ILLUSTRATIONS. 
Frontispiece.—Zentmayer’s New- Model u. s. a. h. Micro- 
scope. page 
Fig. 1. Diagram Showing the Preparation of an Even 
Blood Slide 15 
Fig. 2. Diagram Showing the Effect of Illumination on 
Blood Corpuscles 18 
Fig. 3. Stage Micrometer 21 
Fig. 4. Maltwood’s Finder 23 
Fig. 5. Needle Holder 26 
Fig. 6. Dissecting Microscope 28 
Fig. 7. Specimen Jar 36 
Fig. 8. Microtome 46 
Fig. 9. Diagram Showing the Gouging of a Section Knife 
with Convex Edge, when drawn across the 
Microtome 49 
Fig. 10. Diagram Showing the Bevel in the Edge of the 
Section Knife 50 
Fig. 11. The Author’s Mechanical Knife Carrier 51 
Fig. 12. Freezing Microtome 56 
Fig. 13. Turn-table 84 
Fig. 14. Drying Oven 88 
Fig. 15. Mounting Forceps 89 
Fig. 16. Apparatus for Photo-micrography 104 ZENTMAYER’S NEW MODEL D. S. A. H. MICROSCOPE. COMPENDIUM 
OF 
Microscopical Technology. 
A GUIDE TO PHYSICIANS AND STUDENTS IN THE USE OE THE 
MICROSCOPE AND IN THE PREPARATION OF HISTO- 
LOGICAL AND PATHOLOGICAL SPECIMENS. 
BY CARL SEILER, M. D., 
n \ 
LATE DIRECTOR OF THE MICROSCOPICAL AND BIOLOGICAL SECTION OF THE ACADEMY OF 
NATURAL SCIENCES OF PHILADELPHIA ; CURATOR OF THE PATHOLOGICAL SOCIETY ; 
PATHOLOGIST AND M1CROSCOPIST TO THE PRESBYTERIAN HOSPITAL, ETC., ETC. 
PHILADELPHIA: 
D. G. BRINTON, 115 SOUTH SEVENTH STREET. 
1881. Entered, according to Act of Congress, in the year 1881, by 
D. G. BRINTON, m. d., 
In the Office of the Librarian of Congress, at Washington, D. C. 
Press of WM. F. FELL & CO., 
1220-1224 Sansom St., 
Philadelphia. CONTENTS. 
THE MICROSCOPE, AND HOW TO USE IT. page 
The Stand. The Body. The Stage. The Sub-stage and 
Mirror. The Tube. Oculars. Objectives. Illumina- 
tion. The Camera Lucida. Measuring. The Micro- 
meter. The Maltwood’s Finder 9-24 
CHAPTER I. 
PREPARATION OF ANIMAL TISSUES. 
Teasing. The Dissecting Microscope. Acids. Alkalies. 
Hardening Tissues. Hardening Agents. Softening 
Bone 25-44 
CHAPTER II. 
CHAPTER III. 
CUTTING SECTIONS. 
The Microtome. Imbedding Materials. The Section Knife. 
The Author’s Mechanical Knife Carrier. The Freezing 
Microtome. Bone Sections 45-60 
STAINING OF TISSUES. 
Carmine. Hsematoxylon. Double Staining. Nitrate of 
Silver. Chloride of Gold. Osmic Acid 61-70 
CHAPTER IV. 
INJECTING THE VASCULAR SYSTEM. 
Red Injecting Fluid. Beale’s Blue Injecting Fluid. Method 
of Injecting. Injecting with Syringe. Injecting with 
Pressure Apparatus. Double Injection. Injecting 
Nitrate of Silver 71-80 
CHAPTER Y. 
V VI 
CONTENTS. 
MOUNTING AND FINISHING OF SPECIMENS. page 
Cleaning Slips and Covers. The Turn-table. Mounting 
in Balsam. DryiYig Oven. The Author’s Method of 
Mounting in Balsam. Mounting Forceps. Ringing 
Material. Mounting in Glycerine. Cements. Far- 
rant’s Solution. Mounting Opaque Objects 81-96 
CHAPTER VI. 
CHAPTER VII. 
THE PREPARATION OF VEGETABLE TISSUES AND INSECTS. 
Bleaching. Staining. Double Staining. Mounting of In- 
sects 97-102 
CHAPTER VIII. 
PHOTO-MICROGRAPHY. 
Disposition of Apparatus. Ammonio-sulphate of Copper 
Cell. Collodion Developer. Intensifying the Nega- 
tive. Photographing Large Objects 103-110 
APPENDIX. 
Table of Tumors 111-126 
Index 127-130 PREFACE. 
I was prompted to write this little compendium by 
the want, which I felt in my own studies, of a 
comprehensive treatise on the subject, which I could 
rely upon, and which would not mislead me by a large 
number of methods to be used in the preparation of 
tissues for microscopical examination. All the existing 
books on the subject, although they are excellent and 
indispensable to the advanced student, are too compre- 
hensive, and are filled with the descriptions of methods 
of examination and preparation of objects which have 
not been thoroughly tried by the authors, and which are, 
therefore, frequently incomplete, by the omission of 
seemingly minor, but nevertheless essential, details. 
In the present little volume it has been my plan, to 
which I have strictly adhered, to give a clear and 
short description of processes which I am in the habit 
of using myself, and which I have found to give uni- 
formly satisfactory results. They may, it is true, not 
be the best in every case, but they will give results in 
the hands of the inexperienced which are sufficiently 
good to be serviceable, and as soon as the student is far 
enough advanced he will, without prompting, refer to VIII 
PREFACE. 
the larger books containing other methods, and will 
then be able to use them with advantage. 
I have not thought it advisable to add a description 
of the histological details of tissues, because the field is 
one so extended that it would be impossible to do justice 
to the subject even in a volume many times larger than 
the present one; but I have added as an appendix a 
classification of the more common tumors and neoplasms, 
in tabular form, which I think will be of service to those 
engaged in the study of pathology. 
1346 Spruce Street. 
CARL SEILER, M.D. COMPENDIUM 
OF 
MICROSCOPICAL TECHNOLOGY. 
CHAPTER I. 
THE MICROSCOPE AND HOW TO USE IT. 
The great number of instruments by different makers, 
and of different prices, often bewilders the student who 
wants to buy a microscope; and not knowing what will 
be most serviceable to him, he has to rely entirely upon 
the dealer for advice, which, to say the least, is always 
risky. A short description of what is indispensable in 
an instrument for histological work will, therefore, not 
be out of place. 
The Stand should be of such construction and weight 
that no matter in what position the body of the micro- 
scope may be it will be firm. In practice it has been 
found that the tripod base is the best in this respect. 
The Body, consisting of the tube with the ocular and 
objective, the stage, the sub-stage and the mirror, should 
be mounted upon the base in such a manner that it can 
be inclined at any angle, from the upright position to 
the horizontal, and there should be a stop, which prevents 
further inclination beyond either the upright or hori- 
zontal position. This, although seemingly trivial, is of 
9 10 
MICROSCOPICAL TECHNOLOGY. 
great importance, as it will be found impossible to make 
protracted microscopical observations with the body of 
the observer in a constrained position, which he must 
assume if his instrument cannot be inclined. Further- 
more it is necessary that the body of the instrument 
should be absolutely horizontal in making drawings or 
measurements with the camera lucida, which position 
cannot be obtained without a stop that will not allow 
the inclination to go any further. 
The Stage should be either a mechanical one—that is 
one which can be moved, by means of rack and pinion, 
sideways or up and down—or what is called a hand- 
stage, which consists of a piece of glass held on the 
stationary stage by means of a spring and ivory-pointed 
screw. This arrangement allows the stage and the 
object to be moved in any direction and at any inclina- 
tion. The two clips for holding the object, which are 
found on many instruments, are decidedly objectionable, 
because they are very apt to get in the way and injure 
the specimen. On such microscopes a very good mov- 
able hand-stage may be improvised by removing the 
clips with their posts from the stationary stage-plate, so 
that an even surface is obtained; a piece of plate glass 
about one-sixteenth of an inch thick and a little larger 
square than the stage-plate, with a round hole one inch 
in diameter cut in its middle, is then agglutinated, by 
means of a little glycerine, to the stage-plate and a ledge 
of glass or metal, or even pasteboard, is cemented on to 
the lower edge of the glass plate, upon which the slide 
may rest. It will be found that the atmospheric pressure 
is sufficient to hold this glass stage firmly at all angles HOW TO USE THE MICROSCOPE. 
11 
of inclination and at the same time allows of free motion 
in all directions. The glycerine should be renewed from 
time to time, and the glass as well as the permanent 
stage should be kept clean, to insure easy motion. A 
very great advantage, especially in pathological investi- 
gations, is to have the greatest possible amount of motion 
of the stage, as, otherwise, large sections cannot be 
satisfactorily examined; and there is no doubt in the 
minds of those who work much in histology and path- 
ology that very soon the makers of microscopes will be 
compelled to give us instruments with stages which have 
three or four inches motion either way. 
The Sub-stage and Mirror should be so arranged that 
they can be adjusted to the proper distance from the 
object, and that they should be absolutely centered. The 
bar upon which the mirror is mounted is usually hinged 
to the stage or limb of the instrument, so that oblique 
illumination may be obtained; it should, however, be 
provided with a spring stop which indicates when the 
mirror bar is in a line with the optical axis of the 
objective. 
Most of the cheaper instruments are not provided 
with a sub-stage condenser, nor even with a sub-stage, 
and the owner of such a microscope must use his inge- 
nuity in improvising a condenser, which, for histological 
work, is almost indispensable. The method of using 
this part of the instrument will be considered in the 
section on illumination, but it will not be out of place 
here to say that a sub-stage condenser which is not abso- 
lutely centered, is worse than none at all. 
The Tube should be either ten inches long, measured 12 
MICROSCOPICAL TECHNOLOGY. 
from the objective to the ocular, or should have within 
it a draw-tube which may be drawn out so as to make 
the whole ten inches long. It should be mounted upon 
the body by means of a rack and pinion slide, called the 
coarse adjustment, which latter should work smoothly 
and without jarring, and the instrument should be pro- 
vided with a fine adjustment. In the European instru- 
ments this is usually attached to the tube itself, while 
in the American microscopes it forms part of the body, 
which latter arrangement is to be preferred, because the 
tube is not changed in length when working the fine 
adjustment. In examining an instrument notice should 
be taken whether in moving the fine adjustment screw 
the field moves, and if so the microscope should be 
rejected as unfit for good work. There is a doubt in 
many minds whether a binocular microscope is better 
than a monocular one for histological work, and the 
difference in cost prevents many a one from purchasing a 
binocular microscope. It will, however, be found that 
a binocular instrument is more serviceable in the greater 
number of cases than a monocular, because it enables 
the observer to keep both eyes open, which is a great 
saving to the organs, and it gives him, with low 
powers at least, the benefit of stereoscopic vision ; then 
again, if it be of the Wenham form—the best and most 
generally used—it can readily be changed into a mon- 
ocular instrument when occasion requires it. 
Oculars or eye-pieces are always famished with the 
instruments, and are usually of good quality. They are 
either lettered or numbered (A, B, C or 1, 2, 3), thus 
indicating their magnifying power. For ordinary work HOW TO USE THE MICROSCOPE. 
13 
two eye-pieces, A and B, are sufficient, and only where 
more amplification is absolutely necessary, are the higher 
oculars of use. 
Objectives. The choice of objectives is beset with 
great difficulties for the beginner in microscopy, and it 
is as difficult to give any advice in the matter in mere 
words; a few hints, however, will perhaps help the 
student in picking out good objectives. 
In the first place, the powers best suited for histological 
studies are a one inch or two-thirds, a one-fourth or one- 
fifth, and if desired, a one-eighth or one-tenth objective.* 
Secondly, they should be free from aberration. 
In order to test objectives, both for chromatic and 
spherical aberration, place a few minute globules of 
mercury upon a dark background slide and view them 
as opaque objects, by artificial light. If the image of 
the flame reflected from the surface of the globules 
(focusing the objective in and out) appears as a sharply 
defined circle of light, the lens is corrected for spherical 
aberration, and if the disk of* light is free from color, 
for chromatic aberration also. 
The lenses should also have a flat field, which may be 
determined by examining a layer of blood corpuscles 
upon a glass slip prepared in a manner which will be 
described hereafter. If after carefully focusing the 
disks near the edge of the field are as distinct as in the 
centre, the lens is a good one as regards flatness of field. 
Finally, the objectives should possess a moderately 
* These fractions designate that the system of lenses comprising 
the objective is equivalent, in focal length as well as magnifying 
power, to a single lens of the same denomination. 14 
MICROSCOPICAL TECHNOLOGY. 
high angular aperture, because their working distance is 
large, thus allowing the use of thicker cover glasses, for 
the objects are therefore more easily manipulated, and 
they are not as expensive as the very wide-angle objectives. 
On the whole, the student in picking out lenses is certain 
of getting good objectives by depending upon the repu- 
tation of the maker; but it is an undeniable fact that 
different opticians produce different powers better than 
all other lenses of their make, which renders it some- 
what difficult to get the best in the market. The so-called 
French lenses, which are sold at a very low figure, are 
the only ones which are absolutely useless. 
ILLUMINATION. 
We will suppose, now, that we have a good microscope 
before us, and that we want to use it for the examination 
of an object. The first thing we have to do is to arrange 
our light so that we may get the best possible result from 
our optical combination of ocular and objective. Let 
us remind the reader, here, that often more depends upon 
proper illumination than upon the quality of objectives, 
and that the injury to the eyes due to microscopical 
studies, which is so often complained of, is almost 
entirely caused by a want of proper care in the illumi- 
nation of the object. Artificial light, such as is obtained 
from a good kerosene lamp, is to be preferred to 
daylight, for the simple reason that the former can be 
controlled as to its brilliancy, while the latter is beyond 
our control. 
In arranging our illuminating apparatus we must 
have something to judge of the quality of the light as it 15 
HOW TO USE THE MICROSCOPE. 
passes through the microscope, and it will be found that 
there is no better test than a slide of blood, prepared in 
the following manner : Take a clean one-by-three glass 
slide, and place near one end of it a drop of fresh blood, 
obtained from the prick of a needle in the finger. Then 
take another slide, with a ground edge, and place its 
edge into the drop of blood, inclining the second slide 
until it stands at an angle of about forty-five degrees 
toward the first one, and draw it quickly but evenly 
across the first slide (Fig. 1). The result will be that 
Fig. 1. 
the blood corpuscles are spread evenly upon the slide, in 
one layer only, thus giving an excellent view of their 
outline.* The blood corpuscles being lenticular bodies, 
with depressed centres, act like so many little lenses of 
glass, and show defraction rings, if the light is not prop- 
erly arranged. It will, therefore, be seen that a slide 
prepared in this manner forms one of the best, if not 
ithe best, tests for illumination, as well as for flatness of 
field. 
Having placed the test slide upon the stage of the 
* I am indebted to Dr. J. J. Woodward for this excellent plan 
of making an even blood slide. 16 
MICROSCOPICAL TECHNOLOGY. 
microscope, and using a low-power objective, the lamp 
is next arranged on the left-hand side, in such a position 
that the flame presents a three-fourths profile view to 
the mirror, and is a little in advance and below the stage 
of the instrument when the latter has been placed in a 
convenient position. A bull’s-eye condenser is then 
placed in front of the lamp and so arranged that the 
concave mirror is in the centre of the circle of light as 
it is seen upon a piece of white paper held behind the 
mirror. The latter is then so turned as to throw the 
light up through the condenser, thus illuminating the 
field. In order to neutralize the yellow color of the 
lamp light, which is very fatiguing to the eye, and which 
reduces the brilliancy of the staining of objects, a piece 
of blue glass should be attached to the lower opening of 
the sub-stage, through which the light from the mirror 
has to pass. 
The sub-stage condenser is then to be accurately 
centered, if it has a centering attachment, which may be 
done by moving it np close to the slide and focusing 
upon it with a low-power lens. If out of centre it will 
be found that the circle of light is either to one side or 
the other of the field, and it should be made to fall 
exactly in the centre. When thus centered the one-fifth 
objective is used; if the student possesses a nose-piece* 
* A nose-piece is an attachment to the end of the tube of the 
microscope, by means of which two or more objectives may be 
brought into proper position, one after the other, by simply revolv- 
ing the swivel to which the objectives are attached. It acts some- 
what like the drum in a revolver, which, by rotating, brings the 
different cartridges successively in the proper position to be fired 
out of the barrel. 17 
HOW TO USE THE MICEOSCOPE. 
this change will entail no loss of time; the condenser is 
moved down until the image appears clear and brilliantly 
lighted. When in the right position the light from the 
condenser is frequently too bright to be borne by the eye 
with comfort for a length of time, and it should then be 
toned down, by means of a little perforated cap or 
diaphragm, which is placed over the front lens of the 
condenser, or below and close to the system of lenses. 
When thus illuminated the blood corpuscles should 
appear as slightly olive-colored disks, with a fine but 
intensely black outline, and on changing the focus there 
should appear a spot in the centre. In order to fully 
appreciate the importance of each one of the parts of 
the illuminating apparatus and the necessity of having 
them in their proper position, let the student first 
remove the bulFs-eye and let the light of the lamp alone 
fall upon the concave mirror, without change in anything 
else. He will then see that the outline of the blood 
disks is much less sharply defined, and that there is a 
suspicion of another outline within the outer one. Let 
him then move the mirror bar slightly to the right or 
left of the median line, and he will find that this second 
outline will be more marked and a third one will be 
faintly seen, while the true margin of the corpuscle is 
far from being sharp. Let him, finally, remove the 
sub-stage condenser from its proper position, or throw it 
out of centre, or take it off altogether, and he will find 
the blood disks filled with rings and with a bright spot 
in the centre (Fig. 2). 
Opaque objects, such as are too thick to be made trans- 
parent, or are mounted upon a slide with a dark back- 18 
MICROSCOPICAL TECHNOLOGY. 
ground, must be lighted from above, which may be 
accomplished in the following manner: Place the lamp 
to the left of the stage and raise it so that its flame is 
several inches above the stage of the instrument, when 
the latter is in a position convenient for the observer. 
Then place a small bull’s-eye condenser between the 
stage and lamp, but close to the object, and turn it so 
that the light is concentrated upon the object to be 
viewed. In some microscopes of American make the 
mirror bar is attached to the limb of the instrument at a 
point which is in a line with the object on the stage, so 
that the mirror can be swung around and above the 
Blood disk with 
proper illumination. 
Blood disk with 
bull’s-eye removed. 
Blood disk with 
mirror out of centre. 
Blood disk 
without condenser. 
Fig. 2. 
stage without altering its relative distance from the 
object. In such a microscope opaque objects can be 
illuminated without the use of a bull’s-eye lens, by 
simply reflecting the light of the lamp upon the object 
with the concave mirror swung above the stage and' as 
close to the tube of the instrument as possible. In this 
case the lamp should be in front and a little below the 
stage. 
Still another method is by a parabolic reflector 
attached to the objective, which collects the light and 
concentrates it upon the object. This can, however, only 
be used with very low powers having long working 
distances. 19 
HOW TO USE THE MICROSCOPE. 
The Camera Lueida is a piece of apparatus used in 
measuring and drawing objects under the microscope. 
It consists, in its best form, of a prism of glass attached 
to the ocular in such a manner that the image formed by 
the optical combination of objective and ocular is thrown 
into the eye of the observer, and the image appears, in 
the same direction that the rays of light strike the eye, 
as if reflected upon a piece of white paper placed upon 
the table, upon which its outlines may be traced with a 
pencil. The same may be accomplished by placing a 
slightly tinted piece of glass, known as Beale’s neutral- 
glass camera lueida, held at an angle of forty-five degrees 
to the axis of the instrument, close to the eye-lens of 
the ocular, which, however, does not give as brightly 
illuminated an image, and on account of the double 
reflection, is not suitable for drawing details. Such a 
reflector, answering the purpose admirably, may be im- 
provised by attaching a thin cover-glass at an angle of 
forty-five degrees to the cap of the ocular, by means of 
a small piece of beeswax. In order to use either the 
prism or the reflector the instrument is to be inclined 
until its tube is horizontal, a piece of white paper, 
which should be shaded from all extraneous light, is 
placed upon the table, directly underneath the ocular, 
and the left eye is placed so, above and close to the 
camera lueida, that in looking downward the image 
appears to be upon the paper. Keeping the right eye 
open at the same time, the point of the pencil tracing 
the outline of the objects upon the paper can be seen, 
and thus the motion of the hand holding the pencil can 
be regulated. In order to obtain an image upon the 20 
MICROSCOPICAL TECHNOLOGY. 
paper of the same size as that seen in the microscope, the 
distances from the centre of the eye-lens of the ocular 
to the surface of the paper should be the same as from 
the ocular to the objective, viz., ten inches. 
MEASURING. 
The apparent size of objects seen in the microscope is 
of great importance in their recognition, and as this 
varies with the magnification employed in viewing 
them, it is necessary for the student to know the magni- 
fying power of his objectives and oculars in their differ- 
ent combinations. The magnifying power of an optical 
combination of objective and ocular is expressed by 
saying that it magnifies so many diameters, which means 
that an object seen—a blood corpuscle, for instance— 
has its diameter magnified so many times. In order to 
obtain the magnification of the surface of an object, the 
number of diameters should be squared, and such sur- 
face magnification is expressed by saying that an object 
is magnified so many times, an expression not used in 
microscopy, but utilized by unscrupulous dealers to 
mislead purchasers. 
In order to find the magnifying power of the optical 
combination, the instrument is placed horizontally, the 
camera lucida is attached to the ocular, and a piece of 
paper is placed on the table ten inches from the centre of 
the eye lens, and shaded from extraneous light. A stage 
micrometer (Fig. 3.), which is a slip of glass upon which 
lines have been ruled one-hundredth and one-thousandth 
of an inch apart, is placed upon the stage and the image 
of the lines carefully focused upon the paper. With a HOW TO USE THE MICROSCOPE. 
21 
sharp-pointed pencil, the lines are then marked upon the 
paper and the distance of the dots is measured carefully 
with a pair of compasses and an inch rule; preferably 
divided into tenths of inches. It will thus be seen that 
if the distance between two lines which on the stage 
micrometer are one-hundredth of an inch apart meas- 
ures upon the paper five-tenths of an inch, the magnifi- 
cation is fifty diameters. The student should make 
himself a table giving the different powers of his objec- 
tives in connection with the oculars as found in the 
manner described above, which he will find very con- 
venient for reference. Objects, such as small animalcules 
Fig. 3. 
or histological elements, may be measured in a similar 
manner, viz: By drawing their outline with the camera 
lucida, and then measuring the diameter with a pair of 
compasses, then, knowing the magnifying power of the 
optical combination, a simple calculation will give the 
size of the object. To exemplify this, let us say that the 
objective and ocular give a magnification of fifty diame- 
ters, and the diameter of the object measures five-tenths 
of an inch as seen with that power ; its actual size will 
then be one-hundredth of an inch. 
