanical stage with rotating movement, having %-inch of rectangular motion, 
mechanical sub-stage for holding and adjusting illuminating and polarizing apparatus, 
plane and concave mirrors with jointed arm, and Wenham’s binocular arrangement 25 0 0 
Ross’ New Patent Object Glasses. 
The undoubted superiority of our Patent Objectives (as confirmed by leading microscopists) has de- 
termined us. to abandon the old construction from the upwards. In the new combination a great 
increase of brilliancy and definition is obtained by dispensing with six surfaces formerly used. 
Devised by Mr. WBNHAM. 
Object Glasses. 
Aperture 
Magnifying Powers with Eye-pieces, about 
Price. 
about 
A. 
B. 
c. 
D. 
E. 
F. 
£ s. 
a. 
45° 
100 
160 
250 
400 
500 
800 
4 4 
0 
1-2 
80° 
100 
160 
250 
400 
500 
800 
5 5 
0 
3-10 “ 
60° 
165 
265 
410 
660 
820 
1300 
4 10 
0 
3-10 “ 
00° 
165 
265 
410 
660 
820 
1300 
5 10 
0 
1-5 “ 
85° 
250 
400 
620 
1000 
1250 
2000 
5 5 
0 
1-5 “ 
190° 
250 
400 
620 
1000 
1250 
2000 
6 6 
0 
1-7 “ 
130° 
340 
540 
850 
1300 
1700 
2700 
7 7 
0 
3-10 *• 
140° 
500 
800 
1200 
2000 
2500 
4000 
9 9 
0 
1-15 “ 
150° 
750 
1200 
1800 
3000 
3700 
6000 
12 12 
0 
1-25 “ .. 
160° 
1200 
2000 
3100 
5000 
6200 
10000 
21 0 
0 
The higher powers, from the l-sth upwards, can be used either dry or immersed, merely by approxi- 
mating the lenses with the adjusting collar to the mark “Wet,” thus avoiding the cost of extra fronts and 
loss of time in changing them, 
Ross’ Low Power Objectives. 
Object Glass, 
Aperture 
about 
Magnifying Power with Eye pieces. 
Price. 
£ s. d. 
A. 
B. 
C. 
D. 
9° 
12 
18 
25 
40 
1 11 6 
*8 u 
10° 
15 
20 
85 
60 
2 2 0 
3 “ 
12° 
15 
20 
35 
50 
3 3 0 
*2 “ 
12° 
25 
40 
60 
100 
2 2 0 
2 “ 
15° 
25 
40 
60 
100 
3 3 0 
*1% “ . 
15° 
35 
60 
95 
150 
2 2 0 
iy, “ 
20° 
35 
60 
95 
150 
3 3 0 
(( 
15° 
50 
80 
125 
200 
2 2 0 
i “ 
25° 
50 
80 
125 
200 
3 10 0 
2/ (( 
73 
35° 
80 
130 
200 
300 
3 10 0 
The Objectives marked thus,* being triplets, are best suited for use with eye-pieces of low power. 
Their angular aperture is not so great, nor their defining power equal to the more perfectly corrected 
combinations. 638 
PRICE-LISTS OF MICROSCOPE FIRMS. 
No. 9.—C. Bakee, 244 and 245 High Holhorn, London (1879). 
£ S. d. 
No. 1. Highly finished large compound microscope stand, with all the latest improvements, 
having double supports to prevent vibration, vertical rack adjustment for the approximate 
focus, and fine screw-motion for the more delicate optical adjustment. A mechanical 
stage, with one-inch motion in opposite directions; a sliding and rotating object holder; 
a supplementary stage, with vertical rack and centering adjustment for applying the dia- 
phragm ; polariscope, achromatic condenser, spot lens, etc., etc., with plane and concave 
mirrors, and two eye-pieces 21 0 0 
No. IA. A large microscope stand, with mechanical stage, quick and slow motion, double mir- 
ror, two eye-pieces, etc, etc., as above, but without the supplementary stage 14 10 0 
No. 18. A smaller ditto, and in every respect as No. 1A 11 10 0 
No. 18. A ditto, without mechanical stage 7 15 0 
No. 3. A superior finished binocular microscope stand, with a pair of eye-pieces, double mirror, 
circular rotating stage, and quick and slow motions 6 0 0 
Ditto, ditto, with racks to eye-pieces, as shown above 7 0 0 
No. 4. A similar stand, but of larger and more massive construction, to which a sub-stage and 
all accessories can be adapted 8 0 0 
No. 5. The Student's Microscope, a well-finished instrument, with quick and slow motions, cir- 
cular rotating stage, a combination of three achromatic object glasses, live box, stage, 
and dissecting forceps 4 10 0 
No. 6. The Educational Microscope.—This exceedingly cheap achromatic microscope, which is 
so strongly recommended by most of the Professors at the various Colleges, Schools, and 
institutions for public and private education, has quick and slow motion, sliding stage, 
live box, stage forceps, dissecting forceps, with three achromatic object glasses in combi- 
nation, all packed in a neat mahogany case 3 3 0 
The Medical Microscope.—A superior finished microscope on the Continental model, having 
sliding body, micrometer screw fine adjustment, joint to incline at any angle, and im- 
proved adjusting mirror, with two eye-pieces, in mahogany case 3 3 0 
One-quarter-inch English object glass 1 10 0 
One-inch “ “ 1 5 0 
Condenser for opaque objects j 0 9 0 
Divided glass disk to aid in drawing and measuring objects 0 4 6 
The Seaside Microscope.—This convenient and extremely portable microscope is adapted for 
travelling, or use at the seaside, as it packs, with object glasses and apparatus, within the 
space of 9 inches by 5 inches. It has rack adjustment, draw tube with one eye-piece, 
double mirror, and circular revolving glass stage 2 15 0 
Ditto, ditto, with fine adjustment 0 5 0 
Mahogany case for ditto 0 15 0 
A superior finished dissecting microscope, with rack adjustment, three object glasses, etc., in 
neat case 2 0 0 
C. Balter’s Achromatic Object Glasses. 
Angular Aperture. 
Pour-inch 8 degrees 15 0 
Three-inch 10 “ 115 0 
Two-inch 12 “ 110 0 
Ditto 15 “ 117 6 
One and a half inch 20 “ 117 6 
One inch 15 “ 110 0 
Ditto 23 “ : 117 6 
Ditto 30 “ 2 2 0 
Two-thirds inch 35 2 5 0 
Half inch, with adjustment 60 “ 3 0 0 
Ditto, without -■■- 10 “ 210 0 
Pour-tenths, with adjustment 70 “ 3 5 0 
Ditto, ditto, 05 “ 310 0 
Quarter-inch, with adjustment 75 “ 3 5 0 
Ditto, ditto, 05 “ 315 0 
Ditto, without adjustment 75 “ ... 210 0 
One-eighth, ditto, with adjustment 115 “ 5 5 0 
Ditto, ditto, 125 “ 6 6 0 PEICE-LISTS OF MICROSCOPE FIRMS. 
639 
Apparatus for Achromatic Microscopes. 
Polariscope, with extra large pair of prisms, fitted and attached complete 1 12 6 
£ s. d. 
Ditto, with analyzer expressly mounted for the binocular microscope 1 15 0 
Ditto, with revolving analyzer 117 g 
Folariscopes for student’s or educational microscope 1 g g 
Dr. Beale’s neutral tint glass reflector for drawing 0 g g 
Brooke’s double ncse piece, for carrying two object glasses to facilitate the change of focus 110 
Ditto for students’ microscopes 0 12 6 
C, Baker’s triple ditto, for three object glasses 1 10 o 
Extra eye-pieces from 6s. to 0 12 6 
Kelner’s orthoscopic achromatic eye-piece, giving very large field 1 0 0 
Revolving selenite stage, with complete set of selenites 2 0 0 
Erecting glasses for dissecting, applied to draw tubes 0 10 0 
Ditto prisms for dissecting, applied to any monocular microscope 1 Q 0 
Camera lucida for drawing the magnified image 15s. to 1 5 0 
Stage forceps from 3s. 6d. to 0 7 6 
Dissecting forceps Is. to 0 1 9 
Micrometer for stage 0 4 6 
Ditto for eye-piece, mounted in brass 0 8 6 
Ditto, ditto, unmounted (j g g 
Maltwood’s finder. g 5 g 
Animalcule cages from 2s gd to gig g 
Frog plate from ss. to 0 6 6 
Glass troughs for viewing circulation of plants ..from 0 3 6 
Hollow glass slides g g 2 
Compressoriums from 0 6 6 
Glass stage plates g 1 g 
Daylight reflector, fitted to object glasses 0 15 0 
Ditto, with universal movements adapted to instrument 1 1 g 
No. 10.—Chas. Collins, 157 Great Portland Street, London (1879). 
Collins’ Student’s Microscope 7 7 0 
1 Eye-piece. Plat and concave mirrors. 
Draw tube. Wheel of diaphragms. 
Rack adjustment. Axes for inclining to ans' angle. 
Fine “ 1-in and J£-in. objectives. 
Top sliding stage. Tweezers and glass plate. 
Packed in Polished Cabinet. 
Mechanical stage, extra 2 2 0 
Collins’ Harley Binocular Microscope 15 15 0 
With mechanical stage. I Condenser. 
Rack to draw tubes. Diaphragm. 
One pair of eye-pieces. Flat and concave mirrors. 
1-in. objective, B. Series. Mahogany case. 
X-in. “ “ 
Collins’ Histological Student’s Microscope 3 5 0 
The microscope with coarse adjustment. 
One eye-piece. I }4-in. objective. 
Pine adjustment. Concave mirror. 
1-in. objective. 
Mahogany case 5 10 0 640 
PRICE-LISTS OF MICROSCOPE FIRMS. 
Collins’ Best Harley Binocular Microscope, Jackson Plan 60 0 0 
£ s. d. 
Pair of A eye-pieces. 
“ B “ 
Compressor. 
Zoophyte trough. 
Stage forceps. 
Side parabolic illuminator. 
Large stand condenser. 
Large poiariscope. 
Camera for drawing objects. 
Micrometer for stage. 
Prog plate. 
Double nose-piece. 
Mahogany cabinet. 
Ain. objective, A Series. 
2-in. “ “ 
%-in. “ “ 
M-in. “ “ 
“ “ 
Webster’s achromatic condenser, with 
Collins’ graduating diaphragm. 
Live box. 
These Object Glasses are guaranteed of the Highest Standard, both for Penetrating and Defining Power. 
A Series.—Best Achromatic Object Glasses 
Objective. 
Angle of 
Aperture, 
about 
Price. 
£ ». d. 
Linear Magnifying Power, with each 
Bye-piece. 
A. 
B. 
C. 
D. 
4-in 
9° 
15 0 
12 
18 
25 
40 
3-in.. 
