From the Eleventh Report of the Illinois Industrial University. 
THE BACTERIA. 
By T. J. BURRILL, Ph. D. 
SPRINGFIELD, ILL.: 
H. VV. Rokkee, State Peintee and Bindee. 
1882. THE BACTERIA: 
AN ACCOUNT OF THEIR NATURE AND EFFECTS, TOGETHER 
WITH A SYSTEMATIC DESCRIPTION 
OF THE SPECIES. 
By T. J. BURRILL, Ph. D., 
Professor of Botany and Horticulture, Illinois Industrial University; 
Botanist Illinois State Board of Agriculture. 
CONTENTS. 
Introduction. 
PART I.—Nature and Organization of Bacteria. 
1. Existence and Habitat. 
2. Color, Shape, Size. 
3. Movements. 
4. Structure. 
5. Reproduction and Development. 
6. Vitality and Endurance. 
7. Nutrition. 
8. Origin. / o^n 
9. Place in Nature. 
\A 
PART II.—Effects of Bacteria. 
1. Fermentation and Putrefaction. 
2. Diseases of Plants and Animals. 
3. Benefits. 
PART III.—Classification of Bacteria. 
1. Sphserobacteria. 
2. Microbacteria. 
3. Desmobacteria. 
4. Spirobacteria. 
5. Description of Geneva and Species, 
6. Saccharomycetes. INTRODUCTION. 
Biology—the science of life—has no more interesting and important 
problems than those concerning the smallest and simplest of 
animate objects, the bacteria. These exceedingly common living 
things, visible to us only by the aid of powerful magnifiers, have 
latterly received much attention on account of the endeavor to find 
out by scientific research, the origin of life on our globe; but more 
for the undreamed of power and influence which they have been 
found to possess and exercise in the operations of the organic 
world. Since the discovery of their existence and modes of action, 
many questions previously unanswerable have become easy, and the 
knowledge obtained has passed into science to serve, not only as an 
intellectual stimulus to man, but as sure standing-ground from 
which he may reach other heights and gain at last his rightful 
dominion over the forces and objects of earth. 
It is not too much to say that mankind could not continue to 
exist, could never have existed, on the earth as at present consti- 
tuted, but for these minute though effective agents; the truth of 
this does not depend on any mere figure of speech, or even on any 
delicate adjustment of nature, but on the actual and essential work 
accomplished. Without them, and with other things as they are, 
there could have been no fertile soil, no luxuriant pastures, no 
bountiful harvests, no possibility for man. On the other hand we 
should not suffer many of the ills that flesh is heir to, if we could 
escape their restless activities in certain forms and ways. 
It is the object of this paper to present, in language freed as far 
as possible from technical terms, the principal and most interesting 
facts now known about these silent-working denizens of the earth, 
the air, and the water. Should any one wish to inquire further, he 
may soon find an abundant literature on the subject; but the whole 
matter is still so new that a great proportion of it is only to be 
found in the scientific periodicals of the last two decades, and 
unfortunately for many, mostly in foreign tongues. The best general 
work of American publication is The Bacteria, a translation from 
the French of l)r. Magnin, by Dr. G. M. Sternberg: Little, Brown 
& Co., Boston, Mass., 1880. There are several excellent general 
articles in numbers of the Popular Science Monthly, and very 
instructive reports by Drs. Detmers, Law and Salmon, on infec- 
tious diseases of animals, in the annual reports of the United 
States Commissioner of Agriculture, for 1878, 1879, and 1880. For 
“blight” in pear trees, etc., see report for 1880, of the Illinois 
Industrial University; proceedings American Association for the 
Advancement of Science, xxix, (1880; p. 583. For the possible 
explanation of the origin of certain diseases, see “some vegetable 
poisons,” (Rhus, etc.) 1. c. xxxi (1882.) 
Charles S. Dolley, of Rochester, N. Y., has issued in pamphlet 
form a translation from the German of an interesting general 
article by Ferdinand Cohn. 3 
For the practical study of these minute organisms, a first-class 
compound microscope is required and the ability to use it; but any 
one possessing ordinary capacity for scientific study, with plenty of 
patience, may gain a large amount of information by the aid of an 
instrument costing not more than fifty to one hundred dollars. 
Certain kinds of the organisms may be readily obtained by putting a 
few bits of flesh or of any soft animal or vegetable matter in water 
kept at the ordinary temperature of a comfortable living-room and 
allowed to stand one to several days. Characteristic species often 
occur in given infusions. Others may be sought for in decaying 
fruits and vegetables, on the surfaces of cooked articles of food, as 
of boiled potatoes, rice, beans, etc., while some are commonly present 
in the mouth, especially in the collections on the teeth and the fur 
of the tongue. The pus from external wounds, and very often the 
discharges from pimples, boils, ulcers, etc., contain myriads of the 
organisms. 
Bacteria may be mounted for preservation on the usual thin 
cover glasses used by microscopists, and the covers inverted and 
fastened to the ordinary microscopical slides. First smear the 
cover glass with the material containing the bacteria, and after 
drying a few minutes immerse in strong alcohol to fix the specimens 
by coagulation of the imbedding substance. Then stain by immers- 
ing in common violet ink (aniline) at least five minutes, wash in 
water and mount in a weak, aqueous solution of carbolic acid. 
There are many other processes and materials used to advantage 
in certain cases, but this is the simplest and most generally success- 
ful of any now known. 
I have not considered it wise to encumber these pages with refer- 
ences, yet make no claims to anything original except as indicated 
in the proper places. I have, however, verified by experimental 
studies much of the information presented, gained in the first place 
from others. 
PART I. NATURE AND ORGANIZATION. 
1. Existence and Habitat. 
The minute organisms, to which the term bacteria is now com- 
monly applied, cannot be individually recognized without a magni- 
fying glass of high power; so, to those not accustomed to work 
with the compound microscope, the existence of the little creatures 
as common objects may not be suspected, or at least Rationally 
realized. To be sure much is said of the life of a drop of water or 
other fluid; but a large amount of this sort of retailed information 
is purely imaginary, having nothing or little of truth about it. The 
fact is, pure water, such as is taken from a good well or spring, 
has absolutely no life in itself, nor are there in it any living things 
whatever, no matter what magnifying power one examines it with. 
On the other hand, there are no other living things in nature, from 
the highest to the lowest, so widely distributed in the earth, the air 
and the water, throughout the world, so commonly and multitu- 4 
dinously present, near us, and on us and in us, as the various 
kinds of the microscopic organisms of which we now write. If pure 
well water does not contain these or any other living things, all foul 
waters do. Bacteria or their allies exist in countless myriads in all 
filth, in all decomposing vegetable or animal matter, whether ill- 
‘Scented or not, in all organic substances undergoing apparently 
spontaneous change, as heating in the mass, becoming sour, rancid, 
or putrid, and, generally, undergoing those changes known as fer- 
mentation or decay. 
The water from ill-scented cisterns, and indeed from many in 
which odor is imperceptible, contains varying numbers of these 
minute living creatures. The water of foul ditches, stagnant ponds, 
marshes and sloughs teems with them, in numbers surpassing those 
of the leaves of the forest; a drop under the microscope often pre- 
sents a maze of living forms, more wonderful than imagination ever 
pictured, or of which fiction ever dreamed. The waters of running 
streams are more or less inhabited by them, and the ocean itself is 
the special home of peculiar kinds. 
The air may, like water, be absolutely pure, or clouded by innumer- 
able numbers of the almost imponderable, but living, multiplying 
things. Wherever there is floating dust of organic origin, they may 
be said to be certainly present. The stifled atmosphere of close 
apartments, and of thickly built streets, especially over decomposing 
filth, is laden with various forms of bacteria and allied organisms; 
and these are unavoidably inhaled by ourselves with every breath 
inspired. But in the dry, open country, few of them can be found 
in the pure, fresh, invigorating air, and over wide desert regions 
and the tops of high mountains none whatever exist. With us the 
air in winter, especially when the earth is long covered with snow, 
becomes almost free, while in midsummer and autumn, especially 
after damp and close weather, their myriad numbers are wafted to 
and fro by every movement of the freighted atmosphere. 
The slime on vessels of standing water, on the surface of vegeta- 
able or animal substances, like cold articles of food set away for 
some time, e.g. boiled potatoes, cooked meats, etc., is composed of 
these organisms and their products. Brewers’ yeast, used in bread 
making, is not a Bacterium, but it is a related growth, and the so- 
called salt-rising, not unfrequently used in making bread, owes its 
energy to living bacteria. Sour milk always contains swarms of the 
microscopic, moving things, and during the formation vinegar from 
the juice of fruits, from solutions of whisky and sugar, etc., they 
may always be found in similar numbers. 
They are invariably present in pus from open, suppurating 
wounds, in the discharge from boils and tumors on and in our own 
bodies, and in the ill-scented accumulations of the bodily excretions, 
as from the arm-pits and unwashed feet. If they have any connec- 
tion with bad odor, no one will wonder why the breath sometimes 
smells bad if the material collecting on the teeth or the fur on the 
tongue can be seen under a good microscope. The cleanest human 
mouth can hardly be said to be ever perfectly free from these active 
organisms; while those to which the tooth brush or its equivalent 
is a stranger, are veritable culture boxes, or hot houses, richly sup- 
plied with rapidly growing and prodigiously multiplying forms and 5 
kinds. We swallow them with our food, and at least some kinds 
sometimes retain their activity in the stomach and intestinal tube. 
It now seems certain that the latter is always inhabited by special 
kinds which have to do with the activities there in operation. In 
health the blood is usually quite free from them, but in certain 
diseases this too, as it rapidly courses through the arteries and 
veins, sweeps along in the current myriads of the minute but liv- 
ing and developing, ever active things, inappropriately called 
“germs.” We may well say in such cases that “the blood is out of 
order.” 
What perhaps more than all else gives vivid interest to our 
microscopical studies of this sort, is the fact that special kinds of 
these tiny living beings are found uniformly in connection with the 
severest diseases known to man, either of himself or of the plants 
and animals about him. We may name as examples “blight” in 
pear, apple and many plants; hog and chicken cholera, pleuro- 
pneumonia and splenic fever in cattle; malaria, typhoid fever, 
diphtheria and small-pox in man. What the connection is between 
organisms and the diseases, we leave for another part of this paper. 
Very recently it has been fully demonstrated that consumption, the 
most terrible scourge of the human race, invariably has its accom- 
panying specific form in the diseased tissues and the exudations 
from them. 
It will thus be seen that these microscopic organisms are by no 
means unusually or uncommonly present about, upon and within 
us. Taken as a classified group they are more widely dispersed 
and dwell more numberously everywhere, in everything, than all 
other living things put together. For the truth of this statement I 
need only to appeal to the observation of any one who. having a 
good compound microscope, will take the trouble to state the facts 
as seen. Still it would be unfair to leave the impression that any 
one specific kind is thus invariably near us, or that the most com- 
mon, taken as a simple species, is as widely and thoroughly dis- 
seminated as might be inferred from the foregoing. The statements 
made have reference to the numerous species comprised in the 
entire group, not to certain ones. It is one thing to say that birds 
are very widely dispersed over the earth; it is quite another thing 
to state the facts as they are concerning the common domestic 
fowl or the snowy owl. 
2. Color, Shape, Size. 
As a rule bacteria are white, so that when numerous in water the 
fluid is opalescent or milky. They very frequently settle down, when 
the proper food supply is exhausted, to the bottom of the contain- 
ing vessel, and in this case form a white slimy or flocculent mass. 
But of numerous species each has its peculiar color, .as red, blue, 
yellow or green. On the moist surfaces of prepared articles of food, 
as of cooked potatoes, bread, cheese, rice, etc., spots of a red color 
much resembling drops or splashes of blood are not uncommon. 
Formerly these reputed blood-stains were regarded with superstitious 
wonder, and have been held to indicate guilt, and the anger of 6 
God. These, as well as other colored spots and pigments, are now 
traced to their true cause, and are found due to the distinct color 
of the organisms themselves or to the chemical combination which 
they produce. 
The different kinds of bacteria vary in shape from spherical to 
oval, cylindrical and thread-like; and the latter are straight, or 
crooked, or spiral, flexible or rigid. The spherical ones are often 
connected in two’s or more, and sometimes form bead-like strings 
or chains. The main classifications in use are based on the form 
and size of the organisms. 
It was impossible to know anything about bacteria until after the 
invention of the microscope, because none of them can he individ- 
ually seen with the unaided eye. In transverse diameter, one 
twenty-five thousandth of an inch is a very common measurement, 
while some, including spherical ones, are even less than half this 
size. Now, a dot one two-hundredth of an inch across is barely 
visible to the eye of most persons, hence a magnifying power of 
more than one hundred times across (ten thousand in area) is re- 
quired to barely see a common-sized Bacterium. To make out its 
real shape and any details of structure, ten times the enlargement 
mentioned is necessary, and not unfrequently as much more as can 
be secured by the highest possible powers of the microscope. In- 
crease the heighth of an ordinary man one thousand times,.and his 
would be over a mile above the earth, yet under the same 
magnification one of these organisms would have plenty of room to 
swim freely, to stand on end and dance up and down, in the film 
of water included between two pieces of fiat glass pressed so close 
together as to strongly adhere by capillary attraction. From one 
hundred to two hundred and fifty of them placed side by side would 
be required to stretch across the ordinary thickness of book paper. 
They are the smallest living organisms known to man, yet, as we 
shall see, by no means the least important in the economy of nature 
3. Movements. 
Bacteria have sometimes been divided into groups upon their ap- 
parent ability to move or not; but further study has demonstrated 
that many, if not most, species have states in which they remain 
at rest, and others in which they are freely motile. These states 
depend partially on their stage of development, partly on the sur- 
rounding conditions. For the latter the degree of moisture and 
temperature, and the food supply, are especially effective. 
Some species at most only oscillate and quiver in the fluid medium 
in which they grow, never making progress in any given direc- 
tion ; others slowly and smoothly glide along in a straight but more 
often undulating path, while still others whirl and dance and roll, 
turning over and on end, now spinning round and round, now sway- 
ing gently back and forth, now darting like a Hash across the 
microscopic field. Sometimes they move as though perfectly free, 
and had abundant muscular force, at other times they appear to 
be struggling to overcome obstructions, or to free themselves from 
some impediment. Not unfrequently they may be seen to carry 7 
along little adhering extraneous particles, well showing their vital 
power, or two, in some way attached, pull in opposite directions 
with varying advantage for the one or the other. 
No one, having once seen these motions, can doubt the inherent 
power the little things possess, or can question their right to be 
classed as living objects; whether as animals or plants, will depend 
on his previous information and experience, as well as upon what 
he sees. How they move, that is by what sort of organs or mechan- 
ism, is not easy to make out; but they have this power only when 
immersed in a fluid medium. When dry they are motionless, except 
as carried by external agents, as air currents. 
It is now well known that different species have different methods 
and facilities for dissemination. Many kinds are externally viscid, 
or are always, when moist, imbedded in a mucilaginous exudation, 
and hence in either case adhere to any solid substance they may 
touch. These therefore are rarely found floating in the air. So 
long as the material containing them does not become dry and then 
pulverized, such species are not distributed by the currents of the 
atmosphere. It is quite possible that a foul drain or a filth-filled 
cesspool may contain myriads of disease-producing bacteria which 
are, however, only taken into the human body by swallowing them 
in contaminated water, the vitiated air though laden with fetid 
gases being harmless, yet this can by no means be said of all 
species known to be injurious to man. Their great numbers, their 
exceedingly minute size and their powdery character in mass, 
together in many cases with their long continued vitality, pre-emi- 
nently fit them for aerial distribution. The dust made evident by 
a sunbeam is often in considerable portion composed of these specks 
of living matter, which only await suitable conditions for growth 
and development to take place. What intellectual light the careful 
study of such a sunbeam may throw upon knotty questions of vital 
importance to man! 
4. Structure. 
Small as these organisms are, they possess well differentiated 
parts, which are each, presumably, absolutely necessary for their 
existence as living things. We do not infer that structure is life, 
but there is every reason to believe that life is just as dependent 
on structure in these simple and low forms as it is in the highest 
plants or animals. Solution, separation of parts, can no more take 
place in the one than in the other, without destruction of life. 
Liquids, separated from solids, never possess, nor are possessed by, 
the life principle, whatever that is. Think of dissolving the body of 
a mouse in acids, and then, by proper chemical manipulation, col- 
lecting every atom of the original substance and reforming by this 
means a living mouse! There is, however, just as much ground 
for the supposition that this can be done with the mouse, as there 
is in the case of the minute things of which we now write. To be 
sure, there is not so much complexity of organization, but there is 
■quite as constant a certain and characteristic structure on which 
life depends. 
Bacteria, like other living things, are composed of cells; or, per- 
haps, it is better to say, each Bacterium is an organic cell. There 8 
is an outer wall or membrane closed on every side like the skin of 
a raisin, and within this envelope there is a plastic substance 
forming the entire contents of the cavity. Chemical reagents show 
that the outer membrane is made up of cellulose, the substance of 
which wood consists, everywhere forming the framework of all plant 
structures. This, at first, is uniformly white, but becomes variously 
stained, as in the heart-wood of trees of different kinds. It is, 
except in peculiar states, insoluble in water, but swells and shrinks 
from its power of absorbing and again giving up this liquid. Fire 
destroys it, forming, with the oxygen of the air, carbonic acid and 
water. 
The inner soft substance of the cell is protoplasm, which is even 
more common in higher organisms than cellulose; for while the 
latter is almost without exception confined to plants, the former is 
present in all living things, plants and animals alike. Taken by 
itself, it probably has a uniform composition in all organic nature; 
but it is variously mixed with other substances, rendering it difficult 
to determine the exact chemical components. Besides the carbon, 
oxygen and hydrogen of cellulose, it invariably has nitrogen, which 
cellulose does not have. Though usually semi-fluid, it also is 
insoluble in water. Heat coagulates, and thus destroys its functional 
activity—kills the organisms. Not the least instructive is the power 
of motion possessed by protoplasm. Its mass is often agitated by 
internal currents, made evident by little granules carried along 
by the stream. Sometimes these granules remain for a time at 
rest, then start off in an irregular line across the cell, rolling and 
tumbling on the way. These motions are not easy to see within 
most bacteria, but are readily enough made out in some of the 
larger kinds. 
This is the simple structure of a Bacterium—a minute cell with an 
outer cellulose wall inclosing the protoplasmic contents. There are 
no organs or appendages, save in some, and perhaps all motile 
forms, there is at one, or at most, two points, an exceedingly fine, 
hair-like appendage, to the vibrations of which the movement of 
the organism is attributed. This fine cilium or flagellum, as it is 
called, is a difficult thing to see, even with the best microscopic 
equipment and most expert manipulation, partly on account of 
its exceeding fineness or thinness, partly from its rapid vibrations. 