An easier and more simple method of measuring 
objects is with the eye-piece micrometer, also a slip ot 22 
MICROSCOPICAL TECHNOLOGY. 
glass with fine lines ruled upon it, which is introduced 
into the ocular between the two lenses. The distance 
between the lines of the eye-piece micrometer is not 
known, and varies with the different powers used. In 
order to measure an object under the microscope with 
this micrometer, the object upon the stage is moved until 
the lines fall directly on its margin, and the number of 
intervals the object fills is noted down. The object is 
then removed from the stage and the stage micrometer 
substituted for it, which, in turn, is moved until its lines 
coincide with those of the eye-piece micrometer, and it is 
noted how many intervals between the lines it takes to 
fill the intervals of the eye-piece micrometer, previously 
noted down as having been filled by the object to be 
measured. The distances between the lines of the stage 
micrometer being known, the number of intervals noted 
express the size of the object. For instance, we wish to 
measure an object which exactly covers three intervals of 
the eye-piece micrometer, and find, on substituting the 
stage micrometer, that two intervals of its lines ruled 
one-hundredth of an inch apart cover three intervals of 
the eye-piece micrometer; we then know that the object 
is one-fiftieth of an inch in diameter. 
Drawing and measuring with the camera lucida or 
reflector requires some skill and practice, and the student 
should, therefore, not place too much reliance upon his 
first attempts, but should repeat the measurements deter- 
mining the magnifying power of his lenses over and 
over again, until the results of many trials coincide, 
before he looks upon them as correct. 
Under this head it will be necessary to describe HOW TO USE THE MICEOSCOPE. 
23 
another very useful accessory to the microscope, and one 
which will save the possessor a great deal of time if 
properly and systematically used. This is a Maltwood’s 
finder, by means of which a particular spot or place in a 
specimen can readily be found again. It consists of a 
slide of glass which has photographed upon it a large 
number of minute squares which are numbered in a 
certain system. See Figure 4. If, now, a place in a 
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specimen is found which we wish to be able to find again 
without loss of time—for instance, a trichina spiralis in 
a specimen of muscular fibre—the object is removed from 
the stage and the finder is substituted for it, taking 
care to have it rest against the stop on the ledge of the 
stage. By looking through the microscope the numbered 
squares are seen, for instance, flf, and these numbers are 
then recorded upon the label of the specimen. If we 
now wish to find a place thus marked on a slide, we 24 
MICROSCOPICAL TECHNOLOGY. 
place the finder on the stage and move the latter until 
the numbers recorded on the label of the slide are seen 
in the field; we then substitute the slide for the finder, 
and the spot which we desired to find will be in the 
field of the instrument. Some instruments of American 
make, with mechanical stage, have the moving parts 
divided into degrees and thus may be used as finders, 
for, by observing and recording the number of degrees 
of lateral as well as of vertical displacement of the stage, 
the same spot in a specimen may always be found again 
by displacing the stage to the same number of degrees 
as recorded. 
This method is, however, only applicable to instru- 
ments by the same maker, and, if we wish to send a 
specimen to a friend at a distance who does not own 
such an instrument, he cannot find the spot designated. 
If we use, however, Malt wood’s finder, anybody who 
possesses this accessory can, on any instrument, find the 
place indicated on the label without any trouble and 
without loss of time. PREPARATION OF ANIMAL TISSUES. 
25 
CHAPTER II. 
PREPARATION OF ANIMAL TISSUES. 
All objects must be prepared in some way before they 
can be satisfactorily examined under the microscope. 
Some objects, such as the wings of insects, require but 
little preparation, while others, such as histological and 
pathological tissues, require considerable manipulation 
before they can be studied and their details demonstrated. 
As this latter class of tissues is more difficult to prepare 
than, perhaps, any other, and as it is of greater import- 
ance to most persons using the microscope for investiga- 
tion, it will be considered first. But before entering into 
a detailed description of the different processes employed, 
it is necessary to say a few words in regard to the general 
method the student should follow in order to be suc- 
cessful as a preparer of microscopical specimens. 
First, he should strictly adhere to the formulae given, 
and should not omit even seemingly insignificant details, 
or even try to improve upon them before he is thoroughly 
master of the process. 
Secondly, he should be content, at first, with one 
process, and should not try another and another because 
of failure, for although particular pains will be taken in 
describing all the details of a process, yet the necessary 
skill cannot be imparted to the student in writing. He 
should, therefore, try again and again before condemning 
a formula as useless. 
Thirdly, he should endeavor to trace the cause of his 26 
MICROSCOPICAL TECHNOLOGY. 
failures, and thus learn by them; he will then more 
quickly master the matter in hand. And finally, he 
should preserve scrupulous cleanliness in his laboratory 
or work-room, and should be methodical as regards time 
and saving as regards material. 
If every worker in microscopy would bear these rules 
in mind, less money would be spent for material, fewer 
often valuable specimens would be spoiled through want 
of proper attention, and better preparations would be 
found in cabinets. 
TEASING. 
Any tissue, in order to be fit for examination, must be 
made transparent, so that its histological elements may 
be studied by transmitted light. There is, however, an 
exception to this rule, when only the surface of a tissue 
is to be examined and viewed as an opaque object. In 
order to make tissues transparent they must be made 
thin and must then be immersed in some substance 
which will transmit light readily, and will at the same 
time permeate the tissue, very much in the same manner 
as paper is made translucent by oil. This may be done 
by separating the elements of a tissue with needles 
mounted in handles (Fig. 5), which process is called 
Tig. 5. 
teasing, and immersing them in glycerine. To illus- 
trate the process, let us take, for instance, a piece of 
muscle, as obtained from a fresh piece of beef. A small 
portion is to be removed with a pair of scissors, cutting PREPARATION OF ANIMAL TISSUES. 
27 
parallel with the fibres of the meat, and is placed in a 
small dish, or watch glass, together with a drop of 
glycerine. Then, with a needle in either hand, the fibres 
are separated from each other, until a number of them 
have been isolated, when they should be placed upon a 
clean slide and covered over with a clean, thin glass 
cover. They are then ready for examination by trans- 
mitted light, which means light coming from the mirror 
and through the sub-stage condenser. 
The separation of the histological elements of tissues 
with needles is a tedious process, and requires consider- 
able patience. When the elements to be isolated in this 
manner are very small it becomes necessary to carry on 
the teasing under a magnifying glass, which is so 
arranged that it can be moved up and down, so as to 
place it at the proper distance from the object, which 
latter is placed upon a table or stage having a hole in its 
centre, through which the light is reflected from a small 
mirror fastened below. The whole apparatus is known 
and sold under the name of dissecting microscope 
(Fig. 6). 
Frequently, however, it is desirable to isolate histo- 
logical elements which are too closely united with each 
other to be easily separated with needles, under the dis- 
secting microscope. Or, it is dasirable to render certain 
parts of a tissue more transparent, thus revealing other 
structures, which, by the processes of staining, described 
further on, cannot be clearly demonstrated. For these 
purposes chemical reagents are employed, acting either 
upon thin sections placed under the microscope, when 
their influence may be observed, or upon thicker pieces 28 
MICROSCOPICAL TECHNOLOGY. 
of tissues immersed in the reagent for a longer or shorter 
time, according to circumstances. 
Fig. 6. 
These reagents are of two kinds, viz., acids and alka- 
]ies, and are employed, as a rule, in very weak solutions. 29 
PREPARATION OF ANIMAL TISSUES. 
If the reagent is to act upon a thin section, the latter is 
placed upon a slide and is covered with a covering glass. 
The solution of the reagent is then placed in small 
quantity alongside of the cover, by means of a pipette, 
and is allowed to run under so as to come in contact 
with the tissue and act upon it. In order to facilitate 
the operation, it is well to insert a piece of blotting paper 
or a cotton thread under the edge of the cover, opposite 
to the place where the drop of solution has been allowed 
to run in. In this way a current is established, which 
in bringing fresh portions of the solution in contact with 
the tissue, causes it to act more energetically. Larger 
pieces must be soaked in the solutions for a longer or 
shorter time, and of varying strength, according to the 
purpose to be accomplished. Besides isolating several 
of the elements of the tissues, these reagents are also 
used with advantage to differentiate some of the normal 
and pathological formations, by chemically combining 
with them and forming new compounds of different 
colors. 
Among the acids most commonly used for the pur- 
poses above indicated are— 
ACIDS. 
First. Sulphuric acid (c.p.), which is used in its con- 
centrated state for isolating the cells of cornified epi- 
thelium, nails, hair, etc. These tissues must be placed 
in a few drops of the acid and remain there for a few 
minutes, when they should be removed and washed in 
water to which some ammonia has been added, in order 
to neutralize the acid. It will then be found that the 
elements of the tissue can readily be separated in glycerine 30 
MICKOSCOPICAL TECHNOLOGY. 
with needles, and they can then be mounted in either a 
watery or resinous medium, as will be described below. 
A mixture of sulphuric acid and cane sugar, of the 
strength of one drop of the concentrated acid to one 
centigram of a five per cent, solution of sugar in water, 
may be advantageously used to color some organic sub- 
stances red, such as cellulose, amyloid and albuminous 
bodies, oleic acid, etc. A weak solution of the acid (one 
per cent.) renders connective tissue very transparent in 
from twelve to twenty-four hours, and is thus useful in 
isolating muscular fibres. 
Second. Nitric acid,which is used strong (c.p.) for isolat- 
ing connective tissue corpuscles, bone corpuscles, dentinal 
canals, etc., in the same manner that sulphuric acid is 
used for cornified epithelium ; it is, however, necessary 
that the bone should be cut into thin plates before the 
acid is allowed to act upon it. A twenty per cent, solu- 
tion is useful for isolating the organic or smooth 
muscular fibre cells, which may be accomplished by 
macerating a piece of the muscular coat of the intestine 
for several hours in the solution. The action of nitric 
acid upon the earthy salts of bone in connection with 
chromic acid, will be mentioned in another place. 
Third. Hydrochloric acid. Undiluted, this acid is not 
used in histological investigations, but is very useful 
when diluted, for isolating the corneal corpuscles and 
connective tissue corpuscles. For this purpose a fifty 
per cent, solution is employed and the tissue is allowed 
to be acted upon by the acid for several days. The 
same solution is used in order to isolate the uriniferous 
tubules of the kidney by dissolving the inter-tubular PREPARATION OF ANIMAL TISSUES. 
31 
connective tissue. To do this successfully, make a section 
of a piece of fresh kidney with the freezing microtome, 
and place this for about twelve hours into the acid solu- 
tion, then wash it in water made alkaline with ammonia 
and macerate in distilled water for twenty-four hours. 
The tubules can then be easily separated with needles, 
under the dissecting microscope, and form a beautiful 
object. The tubules of other glands may also be isolated 
in this manner. 
Fourth. Chromic acid. This reagent is most commonly 
used for the purpose of hardening tissues prior to cutting 
sections from them, and for extracting the earthy salts 
from bone in connection with other acids, under which 
heads it will be mentioned. A very weak solution (one- 
eighth grain to one ounce of water) is, however, used to 
bring out delicate nerve tissues, such as the touch cor- 
puscles in the skin and conjunctiva, or the prolongations 
of the ganglionic cells of the central nervous tissues, by 
prolonged maceration of small portions of these tissues 
in the solution. 
Fifth. Oxalic acid, besides being used in some instances 
for fixing the carmine after staining, is also employed as 
a concentrated alcoholic solution to swell up the connect- 
ive tissue and make it transparent, while at the same 
time it hardens the albuminous substances; thus it 
becomes an excellent reagent for demonstrating the rods 
and cones of the retina and of Cordi’s organ. It does 
not seem to make much difference how long the tissue is 
allowed to remain in the solution, provided the former 
has been placed in it as fresh as possible, a few minutes 
after the death of the animal; for it will be found that 32 
MICROSCOPICAL TECHNOLOGY. 
after the lapse of a few hours the desired effect is already 
produced, while the tissue may remain in the solution 
for several days without detriment. 
Sixth. Acetic acid. A one per cent, solution of glacial 
acetic acid has the effect of making the connective tissue 
very transparent in tissues immersed in it, and also of 
rendering the nuclei of cells apparent. On account of 
this action it is used to differentiate delicate nerve fila- 
ments in the tissues, and by means of this reagent 
the terminations of nerves in the striped muscular tissue 
may be demonstrated. To do this, place the pectoral 
muscle of a medium-sized frog, immediately after the 
death of the animal, in a solution of two drops of 
glacial acetic acid in fifty cubic centimeters of distilled 
water, and allow it to remain for twenty-four hours. 
The muscle should then be washed in distilled or filtered 
water and stained in carmine, as described below, and 
the fibres are then to be separated with needles, under 
the dissecting microscope, when they may be mounted in 
glycerine or balsam. 
Osmic and picric acids are used more particularly for 
hardening and staining, and will be mentioned under 
these heads. Many other acids have from time to time 
been recommended for a variety of purposes by different 
workers ; but those mentioned above are mostly used in 
histological investigations, and their action upon the 
tissues is thoroughly understood. 
ALKALIES. 
First. Caustic potash. A thirty per cent, solution of 
caustic potash is very useful in isolating muscular fibres, PREPARATION OF ANIMAL TISSUES. 
33 
nerve elements, ciliated cells, ducts of glands, etc., by 
dissolving the connective tissue, and for this purpose the 
solution is allowed to act upon fresh, thin sections of the 
tissue for about half an hour. The tissue must be ex- 
amined in this solution, and cannot be permanently 
mounted, as the action of the reagent continues and 
cannot be stopped. 
Second. Caustic soda. This alkali acts similarly to 
potash, and is particularly useful in demonstrating the 
anatomy of hair and nails. It should be used much 
weaker than the potash, a fifteen per cent, solution being 
the maximum strength. 
Third. Liquor ammonia. The action of ammonia is 
similar to that of potash and soda, but is most commonly 
used to neutralize acids. 
Various salts are also used with advantage in histo- 
logical investigations for special purposes, but it will be 
sufficient to mention here only a few of them. 
Chlorinated soda solution, commonly called Labar- 
raque’s solution, is chiefly employed to remove coloring 
matters, such as the chlorophyll in vegetable tissues and 
black pigment in animal tissues. 
Bichromate of potash is used for hardening animal 
tissues, under which head it will be considered, but may 
also be used for the same purposes that chromic acid is 
employed for, especially when a less energetic action is 
desired. 
Cyanide of potassium and hyposulphide of soda, in 
very weak solutions, are useful in lighting up too deeply 
stained silver and gold preparations. 
The student should provide himself with a set of 34 
MICROSCOPICAL TECHNOLOGY. 
glass-stoppered bottles filled with the different acid and 
alkaline solutions, and should keep a special pipette for 
each solution, so as to prevent contamination of one 
solution with another. These bottles should be labeled 
and kept, together with a few clean test tubes, in a rack, 
such as chemists use for reagent glasses and test-tubes. 
When using the reagents on the stage of the micro- 
scope great care should be exercised to prevent injury to 
either the lenses or the brass work of the stand, and it 
is advisable to cover the stage with a piece of plate glass, 
and to use, as much as possible, low powers with long 
working distances. 
The histological elements may thus, by teasing and by 
the action of reagents, be separated and even isolated, but 
in normal, as well as in pathological histology, the relations 
of the elements to each other are often of more importance 
than the form of the elements themselves, and therefore 
large portions of tissue must be made thin and trans- 
parent, without destroying the relation of parts. This 
may be accomplished by cutting thin sections of the tissue 
to be examined. Most tissues are, however, too soft when 
fresh to be cut into thin sections, and they must be pre- 
pared for this process by hardening or freezing. 
HARDENING. 
There are several reagents which act upon animal 
tissues in such a manner that they become hard if im- 
mersed in them. Those most commonly used among 
them are, alcohol, Mullers fluid, chromic acid and 
glycerine, and they all produce the hardening effect by 
coagulating the albumen and gelatine in the tissues and 
by abstracting water. It is evident that if this is done 35 
PREPARATION OF ANIMAL TISSUES. 
rapidly a very great amount of shrinkage must take 
place, and if the piece be at all large the hardening agent 
is prevented from entering into the interior of the tissue, 
by its own action upon the outside. These reagents 
should therefore be used with great care, so as to prevent 
shrinkage and distortion as much as possible. All tissues 
should be as fresh as they can be obtained, when placed 
in any of the hardening agents, for if decomposition has 
set in they cannot be properly hardened, and all subse- 
quent manipulations will be useless, as no good specimen 
from such material can be obtained. 
Alcohol. Hardening with alcohol, which acts by ex- 
tracting water and coagulating the albumen and gelatine, 
is to be done as follows: Place a piece of tissue, not 
larger than a cubic inch, into a wide-mouthed jar con- 
taining alcohol of the strength of forty-five per cent., 
and enough to cover the tissue to the depth of at least 
an inch. Let the piece remain in this for three days 
and then place it in a similar jar containing sixty per 
cent, alcohol. After the lapse of another three days it 
should be removed to eighty per cent., and after the 
same length of time, to ninety-five per cent, alcohol, in 
which it should remain until hard enough to cut. Some 
tissues require still further hardening in Squibb’s absolute 
alcohol before they have acquired the necessary degree 
of hardness. This may be tested by taking the piece of 
tissue between the forefinger and thumb and lightly 
compressing it. If it feels springy and elastic, like a piece 
of India-rubber, it should be hardened further by longer 
immersion in alcohol, but if it feels hard, like a piece of 
soap, it is ready for cutting. 36 
MICROSCOPICAL TECHNOLOGY. 
A great deal of time and alcohol may be saved if the 
hardening is done in four jars (Fig. 7), holding about 
one-half pint each,* filled three- 
fourths full of the different 
solutions of alcohol, and labeled 
No. I, forty-five per cent.; No. 
ii, sixty per cent.; No. in, 
eighty per cent.; No. iv, ninety- 
five per cent. One or more pieces 
to be hardened are then labeled, 
by fastening to them, with a pin, 
a strip of ordinary writing paper, 
upon which the necessary remarks 
should be written with ink, and 
dropped into jar No. I. After 
three days they should be transferred to jar No. n, No. 
hi and No. iv, having remained in each one the 
proper length of time. After several specimens have 
been hardened, by passing through different jars, it is 
necessary to degrade each jar to its number below, to 
throw away the contents of No. i and to fill it with 
the contents of No. n, and so on in rotation, filling jar 
No. iv with fresh ninety-five per cent, alcohol. This 
must be done in order to keep the different solutions up 
to strength, because water is abstracted from the tissues 
and makes the alcohol weaker. 
It will be found that tissues thus hardened take the 
different stainings with great brilliancy and are but little 
shrunk or distorted. For this reason, and because of its 
Fio. 7. 
* Whitall. Tatum & Co., of Philadelphia, manufacture a very 
convenient jar for this purpose, and at a very reasonable price. PKEPARATION OF ANIMAL TISSUES. 
37 
quickness and simplicity, this process of hardening is 
preferred by most microscopists in America. In Europe, 
on the other hand, alcohol is very expensive and the 
cheaper methylated alcohol is but little used, on account 
of its disagreeable odor. European microscopists de- 
nounce alcohol in very strong terms, because, they say, 
it shrinks the tissues too much. And so it does if used 
too strong at first; by the gradual increase of strength, 
however, time is given for the alcohol to take the place 
of the abstracted water, and the process of coagulation 
goes on so slowly that the decrease in bulk is almost 
inappreciable. 
Almost all kinds of tissues may be hardened in 
alcohol, with the exception of very young embryonic 
tissues, myxomata and colloid tumors, which are better 
preserved in Muller’s fluid, or may best be frozen, in 
order to cut sections from them. 
Muller’s fluid. Another excellent hardening agent, 
which acts by the coagulation of albumen and gelatine, 
but which abstracts oidy a small percentage of water 
from the tissues, is called Muller’s fluid. It is com- 
posed of— 
Bichromate of potash, 2| grams 
Sulphate of soda, 1 u 
Distilled water, 100 “ 
and is especially applicable to delicate organs, such as the 
brain, spinal cord, eyes, embryoes, etc. 
The tissue to be hardened should be of small size, not 
larger than half a cubic inch, and should be immersed 
in at least ten times its bulk of the fluid, which should 
be renewed every three or four days. The length of 38 
MICROSCOPICAL TECHNOLOGY. 
time required to harden varies with the character of the 
tissue, and is never less than two weeks, while it may 
take six weeks or two months to accomplish the purpose. 
This time may be shortened by finishing the hardening 
in ninety-five per cent, alcohol after the tissue has 
remained in the Muller’s fluid for two weeks. 
In consequence of the slowness of the process of hard- 
ening, the tissues are reduced but little in bulk, and 
their elements are scarcely altered, but this reagent has 
very little penetrating power, that is, it will not exert 
its influence upon the deeper portions of the tissues and, 
therefore, the pieces immersed in it must be small, as 
otherwise they will be hardened only on the outside, 
while the centre undergoes decomposition. 
Sections cut from tissues hardened in Muller’s fluid 
should be soaked for several days in alcohol before stain- 
ing, so as to get rid of most of the yellow stain which is 
imparted to the tissue by the bichromate of potash, as 
otherwise the color of the staining fluid will not be bril- 
liant and will not properly differentiate the histological 
details. 
Chromic Acid.—Very weak solutions of chromic acid, 
not stronger than one-half per cent., are frequently used 
for hardening all kinds of tissues, especially by German 
microscopists, and they act like Muller’s fluid but with 
more energy. For this reason the time required to 
harden tissues in such a solution is less than in the case 
of the Muller’s fluid, but the penetrating power is also 
less, because the very action of the reagent in coagulating 
the albumen and rendering the gelatine insoluble pre- 
sents a barrier to its affecting the deeper parts. It will PREPARATION OF ANIMAL TISSUES. 
39 
be seen that on account of this only very small pieces can be 
satisfactorily hardened in chromic acid solution. This 
chemical imparts a decidedly green color to the tissues, 
which even after prolonged soaking in water or alcohol 
will not entirely disappear, and very materially interferes 
with the staining of the sections. One great disadvan- 
tage of chromic acid solutions is, that mould is very 
readily developed upon their surface. 