12° 
1 15 0 
15 
20 
35 
50 
2-in 
15° 
1 15 0 
25 
40 
60 
100 
1-in 
25° 
1 16 0 
50 
SO 
125 
200 
2-3-in 
35° 
2 0 0 
80 
130 
200 
300 
1-2-in 
90° 
3 10 0 
100 
160 
250 
400 
4-10-in 
90° 
S 10 0 
146 
255 
' 460 
560 
1-4-in 
100° 
4 0 0 
200 
340 
590 
720 
1-B-in 
100° 
4 10 0 
250 
400 
620 
1000 
1-8-in 
140° 
5 10 0 
500 
870 
1500 
1850 
Objective, 
Angle of 
Aperture, 
about 
Price. 
£ s. d. 
Linear Magnifying Power, with each 
Eye-piece. 
A. 
B. 
C. 
D. 
3-in 
10° 
12 6 
15 
20 
35 
50 
2-in 
13° 
12 6 
22 
40 
60 
100 
1-in 
22° 
12 6 
50 
80 
125 
200 
1-2-in 
40° 
15 0 
100 
160 
250 
400 
1-2-in 
45° 
2 5 0 
100 
160 
250 
400 
1-4-in 
05° 
2 10 0 
200 
340 
590 
720 
1-4-in 
80° 
1 17 6 
200 
340 
500 
720 
1-5-in 
05° 
2 10 0 
250 
400 
620 
1000 
1-5-in 
80° 
1 17 6 
250 
400 
620 
1000 
1-8-in 
100° 
3 3 0 
500 
870 
1500 
1850 
It Series.—Achromatic Object Glasses. 
The objectives of both series are cut to the standard screw of the Eoyal Microscopical Society, 
No. 11.— R. & J. Beck, London, and 1016 Chestnut Street, Philadelphia 
(1879). 
New large best binocular microscope stand, with concentric rotating stage and iris diaphragm, ro- 
tating and centering sub-stage, most complete movements to the body, stage, and double 
.mirror, two pairs of eye-pieces, pliers, forceps, etc., mounted on two pillars $250 00 
First Class Microscope Stands. 
New large best monocular microscope stand, with concentric rotating stage and iris diaphragm, 
rotating and centering sub-stage, most complete movements to the body, stage, and double 
mirror, two eye-pieces, pliers, forceps, etc., mounted on two pillars 200 00 
New smaller binocular microscope stand, on the same principle, and with the same actions as No. 
36, two pairs of eye-pieces, pliers, forceps, etc., but with single pillar 150 00 
New smaller monocular microscope stand, on the same principle, and with the same actions as No. 
37, two eye-pieces, pliers, forceps, etc., but with single pillar 115 00 PRICE-LISTS OF MICROSCOPE FIRMS. 
641 
First Class Objectives. 
Angle of 
Nn TiWal r PTio-f-h Linear Magnifying Power N j No. 2. No. 3. No. 4. No. 5. Aperture, Price. 
No, Pocal Length. nearly, with Bye-pieces. about. 
Degree. 
( Draw-tube closed 10 16 26 32 52 ) 
TO 4 inches ■< I Ditto if drawn out, add for f 9 UO 
)| each inch IX f * J 
( ! Draw-tube closed 12 20 40 48 74 ) 
71 3 “ 1 Ditto if drawn out, add for in { 14 27 50 
I each inch 2 4 b ) 
( Draw-tube closed 20 38 70 85 1c 1 „„ _n 
72 2 “ •< Ditto if drawn out, add for f 10 5U 
( each inch 4 b ° io ) 
I Draw-tube closed 30 56 100 120 190 1 „„ rn 
73 1)4 “ -< Ditto if drawn out, add for oo I M s[} 
i each inch 5 7 12 15 M } 
( Draw-tube closed 70 120 220 270 410 ) 
74 I % inch •< Ditto if drawn out, add for if 6Z 25 00 
I ( each inch. 8 14 25 27 48 
( Draw-tube closed 120 210 370 460 710 ; 1 
75 4-10 “ ■< Ditto if drawn out, add for i „„ ! f 05 40 00 
| each inch 14 24 34 46 TO 
( Draw-tube closed 146 255 460 560 890 1 
70 4'lo “ ] Die?chfinchWnoUt’addfor 18 32 48 60 80 j 
| Draw-tube c105ed'.......... 200 340 590 720 1120 jy 
77 X “ 1 Ditto if drawn out, add for mo ( ‘d 40 00 
4 each inch 24 42 63 85 120 ) 
Drawn-tube closed 225 400 700 860 1450 ) 
78 1-5 “ Ditto if drawn out, add for ( °5 40 00 
\ each inch 18 35 60 80 180 
( Draw-tube closed 225 400 700 860 1450 ) 
79 1-5 u •< Ditto if drawn out, add for f 100 50 00 
( each inch 18 35 60 80 130 J 
( Draw-tube closed 400 680 1180 1440 2240 ) 
80 i/ “ -< Ditto if drawn out, add for f 120 65 00 
( each inch 50 85 140 180 280 ) 
Draw-tube closed 500 870 1500 1850 2800 ) 
81 1-10 “ immer.-j Ditto«drawn out, mid for 160 50 00 
I Draw-tube closed 900 1570 2750 3450 4950 ) 
82 1-20 “ i Ditto if drawn out, add for , „„„ „„„ ( 120 00 
u each inch 80 150 300 350 900 ) 
1 Draw-tube closed. 900 1570 2750 3450 4950 I 
«MO •• imm«. 150 300 350 900 j 11001 
Draw-tube closed.;;; 1800 3140 5500 6900 9900 ) 
84 “ ]DirchfincrnOUt’addf°r 160 360 600 700 1800 S “° °° 
Apparatus 
Sorby's spectroscope eye-piece, for the microscope, in mahogany case. (See “ Popular Science Be- 
view,” No. 18) * 
Sorbjf’s dichroiscope 
Sorby’s standard spectrum-scale 
Orthbiscopic eye-pieces, giving a very large field, each * d 
Eye-pieces for the improved large microscope, each ® ® 
Eye-pieces for the improved smaller microscope, each ® 
Erecting-glass 
Draw-tube for first class microscopes 
Achromatic condenser, with revolving diaphragm, with stops, aperture from 25° to 100°, complete 
adjustments, applicable to the first class stands only 
Achromatic condenser, without diaphragm, aperture from 20° to 60°, complete adjustments....... 20 00 
Eight angle prism, for reflecting the light more perfectly than the fiat mirror, for the first class 
stands only 
Amici’s prism, for oblique light, for the first class stands only 
Amici’s prism, on separate stand g 
Nachet’s prism, for oblique light 13 50 
Wenham’s parabolic reflector, for the first class stands 
Wenham’s parabolic reflector, for the second class stands 
(See “ Popular Science Ee- 642 
PEICE-LISTS OF MICROSCOPE FIRMS. 
Spot lens, mounted in brass fitting $4 25 
Equilateral prism on stand, for oblique illumination 8 00 
Adapter on stand, for use of object glass as condenser 4 s(j 
Brown’s iris diaphragm 16 50 
Polarizing apparatus, with 1 film of selenite 20 00 
Polarizing apparatus, with extra large polarizing prism 32 50 
Barker’s series of selenites, adapted for the first class stands only 30 00 
Selenite film, of two colors 2 00 
Selenite stage, red and green, or blue and orange, each 3 00 
Barker’s selenite stage, giving 13 tints 16 50 
Black glass, for polarizing light 4 00 
Bundle of glass, for polarizing light 8 00 
Two double-image prisms and selenite film, with fittings to eye-piece, and brass plate with h01e5.... 16 50 
Single double-image prisms, in fitting 7 25 
Crystals to show rings around the optic axis, each from 4 00 
Tourmalines, each from 7 00 
Beck’s patent illuminator, in a brass box, for viewing objects as opaque under high powers 4 00 
White cloud illuminator 4 00 
Parabolic illuminator, fitted to the IX inch and % inch object glasses 8 25 
Parabolic illuminator with fittings adjusting it to any object glass 10 00 
Parabolic illuminator, same as No. 128, with the addition of Sorby’s reflector 16 00 
Large bull’s-eye condensing lens, on stand 8 00 
Large bull's-eye condensing lens, on stand, with lamp attached 10 00 
Smaller condensing lens, with fitting to limb of the first class stands 7 25 
Smaller condensing lens, on stand 5 00 
Side silver reflector, with fittings to limb of the first class stands 8 25 
Side silver reflector, on stand 8 25 
Bainey’s light moderator, on stand 8 25 
Three dark wells and holder 5 00 
Opaque disk revolver, one tray of disks in case 13 50 
Opaque disk revolver, with three trays of disks, forceps, capsule of gold size, in mahogany case, 
complete ; 23 50 
Opaque disk revolver and forceps 8 00 
Boxes containing 24 disks 4 00 
Trays containing 24 disks 4 00 
Three-pronged forceps, in German silver, with screw adjustment 6 50 
Three-pronged forceps 5 50 
Stage forceps 3 00 
Stage mineral holder 8 25 
Eye-piece micrometer, with Jackson’s adjusting screw 8 00 
Stage micrometer, mounted in brass 4 00 
Stage micrometer, mounted in card 2 00 
Maltwood’s finder in case 3 00 
Indicator to each eye-piece 2 00 
Leeson’s goniometer 20 00 
Wollaston’s camera lucida, with lens to magnify pencil point 8 00 
Neutral tint glass camera lucida 3 00 
Steel disk camera lucida 6 00 
Brook’s double nose-piece, in aluminium, curved 23 50 
Brook’s double nose-piece, curved 11 75 
Quadruple nose-piece 27 50 
Quadruple nose-piece in aluminium , 40 00 
Lever compressorium 7 50 
Parallel compressor 8 00 
Beversible compressor 8 00 
Wenham’s compressorium, for use with Wenham’s parabola 3 00 
Screw live box B 50 
Large live box 3 25 
Smaller live box 2 75 
Large glass trough, with wedge and spring complete 3 25 
Smaller glass trough, with wedge and spring complete 2 75 
Glass slip, with ledge 40 PRICE-LISTS OF MICROSCOPE FIRMS. 
643 
Growing cell, for preserving objects alive in water for many days $4 yy 
Set of six live traps and trough, in case, complete 44 445 
Live trap 3 QO 
Frog plate, with bag, etc., complete 4 yy 
Glass slip, with hollow and ledge 53 
Glass slip, with hollow and ledge and lip , 4 75 
Glass tubes, set of three 25 
Key for tightening joints of first-class instruments 1 75 
Opal glass, for moderating the light, 3xl inch 40 
Blue glass for moderating the light, 3xl inch 40 
Astral oil lamp, flat wick and shade, with arrangement for varying height of flame above the 
table 6 00 
Case for lamp No. 186, and one chimney 4 00 
Gas lamp, Argand burner, shade, and six feet of flexible tubing, with arrangement for varying 
height of flame above the table 42 yy 
Fiddian’s microscope illuminator, in case 45 yo 
Popular Series of Object Glasses. 
Focal 
Length. 
Linear Magnifying Power nearly. 
Degrees 
of Angle 
of 
Aperture. 
Price. 
No. 
Lieber- 
kiihn’s for 
Object 
Glasses. 
Price. 
With Eye-pieces. 
Draw tubes. 
No. 1. 1 No. 2. 
No. 3. 
3 inch. 
Closed. 
12 ) 20 
40 
8 
$13 00 
2 
Closed. 