Sometimes, by introducing a weak solution of iodine, so as to gradu- 
ally subdue the movement, the cilium can be made out when not 
practicable otherwise. 
5. Reproduction and Development. 
Bacteria increase by one dividing itself into two. There is no 
such thing as sexual differentiation, nor is there in the develop- 
ment anything comparable to the germination of a seed. Division 
is affected by the formation of a transverse partition or septum of 
cellulose across the middle of an adult cell, thus making two com- 
partments, after which separation gradually takes place by the 
parting of the outer wall and the middle of the new partition, with 
a rounding off of the contiguous ends; while, during the same 
time, each half grows to the size of the original whole. Thus one 9 
becomes two, each of the latter being in every way similar to the 
first. Under favorable circumstances this process may in some 
species take place within one hour, then in the course of another 
hour be repeated, and so indefinitely. Shorter periods for the 
process have often been reported. If we pause to rationally com- 
prehend this rate of increase, we shall soon be lost in the amazing 
numbers which in a little time spring from one. It may seem in- 
credible, but any one may readily verify the fact that according 
to the rate of one division each hour, the number from one after 
twenty-four hours will be more than sixteen millions, and after 
forty-eight hours nearly three hundred billions. Cohn has com- 
puted that Bacterium termo (a very common species in putrifying 
organic matter) would, at the end of twenty-four hours, at the above 
rate of increase, fill a little cube one-tliousandth of an inch across 
each side; after forty-eight hours the solid mass would amount to 
about a pint; then of course at the end of another hour—since 
each would become two in this time—there would be two pints, in 
two hours four, in three eight, in four sixteen, etc., and such is 
the astonishing increase by this geometrical progression, that at the 
end of five days from the beginning of the mass arising from one of 
these exceedingly minute creatures would be sufficient to fill com- 
pletely full, or to equal in weight the water of, the oceans of the 
world. 
Incredible as this seems it is a simple calculation which any one 
can make on the supposition that the organism is one twenty-five 
thousandth of an inch in transverse diameter and twice as long, 
and that the number is double every hour. That nothing like this 
ever really occurs in nature for any consecutive number of hours, 
we need not be told; but the want of it only shows the harmonious 
interaction of causes and effects among the sum total of forces and 
activities on our earth; it is not because this Bacterium under the 
assumed conditions does not increase at the marvelous rate stated, 
but because such conditions do not continuously exist. The limita- 
tions are fixed by the given supply of proper nutriment, the 
absence of harmful chemical compounds, temperature, electrical and 
mechanical agitations, the effects of other living organisms, etc.; 
nevertheless the computations prepare us for the acceptance of 
facts, which would otherwise be deemed incredible, and they aid us 
in the explanations of observed phenomena otherwise inexplicable. 
When it is known that a certain species may reproduce itself with 
anything like this rapidity, we need not wonder that individuals are 
found, after a short exposure of the nutriment substance, in 
innumerably great numbers; and, if there is any chance for one or 
more of such individuals to gain entrance in the first place, we 
need not resort to speculations concerning spontaneous generation, 
or the transformation of parts of other living things to account for 
the multitudes subsequently found. 
But some species seem never to grow or multiply rapidly, even 
under the most favorable conditions. They differ among themselves 
as do the species of the higher plants. Some varieties, for instance, 
of the cultivated radish may have two or even three generations in 
a season; while others require two years to perfect seed. Some 
weeds come to maturity in a few weeks and produce thousands of 
seeds, while an oak lives through the centuries. 10 
In the process of self-division, complete separation may or may 
not take place. There is indeed considerable variation in this 
respect, even in the same species, according to the external and per- 
haps internal conditions. If, after the transverse dividing septum 
has been formed, further separation does not take place, the result 
is in a little time a filament, made up of cells placed end to end, 
and either quite smooth and of uniform diameter, or more or less 
constricted at the joints, so as to be bead or chain-like. In this 
case, however, each link is really a distinct individual so far as its 
physiological functions are concerned, and life is in no way inter- 
fered with if they are mechanically or otherwise separated. In one 
genus (Sarcina) division appears to take place in two directions— 
transverse and longitudinal—so that little regular squares of cells 
are produced, four or sixteen or more being frequently seen asso- 
ciated together in order. 
The individuals of certain species cohere together without order 
in a somewhat compact mass called zoogloea, bound by the glairy 
substance in which they are imbedded. But this is the case only 
in special conditions or states, for it is easy to see single ones 
free themselves from the immovable mass, and swim away in the 
liquid in which the whole are submerged. The zooghea mass may 
be the result of the multiplication of a single cell, or those origin- 
ally separate may become thus united. 
Besides the method by division, several species are known to re- 
produce themselves under certain conditions by what are termed 
spores. The protoplasm of a cell becomes consolidated into a 
spherule occupying only a small part of the cavity. This afterward 
becomes free by the dissolution of the old cell wall, and. at the 
proper time, under the proper conditions, the spherule develops into 
a full-sized cell like its parent form. The formation of such so- 
called spores usually takes place when the nutriment is nearly 
exhausted, or when not suited, either in kind or in the required 
state as to temperature, etc., to the regular growth of the organism. 
It is a method of self-perpetuation rather than multiplication. 
Still, in a few cases of which record has been made, more than 
one spore is produced by each cell. Touissant, of France, has seen 
within the cavity the formation of spore sacks {sporangia), each of 
which produced from three to six spores. It is often in the form 
of these all but infinitesimal spores that bacteria are carried in the 
atmosphere. When produced in liquid they fall to the bottom after 
the dissolution of the old cell wall, and form, when numerous 
enough, a plainly visible, white sediment. In case the water is 
then evaporated, the sedimentary material becomes a fine powder, 
the particles of which readily float in moving air. 
6. Vitality and Endurance. 
Moisture is essential to the growth of bacteria, but prolonged 
drying does not necessarily kill them. In the case of the species 
causing the blight of pear and other plants, they certainly lose 
little or none of their vitality by preservation during two years in 
the dry state on the point of a quill. Among those kinds producing 
spores, the adult organisms often do not live more than a few days 
or weeks, while the spores seem to absolutely defy time. Pasteur 11 
thinks he has shown that the latter retain their vitality in the earth 
out of doors for at least twelve years. After keeping in a sealed 
tube four years, some virus of splenic fever was sent from England 
to this country, where it was opened and used with fatal effect in 
inoculating animals. It has even been argued by some investiga- 
tors that bacteria never die, except as destroyed by fire or injurious 
ehemical compounds; and whatever may be the case otherwise, so 
far as age is concerned this is true, for on account of their manner 
of propagation an. individual does not grow old. 
Each species is adapted to a certain heat temperature from which 
variation may take place, within only very narrow limits in some 
kinds, or a wider range with others, (75° to 105° F.) None appear 
to be killed by cold, but their vital activities cease at given limits, 
never reaching below the freezing point of water. An artificial tem- 
perature of 123° E. below zero has been tried without killing them. 
On the other hand not only is the limit of activity reached by in- 
crease of temperature, but death always ensues by exposure to a 
given but greatly varying degree of heat for different species. Spores 
immersed in the fluid resist for a time the heat of boiling water, but 
all adult forms are killed in this way. When the medium is alka- 
line a higher degree of heat is required to destroy life than when 
neutral or acid, and if the organisms are dry a still higher temper- 
ature may be withstood; 140° F. in water, fruit juices, vinegar, sour 
milk, etc., is absolutely fatal to such as ordinarily occur in these 
fluids. The highest temperature yet known at which any bacteria 
are able to live and develop is 133° F. ; this has been observed in 
an infusion of beans. But some spores are not killed, especially in 
alkaline fluids, by prolonged boiling, just as some seeds withstand 
a similar test. If either are softened by germination, they quickly 
succumb. 
We make use of these facts in the operations of every day life, 
especially in the process of canning articles of animal and vegetable 
foods, scalding cooking utensils, etc. The heat kills the bacteria 
present. 
Various substances destroy bacteria, or at least prevent their 
propagation in nutritious solutions. Of these, the best known and 
most widely used are carbolic acid and quinine. Several others are 
more deadly to the organisms than these; but they either have some 
objectionable properties, or have not been so generally introduced. 
Grace Calvert asserts that some bacteria can live in pure carbolic 
acid, but there seems to be some mistake in this, at least for ordin- 
ary species, for hundreds of experiments prove that none are devel- 
oped in a liquid containing one-lialf per cent, of this antiseptic. 
The following table, from experiments by M. Jalan de la Croix 
(Revue Scientifique, Feb. 4, 1882), shows the number of parts of 
water to one of the substance named which barely permits the 
development of bacteria in infusions of meat. For instance, if thirty 
parts of water are mixed with one of alcohol, organisms may infest 
the mixture; but if twenty-nine parts of water are used to one of 
alcohol, bacteria do not develop, and the mixture does not ferment: 
Alcohol 30 
Chloroform - - - 134 
Soda biborate 107 12 
Eucalyptol 808 
Phenol (carbolic acid) 1002 
Thymol 2229 
Potash permanganate 804 L 
Picric acid 8041 
Borated soda salycilate 8877 
Benzoic acid 4020 
Etherial oil of mustard 5734 
Sulphurous acid 7584 
Alum acetate 7585 
Salicyclic acid 7077 
Mercury bichloride 8858 
Lime hypochlorite 18092 
Sulphuric acid 10782 
Iodine 20020 
Bromine 20875 
Chlorine 34509 
From my observations these results seem to be trustworthy, though 
others very dissimilar have been published. It is not a sufficient 
test to observe through the microscope the effect that any substance 
has upon the motions of bacteria. Sometimes the addition of pure 
water causes their motions to cease, and sometimes molecular 
oscillations, not always easy to distinguish from those of life, con- 
tinue after the organisms are dead. This has no doubt been a 
source of error in some of the accounts given to the press. The 
above figures were arrived at, by trying more and more water to 
one gramme of the substance until at last bacteria developed and 
putrefaction set in. 
It should be said that it is well nigh impossible to kill bacteria 
in the air, by any kind of fumigation, except in a very thoroughly 
closed space, like an air-tight vessel or box. A mistaken sense of 
security often exists when the atmosphere of living rooms, sick 
chambers, etc., are pervaded by the odors of some supposed antisep- 
tic material. These floating “germs” can at least withstand as much 
fumigating as any human being, and usually very much more. On 
the other hand, much can be done towards destroying noxious bacteria 
or preventing their growth and propagation, by impregnating liquids 
and solids by proper amounts of such destructive agents as are 
enumerated above. Experiments are now in progress of treating 
the carcasses of slaughtered animals with antiseptics not poisonous 
to man, for the purpose of sending fresh meat without ice across 
the ocean or other similar distances, and the results give much 
promise of success. A white powder is offered for sale to keep 
fruit without canning, and it appears to have virtue enough to 
really accomplish the result claimed without detrimentally affecting 
the food. (Compounds of boracic acid). There is, no doubt, much 
to be gained of practical utility in this direction. 
7. Nutrition. 
Bacteria absorb their food by endosmosis through the cellulose coat- 
ing of their minute bodies. The nutrient material must therefore be 
in a liquid state as well as of the kind and strength suited to the 13 
specific organism. Like more highly organized living things, each 
species has its own peculiar kind of food, without which develop- 
ment does not take place. As a cat would starve on hay, and an 
ox on meat, so similar differences are found among these inhabi- 
tants of the microscopic world. But all require organic food derived 
from the bodies of higher plants or animals, though it has been 
sufficiently proved that at least some kinds can take the required 
nitrogen from inorganic sources. Bacteria could not live alone on 
the earth; they are not destroyers, not up-builders; they pull down 
and decompose material prepared by the assimilation of other vital- 
ized workers. 
Some kinds are rigidly confined to dead matter, others develop 
and grow at the expense of living plants or animals, causing little 
or no inconvenience or even conferring real benefit to the latter; 
or instituting varying degrees of discomfort, injury and disease. 
The waste products of their physiological processes are varied, 
after their kinds, as their food,—acids, alkalies, gases, liquids 
fragrant, ill-scented, etc., but always of simpler chemical composi- 
tion than the original, until at last, through perhaps the consecu- 
tive action of several species, the elemental state is reached. Thus 
in the fermentations of solutions of sugar, alcohol is given off as a 
waste product by the “yeast plant” (Saccliaromijcetes) and the 
diluted alcohol ferments through the effects of the “vinegar plant” 
(mycoderma), and in this case vinegar is the substance thrown off, 
while this in turn decomposes in a similar manner by other agents 
into carbonic acid and water. 
8. Origin. 
The question, “Where do bacteria come from?” that is, what is 
their original source, is sure to press itself for answer. This answer 
is by no means an easy one to give with postive assurance of 
correctness. We have already seen how they are reproduced and 
the rapidity with which they may multiply, as well as something 
of the modes by which they are disseminated; but all thinking 
persons wish to know how or whence the first ones came into 
existence. 
Upon this question there have been many experimental inquiries 
by the ablest investigators, and many theories have been pro- 
pounded by those most competent to formulate them, as well as 
the crudest of unsupported hypotheses by untrained minds. Among 
all these opinions we may select three as worthy of special notice: 
1st. Spontaneous formation under proper conditions from inor- 
ganic chemical elements or compounds. 2d. Transformation from 
other living organisms or their parts; and 3d. Direct creation by 
the great Author of all things. 
It would require too much space to even sketch in this place the 
arguments which have been advanced in support of each oi* these 
theories by thorough scientists. The voluminous literature on the 
subject shows the interest that has been felt and the real warfare 
of words that has been waged by contending supporters of their 
own or other ideas. 14 
But no one without personal bias can carefully review this litera- 
ture to-day, with the results of experiments clearly in mind, with- 
out concluding that the first and second have not been proved. 
From a philosophical stand-point the first is highly plausible, since 
these organisms are admittedly among the lowest living things. If 
spontaneous generation takes place anywhere in nature, we should 
look for the phenomenon here; but, while certain experimenters 
have supposed their results showed the theory true, others still 
more expert have uniformly pointed out the fallacies of such experi- 
ments or deductions, so that up to the present time we are bound 
to say the facts known disprove rather than prove the hypothesis. 
The second has not been so fully and conclusively studied, yet the 
most searching investigations have not been wanting, with, upon 
the whole, negative results. No untrammeled scientist, conversant 
with the entire subject as now known, admits the proof of the origin of 
bacteria by transformation of the parts of other plants or animals, 
however close and constant may be the accompaniment of the one 
with the other. In this statement we exclude the idea of evolution 
during centuries of time, the change taking place by numerous un- 
recognizable differences; for, to our mind this belongs under the 
third hypothesis. We have, therefore, just the same scientific infor- 
mation about the origin of bacteria as we have about that of other 
living things, man included. Whether we hold that the Creator 
fashioned each species in the beginning by a direct act, or accom- 
plished the same by instrumentalities, working through the ages, 
makes no difference in the question before us. We are forced to 
refer the origin of bacteria to the same Power to which we attribute 
the origin of man. It is certain that these minute organisms have 
existed in very closely similar, if not identical, forms as at present, 
from remote antiquity, as is proved by the discovery of fossil re- 
mains, as well as the evident effects produced in the past ages of 
the world, according perfectly with those now known to be results 
of these creatures. 
It must be admitted, however, that in the progress of individual 
development some kinds pass through different forms, which have 
been supposed to be characteristic of species, and that, retaining 
the same form, the physiological effects may vary through the pro- 
longed influence of certain external conditions. Thus an individual 
cell may be spherical, then oblong, cylindrical, and filamentous, in 
regular sequence of growth, though each of these forms in other 
species may be characteristic and unchanging. And a species ordi- 
narily living in an infusion of dead vegetation may, by a slow and 
gradual change, become capable of surviving and multiplying in the 
blood of living animals, whereas a sudden transfer from the one to 
the other medium would have permitted no such results. But man 
himself is capable of becoming adapted to as remarkable changes. 
We say we become habituated or acclimatized to things and condi- 
tions, as of eating arsenic and of dwelling in the malarial regions 
of tropical countries. No greater changes than these are known in 
the life history of bacteria, only that it requires less time for the 
modifications to take place; and this should be anticipated from 
their rapid succession of generations. 15 
9. Place in Nature. 
Bacteria are certainly living things, hence, according to the ordi- 
nary thought and classification of objects, must be either plants or 
animals. Formerly spontaneous or self-caused motion was held to 
be characteristic of animals as distinguished from plants; and, as 
many bacteria are seen under the microscope to move freely and 
in some cases very rapidly to and fro, hither and yon, they were 
at one time unhesitatingly classed as animals, as indeed most un- 
scientific observers would at once pronounce them now when view- 
ing them for the first time by the aid of a powerful magnifier. But 
the fact is, self-caused motion is not confined to animals. Really 
all plants more or less possess this power. A seedling causes its 
stem to turn upward and rootlet downward through internal forces, 
and afterward the growing parts bend to or from the light, as every 
one has observed. Leaves quite generally assume different positions 
day and night; flowers open and close, twining plants revolve in 
such manner that the free end sometimes sweeps a circle of four 
feet in diameter about the supporting object, tendrils twine in some 
instances fast enough to be plainly observed by any one possessing 
good eyes and a fair share of patience. It is true that all the 
higher plants are fastened to their supporting substance, and are 
incapable of roaming from place to place; but the lowest members 
of the vegetable kingdom are not thus limited. In some conditions 
at least the latter move as freely as any animals, not simply 
through the controlling influence of external agents, but from forces 
wholly within themselves. Such motile plants are all microscopic 
in size, but no botanist or zoologist hesitates to pronounce them true 
plants, having all the fundamental characteristics of members of 
the vegetable kingdom. 
So, freedom of motion itself, however striking it may be, is not 
sufficient cause for classing bacteria with animals. But it has been 
before stated that the outer coat or wall of the organisms is com- 
posed of cellulose, and this is peculiarly a substance belonging to 
all plants, and, with very rare exceptions, not to any animals. It 
has also been mentioned that bacteria are capable of taking the 
nitrogen required for their nutrition from inorganic salts, and this 
is alone characteristic of plants; there are no exceptions on the 
animal side. 
These and other reasons have in recent times caused all natural- 
ists who have made these objects a special study to pronounce 
them plants. There is no difference of opinion among proper 
authorities, if the choice is limited to one or the other of the two great 
'■kingdoms of animated nature ; but Haeckel, a German scientist, has 
proposed to take the lowest forms of both these kingdoms and 
constitute therewith a third, called Protista; in this case the bac- 
teria would be called neither plants nor animals. 