Muller’s Fluid and Alcohol.—The difficulty of hard- 
ening large pieces in any of the above reagents has long 
been felt, and many other chemicals have, from time to 
time, been recommended as having the desired penetrat- 
ing quality, but they have all been found wanting on 
extended trials. The author, during these experiments, 
has hit upon the plan of combining several of the 
reagents, and has finally found that a mixture of equal 
parts of Muller’s fluid and ninety-five per cent, of alcohol 
produce the desired result. In this fluid whole human 
brains with their membranes intact, whole kidneys, and 
other large organs may be hardened throughout and in 
a comparatively short time. Nerve tissues, especially, 
are better hardened in this mixture than in either alcohol 
or Muller’s fluid alone. 
The manipulations necessary in this process are some- 
what different from those described above, and some care 
is required in carrying out the different steps. The 
following details, carefully observed, have been found 
by the author necessary to success. 
Immerse a brain or a large piece of another tissue in 
the mixture of alcohol and Mullers fluid contained in a large 
wide-mouthed jar, or, better still, an earthen pot holding 40 
MICROSCOPICAL TECHNOLOGY. 
about two quarts ; cover it with a glass plate and set it 
in a cool place where the temperature does not rise above 
45° F., nor fall below freezing point. In summer it 
should be placed in an ice chest, and in winter it should 
be protected from frost. During the first three days the 
brain should be turned at least twice in the twenty-four 
hours, in the solution, so as to preserve its form and 
allow the fluid to act on all portions equally. The fluid 
itself should be replaced by fresh every day for about 
two weeks, when it may be changed every three or four 
days. In the course of five or six weeks the brain will 
be found to be of sufficient consistence to be handled 
without danger of injuring it, and it should then be 
placed into ninety-five per cent, alcohol. This also 
must be changed every two or three days until it shows 
but very little discoloration, and the brain will be found 
hard enough throughout, so that thin sections may be 
made across both hemispheres. The time thus required 
to harden a whole brain is about three months, but 
smaller pieces of tissues may be gotten ready in much 
shorter time; spinal cord, for instance, will be hard in 
about two weeks—one week in the mixture and one 
week in the alcohol alone — provided the fluids are 
frequently changed. This process seems at first sight 
rather expensive, on account of the large quantity of 
alcohol used, but a great deal of it can be used over 
again, and for this purpose the mixture, when poured 
off from the specimen, should be filtered, and a little 
fresh alcohol and some crystals of bichromate of potash 
should be added, when it may be used again for other 
specimens to begin with. The discolored alcohol result- 41 
PREPARATION OF ANIMAL TISSUES. 
ing from the second part of the process may also be 
used for either making the mixture or for the sixty per 
cent, alcohol in the alcohol hardening process. 
The tilting of a large jar or pot containing about two 
quarts of liquid and a brain, which should be handled 
with care, so as not to injure it, is by no means easy, 
and it will be found more convenient to draw off the 
liquid by means of a syphon, which can readily be made 
of a piece of rubber tubing. 
Glycerine. Strong glycerine, as is well known, has a 
great affinity for water, and thus may be employed as a 
hardening agent for small pieces of tissue and young 
embryoes. It should, however, like alcohol, be at first 
used diluted with water, and the strength gradually in- 
creased, as otherwise considerable shrinkage will result. 
It at the same time makes tissues very transparent, 
which often is of great advantage and is an excellent 
preservative, so that the tissues immersed in it do not 
undergo any decomposition. The same is true of the 
other reagents already mentioned. 
There are a number of other substances used in special 
cases and for special purposes, such as arsenious acid, picric 
acid, osmic acid, chloride of iron, chloride of gold, plati- 
num, palladium, and many others; but as this treatise is 
for the use of the beginner in microscopy we will leave the 
consideration of these reagents to larger text books, especi- 
ally as they are not universally applicable to all tissues. 
Sometimes a tissue is composed of parts but loosely 
connected with each other, and yet it is desirable to make 
a section which shall comprise all these parts and exhibit 
them in their proper relation to each other, as, for 42 
MICROSCOPICAL TECHNOLOGY. 
instance, the inner ear, the larynx, the eye, and others. 
The ordinary hardening and imbedding is not sufficient 
to give the necessary resistance to the tissue, and a sec- 
tion, if cut thin enough, will surely break before it is 
completed, or during the process of staining and mount- 
ing. It is, therefore, very desirable to have a means by 
which this difficulty can be obviated and large sections 
of such complex tissues may be successfully cut, stained 
and mounted. This may easily be accomplished in the 
following manner:— 
After the tissue has been thoroughly soaked in alcohol, 
it is placed in a vessel containing sufficient melted cacao 
butter to cover it completely. The vessel is then put in 
the water bath and the temperature is kept for six hours 
at 130° Fahrenheit. Care should be taken not to let the 
temperature rise above this point, for a greater heat will 
injure the tissue and make it unfit for microscopical ex- 
amination. After the lapse of the time indicated the 
tissue is placed in the well of the microtome, is im- 
bedded, and allowed to cool together with the imbedding 
material, which will take some three or four hours. 
Sections may then be cut with great facility, and they 
should be stained before an attempt is made to remove 
the cacao butter from the interstices of the tissue. After 
staining, they should be placed in absolute alcohol, and 
when completely dehydrated, are to be placed into a 
small vessel containing some crude benzole, which will 
not only readily dissolve the cacao butter but will also 
make the section transparent, so that it may be at once 
mounted in balsam. If it is desired to mount the 
section in a watery medium, it should be removed from PREPARATION OF ANIMAL TISSUES. 
43 
the benzole into alcohol, and from thence into water, 
after which it is to be treated according to the descrip- 
tion given for mounting in a watery medium. 
SOFTENING OF BONE. 
The student of histology will frequently desire to 
make sections of tissues containing bone, as in foetal and 
some pathological specimens, or ossified cartilage, the 
removal of which by dissection would defeat the end 
entirely. It is, therefore, desirable to have some re- 
agents by which the earthy salts may be removed and 
the bone or ossified cartilage rendered soft, so that it can 
be cut. 
Most of the mineral acids in very weak solution will 
do this, such as a one per cent, solution of nitric or muri- 
atic acid, but these are not applicable for bone deeply 
imbedded in soft tissue, although they soften isolated 
pieces of bone and teeth in a short time. 
A saturated solution of picric acid frequently re- 
newed will soften small portions of bone very rapidly, 
and at the same time harden the soft tissues, but its in- 
tense yellow color, and the difficulty of removing stains 
resulting from even weak solutions, makes it inconve- 
nient to use. 
The best formula for softening bone, in the author’s 
opinion, is the following :— 
Chromic acid, 1 gram 
Nitric acid (c. P.), 2 c.c. 
Water, 200 c.c. 
Tissues containing bone may be immersed in this 
liquid and allowed to remain four or five days, when by 44 
MICROSCOPICAL TECHNOLOGY. 
piercing the bony parts with a fine needle the student 
can readily tell by the resistance encountered whether 
the bone is soft enough or not. If not, a few drops of 
nitric acid should be added to the liquid, and the speci- 
men allowed to remain therein until the bone is found 
to be decalcified. The tissue should then be soaked in 
several changes of pure water for several hours and 
hardened in alcohol as described. CUTTING SECTIONS. 
45 
CHAPTER III. 
CUTTING SECTIONS. 
There is no doubt that the most satisfactory and most 
instructive way to study histology, both normal and 
pathological, is by thin sections, which should be as 
thin and as large as possible. Various means have been 
employed to obtain these, and various instruments have 
from time to time been devised to facilitate the opera- 
tion of section cutting. 
The simplest, bat by no means the best plan, is to 
take a piece of hardened tissue between the thumb and 
forefinger of the left hand, and to cut thin sections from it 
with a sharp knife, held in the right hand. If the 
piece is too small to be held between the fingers it must 
be imbedded in some substance which, when warm, is 
fluid, and which becomes hard on cooling, such as wax, 
paraffine, or soap, or it may be clamped between two 
pieces of some substance which does not offer any more 
resistance to the knife than the tissue itself, such as 
boiled liver, carrot, elder pith, and so forth. This method 
is employed in most of the laboratories in Europe, but 
the sections obtained are not as satisfactory as might be 
wished, and even if they are thin, they are small in ex- 
tent, and it requires considerable skill to cut even a 
small section. 
With the so-called Valentine’s knife, which consists 
of two small blades that can be separated from each 
other any desired distance, by means of a small set 46 
MICROSCOPICAL TECHNOLOGY. 
screw, sections of fresh tissues may be made by cutting 
into the piece and floating off under water the section 
found between the blades. It is, however, nearly impos- 
sible to have the blades parallel; they are difficult to 
keep sharp, and the sections cut with this instrument are 
usually wedge-shaped. However, Valentine’s knife is 
very serviceable in the post-mortem room when a hasty 
microscopical examination of an organ is desired. 
Fig. 8. 
The Microtome. The most satisfactory and almost 
indispensable apparatus for cutting sections is a micro- 
tome, and the student who is desirous of saving time, 
labor and material, will do well to supply himself with 
one (Fig. 8). Various forms of this instrument are iu the 47 
CUTTING SECTIONS. 
market, the principle, however, being the same in all. It 
consists of a brass tube, called a well, closed at the bottom 
by a disk or block, into which is fitted a long screw, 
having from thirty to forty threads to the inch, and 
which is turned by a large milled head. This screw as 
it ascends in the centre of the well pushes before it a 
loosely fitting false bottom, which is prevented from 
turning around in the tube by a notch cut into its edge, 
into which fits a small bar, soldered to the inside of the 
tube. This tube, with its screw and false bottom, is 
screwed, at its open end, into a metal plate, which may 
be fastened to the edge of the table by a clamp, and to 
its upper surface is cemented a plate of glass having a 
round hole cut in its centre, a little larger than the bore 
of the tube and fitting directly over it. 
In purchasing a microtome, it should be carefully 
examined to see that the micrometer screw has no lost 
motion, or is shaking in its bearings, for upon its steady 
upward pressure depends most of the success of section 
cutting. 
When the microtome is to be used the hardened piece 
of tissue is laid upon the false bottom of the well, which 
has been lowered to such a depth that the tissue is below 
the surface of the glass plate. The well is then filled 
with an imbedding material, which is fluid when hot 
and becomes hard when cold, completely covering the 
piece of tissue. A variety of substances may be em- 
ployed for imbedding, but the author, after many experi- 
ments, has found the following to be more satisfactory 
than any other, in the majority of cases, because if poured 
into the well at a temperature of about one hundred 48 
MICROSCOPICAL TECHNOLOGY. 
and twenty degrees, it will not shrink away when 
cooling, either from the tissue or from the wall of the 
microtome well. 
This imbedding material consists of— 
Pure paraffine, 2 parts. 
Rendered mutton tallow, 1 part. 
After cooling, the imbedding material is cut from the 
surface of the tissue downward and toward the wall of 
the well, in front and on either side, but is left standing 
behind. This is done to prevent the knife from cutting 
through anything but the tissue itself, as otherwise par- 
ticles of the imbedding material adhering to its surface 
might tear the section before it is completed. By turn- 
ing the milled head of the screw in the bottom of the 
well, the false bottom, and with it the tissue, is raised 
above the surface of the glass plate to a slight extent, 
and whatever projects beyond that level is cut off by 
the knife sweeping over the opening of the microtome. 
The Section Knife. An ordinary razor, ground flat 
ou one side, may be used for cutting, but a knife some- 
what longer, expressly made for the purpose, is to be 
preferred. Such a knife should notr be wider than one 
inch ; its back should be of considerable thickness; its 
edge should be straight, and it should be well balanced 
in the handle. One side, the lower one if the knife is 
held in the right hand, the edge pointing from the per- 
son, should be flat and the upper side ground slightly 
concave or hollow, and its cutting edge should be four 
times the length of the diameter of the well of the sec- 
tion cutter. There are reasons for all these minutiae about CUTTING SECTIONS. 
49 
the section knife which it is well for the student to 
know, and we therefore give some of the most important 
ones. 
The edge of the knife should be straight, because in 
the act of cutting the knife must be tilted somewhat, 
that is, the back should be raised so that the edge only 
glides upon the glass plate of the microtome, for if any 
waves exist on this edge the resulting section will be 
uneven in thickness. The same will result if the edge 
is convex, like that of a razor, for then the slightest 
Fig. 9. 
change of inclination of the knife during the act of cut- 
ting will cause a gouging into the tissue. The accompa- 
nying diagram will make this clearer than can be done 
in mere words. 
The under side of the knife should be flat, because it 
is the one nearest the glass plate in cutting from the 
body. It will be found that it is much more easy to cut 
away from than toward the body, because the so-called 
muscular sense, a very important factor in section cut- 
ting, is more highly developed in the extensor muscles 
of the arms than in the flexors. 50 
MICROSCOPICAL TECHNOLOGY. 
The knife should be properly balanced in order to 
insure perfect and continuous contact of the cutting edge 
with the glass plate, thus avoiding dipping of the edge, 
which results from unequal pressure at one or the other 
end of the knife. 
Even if the microtome is a good one, and the knife 
perfect, the student will find some difficulty in cutting 
sections thin and even, because it requires a very steady 
hand and a good deal of practice, for if the knife is not 
carried across the well of the microtome with an even 
sweep and unchanging inclination, the section will be 
wavy if at all large. This difficulty has been long ex- 
perienced, and many contrivances have been constructed 
to overcome it, with varying success. In order to fully 
appreciate the difficulty it will be necessary to examine 
into the process of cutting a little more closely. It will 
be found that the edge of the knife has a bevel produced 
by honeing and stropping (Fig. 10), which will raise the 
Fig. 10. 
cutting edge above the glass plate when the flat side 
of the knife is laid on the plate, and will cause the 
knife to cut upward and out of the tissue, thus breaking 
the section before it is completed ; or, if the operator is 
conscious of this upward tendency, and endeavors to cor- 
rect it, alternate bands of thick and thin portions will be 
observed in the section. This difficulty can be obviated 
by raising the back of the knife slightly, so as to cause it 
to slide on the bevel. It will be seen, therefore, that CUTTING SECTIONS. 
51 
the knife should be carried through the portion of tissue 
projecting above the level of the glass plate with an 
even motion and at the same inclination, to insure suc- 
cess. 
The Author’s Mechanical Knife Carrier. It occurred 
to the author, some time ago, that if the knife could be 
rigidly fastened to some apparatus by means of which 
it could be moved over the well of the microtome in the 
same manner that the hands move it, sections of any de- 
sired size and thinness could easily be cut, even by an 
unpracticed hand. After some experimenting, an ap- 
paratus was constructed which proved to be all that can 
be desired in an apparatus of this kind (Fig. 11). 
Fig. 11. 
It consists of two rigid parallel arms of metal, which 
at one end revolve on pivots attached to the table to 
which the microtome is clamped. On the other end of 
these arms are fastened revolving clamps which hold the 
knife, the edge of which, when in position, rests upon 
the glass plate of the microtome. The handle of the 52 
MICROSCOPICAL TECHNOLOGY. 
knife is removed, so as to prevent any hindrance to the 
motion, but can easily be attached by means of a screw, 
when the knife is to be stropped or honed. When in 
position and ready for cutting, the edge of the knife is 
kept in contact with the glass plate by a slight pressure 
of the fingers upon the upper surface of the blade, and 
a side motion is given to it by the hands, which causes 
it to pass through the tissue and cut a thin, even section 
without any difficulty. 
As has already been mentioned, several mechanical 
microtomes have been constructed by various workers, 
but to my knowledge they are all deficient in one point, 
viz., the knife or cutting instrument in these is carried 
through the tissue like a chisel, or, in other words, the 
cutting edge is pressed through the tissue. But the 
knife, in order to cut well and evenly, must be carried 
through the substance to be cut—especially 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. 
By referring to Fig. 11, it will be seen that in the author’s 
apparatus this is exactly what takes place when the 
knife is moved, the radius of the curve being the length 
of the arms from the centre of the pivots to the centre 
of the clamps holding the blade. 
As has been several times remarked in these pages, 
it is of the greatest importance, in normal as well as in 
pathological histology, to examine large sections, so as to 
obtain a clear picture of the relation of parts to each 
other. Especially is this true when the histology of 
organs which are very composite in their nature is 
studied,and where it becomes necessary to identify large CUTTING SECTIONS. 
53 
agglomerations of elements, as is the case, for instance, 
in the brain, the spinal cord, the larynx, the kidney, 
etc., or in composite pathological new formations. How 
whole organs can be prepared for the cutting has 
already been mentioned, and it remains to describe the 
process of cutting large, thin sections of such organs, 
as, for instance, across the whole human brain. 
It is self evident that sections of the size indicated 
cannot be cut in the ordinary manner, as they would 
break before they are completed, even when cut com- 
paratively thick. Sections thin enough for even the 
higher powers may be cut under a liquid, preferably 
alcohol, so that they are floated off as soon as they are 
cut, and are caught upon a piece of stiff writing paper, 
upon which they remain throughout all subsequent ope- 
rations of staining and mounting. 
This necessitates a special apparatus, which is con- 
structed as follows: Take a microtome which has the 
required size for the organ to be cut (for a human brain 
the microtome well should be about eight inches in dia- 
meter), and fasten it, water tight, in the centre of the 
bottom of a trough lined with zinc, which should be 
six times the diameter of the well in length and three 
times in width, and its side should be about one inch 
high (inside measurement). The knife, which should be 
three times the length of the diameter of the well of 
the section cutter, is to be mounted on arms or levers of 
wood shaped like a Z, in the same manner as is done in 
the author’s mechanical knife carrier. These levers are 
swung on pivots, which are fastened on the table some 
distance beyond the trough, so as to obtain sufficient 54 
MICROSCOPICAL TECHNOLOGY. 
swing for the knife. Those pivots should be of the 
proper height, so that the knife has the necessary inclina- 
tion toward the glass plate of the microtome, as was 
described above. 
When everything is in readiness the brain is to be 
imbedded in the well of the microtome, the trough is 
filled with alcohol so that it stands about a quarter of an 
inch above the glass plate, and after the imbedding 
material has been cut away in front and on either side 
of the specimen, the knife is carried through the tissue 
with one sweep. The resulting thin section should at 
once be floated on a piece of stiff writing paper and 
removed to a vessel containing alcohol. The ordinary 
tin plates used for baking pies will be found well 
adapted to this purpose. After a sufficient number of 
sections have been cut, the levers carrying the knife may 
be unscrewed from the pivots and removed from the 
trough, and the latter may be covered with a large plate 
of glass, to prevent the evaporation of the alcohol, so 
that sections may be made at some future time. 
It is a good plan to number the pieces of paper upon 
which the sections are floated and manipulated, because 
then a record can be kept of the approximate position 
of the section in the organ, and this number can be 
inscribed upon the label of the finished preparation. 
In cutting sections, whether by hand or with the 
mechanical microtome, the edge of the knifeshould always 
be in contact with the glass plate, and should be advanced 
with a steady motion, for the slightest hesitancy or pause 
in the motion will alter the inclination of the knife in 
hand cutting, and the resulting section will be uneven. CUTTING SECTIONS. 
55 
A prerequisite to good section cutting is that the knife 
should be as sharp as it can be made, and the student 
should learn to hone the knife properly, so as to be in- 
dependent of the cutler. After a few sections of any 
tissue have been cut, the knife should be stropped, so as 
to keep its edge in proper condition, and it should be 
well cleaned before putting away, after the requisite 
number of sections have been cut, so as to preserve its 
keen edge. 
The Freezing Microtome.—There are some tissues which 
will not bear the action of hardening agents, such as myxo- 
mata and colloid tumors, and others, so that if sections are 
to be cut from them, they must be hardened in some 
other way. This may be done by freezing them, either 
in a mixture of ice and salt, or by means of the ether or 
rigoline spray, in a freezing microtome. This, if the ice 
and salt mixture is to be used, consists of an ordinary 
microtome, the tube of which is surrounded by a box or 
tank which is filled with the freezing mixture. A few 
drops of a thick solution of gum arabic are placed on the 
false bottom of the well, and the piece of tissue is placed 
thereon. In a short time it will be found frozen hard 
enough to cut, when very thin sections may be made 
from it. The knife should be kept cold and dry, other- 
wise the sections will adhere to its surface, and are 
then difficult to remove without tearing them. 
A more simple and convenient apparatus is the spray 
freezing microtome (Fig. 12), in which the piece of tis- 
sue is placed upon a drum, which can be raised by the 
screw in the microtome, so that the specimen projects 
beyond the surface of a second plate of glass which is 56 
MICROSCOPICAL TECHNOLOGY. 
mounted upon pillars and fastened to the metal plate of 
the microtome. This drum has a hole in its side, and 
through it the atomizing tube is introduced, thus causing 
the spray of the volatile liquid to produce the cold 
within the drum and cause the piece to freeze solid and 
fast to the lid. All condensed liquid is collected in the 
Fig. 12. 
bottom of the drum and may be withdrawn by means 
of a stop-cock. 
There are numerous modifications of the different ap- 
paratus described, each one claiming advantages over the 
others; but as the purpose of this little volume is to 
guide the beginner, and not to bring everything new in CUTTING SECTIONS. 
57 
microscopical technology before the public, this consider- 
ation may safely be left out. Those described the 
author has thoroughly tested and found to answer all 
purposes. 
Every tissue requires a little different management in 
cutting, which can only be learned by experience; it is, 
therefore, advisable for the student to practice on one 
tissue until he is able to make satisfactory sections of it 
before going to another one. Thus, if he takes, for 
instance, the stomach of a medium-sized frog after it has 
been hardened in alcohol, as has been described, and cuts 
sections from it until he is able to obtain extremely thin 
and even sections all the way across the organ (about 
one-third of an inch in diameter) he will have made 
more progress in a shorter time than if he had taken 
different tissues and cut them up. 
The question is often asked how thin should the 
sections be cut ? The answer to this must be that the 
sections should be as thin as the elements will hold 
together, and that this thinness varies with every tissue. 
Sections of injected tissues, that is in which the capil- 
laries have been filled with a colored liquid, so as to 
make them more apparent, should be made thicker, in 
order that the ramifications and loops of blood vessels 
may be clearly seen, which in too thin a section are cut 
away, leaving only those vessels which happen to run 
parallel with the plane of the section. Actual measure- 
ment of the thickness of the sections is altogether 
unnecessary, although it may be made by means of the 
fine adjustment of the microscope, in the following 
manner : Focus the lens upon the lowest plane of the 58 
MICROSCOPICAL, TECHNOLOGY. 
section, which must be perfectly flat upon the glass slip, 
and then turn the fine adjustment until the uppermost 
layer is in focus; now count the number of threads of 
the fine adjustment screw to the inch, note the number 
of degrees that the milled head has been rotated, and 
the distance traversed by'the lens will be found by 
a simple calculation; this distance being equal to the 
thickness of the section. It is impossible to measure 
with accuracy the thickness of the section by the micro- 
meter screw of the microtome, although it seems easy 
enough, because there are so many factors which enter 
into the production of the section, that gross errors of 
measurement are very readily introduced. 