24 1 40 
70 
10 
12 00 
IX “ 
Closed. 
29 48 
90 
15 
15 00 
287 
IX inch. 
$3 75 
1 “ 
Closed. 
55 ( 9(1 
100 
22 
15 00 
238 
1 “ 
3 00 
X “ 
Closed. 
120 200 
360 
40 
17 50 
239 
X “ 
3 00 
“ 
Closed. 
210 350 
600 
75 
20 00 
“ 
Closed. 
420 I 700 
1000 
85 
30 00 
-A “ 
Closed. 
800 ! 1200 
! 
2000 
100 
50 00 
The Monocular Economic Microscope, with sliding coarse adjustment, 1-inch and J£-inch object 
glasses, one eye-piece, concave mirror, condensing lens, glass plate with ledge, brass pliers 
and diaphragm, in mahogany case 35 yy 
The Economic Microscope and Apparatus. 
The Monocular Economic Microscope, with rack and pinion coarse adjustment, with 1-inch and 
X-inch object glasses, two eye-pieces, concave and plane mirrors, side condensing lens, dia- 
phragm, stage forceps, pliers, glass slip, with ledge, in mahogany case 50 00 
The Binocular Economic Microscope, with movable glass stage, concave and plane mirrors hung on 
jointed arm to swing above the stage, lever adjustment for different widths of eyes, two pairs 
of eye-pieces, the same objectives and accessories, in mahogany case . 80 00 
Eye-pieces for the former, Nos. 1, 2, or 3, each 4 00 
Eye-pieces for the second, Nos. 1, 2, or 3, each 5 00 
Side condensing lens 1 75 
Stage forceps 2 00 
Pliers 35 
Lieberkiihn to 1-inch object glass 3 00 
Additional Apparatus. 
Dark well 1 75 
Achromatic condenser and fitting 8 CO 
Wenham’s parabolic reflector for dark field illumination S 00 
Flat mirror (in which case a double one is substituted for the concave single one, which has to be 
returned) 2 75 
Polarizing apparatus, complete with prisms, film of selenite, and adapter 12 00 
Wollaston’s camera lucida for drawing an object 6 00 
Glass micrometer, ruled into one-hundredths and one-thousandths of an inch 2 00 
Small live box 2 00 
Glass trough, complete with wedge and spring 2 50 
All the above “ Additional Apparatus,” if ordered at once 37 50 
Movable glass stage for the Economic Monocular Microscope 7 50 644 
PRICE-LISTS OF MICROSCOPE FIRMS. 
Price List of the Economic Object Glasses. 
Linear Magnifying Power, nearly. 
Degrees of 
Angle of 
Focal Length. 
Price. 
With Bye-pieces. 
Aperture. 
Draw tube. 
No. 1. 
No. 2. 
No. 3. 
2 inches. 
( Closed, 
j Open. 
15 
26 
20 
34 
34! 
57 f 
9° 
$6 00 
1 inch. 
J Closed. 
1 Open. 
48 
68 
63 
93 
105 I 
155 f 
16° 
7 00 
% inch. 
j Closed. 
( Open. 
76 
110 
100 
145 
170 ) 
240 f 
36° 
9 00 
14 inch. 
j Closed. 
| Open. 
150 
215 
200 
290 
340 j 
480 f 
70° 
10 00 
inch. 
j Closed, 
j Open. 
290 
410 
390 
560 
660 1 
900 ) 
85° 
17 50 
A inch. 
j Closed. 
( Open. 
660 
925 
900 
1260 
1500 1 
2100 j 
100° 
35 00 
The Neio Binocular National Microscope, with 1-inch and object glasses, having the respec- 
tive apertures of 19 and 75 degrees, and magnifying from about 47 to 450 diameters ; 2 pairs 
of eye-pieces, stage forceps, condensing lens on stand, a glass plate, with ledge for the ex- 
amination of objects in fluid, and a pair of pliers ; the whole packed in an elegant French 
polished mahogany case, with good brass handle and lock, and a drawer for the accessories, flOO 00 
The New Monocular National Microscope, with two eye-pieces, and the same object glasses and 
fittings as the above. In mahogany case 75 00 
The New Binocular National Microscope, with 1-inch object-glass, 1 pair of eye-pieces, Nos. 1 or 
2, as desired, stage forceps, condensing lens, on stand, glass plate and pliers. In mahogany 
case 85 00 
The New Monocular National Microscope, with 1 eye-piece, Nos. 1 or 2, as desired, and the same 
object glasses and fittings as with the above. In mahogany case 60 00 
The New Binocular National Microscope Stand, with one pair of eye-pieces, concave and plane 
mirrors, diaphragm, stage forceps, glass plate, pliers, etc 65 00 
The New Monocular National Microscope Stand, with one eye-piece, concave and plane mirrors, 
diaphragm, stage forceps, glass plate, pliers, etc 40 00 
Mahogany Cabinet for the New National Microscopes 10 00 
“ “ “ “ “ with side-case and fittings for all accessories.. 15 00 
The National Series of Objectives 
Focal Length. 
Linear Magnifying Power, nearly. 
Degrees of 
Angle of 
Aperture. 
Price. 
With Eye-pieces. 
Draw-tubes. 
No. 1. 
12 
No. 2. 
20 
No. 2. 
32 
7° 
5 6 00 
6 00 
2 “ 
23 
43 
70 
10° 
1 “ 
47 
78 
116 
19° 
8 00 
% “ 
65 
110 
170 
25° 
9 00 
X “ 
100 
170 
260 
38° 
10 00 
% “ 
200 
340 
520 
75° 
12 00 
'Q “ 
365 
620 
955 
95° 
20 00 
i-io “ 
Closed. 
730 
1240 
1930 
110° 
30 00 
Every description of mounting apparatus and materials, fully illustrated and described in their full 
catalogue, mailed to any address. PRICE-LISTS OE MICROSCOPE FIRMS. 
645 
No. 12.—J. Zentmayer, 147 South Fourth Street, Philadelphia, Pa. 
(1879). 
Zentmayer’s American Centennial Stand. 
{Patented 1876.) 
American centennial binocular, with 5 eye-pieces ; diatom stage, draw-tube, bull’s-eye condenser 3, 
4 and 5-inch objectives, 12° angular aperture, IX inch, 22° ; 8-10 inch, 32° ; 4-10 inch, 80°, ad- 
justable for thin covers; 1-5 inch, 85°; 1-5 inch, 120°, adjustable; polarizer, complete; Barker’s 
selenites, Bicknell’s achromatic condenser, achromatic condenser, with centering adjustment 
and achromatic combination of X and 1-5 inch ; double nose-piece (angular), eye-piece micro- 
meter, stage micrometer, camera lucida, parabola, erector, stage forceps, blue and ground- 
glass shade, 1 animalcule cage (large), 1 animalcule cage (small), Wenham’s compressorium, 
achromatic oblique prism, right-angle prism, instead of mirror; parabolic silver side reflector, 
with Sorby’s reflector; 1 pair of orthoscopic eye-pieces, indicators to 2 eye-pieces, mineral 
holder, mechanical finger, Maltwood finder, amplifier, dark wells, Lieberkiihn’s to and 
8-10 objectives, and polished mahogany case, with side case $765 00 
American centennial stand, with 3 eye-pieces, and same accessories as above 715 00 
American centennial stand, with 5 eye-pieces; diatom stage, bull’s-eye, \X inch objective, 22°; 
8-10 inch, 32° ; 1-5 inch, 120° (adjustable) ; polarizer, complete; 2 selenites, Bicknell’s achro- 
matic condenser, indicator to A eye-piece, camera lucida, stage micrometer, animalcule cage, 
Wenham’s compressorium, and polished mahogany case, with side case 490 00 
American centennial stand, with 3 eye-pieces ; same accessories as above .440 00 
American centennial stand, binocular, with 5 eye-pieces 300 00 
American centennial stand, monocular, with 3 eye-pieces 250 00 
Concentric adjustable diatom stage 20 00 
Best mahogany case, with fine handle, and side case for accessories 30 00 
Zentmayer’s United States Army Hospital Stand. 
(Patented 1876.) 
United States army hospital stand, binocular, with 4 eye-pieces ; 8-10-inch objective, 32° angular 
aperture ; 1-5 inch 90° angular aperture; camera lucida, stage micrometer, and mahogany 
case 173 00 
United States army hospital stand, monocular, with 2 eye-pieces, and same accessories as above.. .133 00 
The above is the manner in which the stand was fitted out for the United States Government Hos- 
pitals; it may, however, be fitted out, if so desired, with any of the object glasses or accessories from the 
United States army hospital stand, binocular, with 4 eye-pieces and mahogany case 130 00 
United States army hospital stand, monocular, with 2 eye-pieces and mahogany case 90 00 
Zentmayer’s American Histological Stand. 
{Patented 1876). 
American histological stand, with 1 eye-piece (A or B); 8-10 inch objective, 24° aperture; 1-5 inch 
objective, 75° aperture (which easily resolves p. angulatum), and neat walnut case, with lock 
and handle 1 50 00 
American histological stand, with same accessories as above, but with addition of rack and pinion, 
instead of sliding tube for coarse adjustment 58 00 
American histological stand, same as above, but with binocular attachment, and 1 pair of eye- 
pieces 80 00 
American histological stand, with gliding tube coarse adjustment, 1 eye-piece, and walnut case.... 32 00 
American histological stand, with rack and pinion coarse adjustment, 1 eye-piece, and walnut case. 40 00 
American histological stand, binocular, with 1 pair of eye-pieces, and walnut case 62 00 
Extra eye-pieces 5 00 
Accessories for Histological Stand. 
Polarizer, complete, with 1 selenite A.. 15 00 
Selenites 1 00 
Neutral tint camera 3 00 
Stage micrometer, 100-1000 1 00 
Eye-piece micrometer (disk)... 2 00 646 
PRICE-LISTS OF MICROSCOPE FIRMS. 
Hemispherical spot lens. $4 Oft 
Adapter for using objective as achromatic condenser 1 00 
Stage forceps 1 75 
Animalcule cage 2 00 
Double nose-piece 6 00 
Glass sliding stage, with spring and ivory-pointed screw, complete 4 00 
Rotating stage-plate, with clips 2 00 
Woodward’s prism, unmounted 150 
Woodward’s prisms, mounted 4 00 
Clinical stand, with 2 eye-pieces; 8-10 inch objective, 26° angle of aperture; 1-5 inch objective, 75° 
angle of aperture (non-adjustable). Securely packed in a neat walnut case 50 00 
Zentmayer’s Clinical Stand. 
Complete 80 Oft 
Large Dissecting Microscope 
Botanical Dissecting Microscope. 
Complete 14 00 
3, 4, and 5 inch combined 15 oft 
Achromatic Object Glasses, Zentmayer’s Objectives. 
1% inch, angle of aperture 23 degrees 15 Oft 
8-10 “ “ 32 “ 18 00 
% “ “ 82 “ 18 00 
4-10 “ l! 80 “ adjustable 30 00 
1-5 “ “ 120 “ “ 35 00 
8-10 “ “ 26 “ 10 00 
4-10 “ “ 60 “ 22 00 
1-5 “ “ 90 “ 18 00 
1-10 “ “ 140 “ immersion 20 oft 
Accessories. 