As plants, the bacteria certainly occupy a position at or very near 
the bottom of the scale. They are among the simplest in structure 
of living things, and include among them the smallest objects in 
nature, animated with a spark of that vitality whose nature and 
essence is as unknowable in them as it is in the being created in 
the image and likeness of God. 16 
There is a further and undecided question as to whether the 
bacteria belong to the Fungi or to the Algte, two great divisions of 
the vegetable kingdom; but this depends solely on the definitions 
given to these groups. If greater prominence is given to form and 
habitat, they more nearly resemble the Algte, or sea-weeds; if 
physiological functions are decisive, then the bacteria are unques- 
tionably Fungi. This is now less important, since in a strictly 
natural classification it is undecided whether or not the great groups 
known as Algie and Fungi are entitled to remain as such. Proba- 
bly not; in which case the term Protophytes will almost surely be 
uniformly adopted to designate the lowest division of the vegetable 
kingdom, and in this the bacteria will presumably occupy the lowest 
place under the original name of Schizophytes, a word now in use, 
and meaning dividing or splitting plants. 
PART II. EFFECTS OF BACTERIA. 
1. Fermentation and Putrefaction. 
Until within recent times it has been supposed that organic mat- 
ter, dispossessed of the vitality to which it owed its existence, was 
naturally very unstable in its chemical constitution, and that its 
tendency was to go back to the elementary inorganic state, through 
the operations of simple chemical affinities. The soft parts of 
animal bodies have been considered especially liable to change after 
death; indeed this is now so common and constant a phenomenon 
that it is looked for as a matter of course, unless express provision 
is made to prevent it. We are surprised when told that during 
the summer season the fresh flesh of buffalo on the western plains 
remains sweet and perfectly good until dry in the warm open air. 
The astonishing story is repeated again and again that the bodies 
of the woolly elephant of ancient Siberia have been taken out of 
the ice, in which they perished long ages ago, yet with flesh still so 
fresh that dogs feed upon the carcasses. 
The scrupulous care which we are obliged to take to avoid ill 
consequences to butchers’ meats, makes these exceptional instances 
of preservation in nature really wonderful to us. We say the law 
is for such material to putrify and decompose, for milk and cider 
to sour, for the expressed juices of fruits to ferment, and the fruits 
themselves to decay. A pile of green herbage heats and rots, and 
wood exposed to moisture gradually loses its strength and disap- 
pears to help form vegetable mold. 
These various changes, to which all dead organic matter is sub- 
ject, going on about us so abundantly and so constantly, make up 
a large part of the physical phenomena of the world ; we expect them 
to occur and recur with the same certainty if not the same regu- 
larity of time or rate as the fall of unsupported bodies to the earth, 
the planetary changes and the succession of the seasons. We just 
as much expect fresh meat to spoil in warm summer weather as 17 
we do enkindled wood to burn. The wine maker counts just as 
certainly upon the fermentation of the juice of the grape as the 
engineer upon the pressure of superheated steam, though neither 
the one nor the other may stop to consider the philosophy of the 
phenomena with which they are respectively confronted. They have 
ascertained by experiment the governing conditions, and proceed with 
the confident assurance of what has been, will be. 
Now, to those who herein read for the first time that dead organic 
matter has in itself no such tendency to spontaneous change, that, 
subject, as in nature generally, to all the activities of pure air, and 
pure water, and to these alone whatever the temperature, dead fish 
and flesh will not become ill-scented or putrid, that milk and blood 
will not change from the condition they have when drawn from the 
living animal, that a heap of green, or wet grass will not heat and 
rot, that moist wood will remain as durable as granite, and that 
the substances of their own bodies afterlife has departed are as in- 
corruptible as gold,—these words may seem foolishness and upon 
the face of them absurd; yet this is the teaching of science, and is 
the unavoidable conclusion from many instructive experiments. 
When the whole facts are known, the wonder is rather that the flesh 
of slaughtered animals so surely putrifies with us, not that as a rule 
fresh meat exposed to the pure air of the western plains should re- 
main forever good. These facts could never have been known 
without the aid of the microscope, and since this wonderful instru- 
ment is of modern invention, the knowledge set forth in the follow- 
ing pages has been gained alone by modern investigation. If there 
is still doubt about the matter as a general phenomenon, it is only 
because new ideas are slowly accepted; if there is dispute among 
the informed as to details of the process, it is mostly because so 
few really competent experimenters have yet undertaken the delicate 
but fruitful work. 
The marvelous progress of modern science is based on the well- 
grounded idea that every effect has an adequate cause, and that 
these causes, in the material world at least, are subject to unde- 
viating law. If a body moves, the force is sought, and usually not 
in vain, which produced the motion. If change occurs, a competent 
agent is at once supposed to be instrumental in its accomplishment. 
Students of nature are not content with passing anything as mys- 
terious which can be brought within the domain of knowledge, nor 
with accepting as a fact anything which does not fall within the reign 
of natural cause. Possessed of this spirit, and provided with the 
necessary instruments and means, the subject before us could not 
escape investigation by the quickened intellects of recent times. 
The result is, after much conflict of opinion and difference of inter- 
pretation, the established fact, that the natural changes taking place 
in non-living organic matter, are all due to the vital activity of living 
things. Some of the usual results of life-forces may be accom- 
plished in the chemist’s laboratory, but the processes and conditions 
there and in nature are entirely different. What life is, and to 
what its particular powers are due, we do not know; but we do 
know its effects, and these are as pronounced and unique in the 
natural destruction as they are in the original upbuilding of organic 
matter. Life manufactures, and life in turn pulls to pieces and 18 
destroys. An organic body is not a watch, which, having been 
wound up, runs dowrn of itself; but it is a splendid temple, the rich 
material of which, accumulated from all lands, would require the 
same as its original freighting for its redistribution. But the low, 
microscopic organisms are by no means alone, if they act in any 
sense different from other vitalized beings, in the work of destruc- 
tion. Every living creature is continually destroying itself, reducing, 
through its physiological and normal processes, the solid parts to 
liquids and gases, from the organic to the inorganic. This is the 
waste which all plants and animals suffer as long as life continues. 
After death waste goes on in a different way, through the physio- 
logical and normal activities of other living beings, and the more 
noticeably because there is no repair. 
Among these latter destroyers there are very many kinds of 
animals and plants. Indeed all animals are included in the list, and 
the digestion of food with them is always a work of destruction, as 
is readily understood. There are among flowering plants certain 
kinds which are also purely destroyers—the dodder or golden thread 
(Cuscuta), found sometimes in tangled profusion on weeds, flax, clo- 
ver, etc., is common with us. But it is to the Fungi that we must 
look for the principal agents, of the plant kind, which act as pure 
destroyers of organic matter. These degraded plants live solely on 
the accumulated and organized products of other plants and animals, 
assimilating a portion for the architecture of their own bodily 
structure, and exhaling another very considerable part as waste, in 
one shape or another, but ultimately as carbonic acid and water, 
two prominent ingredients in the original nutrition of green-leaved 
plants. Nitrogenous compounds, as ammonia, nitric and butyric 
acids, are also given off in the destruction of most organic matter. 
An old log in the woods having no tendency to decay, and resisting 
much better than iron the slow corrosion of the oxygen of the air, 
tumbles to powder under the digestive power of insects, toadstools 
and bacteria, each kind working differently, but accomplishing 
nearly the same result. 
It has already been said that in their physiological effects at 
least the bacteria are Fungi. Their food is organic, elaborated in 
the first instance, if not direct, by green-leaved plants. Their 
function is to destroy, like that of other colorless plants and all 
animals. In this process of destruction peculiar and characteristic 
effects are usually produced by each species, and in very many 
cases each species is limited to some special kind of food material. 
In this there is nothing new or strange, for the law holds good 
throughout all nature, among all animals and all plants. 
If, now, we remember the facility of distribution which these 
minute organisms enjoy, their vital endurance and their wonderful 
powers of reproduction, we need not after all be surprised that 
milk, wherever left exposed under the proper conditions of temper- 
ature, etc., becomes sour through the agency of a living organism 
developing in, and feeding on, some element or elements of its 
substance; or that fresh meat becomes ill-scented through the 
respiration of similar living things, acting in a similar way. Keep 
these destroyers out, and no such results will occur. In wide arid 
regions where there is but little material on which they may 19 
develop, their uniform presence in the air or on the surfaces of 
solids, cannot be expected, and this is the secret (now a secret no 
longer) of the fact that meat keeps in such places without putrefy- 
ing. Since the white man has made his habitation in the West 
where the old hunter used to expose his jerked buffalo with 
impunity to the warm sun and air, this can no longer be done 
with butchered flesh. But it is still found possible on these 
wind-swept plains to keep meat fresh for a considerable time by 
sticking it on poles high above the earth, above the usual dissemin- 
ation in these places of living organisms. The same thing is true 
on high mountains, though the warmth of the sun may be fully 
sufficient during mid-summer for the manifestation of all kinds of 
life and of rapid changes in putrefactive substances. 
Among the destructive alterations of organic matter, those known 
as fermentation and putrefaction are peculiarly the effects of cer- 
tain species of the low plants of which we write. Because the lat- 
ter are so minute, they are not commonly known to be present, 
hence the popular idea that the processes are spontaneous, due to 
the nature of the material in which they occur. The French Count, 
Appert, early in the present century, working under the idea that 
the oxygen of the air is the active agent in these destructive 
changes, devised the method now so largely adopted of hermetic- 
ally sealing fruits and meats. He fortunately hit upon the plan 
of expelling the air by heat, and of closing the vessel while the 
contents are hot. The result is what he hoped for, the indefinite 
preservation of the material. This explanation, though the only one 
known to many to-day, is absolutely false, as has been clearly 
shown in several ways. It is by no means necessary to exclude 
the air; it is only essential that living things adhering to the sur- 
faces of the fruits, etc., and often contained in the air, be pre- 
vented from developing and multiplying in the substances. The 
heat destroys such as are in the vessel either on its own interior 
surface or on the fruit, and the closing while hot prevents the 
entrance of fresh germs. A can of such preserved material opened 
in the summer on the house top in the country might not spoil 
for many days or weeks. In such experiment care should be taken 
to keep the article to windward of the person for obvious reasons. 
In a warm time during winter success would be much more certain. 
Two years ago I found that milk taken direct from a cow in a 
heated glass fruit jar, with the simple precaution of previously 
washing the udder and adjacent parts and closing the jar as soon 
as possible, often kept sweet and fresh several days, many 
times as long as that left open in a clean milk room. 
I now proceed to rehearse the results of some more careful and 
conclusive experiments which, it must be admitted, fully substantiate 
what lias been said about fermentation and putrefaction being 
due to living organisms instead of to the air or any quality of the 
experimental material. 20 
Figure 1 represents a 
little glass tiask. invented 
by Pasteur, of France, for 
the purpose of making pure 
►cultures of certain kinds of 
these minute organisms. 
The drawing was taken 
from one of the several in 
actual use by the writer, 
made at the chemical 
laboratory of the Industrial 
University. It will be seen 
to consist of a little bowl 
of the capacity of about 
one fluid ounce, and from 
this arise two tubes, one 
of which is surmounted by 
a short piece of rubber 
pipe, containing a glass 
stopper, the other long 
drawn out and bent down- 
ward, the descending por- 
tion being very fine, with 
an internal continuous 
cavity about the diameter 
of a medium sized horse-hair. The end is left open. 
For our purpose we may take any fermentable or putrefactive 
infusion, as of hay or chicken broth. Filter to remove the solid 
particles, that we may better observe what does or does not take 
place, and fill the bowl of the flask through the stoppered tube. 
We now hold the flask over a dame until the fluid boils, and the 
steam passes out of the larger tube, which we then close, having 
previously passed the stopper through the flame. The steam is 
permitted to rush out of the fine tube for a little time, after which 
we hold the fine open end in or just above the flame until the steam 
within the flask is condensed by cooling and the inrush of air ceases. 
We have now only to set the flask aside and watch results. If any 
change takes place, as a scum forming on the surface, a moldy 
growth on the glass, or a sediment settling on the bottom, it can 
readily be observed; if not, we may see that the clear liquid con- 
tinues limpid and pure. Let us examine closely the conditions, 
supposing the temperature to be that of warm summer weather. 
We use a fluid which, freely exposed to the air or enclosed in a 
bottle without subsequent heating, would rapidly ferment or putrefy, 
becoming turbid and milky, with (if soup) a slimy scum forming on 
the surface, and withal an odor so characteristic that we shall 
know well enough what it means. By boiling in the flask, any 
living organisms in the liquid or attached to the interior of the vessel 
are killed. And by holding the minute opening in the flame—taking 
care that the glass is not melted—until after the condensation 
of the steam by cooling, there is afterward no strong inrush of air 
through the open tube. Now, all living things, no matter how large 
or how small, have solid parts, and are really heavier than the air, 
so that however minute, they cannot float in the latter, except as 21 
swept along by currents; hence, though by every alteration in tem- 
perature, without or within, there will be slow interchange of air, 
the minute solid particles of the external atmosphere are not likely 
to be carried up the fine tube and over into the liquid, which is 
therefore exposed to pure germless air. I have now such a flask, 
filled nearly two years ago with filtered chicken broth which is as 
clear and sweet as when first made, and this has been kept on a 
shelf in the laboratory, where the temperature has been very favor- 
able to putrefactive changes, and where, from the use of the room, 
the air is unusually laden with organic dust. On the same shelf are 
other flasks of similar kind, some of which, after keeping for some 
months in the condition of the one described, have been unstop- 
pered for a few minutes, and then closed again, with sure putrefac- 
tion as the result. Sometimes simply shaking is sufficient to start 
this process, showing well enough the preservation was not due to 
any want of susceptibility of the liquid to such change. If, how- 
ever, we take the precaution to hold the larger tube over a flame, 
we may open and close it without such results, and in this way we 
may from time to time microscopically examine the liquid by tak- 
ing a drop upon a previously heated glass rod. While the liquid 
remains limped and sweet, no organisms are found, but they always 
swarm in profusion when visible changes take place. 
A successful experiment of this kind seems to prove two things: 
1st, that the potential factor in fermentation resides neither in the 
substance itself nor in the pure air; 2d, that organisms do not 
spontaneously develope from germless material. 22 
Tyndale, of England, has taught us 
another mode of experimenting to gain 
answers to the same questions. He 
constructs a W'ooden box with a hack 
door, glass front and side windows, 
and passes through the bottom several 
test tubes, air tight. Through a hole 
in the top fitted with a sheet of India 
rubber and a stuffing box of cotton 
wool wetted with glycerine, a long 
?lass rod with a funnel above may 
be thrust to fill the test tubes, and 
two sinuously bent glass tubes pierce 
the top for the admission of air with- 
out dust, as explained in the account 
just given of Pasteur’s flask. The in- 
terior surfaces are moistened with gly- 
cerine and the box closed. By pass- 
ing a beam of sun, or brilliant arti- 
ficial light, through the windows it 
can be readily ascertained when the 
floating matter has settled and the 
air is pure, after which the test tubes 
ire filled with putrescible liquid, 
which is now boiled by heat applied 
externally. We notice that the boiled 
infusion is freely exposed to the air 
of the box as well as to the outer 
atmosphere through the bent tubes, 
and that the only precaution taken is 
to allow time for all minute solid par- 
deles to settle in the still air of the 
chamber to whose moistened surfaces they adhere. Hundreds of tests 
have been made in this way by Professor Tyndale with the most satis- 
factory and positive results, with very many kinds of putrescible 
substances, as natural animal liquids, infusions of flesh, the viscera 
of animals, of fish and of vegetables. The perfectly sweet and 
limpid filtered infusions remained in this condition for months, 
while outside of the moteless box in the same room they became 
putrid and offensive in some hours. It was sufficient at any time 
to open the back door of a box, if hut for a moment, to secure 
these latter results in the experimental test tubes. In the clear, 
unchanged liquid living organisms were never found; in the ill- 
scented turbid ones, these always existed in countless numbers. 
What can be more instructive? What better demonstration could 
we wish of the non-occurrence under usual circumstances of spon- 
taneous generation of living organisms, or of the stability without 
these of organic substances? 
Fig. 2. 
From the earliest times many of the diseases of man and of the 
domesticated animals have been known to he contagious, i. e. 
capable of being transmitted from a diseased to a healthy subject, 
while some that are now known to be propagated in this way were 
2. Diseases of Plants and Animals. 23 
looked upon as peculiar visitations of Providence for supposed sin— 
the fact of the contagion not having been observed. There have 
also been from earliest history many speculations as well as care- 
ful studies, upon the nature of the poisonous or contaminating 
principle, and physicians, ever since their art has been practiced, 
have endeavored to find out remedies by experiment. Among*the 
diseases of the human skin that is happily much less prevalent 
now than formerly, the itch was the subject of extended and warm 
controversy from the twelfth to the eighteenth century among 
Arabian, Italian, French and German physicians and scientists. 
Some held that want of personal cleanliness was the sole cause 
and that the disease might spontaneously appear at any time and 
place, given only the proper conditions. Others found a minute, 
living, crawling, egg-laying inhabitant of the diseased skin, and 
attributed the ill effects directly to its work. Then came learned 
disputes as to whether this living thing did or did not originate 
from the filth, and whether it came as a consequence simply, or 
was verily the exciting cause of the disgusting malady. The litera- 
ture upon the subject is very full, and if in those days they had 
possessed our aptitude for putting things in type, it would have 
required a library of books to contain the discussions. 
Practicing the experimental method, some investigators at last 
put the living creature, separated from the debris of the diseased 
skin, on their own bodies, and watching its operations, established 
its true parasitic nature. 
The agent, a mite, popularly called an insect, is propagated only 
from eggs laid by parent individuals, and thus maintains its specific 
identity. Its life-history having been satisfactorily made out, and its 
mode of operation fully made known, it is no longer a subject of 
dispute; but the history of the controversy is a valuable one in our 
present studies. Knowing the facts, we now smile at the absurdi- 
ties of the opinions held, and the foolishness of the supposed proofs 
upon which these opinions were founded; yet these were not cruder 
nor farther from the truth than are many of the speculations and 
incredulities of our times concerning “diseased germs.” 
While an illustration of this kind cannot be taken as evidence in 
the case of bacteria, the same questions are now asked about, and 
the same objections made against, these latter organisms as the 
cause of disease. Yet careful investigators are to-day as able to 
handle bacteria, to see their shape, observe their manner of in- 
crease, ascertain their proper food material, and find out the sub- 
stances inimical to their lives, as were Abenzoar and Bonomo in 
their time to similarly study the itch mite,—thanks to the im- 
provement of the microscope, more than anything else, except the 
general acceptance of the experimental and inductive method of study. 