Bone Sections. Sections of hard substances, such as 
dried bone, teeth, and even of rocks, may be prepared 
thin enough to be examined by transmitted light and with 
high powers. Such sections are made in the following 
manner: Cut with a fine saw, such as is used for scroll 
sawing, as thin and as large a piece of the macerated and 
dried bone or tooth as is possible; rub one surface of it 
upon a fine sandstone until an even surface is obtained. 
This is then to be polished, by rubbing upon a fine 
Arkansas hone, using plenty of water during the opera- 
tion, and is to be finished by rubbing upon a piece of 
soft leather, which has applied upon its surface some 
jeweler’s rouge, until a fine polish is obtained and all the 
scratches made by the first coarser stone have disap- 
peared. 
A small piece of evaporated Canada balsam is then 
heated upon a glass slide, over a spirit lamp, and the 
piece of bone or tooth is pressed into the softened CUTTING SECTIONS. 
59 
balsam, with the polished side downward; the slide is 
then again heated until the balsam boils, and the 
specimen is pressed down with considerable force, so 
that it will lie flat upon the glass. After the balsam 
has cooled and become hard, the surplus is scraped 
away, and the piece of bone, which has tightly adhered to 
the glass, is rubbed upon the sandstone, and ground as 
thin as possible. Great care must be exercised to hold 
the glass slide parallel with the surface of the stone, as 
otherwise the section will be ground unevenly and will 
be wedge-shaped when finished. When thin enough, 
the section is polished upon the hone, and finished upon 
the leather with rouge. The grinding and polishing 
should be done with circular strokes and not with a to 
and fro motion of the hand, in order to avoid deep 
grooves being made into the section by coarser particles 
of the stone. 
The section, when thus polished on both sides, is to 
be thoroughly washed with a stream of water from a 
syringe or under the tap, and is then to be examined 
under the microscope, to see whether it is satisfactory as 
regards thinness and polish. When found to be too 
thick or uneven, it must again be put on the sandstone 
and the fault remedied by further grinding. If found 
perfect a drop of balsam is to be placed upon it, after all 
the water has evaporated, and it is to be mounted in the 
manner described below. 
This process is not as difficult and tedious as might 
appear from the description, especially when the student 
has access to a lathe. In that case the work of grinding 
and polishing is done very quickly and easily, and 60 
MICROSCOPICAL TECHNOLOGY. 
several pieces may be ground at once, by cementing 
them side by side upon a piece of glass, and holding 
them against the revolving grindstone. They must 
then, of course, be transferred, when finished, upon 
separate slides, which can readily be done by the appli- 
cation of a little heat. 61 
STAINING OF TISSUES. 
CHAPTER IY. 
STAINING OF TISSUES. 
By staining the tissues or thin sections of tissues, is 
meant the tinging of certain parts, for the purpose of 
differentiating the different elements from each other by 
their color, or by the varying intensity of color. This 
may be accomplished in a variety of ways and by a 
variety of colors, and depends upon the peculiarity of 
certain tissue elements to absorb and retain the coloring 
materials more readily than others. Thus the nuclei of 
cells will take up and retain certain vegetable colors 
whereby they are made distinctly visible under the 
microscope. This faculty is lost entirely by the nuclei 
after decomposition has set in, or partially after the 
tissue has been acted upon by certain reagents, as, for 
instance, chromic acid, and for this reason the tissues 
should be placed into the hardening agent as fresh as 
possible. Strange as it may seem, tissues which are 
perfectly fresh or still living will not stain, and must 
first be killed, so to speak, by some reagent, such as 
glycerine or alcohol, before their nuclei will take and 
retain the coloring matter. Other elements beside the 
nucleated structure may be differentiated or made 
distinct by coloring matters or chemical reagents, so that 
often a combination of colors may be produced in a 
specimen, each of which maps out, so to speak, the ele- 
ments which have an affinity for it, and this is termed 
double staining, because usually only two different color- 62 
MICROSCOPICAL TECHNOLOGY. 
ing materials are used, which may, however, produce in 
the section a much larger number of colors or shades of 
color. 
Carmine. Among all the different coloring matters, 
carmine is best retained by the nuclei, and for this reason, 
and also because it does not fade, it is most extensively 
used for staining. Many workers in this department of 
microscopy have devised a large number of methods of 
employing this color for staining, and to give a descrip- 
tion of them all would only mislead the student, who 
does not know which one to use for his purposes. We 
shall, therefore, give only one, which has proved to be 
certain and satisfactory in most cases, and which is very 
simple in its manipulations. This method was originally 
devised by Prof. Tiersh, but has been modified and im- 
proved by Dr. J. J. Woodward, of Washington, and is 
as follows:— 
Take of— 
Best carmine, No. 40, 15 grains. 
Borax, 1 drachm. 
Water, 5| ounces. 
Alcohol (ninety-five per cent.), 11 ounces/ 
Mix and filter. The liquid which runs through the 
filter paper is but slightly colored and should be thrown 
away as useless. The crystals, however, which will be 
found remaining in the filter should be carefully re- 
moved and dissolved in eight ounces of distilled water. 
In order to save time and trouble, the filter, together 
with the crystals on it, may, as soon as the filtration is 
completed, be thoroughly mixed with the eight ounces 
of water, in a mortar. The solution is then to be STAINING OF TISSUES. 
63 
filtered and evaporated in a water bath, to four ounces, 
when it is ready for use. 
The sections which, after cutting, have been kept in 
alcohol, are then taken out and placed into a small dish 
filled with this lilac-colored liquid, for a short time, from 
thirty seconds to one minute being sufficient; but they 
may be left in it for several minutes without fear. They 
are then placed into what is termed a fixing solution, 
composed of— 
Hydrochloric acid (c.p.), 1 part. 
Alcohol,* 4 parts. 
and allowed to remain therein until their color has 
changed from a lilac to a rose color. The action of this 
fixing solution is to remove the excess of color and to 
bleach all other parts, except the nuclei, which retain 
the carmine staining in spite of the action of the acid, 
so that they alone are brilliantly colored red. This is, 
in many cases, of great advantage, as a much clearer 
picture results than if the coloring is also seen in the 
non-nucleated structures, and the nuclei are only marked 
by deeper staining. If, however, it is desired to stain 
the cell contents and intercellular tissue also, this can be 
accomplished by employing a weak solution of hydro- 
chloric acid in alcohol (ten drops to the ounce), or by 
using a saturated solution of oxalic acid in sixty per 
cent, alcohol, as a fixing solution. The sections are then 
removed from the acid solution and are washed in several 
changes of alcohol, which should be of varying strength. 
* Whenever the term alcohol is used in this volume without 
definitely giving its strength, pure ninety-five per cent, alcohol is 
meant. 64 
MICROSCOPICAL TECHNOLOGY. 
Thus, the first washing should be sixty-five per cent., 
the second eighty per cent., and the last ninety-five per 
cent., in order to prevent shrinkage of the tissue by the 
action of strong alcohol upon it after it has been 
saturated with water absorbed from the staining solution. 
If tissues are stained which do not require hardening, 
such as membranes, and are to be mounted in watery 
media, the alcohol is dispensed with and the fixing solu- 
tion is made with water while the washing is also done 
in water. 
Tissues, whether they be in sections or as thin mem- 
branes, will be found on examination to be evenly and 
brilliantlv stained. 
Hcema'oxylon. Another very valuable staining ma- 
terial is hsematoxylon, which is prepared by mixing a 
strong watery solution of the extract of logwood with a 
concentrated solution of alum, or by treating logwood 
with alum-water, as made and sold by Bullock & Cren- 
shaw, a large chemical house of Philadelphia. 
Tissues to be stained are immersed for some ten or 
fifteen minutes in a strong watery solution of alum, to 
which are then added a few drops of the hsemotoxylon 
solution, sufficient to give a deep purple color In the 
course of five or ten minutes more the sections are stained 
uniformly of a violet color, which on examination under 
the microscope will be seen is chiefly retained by the 
nuclei, very similar to carmine. The specimens are 
then to be washed in water for a few seconds and placed 
in a small dish or watch glass, filled with alcohol, where- 
in they should remain at least twenty-four hours before 
mounting. 65 
STAINING OF TISSUES. 
If the section is placed directly from the alcohol into 
the hsematoxylon solution, a precipitation of the coloring 
matter by the alcohol will occur, and the section will 
either not be stained at all, or will be filled with gran- 
ules of the hsemotoxylon. Also, if the sections are not, 
previous to staining, immersed in the alum solution, 
which acts as a mordant, the staining will be uneven, 
and, therefore, unsuccessful. 
One great drawback to this method of staining is that 
the color is not permanent, and wrill fade, especially if 
the specimen be mounted in glycerine. However, as 
long as it lasts, it gives very satisfactory results, and is, 
in many cases, even preferable to carmine staining. A 
good plan is for the student to stain two sections of the 
same tissue, one with carmine and the other with heema- 
toxylon, and compare the results. 
Double Staining. After a section has been stained 
with carmine, as described above, the cell contents and 
fibrous portions may be stained with a blue color, 
obtained from indigo, which will tinge some parts a 
decided blue, others green, and still others by a combi- 
nation of the red of carmine with the blue, of a violet 
color, this producing a beautiful effect. This is the 
more valuable as different tissues invariably are tinged 
by the same shade of color, so that thereby they may be 
recognized and fine distinctions may be made by the aid 
of color, which are impossible to make in single stag- 
ings. The necessary manipulations are as follows: 
Take a neutral solution, in water, of either indigotate of 
potash, commonly called indigo carmine, orof the sulph. 
indigotate of soda, and add a few drops of it to sixty per 66 
MICROSCOPICAL TECHNOLOGY. 
cent, alcohol, until the liquid assumes a dark sky-blue 
color. Place in this the section, which has previously 
been stained with carmine, and thoroughly washed, for 
from four to twelve hours, according to the rapidity with 
which the tissue takes up the blue color, as this varies 
greatly in different tissues. When the section has as- 
sumed a decidedly blue color, if examined in clear alco- 
hol, it is sufficiently stained, but the exact time when it 
should be removed from the indigo solution can only be 
determined by experience. On examination under the 
microscope, after having been made transparent, the 
section should show its nuclei bright red, while the 
connective tissue, muscular fibres, cell walls, if such be 
present in the cells, blood disks, etc., should be tinged 
with a variety of shades of blue. A quicker, but not 
quite as certain a method of obtaining the same results 
is to immerse the carmine-stained section in a saturated 
watery solution of oxalic acid, to which the concentrated 
neutral indigo solution has been added, in the proportion 
of fifteen drops of the latter to one ounce of the former. 
The sections are first stained with carmine, using the 
watery acid solution for fixing the color, and are thor- 
oughly washed in water; they are then i mmersed for a few 
minutes in this indigo solution, when they will be evenly 
stained with the blue. If, on examination, the blue is 
too dark, the surplus may be removed by soaking the 
sections for some time in a saturated solution of oxalic 
acid. After this the specimen should be carefully washed 
in several changes of water, so as to remove the oxalic 
acid, for if any trace of it remains in the tissue, both the 
blue and the red color will fade iu a short time. This STAINING OF TISSUES. 
67 
latter method of double staining isnot as certain, because 
the blue is apt to combine with the red in the nuclei and 
give them a violet hue, which materially detracts from 
the brilliancy of the staining and from the contrast of 
colors.* 
There are a number of other methods of staining with 
two or more colors, such as with picric acid and carmine, 
hsematoxylon and carmine, aniline colors, and so forth, 
but they are by no means certain, nor are they as satis- 
factory as the process described above, and we therefore 
will not give a description of them. 
It is evident that isolated cells, bacteria, portions of 
teased tissues and so forth, cannot be stained in the 
manner just described, and that if color is to be imparted 
to them, it is to be done on the slide on which they are 
mounted. For this purpose the aniline dyes are prefer- 
able to any other coloring material, and should be used 
in very weak watery solutions, the fuchsine and iosine 
solutions being perhaps the best to use, but other aniline 
colors may be employed. 
To stain isolated cells or bacteria, without displacing 
them from under the thin glass with which they have 
been covered, place a drop of the staining solution on the 
slide, close to the edge of the cover, and allow it to run 
under by capillary attraction, then place a piece of blot- 
ting paper close to the opposite edge of the cover, to 
establish a current. This done, put the slide under the 
microscope and observe the action of the coloring mate- 
* This process was devised by the author, and was published in 
the American Quarterly Microscopical Journal, Yol. i, No. 3, 
April, 1879. 68 
MICROSCOPICAL TECHNOLOGY. 
rial upon the cells; when they have been sufficiently 
stained, remove the drop of coloring solution and sub- 
stitute for it a drop of distilled water, which by passing 
under the cover washes away all superfluous coloring 
material and leaves the cells or teased tissue stained. 
The mounting material, which should be a watery me- 
dium, is then in the same manner introduced under the 
cover, and the slide is finished as described below. 
Nitrate of Silver. Some portions of tissues have an 
affinity for salts of metals in solution, and precipitate 
the base in its metallic form, or as an oxide, by the aid of 
light. Thus the cell cement connecting epithelial and 
endothelial cells may be stained black by the oxidation 
of silver, in the following manner: Place a membrane 
or thin section of a fresh tissue, made with the freezing 
microtome, in a half per cent, solution of pure nitrate 
of silver, and allow it to remain until it appears milky. 
It is then to be washed in distilled water and ex- 
posed to the action of diffused daylight, in a shallow 
dish of porcelain, filled with water, to which a few drops 
of acetic acid have been added, so that it becomes 
slightly acid. The action of light will reduce the silver 
salt to its oxide, and the tissue becomes brown, when it 
should be washed in a weak solution of table salt, in 
order to convert the unreduced nitrate of silver into the 
chloride, and should then be soaked for a few moments in 
a weak solution of hyposulphite of soda (two per cent.), 
with a view of removing the chloride and preventing 
further darkening of the specimen by the action of light. 
In a successfully silver-stained specimen the epithelial 
or endothelial cells will be mapped out with great dis- STAINING OF TISSUES. 
69 
tinctness, but frequently the silver will be deposited in 
the cell itself, instead of in the cell cement, and then the 
tissue presents a mass of cells containing small black 
granules of silver, without having their outlines definitely 
marked by black lines. A tissue successfully stained 
with silver should be afterwards stained with either 
carmine or hsematoxylon, in order to bring out the 
nuclei. 
The cornea of a frog or rabbit may be very success- 
fully stained by painting it with a strong solution of 
nitrate of silver (forty grains to one ounce of water), while 
the animal is alive and under the influence of chloroform, 
and the white skin of the belly of a frog thus treated 
makes beautiful preparations, showing the epithelial cells 
and the stomata between them. 
Chloride of Gold. For differentiating delicate nerve 
filaments, and for bringing the corneal corpuscles into 
view, a one per cent, solution of chloride of gold is an ad- 
mirable reagent. The tissue, as soon as possible, should be 
immersed in the gold solution until it assumes a straw 
color; it should then be washed in distilled water and 
exposed to diffuse daylight for several hours, in some 
acidulated water, until it has assumed a reddish-violet 
color throughout, when it is to be washed again in water, 
and may then be stained with indigo solution, before 
mounting. 
Osmic Acid. In order to stain the ganglionic cells 
of the spinal cord, as well as their processes, so that they 
can be isolated, a thin slice of fresh spinal cord is to be 
soaked for several days in a one per cent, solution of 
osmic acid, until it assumes a brownish color; it should 70 
MICROSCOPICAL TECHNOLOGY. 
then be washed in water and placed for twenty-four 
hours in dilute glycerine, when it may be teased out 
with needles, and the ganglionic cells, which are stained 
of a deep brown if the staining has been successful, 
may be isolated. The red-blood cells of animals may 
also be stained with osmic acid, so that they may be 
easily seen wThen mounted in balsam. In order to do 
this, prepare a blood slide, as described in the section 
on illumination, and place it, with the blood cells down- 
ward, over a shallow vessel containing a two per cent, 
solution of osmic acid, thus exposing the blood cor- 
puscles to the influence of the vapor of the acid. After 
a few minutes the slide may be prepared for mounting 
(as will be described below), and after some time the 
blood cells will assume a distinctly brown color, thus 
making them clearly visible. Osmic acid will stain 
fat cells of a deep brown, almost black, and thus becomes 
a valuable reagent when a differential diagnosis is to be 
made between fat and other substances resembling it 
under the microscope, which are not thus stained. INJECTING THE VASCULAR SYSTEM. 
71 
CHAPTER Y. 
INJECTING THE VASCULAR SYSTEM. 
In order to clearly demonstrate the vascularity of a 
tissue and to show the ramifications of the capillaries, 
the blood vessels must be injected with some colored 
fluid which will remain in the vessels after the tissue has 
been hardened and sections have been cut from it. This 
fluid should hold the coloring matter in suspension in a 
finely subdivided state, and not in solution, so as to pre- 
vent the escape of the coloring matter through the 
stomata of the vessels into the neighboring tissues. 
There are two injecting fluids which have given the 
most satisfaction in the hands of the author, the one of 
a red color and the other blue. This red fluid is made 
as follows :— 
Take of— 
Best carmine, No. 40, 2 drachms. 
Distilled water, 3 ounces. 
Strong liquor ammonia, 20 drops. 
Dissolve this and filter through cotton, covering the 
funnel with a piece of glass plate, to prevent the evapo- 
ration of the ammonia. The filtration is a somewhat 
tedious process but is absolutely necessary ; the solution, 
however, will keep, and may therefore be kept in stock. 
Then take of— 
Coxe’s gelatine, 2 drachms. 
Distilled water, 2 ounces. 
Soak the gelatine in the water until it becomes soft, and 72 
MICROSCOPICAL TECHNOLOGY. 
then dissolve it in a water bath and strain through fine 
flannel while hot. Heat the gelatine solution again and 
add the carmine solution, and bring the temperature up 
to about two hundred degrees, Fahrenheit. Dilute 
acetic acid must then be added,drop by drop, under con- 
stant stirring of the mixture, until the ammonia is just 
neutralized, which is indicated by a sudden change of 
color in the solution, from a lilac to scarlet. If the acid 
is added too quickly or too concentrated, the precipi- 
tation of the carmine is too sudden, and the granules be- 
come so large that they cannot pass the smaller capillaries, 
thus preventing the success of the subsequent injection; 
and if acid is added after the solution has become 
neutral the gelatine will not congeal in the vessels, and 
the fluid will run out when the sections are made. It 
will be seen, therefore, that some experience is necessary 
in preparing this fluid, and the student should not feel 
discouraged if he fails in his first attempts, for repeated 
trials will give him the necessary skill, and he will be 
rewarded by the beauty of his preparations. This fluid 
must be used hot. 
Beale’s Blue Injecting Fluid. Another injecting fluid, 
which is to be used cold, is Beale’s finest blue injecting 
fluid;* it is prepared as follows:— 
Take of— 
Chloride of iron (e.ph.), 10 drops. 
Glycerine, 1 ounce. Mix. 
Then dissolve three grains of ferrocyanide of po- 
tassium in a little water and add to it half an ounce of 
glycerine. Mix the two solutions and add, under con- 
* “ How to Work with the Microscope,” third edition, page 200. INJECTING THE VASCULAR SYSTEM. 
73 
stant shaking, drop by drop, half an ounce of water, 
acidulated with three drops of muriatic acid (c.p.) which 
precipitates the coloring matter in exceedingly fine 
granules. The only drawback to the use of this inject- 
ing fluid is that it fades very soon, unless mounted in 
an acid medium, and even then it is not staple. But 
as the same holds good of other fluids prepared by 
Prussian blue, and as this gives the seemingly only 
available blue coloring matter, and as they have other 
disadvantages, this fluid is the best to use. It might be 
here stated that it is commercially manufactured by 
Bullock & Crenshaw, of Philadelphia, and may be 
obtained from them. 
THE METHOD OF INJECTING. 
The instruments necessary for the injection of the 
capillary system are a dissecting case in good order 
and a syringe of metal holding about two ounces, and 
of such a length that if the piston is drawn out to 
its full extent it can be pushed down by the thumb 
of the same hand that holds the barrel. The plunger 
should fit the bore of the barrel air tight, but should 
move easily and without jerks. The syringe should 
be provided with a removable stop-cock, to which 
several nozzles of different sizes can be fitted. These 
nozzles should have a little bulb at the point, and should 
be provided at the other extremity with a hook-like pro- 
jection to which the thread used in tying the nozzle into 
the vessel is fastened. 
The best animal to inject, for the beginner, is a young 
cat, because its blood vessels seem to be tougher and 74 
MICROSCOPICAL TECHNOLOGY. 
withstand the necessary pressure better than those of 
most other small animals. 
Possessing the dissecting case and syringe, having 
procured the cat, and having prepared about twenty 
ounces of the red carmine injecting fluid, the student 
may proceed to the operation of injecting as follows: 
Place the cat into a box, together with a sponge saturated 
with chloroform, and then close the lid. Very soon the 
animal will be quiet, when it should be placed upon the 
table and an incision made into the skin in a line with 
the sternum and reaching from the clavicle to the end of 
the sternum. This incision is best made with a sharp 
pair of scissors, as a knife is apt to slip in the thick fur 
of the animal. The skin and underlying muscles are 
then to be dissected from the sternum and intercostal 
cartilages, and the thoracic cavity is opened by cutting 
through the intercostal cartilages on either side and 
bending the sternum upward, just as it is done in mak- 
ing a post-mortem examination of a human subject. 
Care should be taken not to sever the mammary arteries, 
and everything should be done as quickly as possible. 
The thoracic viscera having thus been exposed, the 
pericardium is picked up with a pair of forceps and slit 
open, and the apex of the heart, thus disengaged, is cut 
off with a pair of scissors, so that both ventricles are 
opened. The animal must now be thoroughly drained 
of blood, by lifting it alternately by the ears and by the 
hind legs, until no more blood runs from the heart. 
The largest of the nozzles of the syringe that can be in- 
troduced is then pushed through the left ventricle of the 
heart into the aorta, and the latter only is tied around INJECTING THE VASCULAR SYSTEM. 