Achromatic condenser, with centering adjustment and achromatic combination of % and 1-5 inch.. 38 00 
Achromatic condenser (Bicknell’s), with blue and ground glass 20 Oft 
Achromatic oblique prism 14 00 
Amplifier . 8 00 
Animacule cage (large size) 3 50 
Animacnle cage (small size) 3 00 
Adjustable sub-stage adapter 15 00 
Adapter for using an objective as achromatic condenser 1 00 
Adapter for using an objective as achromatic condenser, with centering adjustment 7 50 
Blue glass cap 1 sft 
Blue and ground glass shade (changeable) ~ 400 
Bull’s-eye condenser, for centennial stand 10 00 
Bull’s-eye condenser, for army stand 5 00 
Camera lucida 6 00 
Barker’s selenites 30 00 
Dark wells and holders (set of three) 5 00 
Double nose-piece (straight) 9 00 
Double nose-piece (angular) 13 00 
Draw-tube (graduated) 4 00 
Erector 6 00 
Bye-pieces for centennial stand, each 6 00 
Bye-pieces for United States army stand, each 6 00 
Eye-pieces, Kellner orthoscopic, each 8 25 
Frog-plate, complete 4 00 
Glass slips, with ledge, each Bft 
Indicators to eye-pieces, each 2 00 
Jackson eye-piece micrometer 6 oft PEICE-LISTS OF MICROSCOPE FIRMS. 
647 
Lieberkuhn to 3 inch, 2 inch, and 1)4 inch objectives, each $6 00 
Lieberkuhn to 8-10 inch and % inch objectives, each 4 go 
Lieberkuhn to 4-10 inch and )4 inch objectives, each 4 00 
Mechanical finger (Zentmayer’s) 25 00 
Maltwood finder 3 00 
Polarizing apparatus for Centennial stand 32 00 
Parabolic silver side reflector. 8 00 
Polarizing apparatus for army stand 22 00 
Parabola (Wenham’s) 13 50 
Parabolic silver side reflector, with Sorby’s reflector 15 00 
Eight angle prism, for reflecting the light more perfectly than the plane mirror 20 00 
Selenites, each 1 50 
Separate monocular body, complete with gradual draw-tube and fine adjustment 80 00 
Stage forceps 3 25 
Stage micrometer—loo and 1,000 to the inch ... 1 00 
Stage micrometer—loo, 1,000, and 2,000 to the inch 1 50 
Stage micrometer—millimetre and 1-10 and 1-100 of millimetre 1 50 
Stage mineral holder 9 00 
Wenham’s compressor 3 50 
White cloud illuminator 4 00 
Woodward’s prism, unmounted, $1.50; mounted 8 00 
Zoophyte trough 3 50 
Astral oil lamp, fitted lo mahogany board for centennial stand, with silvered mica shade, 14 00 
Astral oil lamp, flat wick and plain shade 6 00 
Astral oil lamp and silvered mica shade 8 00 
Silvered mica shades 2 00 
No. 13.— G. S. Woolman, 116 Fulton Street, New York (1879). 
1. Histological and dissecting microscope combined, with good % inch objective 25 00 
2. Compound microscope, with hinge, sliding tube, and micrometer adjustment, 1 eye-piece, 
1 inch and inch objectives 85 00 
3. Same, with 2 eye-pieces and rack and micrometer adjustment 50 00 
4. Same as No. 3, binocular 80 00 
5. Compound microscope, concentric stage rack and micrometer adjustment, 2 eye-pieces, 1 inch 
and J4 inch objectives 75 00 
6. Same as No. 5, binocular 100 00 
7. Woodward prisms for oblique illumination 1 25 
8. Polariscope, with selenite and adaptors 13 50 
9. Section cutters 4 50 
10. “ with clamp screw 0 00 
11. Seilee’s section-cutting machine 12 50 
12. Agent for Now York of Charles A. Spencer & Sons’ object glasses and K. & J. Beck’s micro- 
scopes. 
13. National self-centering turn-table 0 00 
14. Glass slips, ground edges, per gross 
No. 14.—Price List of J. Gbunow’s Objectives for Physicians and 
Students, 70 West Thirty-ninth Street, New York (1879). 
3 inch, angle of aperture, 12 degrees 12 00 
“ “ “ 15 “ 13 00 
% ii u u gg ti 15 00 
X “ “ » 75 “ 18 00 
1-6 “ “ ii 100 “ 
1-6 “ « “ 140 “ (adjustable for cover) 25 00 
1-8 ‘i a n 150 ii ii ii 30 00 
1-12 ii ‘I ii log ii ii ii 35 00 
N.B.—The 1-6, 1-8, and 1-12 inch are either dry or immersion objectives, at the option of the purchaser. 
Angular double nose-piece 10 00 
“ triple ii 18 00 648 
PRICE-LISTS OP MICROSCOPE FIRMS. 
Straight double nose-piece f8 00 
triple “ 12 00 
Frog plate 6 00 
Improved Strieker’s warm stage 12 00 
Orthoscopic or Kellner eye-piece 9 00 
Section cutter 12 00 
No. 15.—W. Wales, Fort Lee, N. J. (1879). 
First Quality Objectives. 
4 inch, angle of aperture, 9 degrees 15 00 
3 “ “ . “ 12 “ IT 00 
“ “ •' 23 “ 17 00 
1 “ “ “ 25 “ 18 00 
% “ “ “ SO “ 18 00 
4.10 “ “ *■ T5 “ 30 00 
4-10 “ “ 95 “ 35 00 
4-10 11 “ <• 115 “ 40 00 
1-5 “ “ 100 “ (adjustable) 30 00 
1-5 “ • 135 “ “ 35 00 
1-5 “ “ -1 170 “ “ 40 00 
1.10 k‘ “ '• ITO “ “ immersion) 45 00 
1-15 “ “ “ 170 “ “ “ 65 00 
1-25 “ “ “ 160 “ “ “ 100 00 
Wales’ ex. pat. back for photographing 15 00 
“ “ front “ 15 00 
IX inch, angle of aperture, 23 degrees 15 00 
Best Students*. 
% “ “ “ 30 “ 15 00 
1-5 “ “ “ 100 “ 20 00 
1-10 “ “ “ 135 “ (immersion) 25 00 
Economic. 
IX inch, angle of aperture, 15 degrees 6 00 
X “ “ “ 20 “ 600 
1-5 “ “ “ 80 “ 12 00 
1-10 “ “ “ 120 “ (immersion) 20 00 
No. 16.—Miller Brothers, 1213 Broadway and 69 Nassau Street, New 
York (1879). 
No. 1, Binocular Microscope, is of first-class quality in every respect. The stand is firm and free 
from tremor under observation, even while the adjustment of apparatus may be going on. 
The binocular mechanism is very superior, realizing both the stereoscopic and perspective 
views of the object with remarkable ease and perfection. In addition to a rectangular motion 
of one inch in each direction and rotation by hand, the whole stage rotates concentrically and 
independently by means of a rack and pinion on a circular plate, graduated so as to form a 
goniometer or position micrometer. The secondary or sub-stage has adjusting screws for cen- 
tering all the supplementary apparatus which it receives, and affords facilities for the manipu- 
lation and use in the most convenient and efficient manner, possessing also the means of rota- 
tion by rack and pinion, with graduated divisions at the circumference. The fine adjustment 
is of the most delicate and perfect construction, the index reading off differences in the focal 
position of the objective to the five-thousandth part of an inch, perceptible to the observer’s 
eye. Price of this microscope, including 4 eye-pieces 320 00 
If with single body, 2 eye-pieces 260 00 
No. 2. This instrument is constructed on the same general plan as No. 1, but is rather smaller. 
The stage has the usual rectangular motion and one of rotation, without rack and pinion. 
In workmanship, finish, accurate fitting, and optical qualities it is the same as No. 1. The 
sub-stage has a rotating cylinder, with adjustments for centering the apparatus which it 
receives, and provides for their use and application with freedom. The Hat and concave 
mirror is fitted on a double arm to facilitate the oblique reflection of light. The price, 
binocular, with 4 eye-pieces, is 280 00 
If single body, with 2 eye-pieces 200 00 PRICE-LISTS OF MICROSCOPE FIRMS. 
649 
Stand 12 inches in height, and draw tube; heavy base and arm of green japanned cast-iron; body 
and all other parts of well-finished brass; the body can be inclined to any angle. Coarse 
adjustment by spiral motion, fine adjustment by a new construction, which is efficient with 
high powers. Plane and concave mirrors adjustable for oblique light; revolving diaphragm 
inlaid even with the stage ; the stage is of glass, with perfectly smooth motions in all direc- 
tions One eye-piece, 3 objectives, IX, %, and X inch of focus, of our own make. This in- 
strument having been designed under advice of our most eminent physicians, professors, and 
amateurs in microscopes, is cheerfully recommended by them, especially for medical purposes. 
The whole, packed in an upright black walnut wood case, with drawer, price $5O 00 
4 inch, angular aperture, 9 degrees 12 00 
Miller Brothers’ First-Class Objectives 
3 it un 12 i‘ 16 00 
2 “ “ “ 15 “ 18 00 
IX “ “ “ 20 “ 20 00 
1 it it n 25 “ 20 00 
X 11 n it 32 “ 22 00 
n u it go “ . 25 00 
u u ii 75 n 36 00 
ii it n go it 30 00 
x* “ “ “ 130 “ 40 00 
1-5* “ “ “ 130 “ 50 00 
it i. n jqg ii 60 00 
I.lB*u ii it 175 “ (immersion; 00 
I_36* ii ii it i7Q u ii 130 00 
1-40* ii ii it i7O •“ <i 150 00 
All marked (*) have adjustment for covering glass. 
Student’s Objectives. 
3 inch 10 00 
2 ii " 10 00 
IX - 1G 00 
1 ti 10 00 
% 1. ■" 10 00 
X 11 10 00 
x 1500 
Miller’s Achromatic Triplets. 
(Mounted in Gold and Silver.) 
Gold mountings, 1, X, % 15 00 
Silver “ “ “ “ 10 00 
Sorby’s pocket spectroscope 00 
Sorby’s micro-spectroscope, fitted to any stand, complete 40 00 
Extra eye-pieces, A, B, C, and D each’ 600 
Erecting eye-piece for dissecting 0 00 
a „ ...... *--** 10 00 
Improved micrometer eye-piece 
Kelner’s orthoscopic eye-piece, Cor D, double size field • 000 
Achromatic condenser, with revolving diaphragm and complete adjustments 35 00 
Webster’s achromatic condenser 99 to 20 00 
■r.,11, , ~ $2.00,4.50, to 10 00 
rsuli’s-eye condenser, on stand ’ ’ 
5 , on nn 
Amici’s prism, for oblique illumination, mounted on a separate stand 20 00 
° AUX. UfmCjUU inuuniiurmwii, * Q no 
Nachet’s prism, “ “ 
Rectangular prism, reflection of parallel rays ' ’ ’'' ‘ 99 
Wenham’s parabolic reflector «9-50’ best’ “99 
o ya>i iiuuuu g 
Silver slide reflector, for opaque objects 
“‘iuc ICUCVjUUI., lUi g 
Silver parabolic stage reflector ' ’ ’''' „ 
Bront'o o t l ~ . $6 00 to 800 
■°rook s arm, for two objectives 
Stage micrometer, ruled 100 and 1,000 
“ “ ruled 100, 1,000, 2.000, 3,000, and 4,000 
“ (2 millimetres), ruled in 100 each, with figures 2 50 
. .. J 4l 20 00 
for three “ 
(& UllllllUCUiPOy, 7 
■Maltvvood’s object finder, in case 650 
PRICE-LISTS OE MICROSCOPE FIRMS. 