The fact is, those competent to judge, now agree in holding that 
some severe contagious diseases of man and animals are directly 
due to bacteria, while many scientific investigators, whose abilities 
cannot be questioned, and who have abundant facilities and oppor- 
tunities to learn and to know, claim that all diseases, readily com- 
municable from the infected to the healthy, have their origin in 
the activities of these living organisms, and this opinion is certainly 
growing into wide, if not universal, acceptance. Other diseases, as 24 
fever and ague, not understood to be infectious or contagious, are 
also believed to be due to certain kinds of the same things. 
Herein lies the greatest interest and highest importance attrib- 
uted to these wonderful but excessively minute denizens of the, to 
common eyes, invisible world; and herein, more than anywhere else, 
rests the hope of attaining a scientific basis for medical practice, 
as well as a rational adoption of preventive measures against the 
ravages of disease. It will not do for the hobbyist to assume that 
all the ills that flesh is heir to can be traced to the corrupting 
work of “disease germs,” for, as has been before pointed out, these 
minute things have no life functions which strictly separate them 
from other plants and animals. Their physiology is our physiology; 
they assimilate food material as we do, and, by virtue of this power, 
live as we live. The delicate and complicated machinery of the 
higher animal bodies may be put out of order in many ways, and 
by want of nature’s harmony the normal, vital forces themselves 
may be the agents of disease. 
But while there is no toleration for the hobbyist, those who have 
not investigated and cannot investigate for themselves should not 
hesitate to accept the testimony of capable specialists, when the 
latter find reason to assert that such and such a disease is due to 
the microscopic mischief-makers Their bacteria minuteness no 
longer prevents the demonstration of their presence, the tracing of 
their development, the detection of the actual effects and the ex- 
perimental testing of results. There is now in certain cases just as 
good evidence |that bacteria cause disease as there is that hawks 
destroy chickens, and the evidence is as inductively rigid in the 
one case as in the other. Even without microscopic examination, 
there is good reason to assert that the contagious principle, what- 
ever it is, grows. Any chemical poison decreases in virulence by 
diffusion in a mass of inert matter, and soon loses its effectiveness; 
but it is the special characteristic of the poisons of which we write 
that a minute quantity soon infects the whole system of a large 
animal, and then the smallest drop of fluids from its body is 
sufficient to give origin to the disease in another animal and so on 
perpetually. Increase has taken place; there must have been 
growth; only living things grow; the microscope aids us to see what 
this living thing is; why should we doubt! 
It is true that Dr. Lionel Beale proposed a theory of disease 
germs, which accounts for increase by assuming that degraded, yet 
not dead, parts of the animal body itself constitute the true con- 
tagion, and that every such living but degraded portion has the 
power in some way of over mastering the healthy—a speculation 
which, though brilliantly conceived and sustained at the time, has 
not been definitely supported by later investigations, nor held with 
assurance by any other authority, known to the writer; though, 
from what has just been said, the process is neither inconceivable nor 
a priori impossible, perhaps not even improbable. The only question 
is, “Do facts prove it?” There are indeed some experimental facts 
which seem to favor the idea, viz: the transmissibility of inflammation 
produced by chemical or physical means upon inoculations with the 
exuding serum. It may be said however that even in this there is 
the possibility of independent organisms being the real virus. 25 
The first septic disease well worked oat was that of pebrine, an 
infectious malady of silk worms in France. In 1838 the production 
of coccoons was 57,000,000 pounds avoirdupois, and had doubled 
during the preceding twenty years with every prospect of continued 
increase; but during the next twelve years, owing to the ravages of 
the disease mentioned, the production fell to 9,000,000 pounds, a 
loss in 1865 alone of twenty million dollars. During those twelve 
years of national disaster, the disease had been seduously studied 
by all the scientific and professional skill of the times so far as the 
light of pathological knowledge then attained permitted, without 
practically beneficial results. In this state of things Pasteur was 
besought by the Minister of Agriculture to undertake the investiga- 
tion, though this scientist had no special qualification for the work, 
except his natural talents and his acquirements through studies on 
the origin and effects of the micro-organisms in fermentations and 
putrefactions. Great numbers of minute corpuscles had been seen 
some years before in the bodily tissues of the diseased caterpillars, 
but no one attached any importance to them. Pasteur at once turned 
his attention to these microscopic bodies, proved them to be living 
organisms, studied their propagation and mode of development, be- 
came able to distinguish infected from healthy eggs, and in Septem- 
ber 1865 communicated his results to the French Academy of Science. 
His labors met with inattention or derision, so novel were they, and 
contrary to the learning of the time. To convince the skeptical and 
arouse the heedless, he selected fourteen lots of eggs in 1866 and 
wrote out what would be the fate of the moths hatched from them 
in 1867. These predictions, placed in the hands of a public officer 
in a sealed envelope, were exactly fulfilled in twelve of the fourteen 
cases, and produced the expected effect. His instructions were obeyed 
and France rapidly regained her great silk industry—one of the 
great triumphs of practical science in our triumphant century, and 
the foundation of an entirely new system of research in preventive 
and curative medicine. 
Guided and profiting by Pasteur’s former studies, Lister, then of 
Edinburgh, since of London, began in 1865 to perfect a system of 
anti-septic surgery, which, as introduced by himself and others, has 
been the means of inestimable progress in this difficult art, saving 
life and limb, as well as untold suffering to mankind. Unfortunately, 
either from the want of sufficient information or from placing too 
much stress on certain details, doubts are entertained by some fair- 
minded professional surgeons as to the correctness of the theory, 
though not upon the real progress that has been made. There 
seems good reason to believe such doubts will rapidly pass away, 
and that still further profit will be secured in the practical appli- 
cation of scientific knowledge. It is well known to veterinary 
surgeons that animals may be castrated by a sub-cutaneous rupture 
of the spermatic cords, followed by the death and absorption of the 
testicles, without mischief to the animal, provided the epidermis 
remains unbroken, but this provision is imperative. Gangrene is 
sure to follow if the exterior is punctured. Flesh bruises on our 
own bodies do not suppurate under similar conditions, and wounds 
made with a truly clean instrument heal by “first intention,” if im- 
mediately closed and bandaged in such manner that living organisms 26 
are excluded. This result is more certainly assured by the proper 
application of an antiseptic dressing, as of glycerine, in which a 
small amount of carbolic acid has been stirred. 
The etiology of no infectious disease is now so well understood as that 
known as “splenic fever,” “anthrax” or “charbon” of the domestic ani- 
mals and “malignant pustule” in man. It is said, between 1807 and 
1870 over 56,000 horses, cattle and sheep, and 528 human beings 
perished from this alone in a single district of Russia, while the 
annual loss of live stock in France has been millions of francs. 
This is now practically subdued by prevention of infection and by 
vaccination, the history of which reads like a romance. The con- 
tributions thus made to medical practice opens up boundless visions 
of future welfare to man. Jennerian vaccination against (for ?) 
small-pox was the result of an acute but fortunate observation, one 
almost might say a lucky coincident; but Pastorian vaccination, as 
we may properly term it, is the outcome of methodical and pre- 
cise scientific research, gaining knowledge step by step and reaching 
new facts by logical induction from the known. To this progress 
there have been many contributors, but among them it is not un- 
just to mention Koch, of Germany, and Pasteur, of France; the 
former for his splendid studies on the cause, the latter for the in- 
troduction of a practicable remedy, now adopted on a commercial 
scale in France and Austria. 
The terrible disease is thoroughly known to be due to the inim- 
ical activities of a specific organism, Bacillus anthracis, described in 
another part of this paper. Within the last few years certain re- 
searches have been published which seemed to demonstrate that 
this was a physiologically varied form of a species of the same 
genus common in infusions of vegetable substances, as of hay; but 
very recent investigations make any such transformation questionable. 
Pasteur’s vaccination material is obtained by prolonged cultivation 
of the deadly Bacillus in a decoction of animal flesh kept at a cer- 
tain temperature, in which the organism multiplies rapidly, but 
progressively loses its virulence. At the proper stage, the liquid 
swarming with this particular microphyte is used for the inocula- 
tion of animals which scarcely, or not at all, suffer in consequence, 
but are thereby protected from the virulence of the dreaded para- 
site in its usual condition, bringing almost certain death within 
twenty-four to thirty hours. 
As an experimental illustration, Pasteur and his co-workers made 
a public test, at the request of a provincial agricultural society, and 
before a large assembly of interested persons and experts. Fifty 
sheep were taken from a flock, and from these twenty-five were ear- 
marked and vaccinated, May 3, 1881. This was repeated on the 
17th of the same month. In the meantime the fifty sheep were 
kept together in the same flock, under the same conditions and in- 
fluences. May 31 the whole fifty were inoculated with strong virus, 
and the sheep again turned loose together. Pasteur’s predictions as 
to the result were fully verified the following day—twenty-three 
unvaccinated sheep being dead at two o’clock, and the two other 
during the afternoon, while the twenty-five vaccinated animals re- 
mained in perfect health, save that one purposely receiving an extra 
dose of the strong virus was sick for a few hours, then recovered. 27 
Such satisfactory experiments having been often made, thousands 
upon thousands of domesticated animals have been vaccinated during 
the spring and summer of 1882, with material furnished by the re- 
nowned investigator, and again the linancial interests of France 
owes to her illustrious son and to science a splendid recompense of 
reward. 
Nor is the end reached here. The successful study of this disease 
and the production of a safe vaccination virus, will no doubt lead 
to similar results for other diseases, and not improbably furnish a 
scientific basis for that already practiced upon human beings as a 
preventive of small-pox. The fact is, a study of the disease of 
fowls commonly called cholera, helped in working out that of splenic 
fever, and especially led the way to the preparation of the vaccina- 
tion material as now used. This disease of the domestic fowl 
occurring on both sides of the ocean is really of like nature, but 
want of space precludes further notice of it. Suffice it to say that 
it is readily transmissible, either through external puncture or 
wounds, or by taking the parasite with the food. This fact alone 
should soon lead t’o measures for its extermination. 
In our own country, among other studies of this kind, much has 
been learned about yellow fever, undoubtedly due to a specific or- 
ganism not yet satisfactorily determined; about diphtheria, in which 
the minute but dangerous enemy has been well recognized and 
carefully studied; about several forms of septicfemia or blood poison- 
ing ; and especially about a prevailing disease of swine ordinarily 
known as “hog cholera.” Though “a prophet is not without honor 
save in his own country,” let us hastily review the facts ascer- 
tained by Drs. Detmers and Law in regard to this last-named 
malady. 
Hogs were entirely exempt in the United States from the disease 
until quite recent times, and though the original infection and the 
spreading from the first locality was not .observed, many facts are 
known concerning its introduction in given areas and its subsequent 
mischief, where swine kept under the same conditions were robust 
and healthy before. Numerous speculations were made and theories 
advanced to account for the plague. By some it was attributed to 
the diet (too exclusively corn), by others to filth and unhygienic 
surroundings, and by others again to degeneration from improper 
breeding, etc. 
The gentlemen named above, with others, were appointed by the 
Commissioner of Agriculture of the United States to investigate the 
disease, and, provided with the requisite means and apparatus, 
working separately, they satisfactorily proved the infectious charac- 
ter of the devastating malady. A fraction of a drop of the fluids 
from a diseased animal, placed beneath the skin of one in health 
by an inoculating needle, produced in a few days the characteristic 
affection, as did the diseased parts given in the food. They found 
by hundreds of post mortem examinations the lesions produced, and 
the course and progress of the injuries. They also found constantly 
present a specific organism, and thoroughly studied its morpholog- 
ical and physiological characteristics. They cultivated it outside the 
living body, in harmless fluids, and by further inoculations and ex- 
aminations proved its direct agency in the production of the 
observed results. They showed how this organism was liable to be 28 
transported by infested animals, sometimes other than hogs, by 
water-currents, and, under certain limitations, through the air; they 
found under what circumstances it was naturally destroyed, and 
how preserved, and they succeeded in showing what preventive 
measures could he used through general management, medicinal 
treatment and vaccination. It was my good fortune to witness 
many of the experiments of I)r. Detmers, and can personally vouch 
for most of the above results, making, for myself, conviction irre- 
sistible, that the immediate cause of the disease is none other than 
the living organism always found in the blood and excretions of the 
diseased animals. 
Whether through the information thus derived, or from other 
causes, the loss from this dreaded scourge has been conspicuously 
less during the last few years. Certain it is, men are on the alert 
to prevent, through intelligent endeavors, the infection of herds, 
even though they do not, in words, admit the truthfulness of the 
“germ theory.” 
The investigations of the author on “blight” of the pear tree and 
other plants—the only facts yet made public of injuries to living 
vegetation by bacteria,—have a scientific interest in consequence of 
the readiness with which studies may be made. It is not possible 
to cut pieces from the flesh of live animals and examine them under 
the microscope in their living state; but this can be done with 
plants. In the latter there are no sympathetic inflammatory pro- 
cesses, by which a healthy part suffers in consequence of injury to 
some other part of the body; neither are there facilities for the dis- 
tribution of microscopic parasites through the structure, as there is 
in the blood currents of animals. We often say the sap “circu- 
lates but no such thing really takes place. All the movements 
of fluids in plants are processes of imbibition, or soaking through the 
cell-walls, never in streams in tubular vessels. Hence disease infec- 
tion is local, and the effects are comparatively very easy to make out. 
In animals it is hard to determine whether the injury comes from 
the destructive action of bacteria or from their mechanical obstruc- 
tions, or the poisons they give rise to, etc.; in the pear tree such 
queries are quickly answered, and one soon sees that death comes 
from the fermentation of the cell contents. It is highly probable 
that much can in this way be learned to help in the study of 
similar maladies of man and the domestic animals. 
The studies on blight have also a practical interest in the well 
proved fact that the progress of the disease is slow, instead of the 
rapidly spreading plague formerly thought. Careful examination, 
once or twice a month, will usually suffice for the efficient excision 
of all infected parts, and this, if properly done, is perfect protection 
to the tree. The wounds must be quickly covered with paint or 
other dressing. 
The attested fact that the poisonous principle of certain plants, 
as of poison ivy or oak (Rhus), is a living organism (T. J. Burrill, 
Proceedings American Association for the Advancement of Science, 
1882,) instead of a volatile chemical compound as heretofore sup- 
posed, is also a fruitful beginning in the study of the origin of in- 
fectious diseases. Of a similar nature is the ascertained fact that 
a micro-organism found in the saliva of healthy human beings, 29 
causes death when inoculated into a healthy rabbit, (Sternberg, 
National Board of Health, 1880). 
Such facts offer no contradiction to the disease-producing agency 
*of the observed living organisms; but only show that they may be 
harmless to one host and deadly to another, at least when first 
introduced. Many facts go to show that the physiological system 
may become inured to those poisons as well as to those of a 
chemical nature. As a man becomes habituated to the use of 
deadly doses of opium and arsenic, so in like manner he may resist 
after a time the pernicious effects of bacteria, though the latter 
continue to live and multiply in certain parts of his body. This 
probably explains the peculiar characteristics and effects of “Texas 
cattle fever.” In this very characteristic disease of neat cattle the 
native animals of Texas do not-suffer, while those recently intro- 
duced from abroad are almost certainly affected. Still more 
curiously, the healthiest Texan animals carry the contagion with 
them when transferred to the Northern States, where for a time the 
alarming death of cattle which have in anyway come in contact 
with those from the South excites the liveliest inquiry and most 
earnest investigation as to the cause. Until bacteria became known 
as true disease producers no satisfactory explanation could be made 
of the strange phenomenon. 
What inscrutable mystery has been connected with that terrible 
scourge to human beings, leprosy! How it baffled the skill of the 
physician, and doomed the unfortunate to helpless and hopeless 
misery, making them loathsome though pitiable objects; life a 
wearisome burden to themselves, and their very being a menace to 
their friends! But the puzzle is solved. Through the microscope, 
the cause is visible as a self-perpetuating, parasitic plant, growing, 
propagating, destroying; yet subject to the same general surround- 
ing conditions as other life-possessing things. Its terror is half gone 
from being known, and scientific medical treatment will banish the 
other half. Though by no means a disease of the ancient times 
alone, its uninterrupted career need no longer darken the lives of 
innocent sufferers superstitiously supposed to be under the curse 
of God’s anger. The diseased need no longer be driven to the 
deserts or isolated in asylums for life in order to protect the com- 
munity from the dreadful plague. 
Without attempting to give a resume of what is known of the 
disease-producing effects of bacteria, but simply illustrations of this 
knowledge, mention is here made of only one more case, —the most 
dreaded and destructive of all the ills of the human body, con- 
sumption, (tuberculosis). Since 1865 this has been positively known 
to be transmissible from the diseased to the healthy, though not 
formerly so recognize i. Up to the present year able investigators 
have sought in vain for the parasitic organism which all analogical 
facts strongly indicated must be the cause of the terrible disease. 
But skill and patient research have at last triumphed. By certain 
processes of staining, the first of which rewarded the labors of Dr. 
R. Koch of Berlin, the destroyer has been detected, and has 
now been seen by hundreds of expectant eyes. It inhabits diseased 
parts of the body, which may be in almost any organ as well as 
the lungs; it lives and grows and reproduces, slowly for its kind, 
but surely working its dreadful results. The disease is common to 30 
human beings and the domesticated animals, and is transmissible 
from one to another in either order. With such knowledge and the 
possibility now of definite and sure grounded study, the misery and 
suffering heretofore so calamitously common, must soon be benefi- 
cently controlled, and the world made brighter and happier to un- 
numbered thousands of its inhabitants. We cannot anticipate the 
results in regard to cure, but may comprehend means of preven- 
tion. There need be no more discussion about hereditary taint ex- 
cept as in direct conditions. Let it be well understood that the 
terrible disease is liable to be contracted from an animal or man 
suffering from it by any one predisposed to its attack, and let the 
modes of infection be made known, and instead of one-seventh of 
the human family perishing, as they now do after months and years 
of misery, the statistican, of the future may write one-seventy-seventh. 
Whatever alleviation there may be for those already diseased, the 
above is not too much to reasonably expect as to prevention. 