75 
the nozzle behind the bulbed end, with a piece of stout 
suture silk, the free ends of which are fastened around 
the hook-like projection of the nozzle and drawn tight, 
so as to prevent its slipping out. It is best to fill the 
nozzle with injecting fluid before introducing it into the 
aorta, so as to prevent the introduction of air into the 
vascular system, which might prevent the successful in- 
jection, or cause extravasation by bursting some of the 
vessels. The syringe is then filled with the injecting 
fluid, which has been heated to a temperature of about 
130° Fahr., the stop-cock attached to the syringe is 
introduced into the nozzle, opened and held firmly in 
position with the left hand while the plunger is gently, 
but with a steady motion, depressed by the thumb of the 
right hand. As soon as the fluid reaches the capillary 
system, a resistance to its progress will be felt by the 
operator, and this must be overcome by a slight increase 
of pressure upon the plunger of the syringe. But as 
soon as it is overcome the pressure should again be 
diminished to the degree used at first. When the syringe 
is emptied the stop-cock is to be closed, the syringe dis- 
engaged from it and re-filled. Its permanent nozzle is 
then reintroduced into the stop-cock and the injecting 
proceeded with until the injecting fluid, which has driven 
the bloo(j remaining in the vessels before it, runs out 
pure from the right ventricle. The stop-cock is then 
again to be closed, and all the vessels coming from the 
heart are to be tied with another piece of suture silk, 
around the nozzle, and after opening the stop-cock, a 
little more injecting fluid is forced into the vessels. 
This is done in order to over-distend the vessels, so that 76 
MICROSCOPICAL TECHNOLOGY. 
when the gelatine, on cooling, contracts, it will fill the 
vessels completely. 
If, during the injection, the fluid is seen to ooze from 
any vessels which have been cut, they must be tied, or 
if they be small the leakage can be stopped by picking 
up their extremities with a pair of forceps and twisting 
them. 
The injection completed, which, with a medium-sized 
cat, should not take longer than five minutes, the stop- 
cock is to be closed, the syringe removed from it, and the 
animal placed in ice water for at least six hours before the 
nozzle and stop-cock are removed, or it is dissected; for the 
gelatine must be given time to become solid, as otherwise 
the injecting fluid will be forced out of the smaller 
capillaries by the contraction of rigor mortis. 
If any of the injecting fluid is left over it may be set 
in a cool place with a small piece of camphor in it, and 
will thus keep for several days. Or it may be poured 
on a large glass plate, also placed in a cool place (in 
summer on ice), and when it has become solid the mass 
may be cut into narrow strips, detached from the glass 
plate and hung up to dry, when it will keep indefinitely. 
One ounce, by weight, of this dried material should be 
soaked in ten ounces of water, then dissolved in a water 
bath and strained through a salt bag which lias pre- 
viously been boiled, before using it again for injecting. 
As a general rule it will be found that the lungs of an 
animal treated as described above are either not in- 
jected at all or but little of the fluid has found its way 
into them, and they should be injected separately by 
tying the nozzle into the pulmonary artery, before the INJECTING THE VASCULAR SYSTEM. 
77 
vascular system of the rest of the body is injected. An 
animal which has been dead for some time, and in which 
the rigor mortis has just passed away, or a human foetus, 
or even a separate organ of an animal or man, such as 
a leg or arm, may also be injected with this fluid. In 
order to do so the animal or organ should be placed for 
several hours into warm water, and the same should be 
injected into the vessels, in order to wash out any clots 
of blood before proceeding as described above for the 
recently killed animal. In the case of a separate organ, 
the nozzle should be introduced into the largest artery, 
and all other vessels should be tied, except the largest 
vein, as the injecting fluid makes its appearance at their 
cut extremities. The largest vein should also be tied after 
the fluid has flown from it for some little time, and all 
the vessels should then be over-distended by a little 
more pressure upon the piston of the syringe, for the 
reason given above. 
The cold-flowing blue injecting fluid may be used in 
the same manner as the red, with the exception that 
it is not necessary to warm dead animals or detached 
organs before injecting ; or it may be used, for the latter 
class of objects, with a so-called pressure apparatus, the 
simplest and most convenient form of which consists of 
a funnel attached to a flexible rubber tube. In using 
such an apparatus, one of the nozzles belonging to the 
syringe is to be introduced into the artery, after. having 
been filled with the injecting fluid; the stop-cock is then 
attached to one end of the rubber tube and the funnel 
to the other ; the funnel is filled with the injecting fluid 
and raised to such a height that the hydrostatic pressure 78 
MICROSCOPICAL TECHNOLOGY. 
will be sufficient to force the liquid through the vessels, 
when the stop-cock is to be introduced into the nozzle 
and when opened the injecting proceeds without further 
labor on the part of the operator. 
This method of injecting, although very convenient 
and efficient for the blue fluid, cannot be employed when 
the red is to be used, because the gelatine would become 
cold and congeal in the funnel; and neither the red nor 
the blue can be used with the pressure apparatus in 
recently killed animals, because of the momentary in- 
crease of pressure necessary to overcome the resistance 
felt when the fluid enters the capillary network. 
Double injections, in which the arteries are injected 
with the red fluid and the veins with the blue, can be 
made in detached organs only by injecting the red fluid 
first through the artery until the fluid has reached the 
capillaries, which is known by the increased pressure 
necessary to overcome the resistance. The artery is 
then tied and the nozzle introduced into the vein through 
which the blue fluid is injected. If the experiment has 
been successful, sections made from the organ will show 
the arteries red and the veins blue. 
Another injecting fluid must be mentioned, which is 
used in order to demonstrate the outliue of the endo- 
thelial cells lining the blood vessels in the frog. It is 
made as follows :— 
Nitrate of silver, 3 grains. 
Distilled water, 2 ounces. 
Dissolve and mix with a hot solution of— 
Coxe’s gelatine, l drachm. 
Distilled water, 1 ounce. INJECTING THE VASCULAR SYSTEM. 
79 
The frog is to be put under the influence of chloroform 
by injecting some of it under the skin of the back, and 
the heart is to be quickly exposed and cut in the same 
manner as was described when treating of injecting a 
warm-blooded animal. After all blood has been drained 
out of the body, the fluid is injected while warm, and 
all thin membranes, such as the mesentery, bladder, and 
so forth, are removed and exposed, in acidulated water, to 
the action of light; in fact, they are treated as if they 
had been stained with silver. 
After the injection of any of these fluids all the in- 
struments and vessels used should be carefully washed 
in hot water, so as to have everything in readiness for 
the next time injecting is to be done, for nothing is so 
annoying as to have everything in readiness and find 
that the piston of the syringe will not move up or down 
because the nozzle is stopped up with dried injecting 
fluid, or to find the same state of imperviousness in the 
stop-cock. 
In order to obtain satisfactory preparations of injected 
membranes, such as the mucous membrane of the urin- 
ary and gall bladder, the mucous membrane of the in- 
testine and stomach, the choroid of the eye, etc., it is 
necessary to remove the epithelial cells, which, in a great 
measure, interfere with a good view of the blood vessels. 
To do this, place the membranes, or the tissues to which 
they are attached, into Mueller’s fluid, diluted one-half 
with water, as soon as the injecting fluid has set, if gela- 
tine has been used as a body, and let them soak for two 
or three days. Then gently wash them in clean water, 
and soak them for twenty-four hours in dilute glycerine. 80 
MICROSCOPICAL TECHNOLOGY. 
The membranes may then be separated from the under- 
lying structures, and the epithelial cells can be removed 
by brushing the surface of the membrane in glycerine 
with a sable brush, such as is used by artists for water- 
color drawings. 
If the tissues have been hardened in alcohol, it is very 
difficult to separate the membranes, and almost impos- 
sible to remove the epithelial cells. This is especially 
the case in the membranes of the eye and the pigment 
cells of the choroid. MOUNTING AND FINISHING OF SPECIMENS. 
81 
CHAPTER VI. 
MOUNTING AND FINISHING OF SPECIMENS. 
After the section or thin membrane has been stained, 
it must be made transparent before it can be examined 
by transmitted light and can be mounted or preserved 
permanently, but as this process is part of mounting we 
will first describe the necessary tools employed. 
The student should provide himself with a pair of 
fine-pointed nickle-plated forceps; with which to lift the 
sections from one solution to another; also with several 
needles, already mentioned in the section on teasing. 
Further, some slips of white plate glass with ground 
edges, in size three inches long by one inch wide; 
some cover glasses, preferably circles, three-fourths and 
seven-eighths of an inch in diameter, of No. 2 thickness, 
and a turn-table. 
Cleaning Slips and Covers. The glass slips and cov- 
ers must be chemically clean before they can be used for 
mounting. When new, both slides and covers are more 
or less greasy, from being handled by the workmen, cut- 
ting, grinding and packing them, and no amount of 
rubbing, either with a dry, soft rag or moistened with al- 
cohol, will remove this thin film of oil; besides, the thin 
covers are too frail to be handled roughly. The slips 
should, therefore, be placed for a few hours in a solution 
of— 
Bichromate of potash, 2 ounces 
Sulphuric acid, 3 fl. ounces 
Water, 25 fl. ounces. 82 
MICROSCOPICAL TECHNOLOGY. 
in such a manner that the brown liquid covers them 
completely. They are then to be rinsed under the tap, 
and stood on edge, on several thicknesses of blotting 
paper. AVhen dry they are chemically clean, and 
require no further manipulation except to brush off any 
dust which may have fallen on them, with a soft camel’s 
hair brush. Care should be taken not to touch their 
surfaces with the fingers, nor to breathe upon them, as 
this would soil them again. 
New covers are treated in the same manner, placing 
an ounce or so of them in a wide-mouthed vial, cover- 
ing them with the cleaning solution, and shaking them 
up occasionally, so as to separate the covers from each 
other, and allow the solution to act upon their surfaces. 
After several hours, the solution is to be poured off and 
the covers washed in the bottle, with water, pouring it on 
and off*, until it remains colorless, after continued shaking 
with the covers in the bottle. The water is then to be 
carefully drained off, and alcohol is poured on the 
covers, wherein they remain until wanted for use. The 
bottle should be tightly corked, to prevent the evapora- 
tion of the alcohol. 
When it is desirable to clean off specimens which have 
been mounted, either in balsam or in a watery medium, 
so as to save both the cover and the slide, the specimen 
is to be slightly warmed over a spirit lamp, and the 
cover is then to be pushed, with a pair of forceps or 
needle, over the edge of the slip into a vessel containing 
alcohol and hydrochloric acid in equal proportions. 
The surface of the slip is then scraped clean of the 
remaining balsam or cement, and dropped into the MOUNTING AND FINISHING OF SPECIMENS. 
83 
bichromate of potash solution, where it should remain 
several days, after which it may be washed under a 
tap, and set up to dry on blotting paper, as described 
for cleaning new slips. 
The covers must remain, also, for several days in the 
acid alcohol, and must then be carefully washed under 
the tap, to get rid of the disintegrated film of balsam 
adhering to them; and after this transferred to the 
cleaning solution and treated like new ones. 
Turn-table. A turn-table, which is used for centering 
the object on the slide, for making cells upon it, in 
which to mount in watery media, and for building up 
cement rings around the edge of the cover, consists of a 
circular disk of brass, mounted with its central axis in 
bearings, so that it will revolve rapidly and easily. 
These bearings are fastened to a stand, made either of 
wood or of cast iron, which, when placed upon the work 
table, gives a support for the right hand holding the 
knife or brush. Upon the brass plate are spring clips 
for holding the slide in position, or if the turn-table is a 
self-centering one, two diagonally opposite corners of the 
slip are held in clamps, which, by a mechanism, move 
toward and away from the centre of the plate in like 
ratio. The self-centering turn-table (Fig. 13), although 
a little more expensive than the other kind, will be 
found to be much more satisfactory, as a great deal of 
time is lost in centering the slide by hand, which is also 
somewhat difficult for persons not accustomed to it. 
There are several patterns of these turn-tables in the 
market, the best of which are those whose centering 
mechanism consists of three toothed wheels, fitting into 84 
MICROSCOPICAL, TECHNOLOGY. 
each other and revolving on the under side of the brass 
plate, or those in which the clamps are approached to 
or receded from the centre by a lever. The stand should 
be provided with a little bolt at the right side, which by 
Fig. 13. 
being pushed forward stops the revolutions of the disk, 
so as to prevent its turning while the slide is being 
placed in position. 
MOUNTING. 
For mounting, both resinous and aqueous solutions 
may be used, which each possess advantages over the 
other, and for this reason a controversy has been going 
on for some time, between eminent microscopists, in 
regard to the advantages of glycerine, on the one hand, 
representing the aqueous mounting media, and balsam, 
on the other, representing the resinous class. The truth 
is, that both should be used, as occasion requires. Gly- 
cerine, or its equivalents, should be used when it is 
desired to bring out delicate strife, lines, hair-like pro- 
jections, such as cilia on the epithelium of the respiratory MOUNTING AND FINISHING OF SPECIMENS. 
85 
tract, processes of the ganglionic nerve cells, and so 
forth, and for delicate vegetable preparations. Balsam 
should be used when clearness and transparency of the 
object, and brilliancy as well as durability of the staining 
is desired. 
In order to clearly understand this, the student will 
do well to mount two preparations of the same tissue, 
the one in balsam, or other resinous medium, and the 
other in glycerine or its equivalent, and then compare 
the results. He will find that the one medium is better 
suited for a particular preparation than the other. 
Balsam. Among all resinous substances Canada bal- 
sam is the best for mounting purposes, provided it has 
been properly prepared. To do this, take a clear sample 
of balsam and evaporate it in a water bath, to dryness, 
that is, until, when hot, all odor of turpentine has dis- 
appeared, and, when cold, it is hard and brittle, like 
resin. This will take several days; and great care 
should be exercised in keeping the water bath full of 
water, for as soon as the temperature in the balsam is 
raised above 212° F. it turns brown, and is then unfit 
for use. 
When thus evaporated the balsam is again heated in 
the water bath and enough of Squibb’s absolute alcohol 
is added to dissolve it and make the solution of the con- 
sistence of thin syrup. It is now allowed to cool 
and poured into a spirit lamp, the wick having been 
removed, in which it is kept for use, the glass cap of the 
lamp protecting it from dust and preventing the evapo- 
ration of the alcohol. If, after using for some time, 
the solution becomes too thick, it should be warmed by 86 
MICROSCOPICAL TECHNOLOGY. 
placing the spirit lamp in warm water and adding 
to it some warm absolute alcohol. If the alcohol used 
in dissolving the balsam or in diluting the solution is not 
strong enough, a white precipitate will form, which may 
be redissolved by the application of heat, but will reap- 
pear when exposed to the air, in a thin layer on the slide, 
and the solution thus becomes useless for mounting. 
Having cleaned his slides and covers, and having his 
balsam solution prepared, the student may now proceed 
to mount the objects in the following way: Place one of 
the stained sections which have been kept in alcohol in 
a small shallow dish containing some absolute alcohol, 
and allow it to remain there for some minutes, so as to 
remove all traces of water which may remain in it from 
the staining fluid and which have not been removed 
by the washing in the weaker alcohols. Then float it 
on the surface of some oil of cloves, also contained in a 
shallow glass or porcelain dish, until it has become 
transparent, when it should be removed from the oil, 
spread out on a glass slide and covered with a thin cover 
glass which has been taken from the bottle filled with 
alcohol and wiped dry with a soft rag. The specimen 
is now ready to be examined under the microscope, in 
order to see whether it will pay to permanently mount 
it in balsam. If found good the cover glass is carefully 
removed and all superfluous oil remaining on the section 
and on the slide is taken up with the edge of a piece of 
blotting paper, the object covered with a drop of the balsam 
solution, a fresh, dry cover is placed upon it, taking care 
to exclude any air bubbles, and pressure is made upon 
the cover, to press out all superfluous balsam. In order MOUNTING AND FINISHING OF SPECIMENS. 
87 
to prevent the formation of air bubbles in the specimen 
the cover should be held by the forceps, near the edge, 
the opposite edge should be carefully placed into the bal- 
sam and the cover gradually lowered over the section 
until it lies flat upon it. If, after pressing the cover 
dowD, it is found that the balsam does not extend to the 
edge of the cover all round, a small drop of balsam 
should be placed near the edge, at the point where the 
balsam under the cover joins the empty space, when it 
will run in by capillary attraction. The slide is then 
laid aside to allow the balsam to dry spontaneously, 
which will take place in from four to six weeks, or 
it may be placed in a drying oven, the temperature of 
which is not raised above 130° F., when it will be ready 
for finishing in a much shorter time. An excellent ap- 
paratus of this kind is sold by dealers in microscopical 
appliances, and is shown in Fig. 14. It consists of a 
box of copper containing movable trays, surrounded by 
another larger box, also of copper, so that a space remains 
between the two boxes, which, when the oven is used, is 
filled with water through an opening at the top. A 
thermometer is inserted through this opening, and a lamp 
is placed under the outer box, which raises the tempera- 
ture of the water up to any desired degree, and thereby 
warms the air in the inner box. A current of air is es- 
tablished through the inner box by ventilators, both at 
the top and bottom. Specimens which have been double 
stained with indigo should not be exposed to either heat 
or sunlight, as they will fade under these circumstances. 
The fact that the oil of cloves or other volatile oils 
which may be used in its stead shrink many of the more 88 
MICROSCOPICAL TECHNOLOGY. 
delicate tissues, and the difficulty attending the removal 
of large thin sections from one solution to the other, as 
well as the danger of tearing while they are spread upon 
the slide, has led the author to discard the oil of cloves 
Fig. 14. 
as a clearing agent, and to adopt a plan of mounting in 
balsam, which avoids all these dangers and which has the 
advantage that the slides may be finished immediately. 
THE author’s METHOD OF MOUNTING IN BALSAM. 
After one of a number of sections which have been 
stained together has been examined in oil of cloves, 
and has been found to be good, the others may be in- 
ferred to be also good and worth mounting. One of MOUNTING AND FINISHING OF SPECIMENS. 
89 
them is placed in absolute alcohol, and after it has 
remained therein for some time, is floated upon a cover 
glass, which need not be wiped dry after taking it from 
the bottle of alcohol in which the covers are kept, held 
in a pair of forceps whose ends have been bent so as to 
stand at right angles to the shafts, and to close on top of 
each other. (See Fig. 15.) The cover with the section 
on it is then lifted out of the alcohol, when the specimen 
will be found to be evenly spread out, needing but little 
unfolding at the edges, which sometimes fold over; the 
lower surface is to be wiped dry and a drop of the al- 
coholic solution of balsam is placed on the section, which, 
on the cover, is set aside in a place free from dust, to 
clear up and allow the balsam to get dry. After fifteen 
or twenty minutes another drop of balsam should be 
placed upon it, in order to prevent drying of the tissue. 
After twelve hours the balsam has dried sufficiently on 
the cover, so that the specimen can be mounted, in the 
following manner : Take the cover up with a pair of 
forceps and place a drop of crude benzole* on the balsam 
and quickly place the cover, with the balsam down, on a 
clean slide, as near the centre as possible, and taking care 
to avoid air bubbles. Then warm the slide over a spirit 
lamp, place on the turn-table and quickly centre the 
Fig. 15. 
* The refined benzole or benzine, which is frequently sold for 
benzole, is too volatile for our purposes. 90 
MICROSCOPICAL TECHNOLOGY. 
cover so that its edge does not seem to shake when the 
slide is rapidly revolved. Next run a ring of cement 
around the edge, as will be described presently, and then 
press gently upon the cover, to cause the section to lie 
flat, and to press out the surplus of balsam, which, with 
a little management of the pressure, will run into the 
ring of cement. Another ring of cement may then be 
applied, when the slide is ready to be labeled and put 
away. 
The cement for balsam mounting which is most satis- 
factory was devised by Mr. T. W. Starr, of Philadelphia, 
and is prepared as follows :— 
Clear Canada balsam, 370 grains. 
Deodorized benzine, 140 giains. 
Spirits turpentine, 120 grains. 
Gum dammar, 185 grains. 
Mix the balsam and benzine well together in a bottle, 
then add the turpentine and shake until mixed; finally, 
add the gum dammar, in selected pieces, and shake fre- 
quently till dissolved. If necessary, the solution should 
be filtered through absorbent cotton previously moist- 
ened with turpentine. A portion of this is to be placed 
in a small, glass-capped vial, to the cap of which is 
attached a small sable brush, which will come to a point, 
the ordinary camel’s hair brush not being suitable for 
ringing, as it spreads too much. If the solution is too 
thick to flow readily it should be diluted with spirits of 
turpentine until the proper consistency is obtained. This 
fluid is also an excellent mounting medium when the 
object has previously been cleared in oil of cloves or 
turpentine. For ringing, this cement may be colored MOUNTING AND FINISHING OF SPECIMENS. 
91 
by adding to it a few drops of alcoholic solution of ani- 
line, of any shade desired, or it may be mixed with 
white zinc, when the resulting ring will appear as if 
made of porcelain. 
The specimen to be ringed is placed upon the 
turn-table, and if any balsam has soiled the slide or 
the cover it must be removed by scraping with a sharp 
knife and afterward wiping with a soft linen rag wet 
with benzole. Asa matter of course, the balsam should 
be hard, so that the cover will not be displaced by the 
scraping and wiping. If the cover should not be in the 
centre, and a self-centering turn-table is used, the slide is 
to be warmed until the balsam becomes soft, when the 
cover may be centered on the turn-table. Having thus 
prepared the slide, the brush in the cement bottle is re- 
moved and the surplus scraped off, so that it is almost 
dry ; with the left hand the turn-table is spun around 
rapidly and the point of the brush applied to the edge 
of the cover for a moment only, holding the brush 
slanting in the right hand, and that hand resting upon 
the stand of the table. The brush is then moistened a 
little more with the cement and again applied to the 
edge of the cover, without, however, allowing the hair 
of the brush to touch the glass; the small drop at the 
point of the brush only should be in contact with the 
glass and be carried around by the rapid spinning of the 
turn-table. The slide is then set aside so as to allow the 
ring to become thick by evaporation of the benzine and 
turpentine, when the applications of cement may be 
repeated until the desired thickness is obtained. 
If colored or white zinc cement is to be used it should 92 
MICROSCOPICAL TECHNOLOGY. 
not be applied until after the first rings of clear cement 
have become hard, as otherwise the colored cement will 
run in under the cover and be disseminated among 
the mounting medium. If white zinc cement has been 
used, it may be still further improved by running one 
or two fine lines of asphaltum varnish around it, but 
not before the cement has thoroughly hardened. 
The making of a neat ring around the edge of the 
cover is an art which can only be acquired by practice 
and experience, and therefore a few hints in regard to 
the causes of failure will greatly help the beginner. 
If the ring, when finished, shows irregularities both 
at its inner and outer edge, the cement used is too thick 
and should be diluted with turpentine. If the ring is 
too broad—wider than about one-thirty-second of an 
inch, unless intentionally widened—the brush has been 
pressed down too hard upon the glass, which causes it 
to spread, or too much of the cement has been applied 
at once. This is especially the cause when irregularities 
or bulging in the edges of the ring are noticed. 
If the ring is filled with minute air bubbles, the brush 
has been kept too long in contact with the glass in 
making the first ring, or its point has been brought in 
contact with the first ring in making the second appli- 
cation, when only the minute drop should have touched 
the glass; or, finally, the solution may be too thick. 
MOUNTING IN GLYCERINE. 