Stage tweezers on jointed arm $3 50 
Zoophyte trough, complete with wedge and spring .• 2 50 
Live boxes for insects $2.50 to 3 00 
Frog and fish plate, complete in glass or metal 2.50 to 4 50 
Glass fish boxes 3 50 
Glass stage plates, various 50c. and 1 25 
Holman’s life slide 1 50 
“ syphon slides complete 4 50 
current slide 1 50 
Miller’s prism, for oblique illumination, mounted in German silver $25.00 and 85 00 
Read’s prism 12 00 
Plain achromatic condenser, with Jf-iuch objective, central and annular stops 20 00 
Read’s hemispherical or kettle-drum condenser 13 50 
Camera lucida, Wollaston’s $8 00 to 10 00 
$B.OO and 10 00 
“ “ neutral tint glass.... 3 00 
Polarizing apparatus $20.00 and 25 U0 
Selenites, selected colors, $l.OO each ; brass-mounted 2 25 
Set of Barker’s three selenites, revolving, brass-mounted, showing 13 colors and complementary 
tints 18 00 
Lister’s set dark wells 5 00 
Dark field condenser, with adjustment $4.00 to 5 00 
Miller’s stage light modifier, set of three colors 3 50 
Skeleton stage for very oblique illumination 4 00 
Turn-table for making cement cells and finishing slides, complete 4 00 
Miller’s machine for cutting wood, medical, and other sections $5.00, 7.00, 12.00, 15 00 
Diamond for cutting glass slips $4.00 to 10 00 
Machine for cutting circlers in thin glass with diamond, complete 13 00 
“ thin glass and for writing 400 
Platted crown glass slips, 3by 1 inch dozen, 15c., gross, 1 50 
“ “ with ground edges dozen, 30c., gross, 3 50 
Plate glass slips, excavated cells dozen, 3 00 
Round glass ring cells dozen, 100 
“ “ “ extra thin dozen, 75c., gross, 700 
Bone ring cells, assorted sizes dozen, 50 
“ “ fixed on slips each, 25 
Thin glass covers, cut round dozen, 25, 30, 40, 50c.; ounce, 350 
“ “ cut in squares “ “ “ orrnce, 3 00 
“ “ cut round and square, very thin $6.00 to 12 00 
Thin glass in sheets 1 50 
Snperfine white name labels, oval, in packets 25c. to 50 
Colored backs and gilt fronts, with holes punched, per 1000 1 50 
Gilt front, “ “ “ 75 
Round punches for this purpose each 50c. to 1 00 
“ holes not punched, per 100 50 
No. 17.—Bausch & Bomb Optical Co. Rochester, N. Y, and 37 Maiden 
Lane, New York (1879). 
No. 500. Library Microscope.—This microscope has a finely finished and japanned foot, arm with 
joint to incline, a nickel-plated body or tube, carrying the optical parts of the instrument and 
adjustable by rack and pinion, with draw-tube to increase magnifying power; a concave 
mirror, swinging so as to give oblique illumination when desired, and capable of being 
brought above the stage for illumination of opaque objects. The screw at the lower end of 
the tube is so arranged as to permit the attachment of achromatic triplets, so that if desired 
a much higher magnifying power than the above can be obtained. The stage is made of 
hard rubber, which is not injured by water or ordinary fluids, and is provided with spring 
clamps for holding object-slides. The camera lucida which accompanies this microscope, 
although exceedingly simple, is a valuable addition to the same, and greatly adds to its useful- 
ness ; it is very easily managed and a little practice wdll enable anybody to make by the aid 
of it drawings of the magnified image of microscopic objects. The microscope has one eye- 
piece and a divisible two-lens objective, giving, in combination with the draw-tube, magnifying 
power of from 50 to 125 diameters. 
It is accompanied by a glass slide with cell for fluids, a plain glass slide and one object. 
A neat black walnut case encloses the instrument and accessories. Price 10 00 PRICE-LISTS OP MICROSCOPE FIRMS. 
651 
The same, with two achromatic doublets $l2 00 
No. 510. Family Microscope.—The base and pillars of this microscope are of cast-iron, neatly- 
japanned. They support the axis which carries the arm in such a way that the instrument 
may be inclined to any angle. Back and pinion for adjustment of focus, made with such 
exactness as to leave no perceptible jar, and neither lost or lateral motion while adjusting. In 
order to give greater sensitiveness to the adjustment, the milled heads of the pinion have 
been made of large dimensions, in consequence of which the lower and medium powers can 
be adjusted and used with great ease. The tube is supplied with standard society screw. 
The mirror, which is concave, is so arranged that it can, if desired, be swung above the stage 
for the illumination of opaque objects. A revolving diaphragm is fixed beneath the stage. 
This stand is accompanied by one eye-piece, B (No. 880), mounted in either hard rubber or 
brass, and one objective, X inch (No. 620), which divides so as to permit the separate use of 
the posterior combination, thus giving the power of an excellent 1X inch. Eange of magni- 
fying power, from 60 to 100 diameters. 
In upright walnut case, with handle, lock and key, drawer for accessories, and receptacle 
for objectives and eye-pieces 20 00 
No. 520. Educational Microscope.—This instrument has a japanned cast-iron base, inlaid with soft 
rubber pads on the under surface, on which the weight of the instrument rests, thereby neu- 
tralizing any tremor or vibration communicated from surrounding objects, and preventing 
the instrument from slipping or sliding. Solid brass pillars, supporting axis for the arm 
which carries the body tube. Back and pinion for coarse adjustment. Fine adjustment as 
above described. Bevolving diaphragm below the stage, concave mirror, which may be 
arranged for either central or oblique light. , 
One eye-piece, B (No. 830). 
Two objectives, 2 inch (No. 605), and 410 inch (No. ,625). 
Bange of magnifying power, 30 to 135 diameters. 
In upright valnut case, with handle, lock and key, drawer for accessories and receptacles 
for objectives and eye-pieces 30 00 
No. 525. Research Microscope.—This microscope is constructed after an entirely new pattern. It 
has a neatly japanned iron arm and base, the latter inlaid with soft rubber pads, and of such 
construction and weight as to counterbalance the instrument at any inclination of its body. 
Finely finished brass pillars supporting the axis, which permits the body to incline at any 
angle. The tube has nickeled inner draw-tube, giving a range of 8 inches. Coarse adjust- 
ment by rack and pinion ; fine adjustment by micrometer and screw, acting on our patent 
fine adjustment. This new style of fine adjustment is a peculiar feature of all our higher- 
priced microscopes. It consists of two parallel blades of thin spring steel, placed one above 
the other, each fastened with one end to the arm, with the other to the body, and acted upon 
by a fine micrometer screw, attached to a lever protruding from the body, by means of which 
the latter may be raised or depressed, with extraordinary delicacy of adjustment. It has no 
lost motion, and having no friction is not liable to deterioration. The stage is made of brass, 
and is made as thin as is consistent with firmness and freedom from tremor. Bemovable 
spring clips on stage. The mirror-bar is hung on a point placed above the stage and be- 
tween this and the arm. It swings to any obliquity and any angle above the stage for the 
illumination of opaque objects. Plain and concave mirror adjustable along the mirror-bar. 
One eye-piece, B (No. 830). 
Objectives 1 inch (No. 610), and X inch (No. 635). 
Camera luoida. 
Bange of magnifying power from 54 to 250 diameters. 
In neat black walnut case, with handle, lock and key, drawer for accessories and receptacles 
for objectives and eye-pieces 45 00 
Same with standard size sub-stage and revolving diaphragm, adjustable along the mirror-bar, inde- 
pendent of the mirror and entirely removable, extra 3 00 
In place of the brass stage we affix our glass stage with slide carrier, as described in No. 550, extra.. 500 
No. 530. Student's Microscope.—The stand of this microscope is constructed with a japanned cast- 
iron foot, nicely finished, inlaid with soft rubber pads. Brass pillars which support the axis 
in such a way as to allow the body to be inclined to any angle, the instrument remaining well 
balanced, in all positions of the body. Brass arm, coarse adjustment by sliding tube, the 
latter nickel-plated; fine adjustment by fine micrometer screw, acting upon our patent 
movement described with Microscope No. 525. The stage is supplied with spring clips, and 
with an adjustable shoulder to vary the position of the object-slide on the stage, and to keep it 
parallel to the latter. Plain and concave mirrors, arranged so that their distance from the 
object may be varied, and adjustable for oblique light; revolving diaphragm under the stage. 
Two eye-pieces, A (No. 825), and C (No. 835), the latter arranged with a slot to receive 
eye-piece micrometer. Eye-pieces furnished mounted either in hard rubber or brass, at 
purchaser’s option. 
Two objectives, viz., X inch (No. 615), and 1-5 inch (No 640). 
Camera lucida and eye-piece micrometer. 
Bange of magnifying powers from 50 to 375 diameters. 
In upright walnut case, with handle, lock and key, with drawer for accessories, and 
receptacles for eye-pieces and objectives 50 00 
No. 535. Student's Microscope.—The same stand as No. 530, with rack and pinion for coarse 
adjustment. Fine adjustment the same as No. 530. Sub-stage for accessories into which a 
revolving diaphragm is fitted, the latter being removable. 
Plain and concave mirrors, arranged so as to allow the most oblique light for high powers, 
and also a variation in their distance from the object. 
Accompanying accessories the same as with No. 530. Magnifying power also the same. 
In upright, walnut case, with handle, lock and key, drawer for accessories and receptacles 
for eye-pieces and objectives 60 00 652 
PRICE-LISTS OE MICROSCOPE FIRMS. 
No. 540. Student's Microscope.—The general construction of this microscope is the same as of No. 
535, with the exception of the stage, which consists of a solid glass plate resting on two brass 
pieces joined to the arm. 
This glass plate is provided with a movable metallic slide-holder, which serves as a substi- 
tute for a so-called mechanical stage. It is of very light weight and rests on the surface of 
the immovable glass stage on only four small points protruding from the plate, while the 
prolongations of the latter, bent downward and backward, and acting as springs, press 
against the under side of the glass plate with just sufficient force to keep it in its place when 
the body is inclined. This pressure can be varied at the option of the manipulator; spring 
clips are provided to hold the object-slide. 
This construction of the object-slide carrier, in combination with the smoothness of the 
surfaces of the glass stage, reduces the friction to a minimum, and renders the movement of 
the former very delicate, smooth and firm. Two small knobs on the slide carrier facilitate 
the movement. 