The foregoing might lead one to the conclusion tha t bacteria 
were injurious and only injurious in their effects, but a little 
thought will soon convince us that this is far from the truth. They 
are primarily the agents of decay, yet in this very sense untold 
good comes from their activities. It is indeed no more startling 
than true to say that as at present constituted the organic world 
is indebted to them for its existence; without them man could not 
live upon the earth. The processes of nature run in a circle, the 
possibility and perfection of which depend upon the proper filling 
of every part. Green plants, the architects of the world, build 
solid structures out of gaseous and liquid materials, but must have 
these materials furnished. They create nothing. The supply being 
limited, this would soon be exhausted were there not some provision 
to prevent it. We have seen that organic materials, though dead, 
have no inherent tendency to decompose; kept free from the work- 
ing of living things they endure forever, except when consumed by 
fire. How different the world would be without putrefaction and 
decomposition! Eliminate these processes now, and we should see 
the fallen trunks of trees accumulating in the forests as obstruc- 
tions, instead of helping to form a rich vegetable mould for future 
growths and generations of forests; the mummied bodies of ani- 
mals would remain for all time, like the grotesque cadavers of the 
old Egyptians, teaching history, but teaching only the sad one of 
the reign of death. It is well known that fertile soils have as an 
indispensable part of their composition a certain amount of par- 
tially decomposed vegetable matter; this is in truth the special 
characteristic of the surface soil as distinguished from the subsoil. 
Our field and garden plants are dependent on this rich upper 
stratum, and our valuable animals and ourselves are dependent on 
the plants; hence, following the circle round, we reach the knowl- 
edge of our indebtedness to the bacteria as agents of decomposi- 
tion. 
There is another way in which the fertility of soil has recently 
been shown to depend on bacteria. Green leaved plants require 
nitrogen as an essential part of their food, and they are only able 
3. Benefits. 31 
to make use of this when in the shape of nitrates, or as combined 
with earthy or mineral substances. It has long been known that 
saltpeter (nitrate of potash) collects in caves. In times of need, it 
has been artificially obtained by washing earth in which there 
existed considerable amounts of organic matter undergoing decom- 
position, and to the surprise of the workmen such soil, after certain 
intervals of time, may be washed and re-washed without apparent 
exhaustion. So it came to be understood in time that in suitable 
caves the compound actually formed where it was found, not 
simply collected there through the percolation of water, etc. Upon 
heating a portion of such nitro-ccllecting earth, or treating it with 
chloroform, this peculiar power was observed to be lost, and by 
further investigation it was demonstrated that a microscopic living 
organism is the real agent in the work. Thinking no doubt in part 
of this, a well-known scientist has announced as the topic of a 
paper, “The soil a factory, not a mine.” 
We more directly make use of bacteria in many ways. The fer- 
mentations in which alcohol is the chief product, are commonly due 
to the yeast plants, closely allied to the bacteria; but the latter are 
rarely absent from brewers’ yeast, used in bread-making. The so- 
called “salt-rising” is wholly dependent on the work of bacteria. 
Similar agents make for us vinegar and saur kraut; for the chemist, 
litmus; they “rot” flax; they “bleach” linen and cotton spread out 
on the dewy grass; they clean bones macerated in water by the 
anatomist; they purify the waters of rivers, cisterns and tanks, 
causing it in close reservoirs to “work,” after which it is sweet and 
bright. It is said bacteria play an important part in the manufac- 
ture of cheese, and in the production of certain perfumes and fla- 
voring extracts. They are found in germinating seeds and in the 
digestive organs of animals; but whether or not of real use in these 
cases, cannot be confidently stated. It is even probable that the 
wonder-working little creatures are used in medicine under cover 
of some other name and idea, the physician as well as the patient 
being ignorant of the real action of the dose. It is pretty certain 
that epidemics among noxious insects sometimes occur through the 
influence of bacteria. Considerable interest was recently taken in 
the apparent destruction, under certain conditions, of insects by 
yeast artificially applied to their bodies or given them to eat. But 
the results of experiments seemed to show that the yeast itself was 
not capable of injuriously affecting any insects, and it was left to 
conjecture whether or not there might be something else in some 
specimens of yeast cake or powder which, by its action, would ex- 
plain the few known instances of the death of insects presumably 
from the effects the yeast tried. It has now been demonstrated by 
Prof. S. A. Forbes (American Naturalist, Oct., 1882,) that living 
chinch bugs are sometimes filled with enormous numbers of bacte- 
ria, and the observations so far made go to show that such bugs 
are decidedly unhealthy, and perish in great numbers before com- 
pleting. their full development. Certain it is that these pests of the 
grain fields do die off at times by some epidemic among them, as 
the writer can testify from his own observations. Hundreds of 
them, of all ages, have been found about harvest-time in little 
heaps, at the base of wheat plants, dead and dying, while the 32 
weather and other conditions were favorable for their life and de- 
velopment. The disastrous scourge to “silk-worms,” before men- 
tioned, shows that such diseases of insects are not only possible, 
but they really do exist. Pasteur suggests investigations to find out 
some such destroyer of the Phylloxera now so injurious to the grape 
vines in Southern Europe, and he is quite confident that success 
would crown proper efforts in this direction. There does seem to be 
in this a line of study of most excellent promise, not for one species 
of injurious insects only, but for the mastery by man over many of 
his minute but most dreaded enemies. 
PART III. CLASSIFICATION OF BACTERIA, 
AND A SYSTEMATIC DESCRIPTION OF THE SPECIES. 
No one pretends to have made out a complete, natural classifica- 
tion of the Schizophytce or bacteria; although several naturalists have 
embodied in systematic form, their ideas of the kinds and their 
relations, based on shape, development, motion, physiological effects, 
etc.; but all such classifications are acknowledged to be preliminary 
and more or less artificial. That, however, which proves to be most 
useful and apparently as nearly natural as any, is founded on the 
form of the cells and their organic association. It has been best 
worked out by Dr. Ferdinand Cohn, substantially as follows: 
TRIBE I. SPH.33ROBACTERIA. 
Cells globular, or oval; size, very small, often less in diameter than 
.00004 in.; isolated, in pairs, or in chains of many articles, or when 
young and actively increasing in number, imbedded in gelatinous 
masses, called zooglcea, or when forming a pellicle on the surface 
of liquids, mycoclerina; without true spontaneous motion, but oscil- 
lating in liquids by molecular trepidation. 
But one genus, viz.: Micrococcus. 
TRIBE II. MICROBACTERIA. 
Cells elongated-oval or short-cylindrical; isolated, in pairs, or in 
chains of four, more rarely of many rather loosely attached, or 
sometimes in zooglcea; with active, spontaneous motions, when in 
nutritious liquids supplied with free oxygen. 
One genus, viz.: Bacterium. 
TRIBE III. DE8M0BACTERIA. 
Cells cylindrical, usually several times as long as wide, straight; 
isolated, or usually united in chains; often with spontaneous move- 
ments, but in the case of some species always without motion. 
Genera: Bacillus, and with some doubt, Leptothrix, Bcggiatoa, Cre- 
nothrix. The question about these three genera is whether they 
should be included among the SchizophyUe or referred to the fila- 
mentous Algae. 33 
TRIBE IV. SPIROBACTERIA. 
Celb cylindrical, usually several times as long as wide; curved? 
or spirally wound; isolated, or united in chains of less or greater 
length; with active, spontaneous movements. 
Genera : Vibrio, Spirillum, Spirochceta. 
Besides the above, other species, multiplying by self-division, are 
referred to the following genera: Sarcina, Ascococcus, Streptococcus, 
Myconostoc, Cladothrix and Streptothrix. The old genus Monas, form- 
erly including many species of low animals and plants, has been 
so modified that it now contains only a few forms of doubtful 
affinities. 
It must be remembered that these genera are principally based 
on the shape and association of the cells, and that the latter are 
supposed to be in their adult condition. It may be that very arbi- 
trary separations are made. It is quite possible, indeed, that the 
same specific organism assumes, under certain conditions, several of 
the proposed generic forms; but, it is at least probable that each 
genus named includes some species which do not change beyond the 
limits of the description. For instance, the spores of Bacillus 
would, from appearances alone, be classed as Micrococcus at first, 
and as Bacterium after a certain period of growth; but Bacterium 
termo never changes so much that the genus can be mistaken. 
Billroth goes so far as to claim that all the subjects of Cohn's 
classification, except, perhaps, those constituting the genera Spirillum, 
and Spirochceta, belong to a single species, which he names Cocco- 
bacteria septica, while Nageli supposes there exists a small number 
of true species, each of which takes several forms. 
With such differences of opinion among those most competent to 
judge, we cannot pronounce with any confidence upon the number 
or the actual characteristics of the species in existence; but that 
true species do exist we may feel well assured. When sufficient 
knowledge has been gained of their life histories, a natural classifi- 
cation can be arranged. In the meantime, such as we have already 
outlined must continue to be of much service, as it has been in 
the past. 
Dr. Luerssen has arranged the following key to the genera: 
I. Cells not in [cylindrical] filaments, separating immediately after division, 
or in couples [or chaplets] free or united in colonies (Zoogloea) by a 
gelatinous substance. 
A. Cells dividing in one direction only. 
a. Cells globular ........ Micrococcus. 
o. Cells elliptical or shortly cylindrical Bacterium. 
B. Cells dividing regularly in three directions, thus forming cubical fam- 
ilies, having the form of little bags attached side by side, and con- 
sisting of 4, 8. 16, or more cells Sarcina. 
II. Cells united into cylindrical filaments. 
A. Filaments straight imperfectly segmented. 
a. Filaments very fine and short, forming rods Bacillus. 
b. Filaments very fine and very long ; Leptothrix. 
c. Filaments thick and long Beggiatoa.' 
B. Filaments wavy or spiral. 
a. Filaments short and stiff. 
a. Filaments slightly wavy, often forming wooly flocks Vibrio. 
b. Filaments spiral, stiff, moving only forward and backward Spirillum 
b. Filaments long, flexible, with rapid undulations, spiral through 
their whole length, and endowed with great mobility Spirochceta 34 
Whit follows is chiefly from Dr. Ribenhorst’s Kryptogamic Flora 
of Germany, Austria and Switzerland, of which this part has been 
recently (4831) re-edited by Dr. G. Winter, of the University of 
Zurich, and which is .translated from the German by the present 
writer. The original source of the most of the matter is Cohn’s 
Beitrage zur Biologie der Pfianzen. As the work now stands the 
systematic description of species, herein given, is believed to be 
the fullest and most nearly complete of any in existence. In the 
English language the only similar publication is Dr. Sternberg’s 
translation of Magnin’s treatise. 
Winter unhesitatingly classes the bacteria among the Fungi and 
includes in the latter all cellular Cryptogams (flowerless plants) de- 
void of chlorophyll. It is true that this rigid classification unnat- 
urally separates some species certainly very closely allied; but, 
since the physiological effects are of prime importance in the prac- 
tical study of these plants, this separation is less to be regretted. 
It must certainly serve a useful purpose to present together those 
which, through the want of chlorophyll, are dependent on the 
assimilated products of other plants and animals for nutriment, 
and which thus agree in being agents of destruction in organic 
matter. 
I have added to those in Winter’s work such further species as 
seem to be well established, as well as some doubtful but often 
quoted names—the latter mostly by Hallier, and are copied from 
Magnin. The following are herein described as new species: 
Micrococcus amylovorus, the “blight” of pear trees, etc. 
Micrococcus toxicatus, the “poison” in species of Rhus (Poison 
Ivy, etc.) 
Micrococciis insectorum, in diseased chinch bugs and supposed to 
be the cause of an epidemic destruction of these insects. 
I have also felt obliged to name anew the organism found by Dr. 
Detmers and others in diseased pigs, for though there is a general 
agreement that the species belongs to Micrococcus, no one has pub- 
lished a name for it thus classified. It may now be known as 
Micrococcus suis. For the organisms causing the disease of the 
common fowl usually known as “chicken cholera” I have proposed 
the name of Micrococcus gallicidus. Several species have been re- 
corded without specific names, because properly published names 
for them are not known by me. Thus, while some write Bacillus 
tuberculosis for the recently discovered species in this disease, I am 
not informed that the name as such has been published by Koch 
or any one else according to established usage. Still this may be 
the case and a new name should not be given. I have therefore 
simply written Bacillus of tuberculosis. 
All notes and additions by myself to the German text are inclosed 
in brackets. In the translation I have endeavored to express tho 
evidently intended meaning of the author rather than to make a 
literal rendering of the wording. 35 
PLATE I. 
FROM “MICROSCOPICAL JOURNAL.” 36 
DESCRIPTION OF PLATE I. 
rFig. 1.—Micrococcus prodigiosus (Monas prodigiosa, Ehr.) Spherical bacteria of the red 
pigment, aggregated in pairs and in four s, the other pigment bacteria are not distin- 
guishable with the microscope from this one. 
Fig. 2.—Micrococcus vaccina;. Spherical bacteria, from pock-lymph in a state of growth 
aggregated in short four to eight-jointed straight or bent chains, and forming also irreg- 
ular cell-masses. 
Fig. 3.—Zoogloea-form of Micrococcus, pellicles or mucous strata characterized by 
granule-like closely set spherules. 
Fig. 4.—Rosary chain (Torulaform) of Micrococcus urea*, from the urine. 
Fig. 5.—Rosary chain and yeast-like cell-masses from the white deposit of a solution of 
sugar of milk which had become sour. 
Fig. 6.—Sacharomyces glutinis (Cryptococcus glutinis, Fersen), a pullulating yeast 
which forms beautiful rose-colored patches on cooked potatoes. 
Fig. 7.—Sarcina spec, * from the blood of a healthy man, * * from the surface of a 
egg grown over with Micrococcus luteus, forming yellow patches. 
Fig. 8.—Bacterium termo. free motile form. 
Fig. 9.—Zoogloea-form of Bacterium termo. 
Fig. 10.—Bacterium, pellicle, formed by rod-shaped bacteria arranged one against the 
other in a linear fashion, from the surface of sour beer. 
Fig. 11—Bacterium lineola, free motile form. 
Fig. 12.—Zoogloea-form of B. lineola. 
Fig. 13.—Motile filamentous Bacteria, with a spherical, or eliptical highly refringent 
“head,” perhaps developed from gonidia. 
Fig, 14.—Bacillus subtilis, short cylinders, and longer, very flexible motile filaments, 
some of which are in process of division. 
Fig. 15.—Bacillus ulna, single segments and longer threads, some breaking up into seg- 
ments. 
Fig. 16.—Vibrio rugula, single or in process of division. 
Fig. 17.—Vibrio serpens, longer or shorter threads, some dividing into bits, at * two 
threads entwined. 
Fig. 18.—“Swarm” of V. serpens, the threads felted. 
Fig. 19.—Spirillum tenue, single and felted into “swarms." 
Fig. 20.—Spirillum undula. 
Fig. 21.—Spirillum volutans, * two spirals twisted around one another. 
Fig. 22.—Spirochmta plicatilis. 
All the figures were drawn by Dr. Ferdinand Cohn with the immersion lens No. ix, of 
Hartnack Ocular in, representing a magnifying power of 650 diameters.] 37 
Page. 
1. Cells globular or oval 2 
— Cells short or long cylindrical 5 
— Cells lancet like, Hat, spirally wound Spiromonas. 149 
2. Cells isolated or united in chains, or in form- 
less masses imbedded in mucus Micrococcus. 130 
— Cells united in very great number in regular 
colonies 3 
3. Colonies hollow, with a single peripheral layer 
of cells Cohnia. 137 
— Colonies solid, filled with cells throughout.... 4 
4. Cells united in small but fixed number in 
Tegular families Sarcina. 137 
— Cells united in unlimited number in irregular 
colonies Ascococcus. 136 
5. Cells short cylindrical, single, in pairs, or a 
few more loosely joined Bacterium. 139 
— Cells longer cylindrical joined in filaments... 6 
6. Filaments isolated or felted 7 
— Filaments imbedded in globular jelly-masses.. Myconostoc. 148 
7. Filaments not branched 8 
— Filaments with apparent branches Cladothrix. 147 
8. Filaments straight 9 
— Filaments spirally wound or curved 11 
9. Filaments distinctly articulated, short Bacillus. 141 
— Filaments mostly indistinctly articulated, long 10 
10. Filaments very slender Leptothrix. 145 
— Filaments thicker Beggiatoa. 145 
11. Filaments short with few spirals or a single 
curve, rigid Spirillum. 150 
— Filaments longer with numerous spirals, 
flexible Spiroclueta. 148 
The Genera Spluerotilus and Crenothrix may be found in the 
appendix. 152 
The Sacharomycetes have also been added. 154 
KEY TO THE GENERA OF SCHIZOMYCETES.* 
SYNOPSIS OF THE GENERA. 
Micrococcus.—Cells globular or oval-elliptical, motionless,t dividing 
only in one direction, isolated or united in chains or in zoogloea. 
Ascococcus.—Cells globular, united in irregular families, which are 
often lobed and surrounded by a capsule of firm, cartilage-like jelly. 
Cohnia.—Cells globular, imbedded in a single peripheral layer of 
jelly, which is spherical and hollow, or at a later stage irregularly 
bladder-form; the forms like nets are broken through. 
Sarcina.—Cells globular, dividing in two or three directions; 
daughter cells small, united in solid or tabular families, mostly in 
fours, or some multiple of four. 
*[Dr. Winter adheres to the opinion that the Fungi and Algae are distinct classes of 
plants, and includes the bacteria among the former. For this reason the term Schizomy- 
cetes is chosen rather than Schizophytce.] 
f+i. e., having only “Brownian” movement—not swimming freely from place to place.] 38 
Bacterium. —Cells short cylindrical, or long elliptical, or fusiform, 
with rapid movements; otherwise as in Micrococcus. 
Bacillus.—Cells elongated cylindrical, mostly united in filaments 
dividing transversely; forming spores. 
Leptothrix.—This doubtful genus is characterized by the very long, 
slender, unbranched and apparently uuarticulated filaments. 
Beggiatoa.—Filaments very long, rather thick, mostly indistinctly 
articulated, actively vibrating, containing highly refractive granules. 
Claiothrix.—Filaments very slender, indistinctly articulated, pseu- 
do-branched. 
Mgconostoc.—Filaments very slender, bent and twisted through 
each other, imbedded in globular, jelly-like masses. 
Spirochceta.—Filaments long and very slender, with numerous close 
spirals; movements lively. 
Spiromonas.—Cells flattened, spirally twisted. 
Spirillum.—Cells cylindrical, with a single curve or spirally w'ound, 
mostly with a cilium at each end. 
APPENDIX. 
To the Schizomycetes are appended the following allied genera 
whose systematic position is still doubtful: 
Spfuerotilus.—Cells arranged end to end in a colorless, gelatinous 
sheath, forming long threads and*ffocks. 
Crenothrix.—Cells united in filaments surrounded with a sheath. 
SCHIZOMYCETES. 
The Schizomycetes or cleft-fungi are one-celled plants, which mul- 
tiply by repeated division in one, two or all three directions of 
planes, and which also abundantly reproduce themselves by spores 
formed within the cells. 
Tiiey live isolated or united in various ways, in fluids and in 
living and dead organisms, in which they induce decompositions 
and various—but not alcoholic—fermentations. 
MICROCOCCUS, Cohn. 