When a preparation is to be mounted in glycerine, it 
should, after having been stained, be placed in dilute 
glycerine for twenty-four hours, and then for the same 
length of time in strong glycerine (Bower’s), in order to 93 
MOUNTING AND FINISHING OF SPECIMENS. 
make it transparent. The section is then carefully 
spread upon the slide; a clean cover, which has been 
wiped dry, is placed upon it and pressed down, to re- 
move the excess of glycerine from under the cover, and 
a small spring-clip is applied, so as to hold the cover in 
position during the subsequent manipulation of washing. 
The excess of glycerine must now be removed as care- 
fully as possible, by washing it off with a stream of 
water, either from a syringe or from a tap, taking care 
not to displace the cover in doing so. The slide is then 
stood on edge to dry, the spring-clip still holding the 
cover, and when all the water has evaporated it is ready 
for ringing. In order to do this the spring-clip must 
be removed, the slide placed upon the turn-table, the 
cover centered and a ring of some water-proof cement 
applied, in the manner described above. 
The best cements for this purpose are, first, the so- 
called Bell’s cement, which may be obtained from any 
dealer in microscopical supplies, and the composition of 
which is a secret with the makers; and second, the 
author’s gelatine cement, which is prepared as follows:— 
Take of— 
Coxe’s gelatine, 2 drachms. 
Gum ammoniac, 10 grains. 
Acetic acid, No. 8, 1 ounce. 
Dissolve the gum ammoniac in the acetic acid and filter 
through absorbent cotton ; then warm the acid and gum 
solution by placing the vessel containing it in a water 
bath and add the gelatine, stirring until it is dissolved, 
when the resulting solution should be filtered or strained 
through muslin. After a ring of this cement has been 94 
MICROSCOPICAL TECHNOLOGY. 
made around the edge of the cover, and has become set, 
it should be painted over with a solution of bichromate 
of potash in water (ten grains to the ounce) and exposed 
to either sunlight or ordinary daylight. The action of 
the light is to make the chromate of gelatine which has 
been formed insoluble and thus perfectly waterproof. 
After this gelatine cement ring has become hard, it 
should be covered with a ring of white zinc cement, 
when it will be found that none of the glycerine will 
leak out, even after the specimen has been kept for 
years. 
If thicker pieces than thin sections, such as pieces of 
the mucous membrane of the intestine or bladder of ani- 
mals, are to be mounted in glycerine or other watery 
medium, a cell must be employed. This consists of a 
ring made of either glass, rubber, metal or cement, and 
which is high enough to prevent the cover-glass from 
pressing upon the specimen when mounted. In order 
to do so, the ring, if it be of glass, rubber or metal, is 
first cemented upon the slide with marine glue or the 
gelatine cement, and is accurately centered with the 
turn-table. If the cell is to be made of cement a ring 
of the required diameter (which must be a little smaller 
than the diameter of the cover-glass) is spun upon a 
slide, in the same manner as was described for applying 
the ring to the edge of the cover in finishing slides, and 
is built up to the required height by repeated applica- 
tions of the brush. It should then be set aside to dry 
and harden. Any of the cements may be used for this 
purpose, provided they will stick well to the glass. 
Just before mounting the top of the ring forming the MOUNTING AND FINISHING OF SPECIMENS. 
95 
cell must be moistened with gelatine cement; the 
specimen, which has been made transparent by soaking 
in glycerine, is then placed in the centre of the ring, 
enough glycerine is added to fill the cell and the cover 
is applied. If an air bubble is left under the cover the 
latter must be lifted up and more glycerine must be 
added ; if, on the other hand, too much liquid has been 
used, the surplus must be washed off, as described above. 
A ring of gelatine or Bell’s cement is next spun around 
the edge of the cover, in order to seal up the cell, and it 
is then finished with white zinc cement. 
An excellent substitute for glycerine is Farrant’s so- 
lution, which combines all the advantages of glycerine 
and some of those of balsam, inasmuch as it has nearly the 
same index of refraction as glycerine, and becomes hard 
like balsam, doing away with the necessity of a water- 
proof cement. The formula generally given in the 
text-books for this solution is not correct, and the author 
has found that the following formula is more satisfac- 
tory :— 
Picked gum arabic, 4 drachms 
Camphor water 4 fl. drachms 
Glycerine, 2 fl. drachms. 
Dissolve and strain through muslin. 
Specimens to be mounted in this medium must first 
be made transparent by soaking in strong glycerine, and 
may then be mounted as though the solution were a 
resinous mounting medium. Great care should be taken 
to exclude air bubbles, as they cannot afterward be 
gotten rid of. This medium is especially adapted for 
delicate animal membranes and soft vegetable tissues. 96 
MICROSCOPICAL TECHNOLOGY. 
Some specimens, especially vegetable, such as seeds, 
pollen grains, sections of wood, etc., may often with ad- 
vantage, be mounted dry, i. e., without much previous 
preparation and without any mounting medium, but they 
must then be examined as opaque objects, and must be 
viewed by reflected light. 
If an object is to be thus mounted, a disk is painted 
with asphaltum varnish in the centre of the slide, which 
is spun around upon the turn-table while applying the 
brush with varnish. A disk of dead black paper may 
be pasted upon the slide, instead of the disk of varnish, 
to serve as a dark background. A cell ring is then 
applied around the edge of the disk, and the object is 
fastened in the centre of the cell by means of mucilage 
or glue. This done, the cover is placed upon the ring 
and cemented down as described above. PREPARATION OF VEGETABLE TISSUES. 
97 
CHAPTER VII. 
THE PREPARATION OF VEGETABLE TISSUES AND 
INSECTS FOR MICROSCOPICAL EXAMINATION. 
This volume, small as it is, would not be complete 
without a short description of the methods employed by 
the most successful workers, for the preparation of vege- 
table and insect tissues, especially so, as they are not only 
pleasing to the eye, but also very instructive. 
Like preparations of animal tissues, vegetable specimens 
must be stained in order to bring out the different struc- 
tures, and should for this purpose be soaked for some 
time in alcohol; in fact, it is best to place the plants or 
parts of plants, as they are collected, into a wide-mouthed 
bottle, filled with alcohol. In this way the chlorophyll 
is extracted from thin tissues, without injuring the cell 
contents. For the sake of clearness, we will suppose that 
the student has collected a variety of specimens of plant 
life, such as fern leaves, flower stems, ovaries of flowers, 
and so forth, and that they have been in alcohol for sev- 
eral days. He must now sort them for further treat- 
ment ; the stems, ovaries, roots, etc., should be placed 
in fresh alcohol prior to cutting sections from them ; the 
delicate leaves of flowers are sufficiently decolorized to be 
ready for staining, while the thicker leaves of ferns must 
be further bleached in Labarraque’s solution of chlori- 
nated soda. This reagent removes not only the coloring 
matter, but also the cell contents, which is a great draw- 
back, but without its use a satisfactory preparation of 98 
MICROSCOPICAL TECHNOLOGY. 
thicker leaves cannot be made, and we must, therefore, 
be satisfied with the results thus obtained. Great care 
should be exercised in bleaching, and the specimen must 
be left in the solution only long enough to remove the 
color, as otherwise the tissue itself will be destroyed. 
After the leaf has been bleached, all traces of the chlo- 
rinated soda must be removed by washing in several 
changes of water, when it will be ready for staining. 
Very thick leaves, such as those of the ivy, rubber plant, 
olive, etc., cannot be made transparent, even with the 
use of Labarraque’s solution, and the epidermal layers 
must be separated from the thick pulp between them. 
This may be readily done by cutting, with a pair of 
scissors, a piece from the edge of the leaf, about one-fourth 
of an inch deep, and one-half of an inch wide. This 
piece is then placed into a test-tube containing a few 
drops of a solution of equal parts of nitric acid (c. p.) 
and water, and the tube is held over a spirit flame until 
the solution comes to a boil. It must then be quickly 
poured into cold water, when it will be found that the 
epidermal layers can readily be separated from the pulp, 
and can be opened like the leaves of a book by the aid 
of two pairs of delicate forceps. 
Stems, roots, ovaries, etc., must be imbedded in a mi- 
crotome and thin sections must be cut from them in 
the same manner as from animal tissues. 
STAINING. 
Having thus prepared the specimens they are ready 
for staining, in the following manner: Immerse the 
bleached and thoroughly washed leaves or the sections 
in a saturated solution of alum in water, for from twelve PREPARATION OF VEGETABLE TISSUES. 
99 
to twenty-four hours; then place them in a weak solu- 
tion of the hsematoxylon staining fluid, which has been 
mentioned in the chapter on staining of animal tissues, 
and allow them to remain therein for from eighteen to 
twenty-four hours, until they exhibit to the naked eye a 
uniform purple color. It is impossible to give any 
definite directions in regard to the strength of the solu- 
tion to be used, or the length of time the specimens are 
to remain in it, because no two leaves or sections take 
the color with the same rapidity or facility, and experi- 
ence alone, gained by repeated trials, can be depended 
upon. A preparation successfully stained in this way 
should, under the microscope, show the nuclei, as well 
as the cell-walls, deeply and uniformly stained of a 
purplish-blue color. 
Double Staining. My friend, Dr. J. G. Hunt, of 
Philadelphia, devised, several years ago, a method of 
staining vegetable preparations with two or more colors, 
which gave such uniformly excellent results that it has 
now been universally adopted as far superior to single 
staining. This method, for the detailed description of 
which I am indebted to my friend, Mr. E. B. Crane, of 
New York, is as follows: After the specimens have 
been thoroughly washed in water they are immersed 
in a very dilute watery solution of methyl aniline green 
(brand j.j.j.j.*). 
Aniline dyes are very powerful, and if allowed to act 
too rapidly will stain objects unevenly, besides staining 
* Any aniline dye soluble in water will probably act in the same 
way as the brand recommended, but aniline colors insoluble in 
water should under no circumstances be used for this purpose. 100 
MICROSCOPICAL, TECHNOLOGY. 
parts of the tissue which it is not intended that 
this color should touch. If allowed to act slowly (say 
for at least twenty-four hours in a weak solution), the 
color will pass into the secondary deposits and formative 
material, leaving the nuclei and cell-walls untouched. 
Aniline seems to have a great affinity for new structure; 
hence, in ferns, for instance, the spores absorb the color 
with great rapidity. After the specimens have taken 
up sufficient aniline, that is, when they appear of a uni- 
form color, they must be immersed in a strong solution 
of alum in water and remain there for twenty-four hours 
or more. This is done to remove any of the aniline 
color which may have settled in the cell-walls and to 
prepare the tissue for the subsequent staining with 
hsematoxvlon, in the manner described above. 
The specimens, after having been stained, may be 
mounted either in balsam, or in glycerine, or Farrant’s 
solution, according to the plan described for animal 
tissues. 
Insects. Insects, whether they be large or small, hard 
or soft, may be mounted as microscopical preparations, 
in the following manner: After the insect has been 
caught, place it, with as little handling as possible, under 
a small vessel with a few drops of ether, in order to kill 
it. When dead, wet it with alcohol and place it in 
liquor potassa of the strength of one ounce (Troy) fused 
caustic potassa to one pint of water. Let it soak in this 
solution until the skin or external part is soft and the 
internal substance in such a condition that, by slight 
pressure, the insect can be evacuated by the natural or, 
if necessary, by an artificial opening. This is best done PREPARATION OF INSECTS. 
101 
under water, and the best vessel in which to do it is a 
white plate. After this is accomplished, the insect is to 
be cleaned under water, by holding it down with a 
camel’s hair brush in one hand, and by brushing every 
part of it, on both sides, with the other hand ; then 
float it on a glass slide and arrange each part in a 
natural position. This glass slide is then to be covered 
with another one of the same size, and the two are to 
be gently pressed together, using only sufficient force to 
make the insect as thin as possible without crushing or 
destroying it. The two glass slides with the insect 
between them should next be tied together with fine 
brass wire, and placed for from twenty-four to thirty- 
six hours in clean water. This will give the object a 
position which is not easily changed, and it is therefore 
important that the insect be placed in the position it is 
to have when mounted, before placing it in the water. 
After having remained in water the proper length of 
time the insect is to be removed from between the two 
slides, under water, and is again to be brushed with a 
soft camel’s hair brush, after which it is allowed to float 
in the water for several hours. 
The next step is to again confine the object between 
two slides, and to place it into a vessel containing abso- 
lute alcohol, in which it should remain about twenty- 
four hours. When the insect has been thoroughly dehy- 
drated by the alcohol, it is released from between the two 
slides and floated on a cover-glass, held in the mounting 
forceps, and is mounted in the alcoholic solution of 
balsam, in the manner already described. 
Insects may also be mounted in the dammar medium, 102 
MICROSCOPICAL TECHNOLOGY. 
the formula of which was given under the head of ring- 
ing ; but they must then, after having been dehydrated 
in strong alcohol, be cleared in oil of cloves or turpen- 
tine before mounting. 
Considerable patience is necessary in carrying out the 
different steps of the process, and the utmost cleanliness 
is required in order to produce satisfactory preparations; 
but the results obtained, if the process is faithfully car- 
ried out in all its details, amply repay for the time, 
patience and labor spent in producing the specimens. 
I am greatly indebted to Mr. Charles Zentmayer and 
to Mr. T. W. Starr for many of the points given above, 
in the description of the process for mounting insects. 103 
PHOTO-MICROGRAPHY. 
CHAPTER VIII. 
PHOTO-MICROGRAPHY. 
All workers in microscopy, doubtless, appreciate the 
necessity of correctly recording, not only in writing, but 
also by means of pictures or drawings, many of the ap- 
pearances seen in the field of the microscope. We can 
do this by drawing an outline of the objects observed, 
by the aid of the camera lucida ; but not only does this 
require some practice, but also a considerable amount of 
time, and even then the resulting picture will not be a 
correct representation of the field of the microscope, 
because it will always be tinged more or less by the 
imagination of the draughtsman, and will be more or 
less diagramatical in consequence. 
With photography, on the other hand, an exact repro- 
duction of the image thrown upon the screen can be 
obtained, and in much less time than it takes to make 
even a comparatively simple drawing with the camera 
lucida. It is the object of this chapter to give an idea 
of the means employed to obtain a photographic picture 
of a microscopic object—means which are in the hands 
of every microscopist, and which do not require a great 
outlay of money. 
A room with a southern exposure, which can be 
darkened; a mirror, movable in all directions, outside 
of the window; an achromatic combination of lenses of 
from eight to ten inches focal length ; a microscope 
which can be tilted so as to be horizontal, and a stand 104 
MICROSCOPICAL TECHNOLOGY. 
to hold the screen and sensitive plate, are all the appa- 
ratus absolutely necessary beside the chemicals used in 
ordinary photography. 
These different pieces are disposed of as follows (Fig. 
16): The mirror (a), which should be eight or ten inches 
long by about four inches wide, is attached to a board 
which fits into an opening in the dark shutter of the 
southern window, and is to be moved by rods, from the 
inside. Instead of this mirror, or in conjunction with 
it, a heliostat is of great advantage to throw the light of 
the sun constantly in one direction, for, if once adjqsted, 
it need not be disturbed, and thus a great deal of time 
is saved. Until recently such an instrument was too 
costly for the use of students, but of late Mr. Kuebel, 
of Washington, D. C., has put a heliostat in the market 
which works very satisfactorily and which is sufficiently 
low in price to be within the reach of many who desire 
to work in photo-micrography. The board in the shut- 
ter has in its centre a circular opening containing an 
achromatic combination of lenses (6), such as the back 
combination of a one-fourth portrait photographic lens. 
Fig. 16. PHOTO-MICROGRAPHY. 
105 
The microscope is secured on the window sill, in a 
horizontal position, so that the axis of the tube is in a 
line with the axis of the achromatic combination, and 
at such a distance from it that the burning focus is 
about half, an inch from the back combination of the 
sub-stage condenser (d). The eye piece is then removed 
from the microscope, and the tube lined with black 
velvet, to prevent internal reflection, as far as possible, 
and the whole apparatus is covered with dark cloth, to 
prevent stray rays of light entering the darkened room. 
This done, the sun’s rays are reflected from the mirror 
outside the window, through the achromatic combination, 
which acts as a concentrator and throws a powerful light 
through the condenser, through the object on the stage (s), 
and thus a brightly illuminated image is formed by the 
objective (o) on the screen, which latter, when the nega- 
tive is to be taken, is replaced by the sensitive plate. 
This image, when thus formed, must be focused with 
the greatest care and accuracy, in order to obtain a sharp 
negative; and as the screen must be at some distance 
from the microscope in order to obtain the necessary 
magnification of the object, it is necessary to have some 
contrivance for turning the fine adjustment at a distance. 
For this purpose it will be found that a small pulley, 
placed alongside of the microscope, having an endless 
band running over it and the milled head of the fine 
adjustment, answers the purpose very well, when the 
axis of the pulley is connected by means of a universal 
joint to a fishing-rod, which by its sections can be made 
longer or shorter, thus bringing its end close to the 
screen. 106 
MICROSCOPICAL TECHNOLOGY. 
The tube of the microscope, even when all internal 
reflection has been obliterated, still remains a drawback, 
inasmuch as it reduces the size of the image, or rather 
the disk of light, the more, the longer it is. There are, 
however, some stands made in which the tube can be 
entirely removed, such as the old Ross stand, and they 
are therefore very desirable for photo-micrographic 
purposes. 
Any good objective of wide angular aperture and 
good definition can be employed for photography, pro- 
vided monochromatic light is used in making the nega- 
tive. When such is the case the visual and chemical 
foci fall in the same plane and a special correction of the 
objective for photography becomes unnecessary. 
Such a light is obtained by passing the rays of the 
sun through a cell containing a strong solution of am- 
monio-sulphate of copper (c) before they enter the sub- 
stage condenser. I have found some difficulty in making 
the cell containing this solution, as the copper salt will 
dissolve almost any cement, and if exposed to the action 
of the air, very rapidly becomes decomposed, and the 
solution is thereby rendered useless for the purpose. I 
have used with satisfaction a cell made of a brass ring, 
lined on its inner side with lead or tin, having a thread 
cut on its outside, to which flanged rings are secured. 
Upon the edges of the inner ring a ring of rubber pack- 
ing is applied, and upon it a disk of plate glass is laid, 
which is tightly pressed upon the rubber by the flanged 
ring. Thus a cell is obtained very similar to the round, 
flat spirit levels, and which will hold the ammonia 
sulphate of copper solution for months without change. 107 
PHOTOMICROGRAPHY. 
In filling the cell care should be taken to leave room 
for a small air bubble, for if the' cell is completely filled 
the heat of the sun’s rays will expand the solution 
sufficiently to cause leakage. 
This solution, besides giving monochromatic light, at 
the same time filters out almost all the heat rays from 
the light, so much so that an immersion lens may be 
used for any length of time without the drop of water 
evaporating. 
At the present time, when dry plate photography has 
been developed to such an extent that it has superseded, 
in a great measure, the wet process, it has been thought 
that it would be the most simple, economical and satis- 
factory for photo-micrography; but after repeated trials 
by myself, as well as many others working in the same 
direction, it has been found that it is not only more ex- 
pensive, but also takes more time, in the long run. The 
reason of this is that it is impossible to judge, with any 
degree of certainty, as to the actinic power of the light 
forming the image on the screen by merely looking at 
it, and that a trial plate only will give an idea of the 
length of exposure necessary for a given day, time of day, 
objective, and subject, to be photographed. It is true 
we can expose a dry plate for trial, but then we must 
develop it immediately, and the time of developing a 
dry plate is about three times that of developing a wet 
one, and a dry plate is also about three times as costly 
as a wet one. Therefore the old wet collodion process is 
the best. 
The collodion to be used should be an old one, and 
contain some free iodine. I have found that a mixture 108 
MICROSCOPICAL TECHNOLOGY. 
of “Anthony’s red labeled” and “McCollin’s delicate 
half-tone” collodions—both commercial articles—some 
five or six months old, gives very satisfactory results. 
The nitrate bath should contain forty grains of nitrate 
of silver to the ounce of water, and should be slightly 
acidulated with nitric acid. The developer should be a 
weak one: twelve to fifteen grains of the double salt 
ammonio-sulphate of iron to the ounce of water, con- 
taining a few drops of a solution of gelatine and acetic 
acid as a restrainer. 
After the negative has been fixed in the usual way, 
with hyposulphite of soda or cyanide of potassium, it is 
almost always necessary to- intensify it, which is easily 
done by flowing the plate while wet with a watery solu- 
tion of iodine until the film becomes white; then it 
is to be washed under the tap and flowed with a solution 
of sulphide of ammonium, which imparts to the negative 
a dark brown color, and thus strengthens its printing 
quality. 
The object to be photographed should be as thin as 
possible, because the lens will depict only one plane of 
it, and it should present as much contrast and differenti- 
ation of its elements as possible; this is especially the 
case in animal tissues, and when high powers are used, 
the focus should be taken with the greatest care for one 
particular point to be brought out; a general focus, not 
particularly sharp in any one point, will not give a 
satisfactory negative. 
The screen upon which the image is focused should 
De of plate glass, having an extremely fine ground sur- 
face on one side—the side next to the object. Such a PHOTO-MICROGRAPHY. 
109 
surface can easily be prepared by flowing the glass plate 
with a good negative varnish, and when this is set but 
not yet dry, lightly breathing on it, when an extremely 
fine and even frosting of the surface will show itself, 
sufficient to arrest and reflect the rays of light forming 
the image. 
In photo-micrography, as well as in ordinary micro- 
scopy, proper illumination of the object is of the greatest 
importance, and frequently a poor objective will show 
a better definition in the hands of a skilled manipulator 
than the best objective can when the light is not 
properly managed. In this one point lies the difficulty 
of photo-micrography, and it is the stumbling block over 
which so many fall who undertake to photograph micro- 
scopic objects. 
As a general rale the best light is obtained when the 
back lens of the sub-stage condenser is about half an 
inch beyond the burning focus of the larger condenser 
in the shutter, that is about eight and a half inches from 
this condenser, and when the light is absolutely central. 
But this distance cannot be strictly adhered to, inasmuch 
as different objectives require different illumination. In 
practice, I find that in order to obtain the proper distance 
of the condenser for a particular objective, it is best to 
put a blood-slide, upon which the corpuscles are in one 
layer only, on the stage, and project the image on the 
screen, moving the condenser backward and forward 
until, when sharply focused, no concentric rings are seen 
in the disks. The object to be photographed can then be 
substituted for the blood-slide, and the light will be 
found to be all that is desired. 110 
MICROSCOPICAL TECHNOLOGY. 