The slide carrier can be detached from the stage if so desired. 
The sub-stage consists of a brass ring, joined to the brass pieces supporting the glass stage, 
and is of the standard size. Revolving diaphragm fitted to sub-stage. 
Accompanying accessories the same as with No. 530. Magnifying power also the same. 
In upright walnut case, with handle, lock and key, drawer for accessories and receptacles 
for objectives and eye-pieces $7O 00 
No. 550.—Physician's Microscope.—The stand of this microscope is firm and well balanced, finely 
finished, and of superior workmanship throughout. 
It is a microscope best adapted for the use of physicians and students of histology, and is 
extensively used at present by professional men, and in many of our most prominent institu- 
tions of learning. 
Heavy japanned cast-iron foot, of neat design and finish, inlaid on the under surface with 
three soft rubber pads. Strong solid brass pillar and arm, both connected by a well-fitting 
joint, which allows the body to incline to any angle. Pillar and arm so marked as to indicate 
the correct inclination of the body for the use of the camera lucida. Draw-tube, having a range 
of 2% inches, and supplied with a stop when drawn to standard length. It is nickel-plated, 
and has a firm but perfectly smooth movement. Coarse adjustment by rack and pinion, free 
from either lateral or lost motion. Pine adjustment by sensitive micrometer screw, acting 
upon our patent movement as described with No. 555. Large stage, free from tremor, and sup- 
plied with sub-stage to receive diaphragm, polarizer, etc. The diaphragm receives three extra 
caps, having apertures of 1)4 and. 2X millimetres, and so fitted that they are in the cor- 
rect centre of the field, and just below the plane of the stage. If desired, a simple revolving 
diaphragm will be fitted into the sub-stage, in place of the above. Large plane and concave 
mirrors, and mirror-bar arranged with a double joint, so that they can be brought to any 
obliquity, and can be swung above the stage for the illumination of opaque objects. 
Eye-pieces, A (No. 825) and C (No. 835), the latter arranged with slot for micrometer, 
mounted either in hard rubber or brass, at the option of the purchaser. 
Objectives, % inch (No. 615), and 1-5 inch (No. 640). 
Camera lucida, eye-piece micrometer. Magnifying powers, with tube at full length, 50 to 
375 diameters. 
In upright walnut case, with handle, lock and key, drawer for accessories, and receptacles 
for objectives and eye-pieces 60 00 
No. 555. Physician's Microscope.—The stand of this instrument is of the same general construction 
as that of No. 550, with the exception of the stage, which consists of a solid glass plate, as 
described with No. 540, with this difference, that the sub-stage is fitted into the glass plate 
by a society screw; this arrangement prevents any light from below being thrown upon the 
objects, except through the central opening of the diaphragm. 
Diaphragm as described with No. 550, or with ordinary revolving diaphragm. 
Accessories the same as with No. 550. 
Range of magnifying power also the same. 
In upright walnut case, with handle, lock and key, drawer for accessories, and receptacles 
for objectives and eye-pieces 65 00 
No. 560. Large Student'sMicroscope.—This microscope is designed for the use of higher powers in 
the more delicate microscopical investigations. It has a heavy cast-iron foot, neatly japanned, 
inlaid at the under side with soft rubber pads. Solid brass pillars supporting axis, the latter 
and the pillars so marked as to indicate the proper inclination of the tube for using camera 
lucida. Brass arm, carrying body tube and supporting glass stage, the same as described 
with microscope No. 540. 
Coarse adjustment by rack and pinion, fine adjustment by sensitive micrometer screw, act- 
ing on our patent motion as described with No. 525. 
Plane and concave mirrors, with sub-stage of standard size, revolving diaphragm fitted 
into and separable from latter, all attached to the swinging mirror-bar, the axis of which is 
placed on the level of the object, so that diaphragm and mirror swing concentrically around 
the same. Mirrors movable on the mirror-bar to and from the object, and can also be en- 
tirely detached. The distance between the sub-stage and the object can be varied by revers- 
ing the former. The sub-stage can also be detached when greater obliquity of light is desired. 
Three eye-pieces A (No. 825), B (No. 880), and C (No. 835), mounted either in hard rubber 
or brass, and the 0 eye-piece arranged with slot for micrometer. 
Three objectives, 2 inch (No. 605), % inch (No. 615), and 1-6 inch immersion (No. 680). 
Range of magnifying power, from 22 to 450 diameters. 
In upright walnut case, with handle, lock and key, drawer for accessories, and receptacles 
for objectives and eye-pieces 90 00 
No. 570. Professional Microscope.—This instrument is provided with a heavy brass foot, highly 
finished, inlaid with three soft rubber pads at the under surface. Two solid brass pillars 
support the axis for inclination of the body. Two strong screws with milled heads, placed at PRICE-LISTS OF MICROSCOPE FIRMS. 
653 
the ends of the axis, serve to tighten or loosen the connections by means of which the arm 
can be made to move with more or less ease. 
Coarse adjustment by rack and pinion, moving a long prismatic slide accurately fitted, at- 
tached to the body, and arranged for compensation of wear. Fine adjustment by micrometer 
screw, with milled head, silvered and graduated, acting upon our patent movement described 
with No. 625. 
Glass stage with slide holder similar to that described with Microscope No. 540, but is of 
larger dimensions, circular in form, and fitted to receive the hemispherical immersion con- 
denser. In this stage we gain thinness, while still maintaining its stability. The slide 
carrier moves in any direction, and also revolves. 
Sub-stage and mirrors (plane and concave) are fastened to the swinging mirror bar, the axis 
of which is fixed in the plane of the object, thereby permitting the accessories and mirror to 
swing concentrically around the object. The mirror may be brought to any obliquity and 
swung above the stage for the illumination of opaque objects. The mirror, as well as the 
sub-stage, can be moved on the mirror bar to and from the object, and both can be removed 
altogether, in an improved manner. 
The sub-stage ring receives the revolving diaphragm, condenser, etc., and auxiliary ring 
with internal society screw, which accompanies the instrument, and to which objectives and 
other auxiliaries may be fitted. 
Three periscopic eye-pieces, B (No. 855), C (No. 800), and D (No. 865), the latter arranged 
with slot for micrometer. 
Four objectives, 2-inch (No. 605), %-inch (No. 615), 1-5-inch (No. 640), and %-inch immer- 
sion, adjustable for cover correction (No. 695). 
Hemispherical immersion condenser (No. 975). 
Range of magnifying power, from 30 to 800 diameters. 
In upright walnut case, with handle, lock and key, drawer for accessories, and receptacle 
for objectives and eye-pieces $2OO 00 
Objectives. 
STUDENT’S SERIES. 
Focus. 
Angular Aperture. 
Adjustment. 
Price. 
No. 600 
4 inch. 
6° 
Non-ad justable. 
$6 00 
“ 605 
2 
12° 
(( U 
6 00 
“ 610 
1 
20° 
6 00 
“ 615 
3-4 “ 
27° 
8 00 
“ 690. 
1-2 
40° 
9 00 
“ 625 
410 “ 
55° 
11 00 
“ 630 
3-10 “ 
75° 
u u 
13 CO 
“ 635 
1-4 “ 
10(1° 
u a 
14 00 
“ 640 
1-5 
110° 
15 00 
“ 645 
1-8 “ 
120° 
“ 
18 00 
_ The low-power objectives of this series are remarkable for their excellent definition. The %-inch 
which accompanies our stands when so enumerated in the price-list, has obtained a celebrity for its extreme 
flatness of field and excellent definition; the 3-10 resolves PI. Angulatum by a slight obliquity of light; 
the X resolves the same by central illumination ; the 1-5 the same into dots by central light and the finer 
lines of the Surrirella Gemma (dry) with ease. 
PROFESSIONAL SERIES. 
Focus. 
Angular Aperture. 
Adjustment. 
Price. 
No. 650. 
4 
inch. 
U 
10° 
Non-adjustable. 
66 66 
$13 00 
13 00 
15 00 
“ 655.. 
“ 660. 
3 
I 
15° 
36° 
“ 665... 
“ 670. 
3-4 
1-2 
(( 
u 
35° 
60° 
66 66 
U 66 
14 00 
15 00 
“ 675... 
1-4 
a 
110° 
16 00 
“680.. 
1-6 
“ Im. 
165° 
20 00 
“ 685 
1-6 
165° 
Adjustable. 
23 00 
“690. 
1-8 
1-8 
1-13 
1-16 
370° 
Non-adjustable. 
22 00 
“695. 
170° 
Adjustable. 
25 00 
“ 700. 
175° 
SO 00 
“ 705 
175° 
35 00 
The lower powers of this series are all two-system, and are remarkable for their perfect correction 
1 beantifnl definition. They will compare favorably with any made of corresponding powers. 
, . The easily resolves PI. Angulatum by central light; the 1-6 has extremely large working distance, 
wmch is also the case with the higher powers. Those from 1-8 upward will resolve all objects on Moller’s 
ary plate. 654 
PRICE-LISTS OP MICROSCOPE FIRMS. 
FIRST-CLASS SERIES. 
Focus. 
Angular Aperture. 
Adjustment. 
Price. 
No. 710 
12° 
Non-adjustable. 
$15 00 
18 00 
22 00 
25 00 
28 00 
35 00 
42 00 
46 00 
50 00 
75 00 
“ 715 
2 “ 
20° 
“ 720 
1 “ 
42° 
it U 
“ 725 
1-2 “ 
85° 
it U 
“ 730 
4-10 “ 
110° 
(( (( 
“ 735 
1-6 “ Xm. 
180° 
Adjustable. 
“ 740 
1-8 “ “ 
180° 
“ 745 
1-10 “ “ 
180° 
(( 
“ 750 
1-12 “ “ 
180° 
i( 
“ 755 
1-16 “ « 
180° 
H 
The lower powers have highest resolving power. 
same with central light; the 1-6 and higher powers have an immersion angle of 130°, and will resolve the 
most difficult tests. 
The adjustable objectives are in new and beautiful form of mounting, have inner motion giving rec- 
tilinear movement to posterior systems, and are arranged with graduated and silvered collar. 
The >£-inch resolves PI 
I. Angulatum; the 4-10 the 
With New Compensating Adjustment for Cover Correction 
(Patented Jan. 1, 1878.) 
STUDENT’S SERIES. 
Focus. 
Angular Aperture. 
Price. 
No. 760 
75° 
$17 00 
18 00 
“ 765 
1-4 “ 
105° 
“ 770 
1-5 “ 
112° 
20 00 
“ 775 
1-6 “ 
115° 
22 00 
“ 780 
1-8 “ 
120° 
24 00 
These objectives are of the same optical standard as those mentioned in preceding Student’s Series, 
but give higher results on account of the perfect adjustment. The X-inoh of this series resolves Cyma- 
topleuro elliptica (dry mount), or No. 17 on MOller’s plate, and the others give proportionately good per- 
formance. They all have large working distance. 
PROFESSIONAL SERIES. 
Focus. 
Angular Aperture. 
Price. 
No. 785 
1-5 inch. 