(Beitrage z. Biol. d. Fflanzen, I Bd. 2 Heft, p. 151.) 
Cells colorless or slightly tinted, globular or oval-elliptical, motion- 
less, dividing only in one direction. The daughter cells either soon 
separate from each other or remain in pairs or are united in chains 
or form zoogloea. Not certainly known to produce spores. [The 
molecular oscillations of these minute bodies must not be mistaken 
for spontaneous movements.] 
The species of Micrococcus are not readily discriminated. The 
supposed distinct kinds show in form and size little or no differ- 
ences and there remains only their chemical activities as the mean* 
of distinguishing them, which may be managed with considerable 
completeness. 
A.— Pigment forming Micrococci. 
M. Prodigiosus, Cohn. 
Synonyms: Monas prodigiosus, Ehrb. (Monatsbr. dor. K. Akad. d. Wissensch z Berlin 
18t8.) Palmella nrodigiosa. Mont. (Bulletin <le la Soe. Nat. et cent d’ Agricult. deParis, 2 
Ser. VII. p. 727); Zoogalactiua imetropha, Sette <Mi-m. venezla 1824.) Iiacteridium pro- 
dig iosum. Schroetor (Beitr. z. Biol. I, 2 Heft, p. 110.) 39 
Exsiccata: Rabenhorst, Algae, 2)93; Thumen, Mycotheca Universalis, 1590. 
Cells globular or oval, colorless, .00002 to .00004 in. in diam- 
eter; at first rose-red, then blood-red, finally growing pale; forming 
a slimy substancei 
Micrococcus prodigiosus is the organism which, as known for some time, produces the 
singular phenomenon called in earlier times the blood of bread, the blood of the Host, 
etc. It forms at first minute rose-red points, and little heaps, which, becoming larger, 
form circumscribed, roundish, deep-red spots ; afterward these spots run together and 
spread out. at the same time become dripping with a blood-red semi-fluid material. This 
consists of a red, gelatinous mass in which millions of cells of the Micrococcus are im- 
bedded, The latter are colorless; they give out the pigment to the jelly. The coloring 
matter, in its chemical and physical characteristics, very much resembles fuchsin. It is 
insoluble in water, but completely soluble in alcohol, and this solution evaporated to dry- 
ness and again dissolved is orange-red. On the addition of acids it becomes bright-red; 
with alkalies yellow. In the spectroscope it shows with others a characteristic broad 
absorption band in the green. Palmeila miriflca, Rabh., can scarcely be different. 
M. luteus, Cohn. 
Synonym; Baderidium luteum, Schroeter (1. c. p. 119 und 126). 
Exsiccata'- Thumen, Mycotheca Universalis, 1400. 
Cells elliptical, a little larger than those of M. 'prodigiosus, with 
highly refractive contents; forming light-yellow drops on a solid 
substratum, at first the size of a poppy seed, later the half of a 
grain of pepper, and finally drying up into flat, shield-form, little 
bodies. This species forms, on the nourishing fluid, a thick yellow 
skin which becomes wrinkled if the development is luxuriant. 
On boiled potatoes, etc. 
matter is insoluble in water; it is not changedby sulphuric acid or alka lies 
M. aurianticus, Cohn. 
Synonym: Bacteridium aurantiacum, Schroeter (l. c. p. 119 und 126.) 
Exsiccata: Thumen, Mycotheca Universalis, 1700. 
Cells oval, .00006 in. long; forming, on a solid substratum, orange- 
yellow drops and spots, which finally spread into a uniform coating; 
on nutritive fluid it forms a golden-yellow layer. 
On boiled potatoes and eggs. 
Coloring matte • soluble in water. 
M. ulyus, Cohn, 
Exsiccata: Rabenhorst, Algae Europeae, 2501. 
Cells globular, .00006 in. in diameter; at first forming rust-red con- 
ical little drops .02 in. in diameter, these enlarge and finally appear 
as a broad mass of slime. 
On horse-dung. 
M. chlorinus, Cohn. 
Cells globular (?); forming golden or verdigris-green slime masses, 
or a verdigris-green layer on fluids which gradually becomes colored 
throughout. 
On boiled eggs. 
The coloring matter is soluble in water; it does not turn red with acids. 40 
M. cyaneus, Cohn. 
Synonym: Bacteridium cyaneum, Schroeter, (1. c. 122, und, I2»i). 
Cells elliptical, producing 011 slices of potato an intense blue color- 
ation which also penetrates the substance and even shows on the 
opposite side of the slice. On nutritive fluids zooglcea are formed 
which are at first colorless, then bluish-green and finally an intense 
blue. 
On boiled potatoes. 
The coloring matter is soluble in water: the solution is at first verdigris-green, 
afterwards as a rule pure blue. It is made by acids an intense carmine-red and 
changed again by alkalies to blue or gall-green. In the spectroscope it shows no 
absorption-line but only a darkening of the less refractive parts. 
M. vioiaceus, Cohn. 
Synonym: Bacteridium violaceum, Schroeter (1. c. p. 157). 
Cells ehiptical, larger than those of M. prodigiosus, in little bright 
violet-blue drops of si me which enlarge (to one-fourth of an inch in 
diameter) and run together into spots. 
On boiled potatoes. 
B.—Micrococci producing fermentations. 
M. ureffi, Cohn. 
Cells globular or oval, .00005 to .00008 in. in diameter, isolated 
or united in chains, or forming zooglcea on the surface of liquids. 
In urine. 
Micrococus ureas is the ammoniacal ferment. When fresh urine is allowed to stand at a 
proper temperature (30° C.). it loses in a few days its acid reaction, becomes neutral and 
finally alkaline, showing signs of fermentation. The urea is changed into ammonium car- 
bonate, while at the same time ammonio-magnesium phosphate is precipitated. This 
fermentation follows only when the Micrococcus is developed in the liquid. 
M. crepusculum, Cohn. 
Synonym: Monug crepusculum. Elirb. (Infus, p, 6. t. I, Fig. 1). 
Exsiccata: Rabenhorst, Algon Europa's, 2502. 
Cells globular or short-oval, very small, scarcely .00008 in. in di- 
ameter, isolated or forming zooplcea. 
In and on various infusions and foul liquids. 
This common Micrococcus appears with Bacterium termo in all foul substances and in- 
fusions. 
M. candfdus, Cohn. 
Forms on slices of boiled potato snow-white points and spots. 
[M. of nitrates. 
Schloesing and Muntz have communicated to the French Academy of Science the re- 
sults of studies on the formation of nitrates in ordinary soil, and they prove thata minute, 
globular, or slightly elongated organism, is the cause of the phenomenon so common in 
nature, and of such vital importance in the fertility of the soil. (Comp. Benda*. T. 89, pp. 
891 and 1104). More recently, Oayon and Dupetit have shown that these same nitrates 
are decomposed by another Micrococcus, possibly M. ure<r. (1. c. T. 95, p. (Uh.j 
M. Vaccinae, Cohn. 
Synonym: Microsphaera vaccince, Cohn (Virchow's Archiv. lv.) 
Cells globular .00002 to .00003 in. in diameter, isolated or in 
pairs or united in chains or masses, or forming zooglcea. 
C.—Disease producing Micrococci. 41 
In fresh lymph of vaccine vesicles of the cow, and of man, as 
well as in the pock-postules of variola (small pox.) 
Micrococcus vaccina} must be accepted, after the many reliable investigations, as the 
effective element in vaccine virus. It is the carrier of the contagion of small pox. By 
filtering the lymph the solid constituent can be separated from the fluid. When the latter 
is used for inoculation no effect is produced, while the former induces the formation of 
the pock-vesicles. But that the micrococci and not the lymph cells are the active constit- 
uent of the solid residue appears from the fact that when vaccine virus is exposed to the 
air for a time it becomes less and less effective. Such virus finally putrefies, and with the 
increase of putrefaction the micrococci correspondingly disappear, displaced by rot-pro- 
ducing Bacteria. 
M. diphtheriticus, Cohn. 
Cells oval .000013 to .000004 in. long, single or united in chains 
or forming variously-shaped masses and colonies. 
In the so-called diphtheritic membrane found especially on the 
mucus surfaces of the throat, pharynx, windpipe, etc., but also of 
those of the sexual and digestive organs,, as well as in wounds; etc. 
This organism is of very great pathological importance: for the infection spreads from 
its place of origin through the lymph vessels and their enclosing tissue, later into the 
connective tissue, the kidneys, the muscles, and Anally the organisms gain entrance to the 
blood vessels, where they cause the greatest disturbances. They plug the capillaries and 
cause them to burst. The thinner bones and cartilage are destroyed through this same 
process. The contagious properties of the fungus is also very great. 
M- septicus. Cohn. 
Synonym: Microsporon septicum, Klebs. (zur. patholog. Anat. der Schusswunden, 1872.) 
Cells globular .00002 in. in diameter, united in chains or masses or 
forming zooglcea. 
In wounds; generally with all the kinds of disease known as 
Pycemia and Septicaemia. 
In the various states of suppurating and putrefying in the living body, in blood-fer- 
mentation and blood-poison, this micrococcus plays an active part. Whether all the 
manifold phenomena are called forth by micrococcus septicus or more kinds take part, is 
questionable. In wounds we And the micrococci in the fresh pus, in which they multiply 
rapidly and bring on inAammation and fever, destroying the tissues and penetrating 
deeper and deeper. They gain entrance to the blood vessels and cause obstructions and 
festering; similar phenomena occur in the lungs and liver. 
[M. bombycis, Cohn. 
Synonym: Microzyma bombycis, Bechamp (Comptes Rendus, tome 64, 1867, p. 1046.) 
Exsiscata, Umlant w.; Thiimen Mycotheca Universalis 1799. 
Cells oval .00002 in. in diameter, single or in chains. 
In the gastric juice and intestines of silk-worms, producing in 
them the so-called “Schlaffsucht” [pebrine], an infectious disease 
from which the animal after a short time dies. 
There are probably many other infectious diseases, as cholera, measles, scarlatina, 
typhus fever, etc., which are due to Bacteria. Reliable observations are wanting upon 
them. 
[M. of traumatic erysipelas- 
This disease has been abundantly proved to be contagious and in many cases very 
virulently so. There have also been very numerous observations upon the existence of 
globular organisms in the excretions, but it has not been known until recently whether 
these living things were active agents in, or merely accompaniments of, the disease. The 
investigations of Orth, Recklinghausen and Lukomsky. corroborated by Koch and others, 
seem to demonstrate the fact that a Micrococcus is the real cause of the occurring 
pathological changes and the active element in the contagion. Puerpural fever is prob- 
ably due to the same organism. 
This Micrococcus is described as globular, isolated or in chains, without motion.] 42 
M. of croupous pneumonia. 
Many investigators agree in finding minute organisms in the oxcretions of in- 
flamed tissues affected with this disease. Friealander of Berlin has reoently (1882) 
made care ul researches, which seem to establish the fact that the living organisms 
exist and multiply within the tissues and blood vessels and not simply in the exu- 
dations. The description is as follows: Cells ellipsoidal. .000021 in. wide. .00004 in. long, 
usually in pairs, sometimes in chains or spread out in a film, aggregated in colonies in the 
lymphatic vessels. Lancet (London) March 4, 1882.] 
[M. amylovorus, Burrill. 
Cells oval, single or united in pairs, rarely in fours, never in 
elongated chains, imbedded in an abundant mucilage which is very 
soluble in water; movements oscillatory; length of a separate cell 
.00034 to .000056, in.; width, .000028 in.; length of a pair .00008 in.; 
of four united about .000012 in. 
The cause of “blight” in plants, especially of the pear tree (Are blight) and of the apple 
tree (twig blight and sun scald.) The organism gains entrance to the living tissues 
through wounds or punctures and produces butyric fermentation of the starch 
stored in the cells. The disease is transmissible by artificial inoculation. (Tenth 
Report Illinois Industrial University. Transactions American Association for the Ad- 
vancement of Science, 1880.)] 
M. suis, (Detmers) Burrill. 
Cells globular, or elongated and more or less contracted in the 
middle, single or in pairs or chains of many articles; .000028 to 
.000032 in. in diameter (Detmers). 
Found in the blood and other fluids of pigs suffering with swine plaguo or "hog 
cholera.” Dr. Detmers at first classed this organism with the Bacilli and named it Bacillus 
suis. But Detmers, Meguin and Salmon essentially agree in giving the characteristics of 
Micrococcus, and with this some observations of the author accord. Detmers describes 
a peculiar contraction of the middle portion of elongated forms rendering the sides con- 
cave, and in this condition he finds them in zooghna and in chains. Others, according to 
the same authority, as well as Meguin and Salmon, are spherical. It seems well estab- 
lished that the Micrococcus is the real contagious element in the disease. (Annual Re- 
ports United States Department Agriculture 1870-80.)] 
TM. fox catus, Burrill. 
Cells globular, single and in pairs, rarely in chains of several 
articles; .00002 in. in diameter; movement oscillatory only. 
Apparently parasitic on species of Rhus, and constituting the poisonous principle in 
these plants. Reaehingthe human skin, the organisms penetrate in some way its tissues, 
and multiplying there induce the peculiar inflammation which takes place. (Home Vege- 
table Poisons. Trans. American Association for Advancing Science, 1882. Am. Mie. 
Journal, October 1882, p. 192.)] 
[M. insectorum, Burrill. 
Cell obtusely oval, isolated or in pairs, rarely in chains of sev- 
eral articles; .000022 in. wide and .000027 to .00004 in. long, usually 
about .000032 long; movements oscillatory only; forming zooglma (?). 
In the digestive organs of chinch bugs (Blisms lencopterus). 
Professor S. A. Forbes discovered this minute organism, in 1882, infesting the intestines 
of chinch-bugs, which evidently suffered thereby (S. A. Forbes. American Naturalist, Oct. 
1882.) Very m any of the insects, especially the older ones, were found to harbor the par- 
asite in great numbers, and at certain times very many of the bugs were found dead and 
dying before reaching maturity. It is well known that these pests of the grain fields do 
perish at certain periods by some epidemic disease, from which few individuals escape, 
and there is every reason to believe that the organism found by Professor Forbes causes 
the destruction. He finds it can be successfully cultivated in beef-broth, and the possi- 
bility is thus apparently within reach of artificially introducing and spreading the dis- 
ease. If so. a most important step has been made in economical entomology and scientific 
agriculture. 
The organism is somewhat similar to, but not identical with. Micrococcus bojnhvcis* 
the “disease germ" of the silk w >rm. which was so fatally destructive to the silk indus- 
tries of France, and which became the subject of the successful studies of Pasteur. 43 
On the stems and leaf-sheaths of maize injured by the bugs a Micrococcus, supposed to 
be the same, was found imbedded in firm zoogloea masses. 
The form of the organism approaches the typical shape of Bacterium, being between 
oval and short cylindrical, with rounded ends; otherwise the characteristics are those of 
a true Micrococcus.] 
fM. of fowl cholera. 
While all who have carefully studied this disease agree that the contagious element 
consists of minute globular granules, capable of self-multiplication, it appears that no 
one has either named the organism or given a scientific description of it. Toussaint 
(Compt. Rend, xci (1880) p. 301) supposed he had sufficient proof of the identity of this dis- 
ease of the domestic fowl and septicaemia, or blood-poisoning, and that in both cases the 
diving organism believed to be the active agent, is the same. But Pasteur (1. c. p. 
457) pronounces them similar in appearance but quite distinct in effect. Salmon (Report 
Dpt. Agriculture (U. S.) 1880, p. 401) confirms the infectious nature of the disease, and the 
virulence of the multiplying granules, but is inclined to attribute their origin to the 
transformations of the animal protoplasm (p. 439.) There can scarcely be a doubt but that 
the so-called granules constitute a true species of the present genus. It may be called 
Micrococcus gallicidus.] 
DOUBTFUL SPECIES. 
M. griseus, Winter. 
Synonym: Bacterium griseum, Warming. 
Cells nearly globular or oval, colorless; .00010, to 00016 in. 
long, with those dividing .00021 to .00028 in. long, .000072 to 
.00010 inches wide. 
In infusions of fresh and salt water. 
Since according to Warming this form appears only in the motionless state, (and then 
forms no zoogloea) and since the shape of its cells corresponds better to the genus 
Micrococcus than to Bacterium, I have placed the fungus in the former genus. 
M. ovatus, Winter. 
Synonyms: Panhistophyton ovatum, Lebert. (Ueber die gegenwartig herrschende 
Krankheit des Insect der Seide in; Jahresbericht ueber die Wirksamkeit des Vereins zur 
Beforderung des Seidenbaues fur die Provinz Brandenburg im Jahre 1850-57, p. 28 und 
foigde.) 
Nosema bombycis, Naegeli. (Botan. Zeitg. 1857, p. 760; Flora 1857, p. 684. 
Cells oval, twice as long as wide, rounded at the ends; .00016 to 
.0002 in. seldom 00024 in. long, .00003 to .00012 in. (mostly 
.00010 in.) thick, isolated in pairs or united in little masses. 
In various organs of the silk-worms, their pupae, and winged 
forms. 
It is questionable whether the described cells belong to the Schizomycetes. They were 
first discovered by Cornalia in Mailand and designated corpuscles: according to him 
they are also found, though very scarce and more incidentally, in the blood of healthy 
caterpillars. Later these small bodies have been recognized as the cause of the epidemic 
disease of the silk-worm known as “gattine.” 
As the cells in shape and want of motion agree very well with Micrococcus, I have 
introduced them here. 
[The eight following, by Hallier, are given without much confidence in the correctness 
of his observations and interpretations. These are taken from Magnin’s “Bacteria.”] 
M. of animal variola, Hallier. 
Small, endowed with lively movement, furnished with a very delicate appendage, some- 
times united in the form of little elongated rods; found in spontaneous or inoculated 
pustules, in the lymphatic canals and the ganglia ot animals attacked with variola. 
M. of rugeola, Hallier. 
Very small, without color, often with a caudal prolongment; in the sputa and blood of 
the sick. 44 
M. of scarlat'na, Hallier. 
Free or in colonies, either on the surface or in the interior of blood corpuscles, or in 
chains. 
M. of ep demic diarrhoea,, Hallier. 
In intestinal matters with vibrios, cells and monads. 
M. of exanthematous typhus, Hallier. 
Relatively large brown, endowed with rapid movement, sometimes in chains, in the 
blood. 
M. of intestinal typhus, Hallier. 
Very small, without movement in the blood; larger forms with quick movements, fur- 
nished with contractile appendages; in dejections. Similar Micrococci are found in 
cholera diarrhoea, but in less number. 