When large objects, such as whole insects, are to be 
photographed under low powers, of small angular aper- 
ture, as, for instance, with a three, four or five inch 
Zentmayer objective, the mode of illumination must be 
somewhat altered, so as to obtain an evenly illuminated 
field on the screen. Under such circumstances it is 
necessary to remove the sub-stage condenser from the 
microscope and substitute for it a plano-convex lens of 
some three to four inches focus, placed close to the 
object. The instrument must then be moved close to the 
large concentrating lens in the shutter, when it will be 
found that objects, even as large as three-fourths of an 
inch in diameter, are evenly illuminated. APPENDIX. 
A short, concise and at the same time comprehensive 
classification of the more common tumors and neoplasms, 
in tabular form, such as is given as an appendix to the 
present volume, will, no doubt, be welcome to the stu- 
dent of pathological histology. Great care has been 
exercised in its compilation, to introduce all the accepted 
modern views on the subject, so as to bring it up to the 
standard of the present time. 
The names of tumors and neoplasms heading the 
different columns are those most commonly used in this 
country; while under the head of synonyms will be 
found the terms occasionally employed by continental 
authors. 
The table is divided into four sections : 1, the macro- 
scopic appearances ; 2, the microscopic appearances ; 
3, the clinical features; and 4, a definition; thus giving, 
at a glance, a clear picture of the life historv of the 
different neoplasms. 
The general arrangement is such that the table begins 
with tumors which are developed in preexisting, fully 
formed tissues, anti consist mainly in an exaggeration in 
size, or in a misplacement of the elements naturally 
Ill 112 
APPENDIX. 
present in the normal tissues, or in other words, homo- 
logous tumors—these are essentially non-malignant— 
and it ends with those tumors which are formed 
within the fully developed tissues, but consist of more 
or less developed embryonic elements, which may either 
belong to the connective tissue series (sarcomata), or to 
the epithelial series (carcinomata). These are essentially 
malignant. Synonyms. 
MACROSCOPIC 
APPEARANCE. 
Size, Color and Juice. 
Consistence. 
Shape and Arrangement of Cells. 
Stroma and Vessels. 
Degenerations. 
Age of Patient. 
Glandular Involvement. 
Infiltration of Surrounding Parts 
Pain and Rapidity of Growth. 
Definition. 
MICROSCOPIC 
APPEARANCE. 
CLINICAL 
CHARACTERISTICS. CYSTS. 
MYXOMA. 
Cystic tumor, cystoma, or encysted tu- 
mor. 
Mucous, gelatinous or colloid tumor; 
collonema, gelatinous sarcoma and 
net-celled sarcoma. 
Size varies from that of a small seed to 
that of a man’s head and larger; vari- 
able in color; juice variable ; depends 
upon contents. 
Usually small, but may be come very 1 arge; 
if projecting from surfaces may become 
pedunculated; translucent; greenish, 
yellowish or yellowish-gray in color ; 
smooth or nodulated in outline ; juice 
clear, viscid, filamentous. 
Fluctuating; soft; elastic. 
Soft, trembling, gelatiniform. 
A cyst is made up of a wall and its con- 
tents ; the structure varies according to 
its nature, whether it be a new forma- 
tion or part of an old tissue; in the 
latter case it is usually lined with epi- 
thelium ; the contents vary and are 
either the natural secretions altered or 
hemorrhagic and serous effusions. 
Angular, stellate and fusiform, with 
anastomosing prolongations ; in young 
tumors oval and round isolated cells, 
separated by the intercellular sub- 
stance. 
Very abundant; homogeneous, viscid; 
yielding mucin, or may be fibrous ; ves- 
sels are not numerous, but with well 
developed coats and are easily iso- 
lated. 
The wall may ossify or undergo fatty, 
mucoid, calcareous degeneration, and 
may be the seat of secondary cysts, 
hemorrhagic or otherwise. 
May contain hemorrhagic depots and 
may undergo fibrous or fatty degene- 
ration, and more rarely cartilaginous. 
All ages. 
Adult age. 
None. 
None. 
Not usual. 
Tendency to infiltrate. 
Pain depends upon seat and size of cyst; 
growth is slow. 
Pain usually absent; rapid in growth. 
A greenish-gray, smooth or nodulated 
mass, of a soft, trembling consistence; 
usually not larger than an apple ; ex- 
hibiting under the microscope a highly 
refractive homogeneous or fibrous 
stroma, containing stellate and spindle, 
anastomosing or round and oval cells ; 
the mass being divided into lobules 
by small bands of connective tissue 
surrounding the blood vessels. 
A more or less spherical, smooth or lobu- 
lated, fluctuating, soft, elastic growth, 
of indefinite size, being composed of a 
wall and contents ; the former having 
the character of the tissue from which 
it sprung, and is usually lined with 
epithelium; the latter is variable in 
character, usually being the secretions 
of a gland somewhat altered, or hemor- 
rhagic or serous effusions. 
115 LIPOMA. 
FIBROMA. 
Fatty tumor. 
Fibrous tumor; connective tissue tumor; 
desmoid, and issoma. 
Usually large; yellow, or pinkish-yellow 
in color. No juice. 
Size varying from that of a small seed to 
that of a man’s head; smooth, round, 
or lobulated; glistening white, or 
pinkish, juice not obtainable. 
Soft and doughy, with a lobulated sur- 
face. 
Hard and elastic, creaking under the 
knife. 
Large round cells containing liquid, and 
sometimes crystallized fat, with the 
nucleus pushed to the margin; ar- 
ranged in clusters. 
Cells very few in number, spindle- 
shaped, or stellate in shape, with small, 
indistinct nucleus. 
Bands of fibrous tissue separating the 
cell clusters into lobules. Numerous 
fully formed vessels running in the 
fibrous bands between the lobules. 
Stroma composed of white fibrous tis- 
sue. The fibres arranged in bundles, 
which run in different directions 
through the growth. The vessels are 
not usually numerous, but well devel- 
oped, and closely adhere to the fibrous 
tissue. 
The fibrous septa may become exagge- 
rated, or ossified, or calcified; the 
cells may undergo mucoid degenera- 
tion. 
May undergo mucoid, fatty, caseous, 
calcareous and melanotic degenera- 
tion. May ossify ; may become caver- 
nous, the cavities being filled with 
blood and in communication with the 
vessels; if such is the case the new 
growth is termed an erectile tumor. 
All ages. 
All ages. 
Never occurs. 
Does not occur. 
Always encapsulated. 
Always encapsulated. 
Pain depends upon position and size of 
growth. Growth usually slow. 
Pain depends upon position of tumor. 
Growth usually slow. 
A large, soft, elastic, yellow or pinkish 
mass, lobulated on its surface, pre- 
senting under the microscope large 
round cells filled with liquid, and 
sometimes crystallized fat, separated 
into larger or smaller clusters, or lo- 
bules, by bands of fibrous tissue. 
A round or lobulated, glistening white, 
or pinkish, hard mass, creaking un- 
der the knife, and exhibiting under 
the microscope bundles of white fib- 
rous tissue running in different direc- 
tions, with here and there spindle- 
shaped,or stellate cells, having small 
and indistinct nuclei. ANGIOMA. 
LYMPHANGIOMA. 
Vascular tumor ; cavernous tumor; erec- 
tile tumor; naevus ; arterial vascular 
tumor. 
Lymphatic angioma. 
Usually small; red, violet, or bluish 
purple ; no juice except blood. 
Small and pale ; yields a milky juice. 
Soft and elastic; erectile. 
Soft, fluctuating, depressible and ad- 
herent to the skin. 
These growths consist of fully formed 
capillary blood vessels held together 
by a small amount of connective tissue, 
or they consist of a larger amount of 
fibrous tissue filled with caverns lined 
with endothelium, communicating 
with each other and through which 
the blood circulates freely; or new 
formation of arteries may predomi- 
nate. 
This growth is made up of a network of 
dilated lymphatics, held together by a 
small amount of connective tissue; or 
it is composed of caverns lined with 
endothelium, communicating with 
each other and containing lymph. 
Adult life. 
Usually congenital. 
None. 
None. 
Always circumscribed. 
None. 
Pain depends upon seat of growth; of 
slow growth. 
Pain depends upon seat of growth ; du- 
ration of development uncertain. 
A small, soft, but elastic and sometimes 
erectile mass, of a red, violet or pur- 
ple color; exhibiting under the mi- 
croscope a network of vessels held 
together by a small amount of connec- 
tive tissue, or of a larger amount of 
connective tissue containing caverns 
lined with endothelium and filled with 
blood. 
A small, pale, soft, fluctuating, depres- 
sible mass; exhibiting under the 
microscope a network of dilated lym- 
phatics held together by a small 
amount of connective tissue, which may 
surround a system of communicating 
caverns lined with endothelium and 
containing lymph. 
117 MYOMA. 
NEUROMA. 
Muscular tumor; variety, (1) leiomy- 
oma or fibro-myoma ; (2) rhabdo-my- 
oma or myoma strio-cellulare, or true 
myoma. 
Nervous tumor. 
Usually small; of a pinkish or red color; 
no juice. 
Small; white or yellowish; no juice. 
Firm and elastic. 
Soft, friable, or partly solid. 
Spindle-shaped cells with long, rod-like 
nuclei; unstriated (leio-myoma) or stri- 
ated (rhabdo-myoma) ; lying parallel 
to each other and forming bands. 
Neuromata consist either of ordinary 
medullated nerve fibres or of ganglio- 
nic nerve tissue, and are usually found 
as small, round tumors on the peri- 
pheral nerves, or at the extremities of 
cut nerves in amputation stumps. 
Fibrous connective tissue very abundant; 
vessels fully developed; usually to be 
found in the connective tissue. 
May calcify; undergo fatty or mucoid May undergo fibrous, myxomatous, 
degeneration; contain hemorrhagic- glious, and telangiectatic degenera- 
effusions or cysts. tion. 
Adult life. Sometimes congenital.. 
All ages. 
None. 
Absent. 
Usually circumscribed; but may form 
irregular masses in the mother tissue. 
Absent, 
Pain depends upon seat of tumor; of 
slow growth. 
Pain usually very severe; rapidity of 
growth uncertain. 
A small, pinkisli or reddish, firm and 
elastic mass, sometimes pedunculated ; 
exhibiting under the microscope large 
striped or unstriped spindle cells, with 
large rod-like nuclei; arranged paral- 
lel to each other, forming bands ; situ- 
ated in a fibrillated connective tissue 
stroma. 
A small, white, round mass, soft and 
friable ; exhibiting under the micro- 
scope the normal appearances of ordi- 
nary medullated nerve fibres, or of 
ganglionic nerve tissue. 
118 Cartilaginous tumor ; enchondroma. 
CHONDROMA. 
Bony tumor ; exostosis and endostosis. 
OSTEOMA. 
Usually small, but may attain a large 
size ; pearly white and glistening ; no 
juice. 
Usually small; pinkish or yellowish red 
in color ; no juice. 
Hard and elastic ; nodular on the sur- 
face. 
Hard, 
Round, oval, lenticular or stellate cells, 
with a more or less distinct capsule ; 
singly or in groups. 
The same as in normal bone. 
Hyaline, fibrous, reticulated or mucoid ; 
bands of fibrous tissue separating the 
growth into lobules ; vessels are to be 
found only in interlobular fibrous tis- 
sue. 
As in normal bone tissue ; eburnated, 
compact or cancellous ; vessels are the 
same as in normal bone. 
May undergo myxomatous, fatty, cal- 
careous and ossific degeneration. 
None. 
Early life. 
Early life. 
Yery rare ; metastasis not unfrequent. 
Absent. 
Usually encapsulated. 
Always circumscribed. 
Pain depends upon position and size of 
growth ; rapidity of growth is slow at 
first; later rapid. 
Pain depends upon seat of tumor; of 
slow development. 
A hard, elastic, nodular mass, shiny, 
pearly white in color; presenting un- 
der the microscope large, oval, round, 
lenticular, or stellate cells, surrounded 
by a more or less distinct capsule, held 
singly or in groups in a hyaline, fibrous, 
or mucoid stroma, which is divided 
into lobules by bands of fibrous tis- 
sue. 
A hard, pinkish or yellowish-red mass ; 
exhibiting under the microscope the 
same structural elements as are seen 
in normal osseous tissue. 
119 LYMPHAOMA. 
ADENOMA. 
Lymphatic gland-like, round-celled sar- 
coma. Lymphadenoma. 
Glandular tumor. 
Varying in size from a millet seed to 
that of an adult head; grayish, or yel- 
low-white in color. Juice abundant, 
clear, containing many granular cor- 
puscles. 
Pink, or yellowish-red in color; usually 
in small nodules; juice clear and 
scanty. 
Soft. 
Soft and elastic. 
Small granular corpuscles in the re- 
ticulated meshes of the stroma. 
This tumor being an abnormal develop- 
ment of glandular tissue, is formed by 
the glandular tubules lined with epi- 
thelium, their lumen, however, usually 
obstructed, and not communicating 
with the excretory duct of the gland. 
The vessels which are not numerous 
are contained in the intra-tubular con- 
nective tissue. 
Network of stout fibrils, with more or 
less distinct nuclei at some of the 
angles of the meshes ; vessels numer- 
ous, wide, with thin walls. 
May undergo fatty, caseous, mucoid, 
calcareous, melanotic degeneration, 
and may contain hemorrhagic depots. 
May undergo fatty, caseous, myxomat- 
ous, or cystoid degeneration. 
Common in young, vigorous subjects. 
Youth and adult age. 
Very extensive from the first; metas- 
tasis frequent. 
Secondary glandular involvement in 
later stages. 
Encapsulated. 
Usually encapsulated. 
Pain caused by pressure of tumor upon 
neighboring nerves only; duration of 
growth uncertain, sometimes rapid. 
Pain not severe ; growth slow. 
A grayish, or yellow-white, soft mass, 
smooth, or nodulated, varying in size 
from that of a millet seed to that of an 
adult head, and yielding an abundant 
juice, rieh in cellular elements. On 
microscopic examination it presents 
small, round, granular corpuscles, 
contained in the meshes of a delicate 
reticulated, fibrillated stroma, which 
shows more or less distinct nuclei at 
the angles of some of its meshes. 
A soft, elastic, pinkish mass, exhibiting 
under the microscope abnormal de- 
velopment of glandular tissue, the 
ducts of which are, however, not con- 
municating with the excretory duct of 
the gland, and are usually obstructed 
by cell debris and mucoid material. 
120 PAPILLOMA. 
SYPHILOMA. 
Warty growth ; condyloma ; cauliflower 
excrescence; villous tumor. 
Syphilitic tumor ; gummy tumor. 
Varying from the size of a pea to that of 
a walnut; pinkish or whitish ; no juice 
except blood. 
Varying in size from that of a hemp seed 
to that of a small orage; yellowish- 
white, or pinkish in color; globular, 
smooth, more or less circumscribed ; 
no juice. 
Hard, often horny ; or soft, according to 
situation. 
Moderately firm and elastic. 
Small, round, granular cells, massed and 
compressed together at the circum- 
ference of the nodule ; depot of cell 
debris in the centre. 
The new growth, consisting of an undue 
development of the normal papillae of 
the skin or mucous membrane, exhib- 
its all the features of the normal struc- 
ture, but is frequently much more 
vascular. 
Stroma consists of incompletely fibrilla- 
ted tissue; vessels few, but well de- 
veloped on the circumference ; become 
occluded toward the centre and disap- 
pear. 
Ulceration or hemorrhage. 
Usually undergoes caseous or fatty de- 
generation, but may suppurate or form 
cicatricial tissue. 
All ages. 
All ages. 
Absent. 
Usual in later stages of disease. 
Never infiltrating. 
Surrounding parts not infiltrated. 
Pain usually absent; rapidity of growth 
variable. 
Pain depends upon location ; usually ab- 
sent ; of slow growth. 
A small, pinkish or whitish mass, of ir- 
regular outline, situated on the skin 
or mucous membrane ; exhibiting un- 
der the microscope the normal struc- 
ture of skin or mucous membrane. 
The growths are usually highly vascu- 
lar, and are apt to ulcerate. 
A globular, smooth, elastic, pinkish or 
yellowish-white nodule, varying in 
size from that of a hemp seed to that 
of a small orange ; presenting under 
the microscope a central depot of cell 
debris, surrounded by small, round, 
granular cells, contained in more or 
less imperfectly fibrillated stroma. 
121 TUBERCLE. 
GLIOMA. 
Miliary tubercle; gray granulation. 
Glious tumor; neuroglioma. 
Small masses, up to the size of a millet 
seed; gray or yellowish, semi-trans- 
parent ; juice cannot be obtained. 
Usually small, but may become large 
from hemorrhagic effusions; pinkish 
or grayish white; clear juice, con- 
taining granular corpuscles. 
Resisting under pressure. 
Soft, and easily crushed ; irrregular in 
outline. 
Free nuclei, granular small cells; larger 
cells, with many nuelei massed to- 
gether ; surrounded by adenoid tissue. 
Small granular corpuscles, resembling 
the white blood corpuscles; occasion- 
ally larger, and rarely fusiform; 
massed together. 
Absent, or a scanty, very delicate net- 
work of adenoid tissue; vessels are 
•not perceptible. 
Soft, scanty, amorphous; occasionally 
fibrillated ; vessels of mother tissue in 
greater part maintained. 
Usually undergoes caseous degeneration, 
■but may also become the seat of fatty, 
mucoid and calcareous degeneration. 
May undergo fatty caseous, calcareous, 
melanotic, and mucoid degeneration, 
May occur at all ages. 
Infancy and early youth. 
Usually in later stages. 
Occurs in later stages only. 
Never encapsulated. 
Never encapsulated. 
Pain depending upon position of tu- 
bercles ; duration of growth cannot be 
determined. 
Little, if any pain ; of rapid growth. 
A small, gray, semi-translucent or yel- 
lowish opaque nodule, up to the size 
of a millet seed ; resisting under pres- 
sure ; presenting under the microscope 
free nuclei, small, round, granular and 
large, many—nucleated cells, with no 
visible stroma, but the mass of cells 
surrounded by adenoid tissue. 
A soft, grayish, or pinkish-white mass; 
occurring primarily in the orbit and 
brain; composed of small, round, 
granular cells; with one or two 
bright spots in the centre; arranged 
in masses, in a delicate amorphous in- 
tercellular substance. 
122 ROUND-CELLED SARCOMA. 
SPINDLE-CELLED SARCOMA. 
Sarcoma globo-cellulare simplex; em- 
bryoplastic tumor; granulation tu- 
mor ; encephaloid sarcoma; medul- 
lary sarcoma; alveolar sarcoma; lym- 
phadenoid sarcoma. 
Recurrent fibroid ; fibro-plastic tumor ; 
fibro-nucleated tumor; fibrous sar- 
coma ; plasmoma, and fasciculated 
sarcoma. 
Yellowish, or pinkish, or brain-like. 
May become very bulky. Scanty, 
clear juice, containing but few cells 
when fresh. Abundant, creamy, con- 
taining many cells after twenty-four 
hours. 
Usually small, but may attain large di- 
mensions ; of grayish-white color. 
The juice is scanty, containing few 
cells. 
Soft, elastic, homogeneous. 
Hard and firm. 
Small round or large oval cells with 
large nucleolated nuclei; the pro- 
toplasm of the cells small in amount 
and the cells in close contact with 
each other. 
Large or small fusiform or spindle cells, 
with oval nuclei and tapering ends, 
arranged parallel to each other in 
strands, or trabeculae, which run in 
different directions. 
Soft, scanty, and amorphous ; some- 
times fibrillated, sometimes alveolar, 
sometimes lymphatic gland-like ; ca- 
pillaries mere channels between the 
cells. 
Scanty and homogeneous, or fibrillated. 
Vessels are numerous, but without 
walls. 
May become ossified or calcified. The 
cells may undergo fatty, mucous, 
caseous or melanotic degeneration. 
May undergo melanotic, fatty, cystoid, 
myxomatous, caseous, calcareous, os- 
sific and telangiectatic degenera- 
tions. 
All ages. 
All ages. 
Seldom met with. Metastasis not unfre- 
quent. 
Not usual, but may occur. Metastasis 
frequent. 
Common. 
Very common. 
Pain usually dull, and not frequent. 
Growth not usually rapid. 
Pain dull and persistent in most cases. 
Usually of rapid growth. 
A soft and elastic mass, usually very 
vascular, of a pinkish or yellowish-red 
color, yielding when fresh a scanty, 
clear juice, and presenting on micro- 
scopic examination small round or 
larger oval cells, with large nucleo- 
lated nuclei embedded in a scanty, 
soft and amorphous, but sometimes 
fibrillated stroma, with the walls of 
the vessels but slightly developed and 
the capillaries mere channels between 
the cells. 
A white or pinkish, hard and firm mass, 
yielding a scanty juice, which presents 
under the microscope small or large 
spindle cells, with oval nuclei. The 
cells being parallel with each other, 
and arranged in bundles which run in 
different directions through the 
growth, giving the appearance of oval 
or round cells, when cut transversely. 
123 GIANT-CELLED SARCOMA. 
EPITHELIOMA. 
Myeloid tumor ; tumeur a myiloplaxes ; 
myeloplastic tumor. 
Epithelial carcinoma; epithelial cancer; 
epidermal cancer ; cancroid ; squam- 
ous epithelioma. 
From hazelnut to adult head ; maroon, 
or reddish brown, or yellowish white; 
dotted with crimson; the juice is 
scanty. 
Extremely variable in size and color; 
juice scanty, thick and stringy. 
Moderately firm. 
Hard, resisting; forming ulcers with 
raised edges, in later stages. 
Large, polymorphous, and odd multi- 
nucleated cells, separated by granular 
intercellular substance. 
Large, squamous, epithelial cells, ar- 
ranged in compact masses; with a 
tendency to a concentric arrangement; 
forming the so-called “nests,” or 
“pearls.” 
Stroma of spindle and round cells ; ves- 
sels rather numerous; with thin, if 
any walls. 
The cell masses are separated by the 
connective tissue, which is infiltrated 
by granulation cells; numerous ves- 
sels are found in the connective tissue. 
May undergo fatty, cheesy, mucoid, 
cystoid, calcareous, osseous, cartila- 
ginous, fibrous, and telangiectatic 
degeneration. 
The cells may undergo a fatty, or mu- 
coid degeneration; the growth may 
become calcified, or even ossified. 
Usually before thirtieth year. 
Advanced life. 
Occasional. 
Common in later stages ; but depending 
upon the position of the primary 
growth. 
Encapsulated; but occasionally infil- 
trating. 
Infiltrating from the first. 
No pain, as a rule, and of rather rapid 
growth. 
Pain extremely severe in later stages ; 
usually of slow growth. 
A moderately firm, reddish brown, en- 
capsuled mass ; which presents, under 
the microscope, multi-nucleated, ovoid 
and queerly-shaped cells, in a stroma 
of spindle and round cells. 