120° 
$25 00 
28 00 
“ 790 
1-6 “ 
170° 
“ 795 
1-8 “ 
170° 
33 00 
The performance of these is unsurpassed for dry-working objectives. They are mounted in the same 
elegant form of mounting as described in First-class Series. 
Focus. 
Angular Aperture. 
Price. 
No 800 
4-10 inch. 
115° 
$35 00 
Huygenian Eye-pieces. 
No. 825 A. or l)£-inch, mounted in hard rubber or brass $3 00 
No. 8808. or 1 “ “ “ “ “ 3 00 
No. 835 C, or % “ “ “ “ “ 300 
No. 840 D. or “ “ “ “ “ 3 00 
No, 8458 and D combined in one 4 50 PRICE-LISTS OF MICROSCOPE FIRMS. 
655 
Perlscopic Eye-pieces. 
No. 850 A, mounted in hard rubber or brass §ll 00 
v‘ o’ .. u » » 10 00 
No- 800B> 
No'seoc! 
„ ' ’ lt .4 44 4. 9 00 
NO-BCOD’ 
*. ’ 9 00 
Higher powers . . . 
Eye-pieces C and I) arranged with slot to receive micrometer, and supplied with ring to exclude light, 
eye-lens being adjustable for focus, 75 cents extra. 
No. 870. Aplanatio triplet, 17-32 inch diameter, 1 inch focus, in tortoise-shell mounting 10 00 
No. 875. Same in brass mounting, nickel-plated 
No. 880. Aplanatic triplet, 14-32 inch diameter, % inch focus, in tortoise-shell mounting 9 00 
No. 885. Same in brass mounting, nickel-plated ; ® 50 
No. 890. Aplanatic triplet, 11-32 inch diameter, X inch focus, in tortoise-shell mounting 8 00 
No. 895. Same in brass mounting, nickel-plated • • 850 
No. 898. Achromatic magnifier, two doublets, giving powers of 7, 10, and 18 diameters, in tortoise- 
shell mounting 
No. 900. Double convex condensing lens, IX hich diameter, on stand 1 25 
No. 905. Bull’s-eye condenser, IX in. diameter, on stand 2 50 
No! 910.' “ “ 1% in. “ “ 450 
No. 915. “ “ 2% in. “ ‘ * ou 
No. 920. “ “ 3 in. “ “ ™ 
No. 925. “ “ 3 in. “ with joint 4~ 00 
2% in. “ “ ?50 
No. 930. Mirror stand, for supporting mirror to illuminate opaque objects. 1 00 
No. 940. Polariscope, mounted in brass and arranged with adapter to fit into the tube above the 
objective, with opening on each side to allow the inner prism to be turned 11 ou 
No. 945. Paraboloid, for dark ground illumination 8 00 
No. 950. Camera lucida, prism for any eye-pieces 5 50 
No. 955. Camera lucida, neutral tint 4 50 
No. 960. Spot lens, with society screw 2 50 
No. 975. Hemispherical immersion condenser. 
This condenser is mounted in brass, and made to fit either in stage or stationary sub-stage. It con- 
sists of ba truncated cone of crown glass, with a convex base, the centre of convexity of which coincides 
isists oi a [ruuuateu wuc ui wv».u . 7 ~ . j , ~ 
With the point where the optical axis of the microscope crosses the plane of the object, and where all the 
light which passes through the condenser concentrates. No matter in what position the mirror may be 
Placed the light always enters the convex side of the condenser without refraction, and is therefore free 
from aberration. The best results are attained when the plane surface of the condenser is connected with 
the under surface of the object slide by water or glycerine 1U DU 
No. 980. Achromatic condenser, mounted in brass, and fitted for sub-stage, with revolving dia- 
phragm having central stops 
No. 985. Paraboloid for dark ground illumination, with adjustable stop, mounted in brass and fitted 
for sub-stage 
No. 990. Paraboloid plain, mounted in brass and fitted for sub-stage ~ 8 50 
No. 995. Spot lens, mounted and adapted to fit sub-stage • • 400 
No, 1000. Polariscope, with extra large prisms, and selenite plate ; the analyzer is connected with 
goniometer and separate eye-piece uu 
No. 1005. Polariscope mounted in hard rubber, with separate and revolving eye-piece 15 00 
No. 1010. Camera lucida with prism, with lens to magnify pencil-point to fit any instrument 8 00 
No. 1015. Eye-piece micrometer, divided in 1-10 or l-2Umm 4 00 
No. 1020. Woodward prism for gaining great obliquity of light 2 00 
No. 1025. Double nose-piece (bent) 5 00 
The obstacle to the more extensive use of this exceedingly useful accessory has been the fact that no 
me oostacie to me more extecsivt; use ui . - * . ... , , . ~ 
matter how well centered the nose-piece may be, objectives not specially fitted to it will be out of the line 
of the optical axis, and that each must separately be brought in focus when used, theieby earning mcon- 
venienoe and delay. We therefore arrange, when a double nose-piece is desired, the powers of the objec- 
tives accompanying our microscopes in pairs, in such a way that each pair is correctly centered, and cor- 
accompanying our microscopes in paira, m 
responds in focus without necessitating further adjustment. 
No. 18.— T. H. McAllister, 49 Nassau Street, New York (1879). 
Professional Microscope Stand. Price, with 2 eye-pieces 50 
* A 4SO 
Walnut case, with lock and handle 
am ut case, wren iock ana 
The Professional microscope is 15 inches high when inclined at angle for convenient obser- 
vation; the base and body of brass, finely finished, with extension draw-tube. The qm.k 
focal adjustment is by chronometer chain, much more uniform and exact than the ordinary 
rack movement; the fine adjustment is by a delicate micrometer screw theentre 
optical system vertically; glass stage plate, movable in every direction, concave and plain 656 
PEICE-LISTS OF MICROSCOPE FIRMS. 
mirrors, etc.; removable collar beneath the stage for carrying polarizer, parabola, and other 
accessories. The mounting for objectives is made with the “ Society Screw,” so that the 
objectives of all flrst-class makers can be used with the instrument. 
Physician's Microscope Stand. Price, with 2 eye-pieces $5O 00 
Walnut case, with lock and handle 3 50 
The Physician’s microscope is a first-class instrument, especially adapted for the use of 
medical men. It is very compact in form, but capable of receiving all the accessories usually 
desired. The main tube of the body is about six inches long, thus enabling an observer to 
use the microscope with ease in a vertical position, so often necessary when fluid objects are 
on the stage ; the total height from the table to the eye-piece 11 inches, yet can be increased 
to the usual height of the large stands by the extension of the draw-tube. 
The focal adjustments are the same as in the professional microscope; movable glass stage 
after the construction originated by Zentmayer; concave and plane mirrors; removable 
collar beneath the stage for carrying polarizer, parabola, and other accessories; society screw 
mounting for objectives. 
Student's Microscope Stand. Price, with 1 eye-piece 30 00 
Walnut case, with lock and handle 3 50 
The Student’s microscope is a neat, serviceable instrument, adapted for a good “ working ” 
microscope. It stands 12 inches high when conveniently inclined ; the base is of iron, bronzed, 
of neat design ; the body of brass, well finished, with extension draw-tube; the quick focal 
adjustment is by a chronometer chain movement, as in the Professional and the Physician’s 
Microscope stands, and the fine adjustment is by a micrometer adjustment attached to the 
stage; concave and plane mirrors ; removable collar beneath the stage for carrying polarizer, 
parabola, etc ; society screw mounting for the objectives. 
*** The Student's microscope is offered, with good achromatic French objectives, 1 inch and 
1-sth inch, giving every grade of magnifying power from 50 to 450 diameters, complete in 
walnut case, with lock and handle 43 00 
Bull’s-eye condensing lens, on brass stand, for the “ Professional ” microscope 8 00 
Microscopic Accessories. 
Polarizing apparatus for the “ Professional ” microscope 20 00 
“ “ “ “ for the “ Physician’s ” or the “ Student’s ” microscope.. 5 00 
“Physician’s” “ 15 00 
Animalcule cage, best 8 50 
“ “ “ “Student’s” “ 12 00 
Zoophyte trough 2 50 
“ “ second quality 200 
T, H. McAllister’s reflector for drawing; more practical than the camera luoida, and can be attached 
to any microscope 2 00 
Stage micrometer, 1-100, 1-1000 1 25 
Bye-piece micrometer 1 30 
Maltwood finder 8 00 
Erector 
Amplifier 1 80 
Stage forceps 2 50 
German study lamp, nickel-plated, latest improved 6 00 
Holman life slide 1 80 
“ current slide 183 
“ syphon slide 430 
Glass object slides, 3xl inches Per dozen, 18 to 60c. 
Mounting Materials. 
Thin glass covers, various sizes, circles and squares per dozen, 18c. to 35c. \ per ounce, $1.50 to 300 
Section cutters to 20 00 
per gross, $1.50 to 6 00 
Turn-tables 3.00 to 7 00 
Canada balsam Per Pottle, 50 
Damar cement 80 
White zinc cement ®3 
Glycerine jelly 80 
Gold size ~8 
Brunswick black ~8 
Carmine, ammonia, borax 25 
Carmine or indigo 25 
Aniline—magenta, blue, or violet • 25 PRICE-LISTS OF MICROSCOPE FIRMS. 
657 
Bosin _ 25 
Haematoxylin _ 25 
Glass-capped bottle for balsam, etc gg 
Dropping and dipping tube 
unci dipping ludg jq 
Labels, square, for 3xl inch slides jqq gg 
“ oval “ 10 
Cabinets, white wood, for 25 objects jg 
polished mahogany, 36 objects, flat $3 00 
72 “ “ 500 
“ 144 “ “ 800 
“ ‘‘ 13 drawers, COO objects 28 00 
“ “ “ 20 “ 1,200 “ 4000 
Mounted specimens for the microscope, from $1.50 per dozen upwards. 
No. 19.—Charles A. Spencer & Sons, Geneva, JST. Y. (1872). 
Student's Microscope, No. 1, height, 15 inches; weight, 6 pounds. The arm, pillar, and base are 
of japanned iron; arm attached by cradle joint, and taking any position from vertical to 
horizontal; coarse adjustment by sliding tube in velveted-clip, and the fine by milled head upon 
the stage; by a curved arm the double mirror (plane and concave) has a lateral movement for 
oblique light, or may be swung above the stage for side illumination of opaque objects. It is 
furnished with B eye-piece, 1 inch objective of 20 degrees angle of aperture, with a very flat 
and well defined field, giving a power of 85 diameters; a % inch of 60 degrees angle of aper- 
ture, adjustable by front lens, giving a power of 325 diameters. In neat cabinet 60 00 
Stand No. 2, like No. 1, with addition of rack and pinion for coarse adjustment, and micrometer 
screw and lever, fine adjustment to nose-piece; camera lucida and animalcule cage; same 
objectives, eye-piece, and cabinet 100 00 
Stand No. 3. Stand of finished bronze and brass; complete as in No. 2; A and B eye-pieces: 
2 inch objective of 12 degrees angle of aperture; 1 inch objective of 20 degrees angle of aper- 
■fnVhi • 1/ flf AH rl on-ivinn • rwvrvinvn L ° ... .. „ 
is • -i -I ° —, x . ’ * vwjvuwn. ksx. ,w UUSICCO angle Ui aper- 
ture , M men or 60 degrees; camera lucida, cabinet 125 00 
Standard Microscope, No. I.—Stand 17 inches high, weight, 11 pounds. This mounting of the sim- 
plest and cheapest form; has the arm, pillar, and base of finished japanned iron; the arm 
attached by cradle joint, and taking any position from vertical to horizontal; the coarse 
adjustment by rack and pinion, or by new friction pinion; the mirror (plane and concave) 
adjustable for oblique light or for side illumination of opaque objects; packed in cabinet 75 00 
Other forms and sizes of stands made to order. 