M. of glanders, Zurn. 
Cells free or adhering to the blood corpuscles, or even penetrating in their interior; 
sometimes in chains; in the blood. Very numerous, endowed with rapid movement; in 
the lymphatic ganglia, in the mucus of the frontal sinus and in chancroid ulcers. 
M. of syphilis, Hallier. 
Numerous, colorless, free or in globules: in gonorrhoea, the primitive ulcer, and in the 
blood of subjects with constitutional syphilis. 
(Beitr. z. Biol. I. Bd. 3, Heft, p. 154.) 
ASCOCOCCUS, Cohn. 
Cells colorless, very small, globular, united in larger or smaller 
globular or irregular families in shapeless masses. Families often 
lobed, the lobes again incised, inclosed in a firm cartilage-like gela- 
tinous capsule of rounded form. 
The value of Cohn's genus Axcococcus is to me as questionable as that of Billroth's 
genus of that name; it is also doubtful whether the two are identical. Possibly Axvo- 
coccus is only a stage of development of Micrococcus. 
A. Billrothii, Cohn. 
Families lump-like, .00080 to .00640 in. in diameter, inclosed in a 
capsule from .00004 to .00060 in. thick; covering the surface of the 
liquid in a thick, flaky layer. 
On a solution of acid ammonium tartrate, forming a pellicle. 
The colonies consist of a sharply defined cartilage-like gelatinous en velope, in which 
either one or more families are inclosed. The families are of very different size and 
shape, solid, composed of numerous, exceedingly minute, globular cells. This fungus 
induces in its nourishing (luid singular fermentations. It produces of ammonium tar- 
trate, butyric acid an i butyric ether, and changes the originally aeid solution to alkaline 
while free ammonia is given off. 45 
COHNIA, Winter. 
Synonym: Clathrocystis (Henfry), Cohn (Rabenhorst’s Algen Europas, No. 2318. 
Cells globular; inclosed in a single, peripheral layer of jelly, form- 
ing a spherical, or later an irregularly shaped bladder or sack, the 
walls of which finally break up in a net-form manner. increase 
takes place by repeated separation of the cells in twos; of the fam- 
ilies through the folding in and lobing of the daughter families. 
The genus Clathrocystis. Cohn, is removed according to my idea of the distinction be- 
tween the Alga, nn&Fungi. Since this generic name was primarily adopted foran alga (Cl. 
aeruginosa, Henfry) it is advisable to retain the name for it and to make this species be- 
longing to the Fungi the representative of a new genus, to which I have given the name 
Cohnia. in honor of Dr. F. Cohn, of Breslaw, highly merited for his investigations upon 
the Scliizomycetes. 
C. roseo-persicina, Winter. 
Synonyms: Protococcus roseo-persicina. Kiitz. (spec. Alg. p. 196); Pleurococcus roseo- 
persicina, Rabh. (Flora Europ. Alg. Ill, p. 28); Microhaloa rosea. Kiitz. (Linn®a VIII, p. 341): 
Bacterium rubescens, Lankaster. (Quart. Jour. Mic. Lc. XIII, New Series, p. 408, PI. XXII, 
XXIII); Clathrocystis roseo-persicina, Cohn, (Rabh. Alg. Europ. No. 2318 and Beitr. z. Biol, 
I. Bd. 3, p. 157, Taf. VI, Fig. 1-10.) 
Exsiccata: Rabh. Algen Sachsens, etc., 986 und 2318; Wartmann und Schenk, Schweiz* 
Kryptog, 343. 
Cells globular, oval, or through mutual pressure, polygonal; from 
rose to purple-red; .00010 in. in diameter. They form at the be- 
ginning little solid families in which the single cells are joined by 
gelatine, while the whole family is inclosed in a gelatinous envelope. 
Later, there forms a larger, globular or oval, finally irregular, hol- 
low body, attaining a diameter .02640 in., and filled with a watery 
liquid. In this the cells are arranged in a single peripheral layer. 
These bladders are often torn or perforated, becoming elegant nets, 
which finally break up into irregular patches and shreds. 
In swamps, swimming on the surface or among algae and duck- 
weeds ; often also in aquaria, in which algae, etc., are decomposing. 
The only species of this genus, so far known, is remarkable for its red coloring matter’ 
which is essentially different from that of Micrococcus prodigiosus, and is known as “bac- 
terio-purpurin.” This is insoluble in water, alcohol, etc., is changed by hot alcohol into 
a brown substance, and is otherwise characteristic by its optical deportment. It shows 
through the spectroscope the same strong absorption band in the yellow; weaker ones in 
the green and blue, as well as the darkening of the more refrangible half of the spectrum. 
The single cell is surrounded by a firm, almost cartilaginuous membrane; their contents 
are, when young, homogeneous, but when older there appears within, one or more opaque 
granules, which are none other than metallic sulphur. 
SARCINA, Goodsir, (Extended). 
Cells globular, dividing in two or three planes; daughter cells a 
long time united, forming little solid or tabular families, which are 
often again united into larger colonies. As a rule, the families 
consist of four, or some multiple of four cells. 
S. ventriculi, Goodsir. 
Synonyms: Merismopedia Goodsirii, Husem (de anim. et veg., p. 13). M. ventriculi, 
Robin (Hist, des Veget. paras., p. 331, T. I, Fig. 8, et T. XII, Fig. 1). 
Exsiccata: Rabh. Algen 600. Wartmann und Schenk, Schweiz. Kryptog, 247. 46 
Cells globular, four, eight, sixteen or a few more united into 
little cubes with rounded corners—the parts in contact flattened; 
cells of the colony attaining a diameter of .00016 in.; colonies 
strung together by the partition walls of the cells; again united 
into larger masses. Cell contents greenish, yellowish or reddish- 
brown, somewhat polished. 
In the stomach of healthy and diseased man and higher animals; 
also sometime occurring in other parts of the body. 
S. urince, Welcker. 
Synonym: Merismopedia urince, Rabh. (Flora Europ. Alg. II, p. 59). 
Cells very small, .00004 to .00008 in. in diameter, eight to sixty- 
four united in a family; eight united cells .00008 to .00012 in., 
sixty-four cells .00016 to .00020 in. in diameter. 
In the bladder. 
S. littoralis, Winter. 
Synonyms: Erythroconis Utoralis, Oersted; Merismopedia litoralis, Rabh. (Flora Europ. 
Alg. II, p. 57). 
Cells globular or, when ready to divide, oval; .000012 in., seldom 
.00008 in. or more in diameter; united in families of four, six, 
eight, etc., which are again grouped in larger colonies (as many as 
sixty-four 4-parted cells)./ Cell contents colorless, but there is in 
each cell one to four red granules of sulphur. 
In putrid sea-water. 
S. Reitenbachii, Winter. 
Synonym: Merismopedium Reitenbachii, Caspary (Schriften der physikal, okon, Gefell- 
achaft zu Konigsberg, XV, 1874, p. 104, T. II, Fig. 7 to 15). 
Cells globular, or when ready to divide, oval or elliptical, .00006 
to .00010 in diameter, dividing ones attaining .00016 in. long; 
rarely single or in twos or threes, usually four or eight, or more 
often sixteen or more united. Cell wall colorless, with the forming 
wall-borders rose-red. 
On the submerged parts of aquatic plants and dead sticks, and 
swimming free in fresh water. 
The families consist at most of thirty-two cells; those of eight globular cells measure 
.0W4U in. long. .000175 in. wide: tabular families of eight cells .00020 in. long, and .000175 in. 
wide, while those of sixteen cells are .00005 long and .00043 wide. 
Probably also Merismopedia vialacea (Breb.) Kutzing, (Spec. Alg. p. 472, und Tabul. phyc. 
v. T. 38. Fig. 7; ltabenhorst Flora Europ. Alg. If. p. 57) belongs to the Fungi. This agrees 
in its large size nearly with Sarcina Reitenbachii. yet differs on account of the color, 
especially as not rarelv one hundred and twenty-eight cells are united in a family. Very 
similar, but hitherto perhaps only found in Sweden, is Merismopedia chondroideum, 
Wittr. (Wittr et Nordstedt, Alga* Exsiccata, 200). 
S. hvalina. Winter, 
Synonym: Merismopedia hyalina.Kutz. 
Cells globular, almost colorless, .00006 in. in diameter; families 
mostly of four to twenty-four (rarely more) united cells, attaining 
.00060 in. in diameter. 
In swamps. 47 
Sarcina renis. Hepworth (Mic. Jour., v. 1857, p. 1, pi. 1. Fig. 2). is bright-green; it shows 
little connection with the species of this genus, therefore I shall only mention it. 
Besides the foregoing species of Sarcina there are those hitherto classed as fungi on 
various substrata; on boiled potatoes (in little chrome yellow masses,) on cooked white of 
egg (bright yellow spots), also in solutions, and even in the blood of healthy and diseased 
human beings. Compare Cohn’s Beitr. zur Biologie I, Bd. 2, p. 139. 
BACTERIUM, Cohn. 
Cells short-cylindrical, long-elliptical or fusiform; increasing by 
transverse division; having the power of moving spontaneously. 
The daughter cells separate soon after the division or remain at- 
tached in pairs or in a greater number forming a chain; frequently 
forming zoogloea; formation of spores similar to that of Bacillus. 
[Aside from their shape the species of this genus mainly differ from those of Micrococ- 
cus in their power of movement. While the latter oscillate and tip and turn in the sus- 
pending fluid, but make no advance, the former freely move from place to place. Of these 
the motion is of every kind: rolling, spinning, turning end over end, swaying as if at- 
tacked at one end by an invisible thread, quivering without change of place, sailing 
steadily and stately, darting like a flash, whirling, bobbing, dancing—a maze and labyrinth 
of movement. But these active motions are observed only when the organisms are in a 
rich nutritive fluid and are supplied with free oxygen. The zooglaea differ from those of 
Micrococcus in having a firmer and more abundant intercellular substance.] 
B. termo, Dujard. 
Synonyms: Monas termo, Muller (Infus. T. I, Fig. 1—non Ehrb.); (?) Palmellainfusionum, 
Ehrb. (Inf. p.526n Zooglaea termo, Cohn (Nova Acta Acad. Caes. Leop. Carol. XXIV, Bd. 1, 
p. 123, T. 15, Fig. 9). 
Exsiccata: Thiimen Mycotheca Universalis, 1000. 
Cells short-cylindrical, oblong; .00006 to .00008 in. long [.00008 
to .00012 in. long, .000025 to .00012 in. wide, Magnin]; furnished 
at each end with a cilium. 
In all putrescible substances, especially water in which meat is 
macerated. 
Bacterium termo is the ferment of putrefaction; it produces putrefaction of organic sub- 
stances, and rapidly multiplies itself as long as the substances capable of putrefaction 
are present, while it disappears as soon as the decomposition is ended, It is certainly 
obtained when a piece of meat is put into water in a vessel left open and allowed to stand 
in a warm place. The reproductive power is so enormous that the bacteria cells reach- 
ing the liquid through the air, or as attached to the meat, have, in a short time, so great a 
Erogeny that in twenty-four hours the water has a conspicuous milky appearance, caused 
y the swimming fungi. That the Bacterium is the cause, and not simply an accompani- 
ment of the putrefaction, is made apparent by a simple experiment. Putrefaction begins 
as soon as air is allowed to freely pass to a putrescible substance, because the air always 
contains a number of the bacterium cells. But when the putrescible substance is heated 
over 50° Cent., and the air excluded, it does not ferment. It can be objected that the air, or 
the oxygen ot the same, causes the putrefaction, but this can be readily refuted. Air filtered 
through cotton-wool, and thus freed from the bacterian cells, can easily be passed to a 
putrescible liquid which has been highly heated; in this case no putrefaction takes place. 
B. lineola, Cohn, 
Synonym: Vibrio lineola, Muller (Vermium Historia, p. 39). 
Bacterium triloculare, Ehrb. (Infs., p. 79). 
Cells similar to those of Bacterium termo, but larger; .00012 to 
.00015 in. long by .00006 in. wide; with two cilia at one end. 
In various infusions without producing a special fermentation. 48 
[Takes the form of zooglcea in which the rods are motionless. Its protoplasm is often 
siudded with dark granules. This is the only statement known to the translator con- 
cerning the two cilia, and his own observations have failed to confirm it.] 
B. litoreum, Warming. 
Cells ellipsoidal or elongated, usually rounded at the ends, .00008 
to .00024 in. long, .00005 to .00010 in. wide; colorless; motile or 
still, but never united in chains or zooglcea, nor in large masses. 
B. fusiforme, Warming. 
Cells fusiform with sharpened ends .00008 to .00020 in. long, 
.00002 to .00003 in. wide. 
In a loose layer on the surface of sea water. 
B. navicula, Reinke and Berthold. (Die zetsetzung der Kartoffel durch Pilze. p. 21, 
T. VII., Fig. 10.) 
Cells fusiform or elliptic, diminished at each end; rather large; 
motile or at rest; having within one or more opaque granules 
which are colored blue with iodine. 
In moist-rotting potato. 
B. synxanthum, Schroeter. 
Synonyms: Vibrio nynxanthns, Ehrb. (Bericht uber die Verhandl. der Berl. Akademie 
1810, p. 202, Mo. 51). Vibrio xiuthogenus, Tchs. (Magaz, f. d. ges. Thierheilkunde, Bd. vn, 
p. 104.) 
Not different in form from Bacterium tcrmo; .Of,003 to .00004 in. 
long; motions lively; single or as many as five united in a chain. 
Causing the so-called yellow milk. 
Boile I milk becoming after a time coagulated often suddenly turns citron-yellow; the 
casein gradually disappears until very little remains. The milk, at first neutral b •cornea 
sour, then intensely alkaline. The filtered citron-yellow liquid becomes by evaporation 
amber-yellow; the resulting yellow-brown crust is insoluble in alcohol and ether, but en- 
tirely soluble in water. Alkalies do not change its color, while acids cause instant 
decolorization. 
B. syncyanum, Schroeter. 
Synonyms: Vibrio xyncyanus, Ehrb. (1. c. p. 124 und 126), Vibrio cyanoycnus, Fohs. (1. c 
p. 190). 
Like the preceding in form. 
Producing “blue milk.” 
The coloring matter is changed by alkalies to peach or Dlood red. while acids restore 
the original color. Ammonia, in turn, only changes the blue to a violet tint. 
B. a ruginosum, Schroeter. 
In the so-called green (or blue) pus sometimes found in wounds, 
etc. 
The cells themselves are also colorless in this case; they impart the verdigris-green 
often changing into blue) coloring matter to the surrounding medium. 
'B. punctual, Ehrb. 
Cells elongated, ovoid, colorless, often in pairs; movements slow 
and oscillating; length .00021 in., thickness .00007 in. 
In infusions of animal substances. 49 
B. catenula, Duj. 
Cells cylindrical filiform, often three, four or five united; length 
.00012 to .00016 in., thickness .00002 in. 
In fetid infusions and in typhoid fever (Coze and Feltz.) 
This and the preceding are taken (translated from the French) from Magnin’s work on 
Bacteria, but they are put down as doubtful speeies. They seem from the shape of the 
cells to belong rather to Bacillus. 
The four following, also copied from Magnin, are said by him to 
require further study, though apparently species of Bacterium: 
Vibrio lactic, Pasteur. 
Cells almost globular, very short, a little swollen at the extremities; length, .000064 
in. in a series; .00200 in. long. 
Develops, according to Pasteur, in sweet liquids, in which it causes the formation 
of acetic acid and in milk the coagulation ot' the casein. According to other re- 
searches the coagulation of the casein is influenced by a soluble (zymase), and not 
an organized, ferment. 
Mycoderma aceti, Pasteur. 
Synonym: Ulvina aceti. Ktg. 
Exsiccata: Thiimen Mycotheca Universalis 1599. 
Cells short, narrowed in the middle, often united in long chains, forming a pellicle on 
the surface of liquids; length of a cell .00006 in., which is two or three times the width. 
This species is thus very near the preceding; it should not be confounded with Myco- 
derma vini, which may develop in the same liquids, but which belongs to the Saccharo- 
mycetes. 
Vibrio tartaric right, Pasteur. 
Cells globular, short, .00004 in., united in chains about .00200 in. long; similar to the pre- 
ceding. 
Decomposes racemic acid, causing right tartaric acid to disappear, and liberating left 
tartaric acid. 
The acid fermentation of beer. 
Cohn thinks this is due to a Bacterium similar to B. termo, but a little larger. He has 
found it with oval Saccharomycetes in acid beer— elliptical Bacteria endowed with motion, 
often united in pairs, rarely in fours]. 
BACILLUS, Cohn. 
(Beitr. z. Biol. I. Bd. 2, Hefl. p. 173). 
Cells elongated cylindrical, almost always attached together in 
straight rod-like (stielrlinden) rows or threads (not or little inter- 
laced); multiplying by transverse division. They form zooglcea, but 
often also occur united in thick swarms without gelatinous secretion. 
Propagation by spores. 
The genus Bacillus is closely related to Bacterium; especially is Bacterium lineola with 
united cells very similar to Bacillus rods. Yet there is this difference, that in the longer 
Bacterium cells the appearance of dividing is perceptible, while in the Bacillus cells of 
equal length it is not. 
Some of the species are always motionless, some are spontaneously motile, but go into 
a resting condition. The rod-like cells elongate by intercalary growth to about double 
the typical length, and then divide by a transverse partition into two daughter cells, which 
often separate from each other, but often also remain attached. When the products of re- 
peated division continue joined together filaments are produced, which are zigzag or 50 
straight, apparently jointless, but the cells become apparent by the use of coloring 
macters. In the formation of spores the greater part of the cell-contents collects in one 
place of the rod. w lich often swells at the point, and the protoplasmic contents becomes 
sharply defined from that of the rest of the cell. Later, this highly refractive, dark-ap- 
pearing body (the spore) separates from the sterile part of the coll, and falls to the 
ground; the ripened spore continues to remain apart. These spores possess the ability 
to endure unfavorable influences of various kinds, without detriment to their vitality. 
They can remain a long time in the soil, often many years, before beginning to grow, but 
also have the power to germinate at once. In germination, the spore first loses its pol- 
ished appearance and swells a little; the cell-wall then splits around the middle of the 
spore. Through the opening thus made the spore protrudes by the arching of its sub- 
stance, and grows into a new rod, to the base of which the old cell wall of the spore 
adheres, and is often thrown off only at a late period. 
The determination of the different species is also here very difficult. 
B. subtilis, Cohn. 
Synonym: Vibrio subtilis, Ehrb. (Infs. p. 80, No. 91. T. V., Fig. *i). 
Exsiccata: Thumen Mycotheca Universalis, 1200. 