A hard mass of variable size and color; 
usually ulcerating on the surface; 
yielding a scant, thick juice, contain- 
ing epithelial cells ; exhibiting, under 
the microscope, compact masses of 
large, squamous, epithelial cells, with 
a tendency to a concentric arrange- 
ment, and the formation of “nests,” 
or “pearls.” the cell masses being 
separated by the subcutaneous or 
submucous connective tissue, in a state 
of inflammatory infiltration. 
124 CYLINDER-CELLED EPITHELIOMA. 
SCIRRHUS. 
Columnar epithelioma; villous cancer. 
Hard carcinoma; simple carcinoma; con- 
nective tissue cancer ; fibrous cancer; 
chronic cancer ; tubular cancer. 
Variable in size ; yellowish or pinkish 
white in color ; abundant milky juice, 
containing many cells. 
Varying in size from that of a pea to 
that of a fist; milky juice, containing 
many cells. 
Soft and easily crushed. 
Dense and hard. 
Columnar epithelial cells lining the in- 
ner surface of tubules. 
Epithelioid cells of various shapes, with 
large, oval, nucleolated nuclei, disor- 
derly grouped together, floating loosely 
in a clear liquid, contained in elonga- 
ted alveoli of the stroma. 
Fibrillated connective tissue, forming 
tubes or cylinders; fully formed ves- 
sels running in the fibrillated stroma 
between the cylinders. 
A more or less fibrillated, dense tissue, 
containing alveoli, in which the cells 
are grouped together, and into which 
open lymphatic vessels; numerous 
blood vessels contained in the stroma. 
May undergo fatty and mucoid degener- 
ation. 
The tumor may become ossified, carti- 
laginous or calcified ; the cells usually 
rapidly undergo fatty degeneration. 
Adult life. 
Later adult age. 
Usual in later stages. Metastasis fre- 
quent. 
Very common; metastasis frequent. 
Always infiltrating. 
Always infiltrating. 
Pain severe ; of slow growth. 
Usually severe, lancinating and inter- 
mitting pain ; of slow growth. 
A soft, reddish mass, springing prima- 
rily from mucous membranes; exhib- 
iting under the microscope tubules of 
connective tissue, lined on their inner 
surface with columnar epithelial cells. 
A hard, white nodule, yielding an abund- 
ant milky juice, containing many cells ; 
exhibiting under the microscope a 
more or less fibrillated, dense, cavern- 
ous framework, whose alveoli are 
filled with loose cells of an epithelial 
type, grouped together disorderly, 
bathed in a clear fluid, and having no 
visible intercellular material. 
125 ENCEPHALOID CARCINOMA. 
COLLOID CARCINOMA. 
Medullary, soft, acute, acinous carci- 
noma. 
Alveolar cancer; gelatinous cancer. 
Variable in size; yellowish-white, or 
pinkish; abundant, creamy juice, 
containing many cells. 
May attain an enormous size; trans- 
lucent amber color ; gelatinous juice, 
containing few cells. 
Frequently lobulated; soft ; brain-like. 
Jelly-like; trembling. 
Epithelial cells of various shapes, with 
large nucleolated nuclei. 
Large ovoid cells, with large nucleo- 
lated nuclei; these are surrounded by 
concentric rings, grouped irregularly 
in the middle of the alveoli of the 
stroma. 
Slender trabeculae of fibrous tissue, 
forming a large meshed network; 
vessels abundant in the stroma. 
A network of fibrillated tissue, forming 
regular round alveoli, of various sizes, 
visible to the naked eye, and filled with 
a gelatinous mass, holding the epi- 
thelioid cells in the centre ; vessels 
not numerous, and small, running in 
inter-alveolar tissue. 
The cells rapidly undergo fatty degene- 
ration ; rupture of vessels and hemor- 
rhage frequently follow the fatty or 
mucoid degeneration of the stroma. 
May undergo fatty, and mucoid degene 
ration. 
Advanced adult life. 
Adult life. 
Common. Metastasis very frequent. 
Usually absent. 
Infiltrating from the first. 
Always infiltrating. 
Severe, intermitting pain; of rapid 
growth. 
Pain slight; of very rapid growth. 
A lobulated, pinkish, or yellowish, soft, 
brain-like mass, yielding an abundant 
creamy juice, and exhibiting under the 
microscope epithelioid cells with large 
nucleolated nuclei, floating loosely in 
the large ovoid meshes, or alveoli of a 
fibrous stroma. 
A large, trembling mass, of an amber 
color; yielding a gelatinous, stringy 
juice, containing few cells : exhibit- 
ing under the microscope, round 
alveoli, formed by a network of fibril- 
lated connective tissue, containing in 
their lumina a tenacious substance, 
and in the centre a few ovoid large 
cells, of an epithelial type, with large 
oval nucleolated nuclei. 
126 INDEX. 
A. 
Aberration, 13. 
chromatic, 13. 
spherical, 13. 
test for, 13. 
Acids, 28, 29, 34. 
Acid, acetic, 32, 68, 72, 93. 
chromic, 31, 33, 34, 38, 43, 61. 
hydrochloric, 30, 43, 63, 73. 
nitric, 30, 43, 98, 108. 
osmic, 32, 41, 69, 70. 
oxalic, 31, 63, 66. 
picric, 32, 43, 67. 
sulphuric, 29, 30, 81. 
Achromatic combination, 104, 105. 
Adjustment, coarse, 12. 
fine, 12, 57, 58, 105. 
Alkalies, 28, 32, 34. 
Alcohol, 34, 35, 39, 42, 62, 63. 
absolute, Squibb’s, 35, 42, 85-89. 
methylated, 37. 
Alum, 64, 99. 
Ammonia, 33, 71, 72. 
Ammoniac gum, 93. 
Ammonio-sulphate of copper, 106. 
iron, 108. 
Ammonium sulphide, 108. 
Angular aperture, 14. 
Aniline, 67, 91, 99. 
Animal tissues, preparation of, 25. 
Animalcules, 21. 
Arabic, gum, 95. 
Arsenious acid, 41. 
Artificial light, 13, 14. 
B. 
Bacteria, 67. 
Balsam, 32, 59, 84-92. 
Canada, 58, 85-92. 
Beale’s blue injecting fluid, 72, 73. 
neutral glass camera lucida, 19, 
Bell’s cement, 93, 95. 
Benzine, 90. 
Benzole, 42, 89, 91. 
Bichromate of potash, 33, 81, 82. 
Binocular microscope, 12. 
Blood corpuscles, 15. 
disks, 17. 
slide, 15, 70, 109. 
Blue glass, 16. 
Bone, 30, 31, 34. 
corpuscles, 30. 
sections, 58. 
softening of, 43. 
Borax, 62. 
Bull’s eye condenser, 16, 18. 
C. 
Cacao butter, 42. 
Camera lucida, 19, 20, 22, 103. 
Beale’s neutral glass, 19. 
Camphor water, 95. 
Canada balsam, 58, 85, 92. 
Cane sugar, 30. 
Carmine, 32, 62, 65,67, 69, 71, 72. 
indigo, 65. 
Caustic potash, 32, 100. 
soda, 33. 
Cell, 94-96, 106. 
Cement, 90-92. 
Bell’s, 93, 95. 
water proof, Seiler’s, 93, 95. 
white zinc, 91, 94. 
Centering of sub-stage condenser, 16. 
Chemical reagents, 28, 61. 
Chloride of gold, 41, 69. 
iron, 41, 72. 
platinum, 41. 
palladium, 41. 
Chlorinated soda, 33, 97, 98. 
Collodion, 107, 108. 
Chloroform, 69, 74, 78. 
127 128 
INDEX. 
Chlorophyll, 97. 
Chromatic aberration, 13. 
Chromic acid, 31, 33, 34, 38, 43, 61. 
Cleaning of slips and covers, 81, 83. 
Concave mirror, 16, 17. 
Condenser, bull’s eye, 16, 17. 
sub-stage, 16, 105, 109. 
Connective tissue, 30. 
corpuscles, 30. 
Copper, ammonio-sulphate of, 106. 
Cordi’s organ, 31. 
Corpuscles, bone, 30. 
blood, 15. 
Covers, cleaning of, 81, 83. 
Cover glass, 14, 19, 29, 81-96. 
Coxe’s gelatine, 71, 74, 78, 93. 
Crane, Mr. E. B , 99. 
Cutting of sections, 45, 47, 49, 50. 
Cyanide of potassium, 33, 108. 
D. 
Dammar, 90. 
Defraction rings, 15. 
Diameters, 20, 21. 
Diaphragm, 17. 
Dissecting microscope, 27, 32. 
Double injection, 78. 
staining, 61, 65, 66, 99. 
Drawing, 19, 22. 
Draw tube, 12. 
Drying oven, 87, 88. 
E. 
Eye lens, 19, 20. 
piece, 12, 13, 105. 
micrometer, 21, 22. 
F. 
Farrant’s solution, 95. 
Ferro-cyanide of potassium, 72. 
Field, 13. 
flatness of, 13. 
Fine adjustment, 12, 57, 58, 105. 
Finder, Maltwood’s, 23, 24. 
Flatness of field, test for, 15. 
Forceps, 81, 87. 
mounting, 89. 
Formula for Miieller’s fluid, 37. 
French lenses, 14. 
Freezing microtome, 55, 68. 
Frog, stomach of, 57. 
Fuclisine, 67. 
C. 
Gelatine, 76. 
Coxe’s, 71, 72, 78, 93. 
Glass slide, 15, 29. 
Glycerine, 10, 26, 29, 32, 34, 41, 61, 72, 
79, 84. 
mounting in, 92-95. 
Gold, 33. 
chloride of, 41, 68. 
Gum ammoniac, 93. 
arabic, 95. 
H. 
Hsematoxylon, 64, 65, 67, 69, 99. 
Hand stage, 10. 
Hardening tissues, 34. 
Heliostat, 104. 
Hunt, Dr. J. G., 99. 
Hydrochloric acid, 30, 43, 63, 73. 
Hyposulphide of soda, 33, 68, 108. 
Illumination, 14, 109. 
oblique, 11. 
test for, 14. 
for opaque objects, 18. 
Image, 13, 19, 105. 
Imbedding material, 42, 45, 47, 48. 
Indigo, 65. 
carmine, 65. 
Indigotate of potash, 65. 
soda, 65. 
Injecting, 71-80. 
fluid, 71-73, 75-80. 
Beale's blue, 72, 73. 
Injecting, method of, 73-79. 
lungs, 76-77. 
Injection, double, 78. 
of nitrate of silver, 78. 
Insects, wings of, 25. 
preparation of, 100-102. 
Iodine, 107, 108. 
Iron, ammonio-sulphate of, 108. 
chloride of, 41, 72. INDEX. 
129 
J. 
Jar, 36. 
K. 
Kidney, isolation of tubules, 30, 31. 
Knife, 45, 48, 49, 50, 52, 53, 55, 74. 
carrier, mechanical, 51. 
Valentine’s, 45, 46. 
L. 
Large sections, 53. 
Labarraque’s solution, 33, 97, 98. 
Lens, 13, 14, 106. 
Light, artificial, 14. 
monochromatic, 106, 107. 
Liquor potassa, 100. 
Lungs, injection of, 77. 
M. 
Magnification, 20. 
Magnifying power, 20-22. 
Maltwood’s finder, 23, 24. 
Material, imbedding, 42, 45, 47, 48. 
Mechanical microtome, 52. 
knife carrier, 51. 
stage, 10, 24. 
Method of injecting, 73-79. 
mounting in balsam, 88. 
Methylated alcohol, 37. 
Micrometer, eye piece, 21, 22. 
screw, 47, 58. 
stage, 20, 22. 
Microscope, binocular, 12. 
dissecting, 27. 
Microtome, 46-48, 50, 51, 53, 56. 
freezing, 53, 68. 
Mirror, 11, 16, 18, 104. 
bar, 11, 17, 18. 
Monochromatic light, 106, 107. 
Mounting, 53, 81-96. 
forceps, 89. 
in glycerine, 92-95. 
material, 68, 92. 
of opaque objects, 96. 
Mueller’s fluid, 34, 37, 38, 39, 79. 
formula for, 37. 
N. 
Needle, 15, 26, 30, 81. 
Nerve termination in muscle, 32. 
Nitrate of silver, 68, 69, 78. 
injection of, 78. 
Nitric acid, 30, 43, 108. 
Nose piece, 16. 
Nozzle, 73. 
Nuclei, 61, 63, 66. 
O. 
Objective, 13, 19, 20, 21, 105. 
Oblique illumination, 11. 
Ocular, 12, 19, 20, 21. 
Oil of cloves, 86-88. 
Opaque objects, 17, 96. 
mounting of, 96. 
Osmic acid, 32, 41, 69, 70. 
Oxalic acid, 31, 63, 66. 
P. 
Palladium, 41. 
Parabolic reflector, 18. 
Paraffine, 45, 48. 
Photo-micrography, 103-110. 
Picric acid, 32, 41, 43, 67. 
Pipette, 29, 34. 
Platinum, 41. 
Potash, bichromate, 33, 81, 82. 
caustic, 32, 100. 
Potassa, liquor, 100. 
Potassium, cyanide, 33, 108. 
ferro-cyanide, 72. 
Power, magnifying, 20. 
Preparation of animal tissues, 25. 
Pressure apparatus, 77. 
Prism, 19. 
Prussian blue, 73. 
R. 
Razor, 19, 22. 
Reagents, chemical, 28, 61. 
Reflector, 19, 22. 
parabolic, 18. 
Ringing, 91, 92. 
S. 
Section cutter, 48. 53. 
cutting, 45, 47, 49, 50. 
knife, 48, 49. 
Sections of bone, 58. 
large, 53. 
thin, 29, 45, 46, 48-50, 53, 67. 130 
INDEX. 
Seiler’s method of mounting in balsam 
88 
Silver, 33, 69. 
nitrate, 68, 69. 
Slips, 81. 
cleaning of, 81. 
Slides, 81. 
Soap, 45. 
Soda, caustic, 33. 
hyposulphide, 33, 63, 108. 
Softening of bone, 43. 
Spherical aberration, 13. 
test for, 13. 
Spring clip, 93. 
stop, 11. 
Squibb’s absolute alcohol, 35, 42, 85. 
Stage, 10, 18, 34. 
plate, 10. 
micrometer, 20, 21. 
Staining, 53, 61-70, 99. 
double, 61. 
Stand, 9, 34. 
Starr, Mr. W. T., 90, 102. 
Stereoscopic vision, 12. 
Stomach of frog, 57. 
Stop, 10. 
Sub-stage, 11, 16. 
condenser, 11, 16, 105, 109. 
Sulphide of ammonium, 108. 
Sulphuric acid, 29, 30, 81. 
Syringe, 73, 79. 
Syphon, 41. 
T. 
Tallow, 48. 
Teasing, 26. 
Test for aberration, 13. 
flatness of field, 15. 
illumination, 14, 15. 
Test tube. 34. 
Tiersch, Prof., 62. 
Transmitted light, 27. 
Tripod base, 9. 
Tube, 11, 105. 
Tubules of kidney, 30, 31. 
Turn-table, 83, 84, 89, 91, 93. 
Turpentine, 90. 
V. 
Valentine’s knife, 45, 46. 
Vegetable tissues, preparation of, 97. 
Vision, stereoscopic, 12. 
W. 
Watch glass, 27, 64. 
Water bath, 42, 63, 72. 
Wax, 45. 
Wenham, Mr., 12. 
Wings of insects, 25. 
Woodward, Dr. J. J., 15, 62. 
Working distance, 18, 34. 
Z. 
Zentmayer, Mr. Chas., 102. 
Zinc cement, white, 91, 94. JOSEPH ZENTMAYER, 
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THE PRINCIPLES AND METHO DS 
OF 
THERAPEUTICS. 
BY ALPHONSE GUBLER, M.D., 
Professor of Therapeutics in the Faculty of Medicine of Paris, etc. 
TRANSLATED FROM THE FRENCH. ONE VOL., 8vo. 
INT PRESS. REAJDY MARCH 1st, 1881. 
Gxjbler may he said to have been the most distinguished exponent 
of scientific therapeutics—in the best sense of the term—of this genera- 
tion . Following Trousseau in the professional chair, aud a pupil of that 
great teacher, he took a long step in advance of liis master, and may be 
said to have developed the only method of therapeutics which reconciles 
the empirical and clinical art of medicine with the demands of exact 
and logical science. His labors created a new epoch in professional 
practice in France, and in all other countries where they have become 
known have made a profound impression on the professional mind. 
5 DIFFERENTIAL DIAGNOSIS: 
A MANUAL OF THE COMPARATIVE SEMEI0L0GY OF THE 
MORE IMPORTANT DISEASES. 
By DE HAVILLAND HALL, M.D., 
Assistant Physician to the Westminster Hospital, London. 
Second American Edition, with Extensive Additions. 
EDITED BY FRANK WOODBURY, M.D. 
One Volume, 8vo, pp. 223. Printed on handsome tinted paper; bound in English pebbled 
cloth, with beveled boards. Price $2.00; 
Dr. Hall’s work has received the highest encomiums from the 
English medical press, for its lucid arrangement, completeness and accu- 
racy. He himself is known in London as a practitioner of great skill, 
and an unusually successful medical teacher. 
Most of the diseases which may be confounded are presented in 
comparative tables, setting forth their distinctive characteristics in the 
clearest possible light, and thus greatly facilitating their prompt diag- 
nosis. 
THE DISEASES OF LITE STOCK, 
INCLUDING HORSES, CATTLE, SHEEP AND SWINE. 
Containing a description of all the usual diseases to which these animals are 
liable, and the most successful treatment of American, 
English and European Veterinarians. 
By LLOYD V. TELLOR, M.D. 
1 vol. 8vo. pp. 474. Price, Cloth, $2.50. 
This work is divided into four parts, as follows: I. General Princi- 
ples of Veterinary Medicine. II. Diseases of the Horse. III. Diseases 
of Cattle, Sheep and Swine. IV. Hygiene and Medicines. 
The author of this work is a regular physician, whose practice in the 
country lias led him to study the diseases of domestic animals, and we 
can point to it as the first and only hook, by an American physician, 
which describes, with scientific accuracy, and yet in plain language, 
these common and important maladies. 
From, WILLIAM A. HAMMOND, m. n., of New York City, Late Surgeon General, V. S. 
Army. 
“ I have gone through Dr. Tellor’s book very carefully, and regard it as admirably adapted for 
the use of those who are obliged to treat their own animals. It is eminently practical and full of 
common sense.” 
6 LESSONS IN GYNECOLOGY. 
BY WM. GOODELL, A.M., M.D., 
Professor of Clinical Gynaecology in the University of Pennsylvania. 
SECOND EDITION. 
THOROUGHLY* REVISED AND CONSIDERABLY ENLARGED, WITH 
NUMEROUS ILLUSTRATIONS. 
One Volume, 8vo. Price, Cloth, $4.00; Sheep, $4.50. 
The Second Edition of this able work was demanded within three 
months from the publication of the first. The author has, however, 
taken the time to give it a very careful revision, and has added a large 
amount of new and unpublished material. 
“This volume is one which must take a high rank among works upon the subject of which it 
treats. It presents striking and rare merits, showing close observation, accurate description and 
sound reasoning.”—Medical Times and Gazette, London, November, 1880. 
“We commend this book to those who are, or who wish to become, gynaecologists. Its great 
value is its practicalness. Little points of detail teem up on almost every page, showing that it is 
the work of a man who has often done what he wishes his readers to do ."—Glasgow Medical Jour- 
nal, November 1880. 
COMMON MIND-TROUBLES, 
AND 
THE SECRET OF A CLEAR HEAD. 
By J. MORTIMER-GRANVILLE, M.D., F.R.C.S., LONDON, etc. 
One Vol., Crown 8vo, Cloth, pp. 185. Price $1.00. 
Reprinted from the Eleventh thousand of the London Edition, with 
additions by the American Editor. 
PART I. Mental Failings—Defects of Memory—Confusions of 
Thought—Sleeplessness from Thought—Hesitations in Speech—Low 
Spirits—Good and Bad Tempers—Mental Languor and Listlessness— 
Morbid Fears —“ Creatures of Circumstance.” 
PART II. Temperature—Habit — Time—Pleasure—Self-Import- 
ance—Consistency—Simplicity—The Secret of a Clear Head. 
CONTENTS. 
7 Atkinson. Hints on the Obstetric Procedure. 8vo. Cloth, $1.00. 
“The many valuable points cited, the practical manner in which they are stated, together with 
the sound views of practice enunciated, make this little monograph truly valuable.”—The Southern 
Practitioner, January, 1879. 
“It is the gist of the obstetric art in convenient form, and will serve to refresh the practitioner's 
mind in any case pertaining thereto.”—Maryland Medical Journal, June, 1879. 
Bernard and Huette. Operative Surgery and Surgical Anatomy. 
Magnificently illustrated on steel. Colored plates. Hew edition 
in preparation. 
Dowell. Yellow Fever .and Malarial Diseases. AYitli a Map. Cloth, 
$2.00. 
Dobell. On Coughs, Consumption, and Diet in Disease, pp. 222. Cloth, 
$2.00. 
As an authority on the above subjects Dr. Dobell ranks second to none in Great Britain. His 
experience has been immense, and the peculiarly practical tone of his mind renders his writings 
unusually instructive to the practicing physician. 
Hargis. Yellow Fever, its Ship Origin and Prevention. 8vo. (Just 
issued). Cloth, $1 00. 
Landolt. Manual of Examination of the Eyes. Illustrated, pp. 307. 
Humerous illustrations and Chart, $3.00. 
“ This book is a most admirable and complete expose of our means and methods of making a 
thorough scientific examination of the human eye. Written in the attractive, easy style of lectures, 
unencumbered by unnecessary mathematical formula}, printed on heavy paper and in large and 
clear type, translated with care and skill into fluent English, this book will contribute largely toward 
awakening greater interest for ophthalmology among the reading members of our profession.”— 
Chicago Medical Journal and Examiner, August, 1879. 
Seiler. Compendium of Microscopical Technology, pp. 8vo. (Just 
issued.) Price, $1.00. 
Dr. Carl Seiler, of Philadelphia, gives in this admirably lucid epitome of microscopy just that 
information which the student and physician requires to work the microscope advantageously. It is 
well illustrated and contains a comparative table of neoplasms of great value. 
In Preparation. 
Ready about A-i>ril 1, XSSI. 
HYDROPHOBIA, 
.A. Monograph for the Profession and the Pnhlic. 
By H. R. BIGELOW, M.D. 
This treatise, the outcome of several years’ study of this terrible 
complaint, will contain the latest investigations into its pathology, 
causes, communicability, prognosis, prophylaxis and treatment. 
8