Focal Length. 
Angle of 
Aperture. 
Price. 
Focal Length. 
Angle of Aperture. 
Price. 
4 inch, adjustable to 3 inch.. 
$35 
30 
30 
30 
40 
40 
45 
50 
160° 
170° to 175°, new form, 
175°, new form. 
175°, “ 
175°, 
175°, 
175°, 
#65 a 
80 Z 
100 B 
iso r g 
150 S 
200 j o 
~ inches ... 
27° 
37° 
30° 
40° to 45° 
80° 
90° 
inch 
% “ .. 
1 inch ... 
1 “ 
1-15 or 1-16 inch. 
“ 
4-10 inch 
1-50 44 
1-4 or 1-5 ... 
140° 
First-class Objectives.—Large Angles of Aperture 
First-class Objectives.—Medium and Smaller Angles of Aperture. 
Focal Length. 
Angle of 
Aperture. 
Price. 
I 
Focal Length. 
| 
Angle of Aperture. 
Price. 
2 inch 
19o 
jft1R 
' 1-4 or 1-5 inch.. 
80° 
1 4k 
20° 
20 
35 
60°, adjust, by fr, lens. 
25 
X 44 .. 
X 44 .. 
40° non-ad- 
justment. 
20 
140° 
70 
Oesireq^eCt^Ves are ma 4° thc 
M. Society’s screw, or our standard bayonet catch, as may be 658 
PEICE-LISTS OF MICROSCOPE FIRMS. 
No. 20.— K. B. Tolles (Charles Stodder, Agent), Devonshire Street, 
jßoston, Mass. (1879). 
Student’s Microscope. 
Fifteen inches high, weight, six pounds. The base, uprights, and curved arm are of iron, hand- 
somely japanned ; on a trunnion joint, made on a new plan to wear well, by which the instru- 
ment can be placed in any position, from vertical to horizontal, with a stop to prevent move- 
ment in either direction beyond these points. It is furnished with a 1 inch eye-piece, 2 
second quality objectives, of about 1 inch and inch power, giving about 80 and 350 diame- 
ters ; a plain stage, with spring clips for holding the object slides; revolving diaphragm, 
concave mirror, with movement to give oblique light; for illumination of opaque objects the 
mirror is removed to an upright stand; coarse adjustment for focus is effected by sliding the 
compound body, which is held in its place by a spring ; fine adjustment by a movable plate 
and screw on the stage, which is efficient with high powers. Price, in an upright black wal- 
nut case $5O 00 
Stand and case alone 28 00 
VARIATIONS AND ADDITIONS. 
Extra eye-pieces, 2 inches, 1% inch, and % inch, each 400 
Superior camera lucida 5 00 
Sub-stage for accessory apparatus 5 00 
Sliding stage, giving vertical and horizontal motions by the hand, and adapted for the use of Malt- 
wood’s finder 15 00 
Pine adjustment by lever and micrometer screw -. 20 00 
Rack and pinion for coarse adjustment 12 Q0 
Draw tube 4 Q0 
Plain mirror 3 00 
Thin glass stage to rotate on the optical axis 10 00 
The stand all brass 10 00 
S5, JLarge Microscope. 
This instrument is intended to meet the wants of the highest scientific investigation; to attain 
everything that the microscopist can accomplish, without sparing the cost, and to permit the 
use of all the modern assessory apparatus. It is constructed on the curved arm (Jackson) 
model. The instrument is 18 inches high and weighs about 14 pounds. It is of simple con- 
struction, with fewer screws and pieces than any other first-class microscope. The curved 
arm is supported on a steel trunnion, between two strong brass pillars, made for durability, 
and not liable to get out of order, and provided with a method of compensation for wear. 
Has rack and pinion for coarse, and micrometer screw for fine adjustment of focus; gradu- 
ated draw tube; sub-stage with rack and pinion, and centering screws for accessory appara- 
tus ; plane and concave mirrors on double-jointed arm ; Tolles’s thin stage, admitting light of 
great obliquity, with rectangular movements by screw and rack and pinion, and rotation on 
the optical axis of about 325 degrees—all that is essentially necessary. Price 225 00 
A modification of this size, with the stage carried by friction rollers, and entire rotation on the 
optical axis, can be made at an advanced price. 
This instrument is one of the largest yet produced anywhere. It is similar in all respects of style 
and construction to the B instrument, but larger and heavier, weighing 20 pounds. The 
stage is six inches in diameter, and makes a complete revolution on the optical axis. The 
whole instrument rotates on a stout plate graduated to degrees. Price of stand 300 00 
A. largest Microscope. 
Can be furnished with radial arm, which describes a curve, of which the focal point is the centre, 
to carry accessory apparatus at any angle, for 50 00 
A graduated arc registers the obliquity of the incident light. 
The Professor’s Microscope. 
This is an instrument similar to the clinical. It is intended to pass around a class of students. Is 
provided with a means of clamping the object slide to the stage, so that the particular object 
the lecturer is explaining cannot be moved out of the field, while each observer can adjust the 
focus to his own eye. Price, without objectives 25 00 
This instrument, and the “ Pocket,” are used without a stand by holding it in the hand and 
looking at the light. 
For clinical and field, or seaside use ; is a simple tube 6 inches long, with inch objective and B 
eye-piece ; fine and coarse adjustment for focus; a stage with spring clips to hold the object, 
The Pocket Microscope, PRICE-LISTS OF MICROSCOPE FIRMS. 
659 
which can be removed when not in use, and the objective covered with a brass cap, making 
the most compact and efficient portable instrument in use. Price $25 00 
With a draw tube for increasing the power 29 00 
Microscope Objectives. 
FIRST QUALITY OF LARGE ANGULAR APERTURE. 
fibre, cell-formation, resolution of Nobert’s lines, etc., etc. 
X inch, angle of aperture, 60° to 40 60 
These are made for the highest requirements of the microscopist and histologist, as tracing nerve- 
4-10 inch, “ “ 90° to 120° 45 00 
4-10 “ “ “ 135° to 0500 
This objective may be used as an achromatic condenser, with special advantage. 
X or 1-5 inch, angle of aperture 120° to ? 45 00 
\or 1-5 “ “ up to 150° 55 00 
Xor 1-5 “ “ “ up to 180° 70 00 
1-6 inch. $5 advance on % inch. 180° 00 
1-8 “ angle of aperture to 160° 60 
1-8 “ “ “ to 180° 80 00 
1-10 “ $5 advance on price of 1-8 inch. 180° 85 00 
1-12 “ angle of aperture under 140° 80 00 
1-12 “ “ “ up to 160° 60 00 
1-12 “ “ “ up to 180° HOOO 
ITS “ “ “ up to 160° HO 00 
115 “ “ “ up to 180° 120 00 
120 “ “ “ up to 180° 150 00 
1-25 “ “ “ up to 180° 175 00 
1-50 “ “ li by special contract. 
1-75 “ 
All objectives of 180° may be duplex front, or three systems. 
Having less angular aperture, more penetration, with first-class adjustment for cover. 
FIRST QUALITY OBJECTIVES. 
1-2 inch, angle of aperture 60° or less 85 00 
4-10 inch, “ “ 85° or less 40 00 
1-4 and 1-5 inch, angle of aperture 100° to 120° 40 00 
1-6 inch, angle of aperture 100° to 120° 45 00 
1-8 “ “ “ 100° to 45 00 
140 “ “ “ 100° to 50 00 
4-12 “ “ 4< J2o° 55 00 
4-15 “ » <> 120o 60 00 
1-20 “ .< „ 140° 80 00 
All of 1-5 inch, or higher powers, will be made either dry or immersion, at the same price, to work 
rp°-, Ways with the same lens. With an extra “ front ” lens $lO to 2-sths extra. All the foregoing have 
roiies s adjustment for covering glass, which does not move the front lens, and has no back lash. 
FIRST QUALITY OBJECTIVES. 
Without adjustment for cover. 
4 inch, adjustable to 3 inch .. 35 00 
2 inch ... 20 00 
2 inch, higher angle of aperture 23 00 
% and 1 inch in one 25 00 
1 inch, 14° 10 00 
1 “ 25° .... 23 00 
1 “ 50°.. 30 00 
4 “ new formula, specially flat field 30 00 
‘ 25° to 40°. 23 00 
t u sPe°ially constructed for viewing opaque objects 23 00 
1 40° to 70°, adjusting by front lens, specially constructed for viewing opaque objects 23 00 660 
PEICE-LISTS OP MICROSCOPE FIRMS. 
SECOND QUALITY OBJECTIVES. 
Without adjustment for cover. 
1-8 inch, immersion, 120° $25 00 
1-10 “ “ 120° 30 00 
1-6 “ 905 to 100° 18 00 
1-4 or 1-5 inch, 70° to 90°, will resolve well PI. angulation 15 00 
inch, 40° to 50°. Has a long working distance for opaque objects 12 00 
X inch 12 00 
2andljginch 8 00 
1 inch 6 00 
All objectives are made with the “Society” screw, so as to fit all recent English or American stands, 
unless ordered otherwise. 
No. 21.— W. H. Bulloch, 126 Clark Street, Chicago, 111. (1879). 
Al, Congress patent, May 27, 1879, with all the latest improvements. Binocular mechanical stage, 
concentric; adjustable to the optic axis ; swinging sub-stage and mirror; broad gauge screw 
for wide angle; low powers; safety nose-piece, with Society screw; rack and pinion coarse 
motion; lever slow motion, moving the whole body; adjustable sub-stage, revolving with 
rack and pinion (the stage, sub-stage, mirror, base, and side of body tube are graduated). 
Iris, and G-illet diaphragm, 5 eye-pieces 300 00 
Professional stand, patent 1879; 16 inches high when arranged for use; swinging sub-stage and 
mirror; can be used over the stage; rack and pinion coarse motion; lever fine adjustment, 
moving the whole body; London Society screw, also the broad gauge screw; sliding glass 
stage; has complete revolution, and is adjustable; single pillar and tripod base; Gillet 
diaphragm, 2 eye-pieces, and case 90 00 
Biological stand, patent 1879; 12 14 inches high when arranged for use ; stage 3X inches from table 
when in a horizontal position; tube 5 inches long, but with draw to 9 inches; rack and pinion 
coarse motion; lever fine motion, moving the whole body; single pillar and tripod base; 
stand all brass; plain stage, with spring clips. Diaphragm, sub-stage, and mirror each swing 
over the stage. Stand, 1 eye-piece, and case 40 00