Cells cylindrical, about twice as long as thick, attaining .00024 
in. long; bearing a cilium at each end. Mostly several cells, joined 
into apparent filaments which are motile, flexible and are fur- 
nished at each end with a cilium. The spore-forming cells 
are three to four times as long as thick, isolated or united in fila- 
ments. The spores are usually somewhat greater in diameter than 
the rods. 
In different infusions and substances—very probably in the rennet 
stomach of living ruminants. According to Cohn, the producer of 
butyric fermentation, and also the active principle in the ripening 
of cheese. 
The extraordinarily great power of resistance of the spores of Bacillus subtilis and the 
other species is a peculiar property. They are not killed by boiling, but made to germi- 
nate very quickly, though the duration of the boiling must of course be considered. 
Fifteen minut-s boiling does them absolutely no harm, while most are killed after one 
hour and all after two hours’ boiling. They are insensible to poisons and weak acids. 
B. tremulus, Koch. 
Very similar to the preceding but more slender and mostly shorter, 
always with a cilium at each end. Spores plainly thicker than the 
cells, often arranged in lines. 
On the surface of foul vegetable infusions, forming a thick slimy 
layer. 
B. amylobacter, VanTieghem. 
Synonym: Closlerdium butyricum, Praz. 
Exsicatta: Thiimeh Mycotheca Universalis, 1800. 
Morphologically similar to Bacillus subtilis, but distinguished by 
the fact that at certain times it contains starch in its cell-con- 
tents as can be easily proved by the addition of iodine. 
In the cells of plants having milk-sap, in foul vegetable infus- 
ions, etc. 
According to Van Tieghem’s first communication this species is the producer of cellu- 
lose fermentation. Later Bacillus amylobacter (not B. subtilis) was pointed out by him 
and Prazmowski. (Botan. Zeitung. 1879. No. 2ti) as the cause of butyric acid fermentation 
(Vibrion butyrique, Pasteur). According to Prazmowski, B. amylobacter is distinguished 
especially and essentially fr >m B. subtilisin the m inn -,r of thegerminationof the spores. 
In the first .‘mecies the germinal tube does not appear at the equator, but at one end of 
the spore. But to found a new genus upon this, as proposed by Prazm >wski, does not 
seem to me advisable. 
[Trecul has held that this organism originates within the closed cells of plants by a 
direct transformation of the protoplasm, an idea combatted by Van Tieghem. (Comptes 
Rendus, t. 89, p. 205; t. 61, pp. 156 and 436; t. 65. p. 513)]. 51 
B. ulna, Cohn. 
Filaments thicker than in Bacillus subtilis, somewhat flexible, with 
dense, finely granular protoplasm. A single cell attaining .00040 
in. length, .00098 in. wide. Spores oblong cylindrical. 
In various infusions, for example in the white of egg. 
Appears to be scarcely different from Bacillus subtilis; intermediate forms between 
them have been observed. 
B. anthracis, Cohn. 
Exsiccata: Thumen Universalis. 1499. 
Very similar to Bacillus subtilis, but motionless and without cilia; 
cells .00016 in. long and longer, very slender, mostly extended; 
often united in crooked filaments. Spores not, or but little thicker 
than the threads. 
In the blood of animals which have died with splenic fever (An- 
thrax, Miltzbrand); the cause of splenic fever in cattle, sheep, etc., 
and malignant pustule in man. 
Bacillus anthracis and the disease symptoms caused by the organisms are. among all 
pathological processes induced by Schizomycetes, the most accurately investigated. 
The Bacilli are found without exception in the blood of animals dead from splenic fever 
and the proof has now been sought and found that they are the cause of the disease. So 
long as only the vegetative rods were known it was difficult to gain this evidence; for 
these retain their vitality only a comparatively short time and blood containing only 
these soon loses its power of infection. The remarkable thing about splenic fever is 
that it often occurs very suddenly in a region, then disappears for a long time to reappear 
just as unexpectedly, without any transmission having been allowed. From this fact it is 
to be inferred that the contagion can retain its virulence a long time. The discovery of 
the spores of Bacillus anthracis, which form only in the blood of dead animals or when 
the blood of animals sick with splenic fever has been a long time dried, explains this 
power of long duration. For as the spores of Bacillus anthracis possess a great power of 
resistance to outside influences, especially dryness, they are capable of developing after 
many years. They are often produced within the buried bodies of animals dying with the 
disease, and from these they may be diffused in various ways. Then if in any manner 
they reach the bodies and gain entrance to the blood of cattle, etc., they germinate, re- 
producing the rods which multiply richly and soon begin their destructive activity. 
[Recent investigations (1881-1882) have added further information upon and new interest 
to this species. It seems well established that Bacillus subtilis may, by graded cultiva- 
tions, be physiologically changed, so that it is capable of developing in th'' blood of 
living animals and thus become the cause of disease; but such changes do not take place 
suddenly and seldom occur in nature, though the possibility of the latter may explain 
what has heretofore been mysterious and perplexing. But by far greater scientific and 
practical interest is attached to the results of modifications through artificial cultivation 
of Bacillus anthracis itself. By cultivating the deadly organism in well aerated chicken or 
other broth at a certain temperature, the virulence of its physiological effects is gradually 
lost, but may be restored after several generations by equally feasible methods. The 
practical importance of this is at once seen to be very great when it is further made 
known that the organism modified by habit to a harmless condition constitutes a pro- 
tective virus which, after inoculation, relieves the animal from danger however exposed 
to the Bacillus in its malignant state. Some account of this has been given on a preceding 
page, and the matter has been widely published in recent periodical literature. No 
greater contribution has ever been made to pathological and medicinal knowledge, and 
the good results already attained opens boundless anticipations of mastery over other ills 
that flesh is heir to. Pasteur supposed he had conclusive proof that the spores buried 
with dead animals retained their vitality during ten or more years, but the changes now 
known possible in other species renders the evidence less valuable.] 
B. ruber, Frank and Cohn. 
Exsiccata: Rabenhorst, Algen2441. 
Rods .00024 to .0C032 in. long, scarcely .00004 in. thick, actively 
moving, isolated or united in twos or fours. Rods (cells) just divi- 
ded sometimes shorter, only .00012 to .00016 in. long. Imparting a 
brick-red pigment, different from that of Micrococcus prodigiosus. 
On boiled rice. 52 
B. erythrosporus, Cohn. 
Motile, short, slender rods, forming sometimes longer lilaments in 
which originate numerous, oblong-oval, highly polished, dirty-red 
spores. 
On solutions of beef extract, putrid infusions of white of egg and 
of meat. 
This species forms in part little swimming scales, in part a continuous pellicle; the fila- 
ments at length decompose into a gelatinous mass whereby the spores are liberated, 
which now united in little gelatinous masses sink to the bottom. The species is easily 
recognized by the dirty-red color of the spores. 
[B. of tuberculosis. 
Cells very slender, cylindrical, about .00002 in. wide, .00010 to 
.00012 in. long, isolated or in chains of a few articles; motionless; 
sometimes containing spores which, from their size, cause slight 
fusiform swellings of the containing cell. 
That this dreaded scourge of the human family as well as of the higher animals is in- 
fectious has of late been repeatedly shown, and the most careful search has been made 
for the organism which, from analogy, was supposed to constitute the materie* morbi. 
After many.failures on the part of numerous investigators. Dr. H. Koch, of Berlin, suc- 
ceeded, by a special method of preparation, in discovering the minute species character- 
ized above. In order to see the Bacillus it is first stained as follows; Smear a cover glass 
with the tuberculous matter (sputa or a small portion of tubercle), dry over a lamp; 
float the smeared cover several hours (24) on—a concentrated alcoholic solution of 
methylene-blue 1 part, a ten per cent, solution of potash 2 parts, distilled water 200 parts; 
wash, and treat with a few drops of aqueous solution of vesuvin. The Bacilli retain the 
blue, while the rest of the material does not. Now that we know what to look for, the or- 
ganisms can be seen without staining, but they are very indistinct The common violet 
stain of the accompanying material somewhat aids—the Bacilli showing white. 
Abundant experiments by Koch and others, have shown that these Bacilli are the true 
agents in the wasteful processes of the disease—the real cause of consumption in man 
and animals. It is also demonstrated that they do not develop in nature outside of the 
living body, hence that the disease is only communicated from the diseased; and, further, 
that the supposed hereditary peculiarities consist simply and only in the organic inability 
to resist infection. The children of consumptive parents may remain healthy if kept 
away from diseased individuals and their excretions]. 
IB. leprae, Hansen. 
Cells slender, elongated, .00016 in. long, .00004 in. wide; 
isolated or united in chains of a few articles, often arranged side 
by side; motionless. 
In any or all tissues of the body of those afflicted with leprosy. 
The investigations of Hansen, Neisser and others, have fully established the cause of 
this scourge of the human family in various parts of the world. The contagious character 
of the disease was among the earliest recognized, and has long been fully understood; 
but in what the contagion consists, has been entirely unknown until o ir own time. It is 
now added to the increasing list of known affectations due to the injurious activities of 
minute parasites which we are just beginning to know and understand. Jlacillux Ixprif, 
like the preceding, is nearly invisible without staining, but is readily seen after treatment 
with aniline dyes in the manner just given]. 
(B. of foot-rot in sheep. 
Cells cylindrical .00012 to .00016 in. long, isolated or more 
generally united in pairs, of which one cell is larger than the other; 
actively motile. 
In pustules in tissues of animals affected with above named 
disease. 53 
The course of the disease occupies about thirty-five days. In the vegetative stage the 
organisms are very active, but in liquids (broth of rabbit or mutton) from which the nutri- 
ment is nearly exhausted the larger cell of a pair produces a spore at each end and some- 
times one in the middle, the smaller cell produces one spore of larger size, about .1)0004 
in. in diameter. The spores, as in other cases, sink to the bottom as a white sediment. 
Upon inoculations with this material pustules are formed which reach their greatest size 
in about eighteen days. They never suppurate and appear to be local in effect, though 
the temperature of the animal rises somewhat by the fifteenth day. (Comptes Rendus . 
xcii, 1881, pp. 362-4.)] 
LEPTOTHRIX, Kutzing (Emend). 
Filaments very long and slender, unbranched, apparently not 
jointed, colorless, motionless, without granules, free or felted. 
The fungi referred to the genus Leptothrix are, with reference to 
their specific value, very questionable; I place here the following 
kinds only provisionally. Leptothrix species very commonly occur 
with those of Bacillus. Since the genus will probably have a place 
among the fungi only a short time, I will not give it a new name. 
The greater number of the species are typidal phycochromous algae. 
[Treatment with iodine renders the articulations very distinct], 
Ii. buccalis, Robin. 
Filaments very long and slender .000028 to .00001 in. (seldom 
something more) in diameter; jointless, colorless; felted into dense 
white masses. 
Mixed with Micrococci (usually also Vibrio, etc.,) in the white 
slime on the teeth, on the epithelium of the mouth and in hollow 
teeth. Probably the cause of caries (rotting) of the teeth. 
The seat of the fungus is especially in the canals of the tooth-bone (the dentine pipe); 
but it seizes also upon the substance of the enamel which it gradually destroys. In the 
canals the fungus produces marked enlargement, later the walls themselves become pen- 
etrated by fissures and chinks and broken in pieces. 
L. parasitica, Kutz. 
Filaments very slender, mostly curled and crisped, obscurely 
jointed; loosely felted, nearly colorless; .004 to .0056 in. long, .00004 
in. thick. 
Parasitic on Scytoneuiacece and other related Algce. 
Leptothrix jpwsiifa.Rabh, and L. lanugo, Kxitz, are, perhaps, also to be accounted Fungi. 
BEGGIATOA, Tkevisan. 
Filaments very long but thicker than those of Leptothrix, usually 
obscurely jointed, quite rigid hut actively oscillating, imbedded in 
jelly, colorless, with numerous highly refractive granules in the pro- 
toplasm which consists of sulphur. 
The genus Beggiatoa is easily recognized by the chalk-white 
slime-forming, actively moving filaments, whose joints cannot as a 
rule be distinguished without special processes. In order to see 
them it is necessary to let the filaments dry on the microscopic 
slide and then apply bisulphide of carbon, which gradually dissolves 
the granules of sulphur which in the living plant obscures the 
joints. The species of Beggiatoa live for the most part in thermal 54 
sulphur springs where they decompose, the dissolved sulphur com- 
pounds in the water and give off free sulphureted hydrogen. For 
this reason such water with Begyiatoa put into a stoppered bottle, 
develops an extremely intense odor of sulphureted hydrogen. 
The supposed species of Begyiatoa are of very uncertain value ; 
they are distinguished by very little else than the diameter of the 
threads. 
B. alba, Trev. 
8ynonyms: Begaiatoa punctata, Trev. (Flora Enganea, p. 56); Oscillaria alba, Vauch 
(Conferv, p. 198, T. XV. Fig. 11): Hyarocrocis Vandelli, Monegh, (Kutzing’s Algae exsc. 
No. 16-Tab. phycol. I. T. XXXVill, Fig. 3). 
Exsiccata: Wartmen und Schenk, Schweiz. Kryptog. 639. 
Filaments without evident joints, forming dirty or chalky-white 
slimy masses; .00012 to .00014 in. thick. 
In sulphur springs and swamps. 
Var. marina, Cohn. 
Filaments densely filled with blackish granules, only .00008 thick. 
In a salt-water aquarium, forming a snow-white, then slimy mem- 
brane on dead animals and algae. 
B nivea, Rabh. 
Synonym: Leptonema niveum, Rabh. (Alg. Decad. 653). 
Filaments very slender, obscurely jointed; .00004 to .00000 in. 
thick (according to Rabenborst) forming flocks of snow-white color. 
In sulphur springs. 
In Wartmann and Schenk's Swiss Cryptogams.’639, this species is given under the name 
of Symphyoihrix nivea. Brugger. Both the above names are cited, pari passu, as syno- 
nyms. I take the following from their description: “Filaments not polished, without 
joints, also without movement, only .00002 to .000052 thick, parallel and variously entwined, 
united in pencil-like tufts, strings and bundles of very unequal thickness, which are en- 
veloped in a common, homogeneous slime-mass.” 
B. leptomitiformis, Trev. 
Synonym: Oscillaria ’leptomitiformis, Menegh. (Ragazz. Nuovo ricerch. flsico-chim. 
p. 122.—Kutzing, Tab. phycol. I. T. XXXVIII, Fig. 1.) 
Exsiccata: Rabenhorst's Algen, 1813. 
Filaments very slender, obscurely jointed, .00007 to .00010 in. 
thick; forming a thin chalk-white slimy layer. 
In sulphur springs. 
B. archnoidea, Rabh. 
Synonyms: Oscillaria archnoidea, Ag, (Regensb. “Flora," 1827, p. 634, No. 38.) Oscillaria 
versatilis, Kutz. (Phycol. gener. p. 184). 
Filaments rather thick, evidently jointed, with rounded, slightly 
curved ends; movements active. Joints as long, or half as long as 
thick. Filaments .00020 to .00026 in. thick, forming a very thin, 
cob-webby, chalk-white, slimy pellicle. 
In sulphur springs and swamps. 55 
B. pellucida, Cohn, (Hedwigia 1865, p. 82, T. I, Fig. 2.j 
Filaments .00020 in. thick, motile, evidently articulated, with 
rounded ends; joints scarcely as long as thick; pellucid, containing 
but few granules. 
In a salt-water aquarium. % 
B. mirabilis, Cohn, (1. c. p. 81, T. I, Fig. 1.) 
Filaments thick, variously crooked and curled, with rounded ends, 
evidently articulated; attaining .00064 in. thick; joints half as long 
as thick, filled with numerous rather large granules. Threads 
twisted and woven through each other, forming a snow-white, slimy 
web. 
With the preceding. 
DOUBTFUL SPECIES. 
B. tigrina, Rabh. (Flora Europ. Alg. II, p. 95.) 
Synonym: Oscillaria tigrina, Romer (Die Algen, Deutchlands p. 58.) 
Filaments rather thick,oscillating, evidently jointed, with slight and obtuse curves, now 
and then suddenly reduced in size, with rounded ends; pellucid, .00014 to .00018 in. thick; 
forming a thin white layer. 
In swamps and on wood under water. 
B. minima, Warm. 
Very small, flexible and actively moving; the longest .0016 in. .00007 to .00008 thick; jointed: 
distinguished by the order of the delicate stripes. Each joint about half as long as 
wide. Without granules. 
In sea-water. 
CLADOTHRIX, Cohn. 
Filaments leptothrix-like, very slender, colorless, without joints, 
straight or slightly undulating, or irregularly spirally wound, with 
apparent branches. 
I am unable to find a satisfactory difference between the genera 
Claclothrix and Streptothrix. Both are very doubtful genera. Com- 
pare Cienkowski’s “Zur Morphologie der Bacterien” (Memoires de 1’ 
Acad. imp. d. Sciences de St. Petersbourg. YII Ser. Tome XXY, 
No. 2, p. 11.) 
C. dichotoma, Cohn. 
Filaments repeatedly dichotomously branched, straight or slightly 
bent, .000012 thick, forming little webs (Kaschen) .02 in. and more 
in diameter. 
In foul water, sometimes floating on the surface, sometimes 
attached to algae. 
The branching in this case, as with Cladothrix Forsteri, is only apparent. The filament 
split themselves into two halts, which independently elongate and so grow side by side; 
in this way the separated pieces are crowded to one side and appear as branches. 
(Streptothrix, Cohn, Beitr. z. Biol. Bd. I, Heft 3, p. 204.) 56 
C. Forsteri, Winter. 
Synonym: Strep tothrix For stem, Cohn. (Beitr. z. Biol. I, 3 Heft., p. 180 und 204. 
Filaments straight or curved, irregularly spirally twisted, sparsely 
and irregularly branched, occurring in pieces of various lengths. 
In the lachrymal ducts of human eyes, forming greasy or crumb- 
ling yellowish-white or blackish concretions, .125 to .25 in. long, 
.083 in. thick. 
MYCONOSTOC, Cohn. 
(1. c. p. 183 und 204.) 
Filaments very slender, colorless, not jointed, but upon drying 
separating into short cylindrical articulations, variously curved and 
entwined, imbedded in jelly, forming globules from .00040 to .00068 
in. in diameter. 
Multiplying by the infolding and the division of the globules of 
jelly in two parts. 
M. gregarium, Cohn. 
Gelatinous globules, floating on the surface of foul waters, single 
or aggregated in little slimy drops, with the circumference sharply 
defined. 
On water in which there are decomposing algae. 
SPIROCILETA, Ehrb. 
(Abhaudl. d. Berlin. Acad. 1X13, p. 313). 
Cells united in long slender threads, mostly showing narrow spiral 
windings. The filaments have the liveliest movements, and clearly 
propel themselves forward and backward, but are also able to bend 
in various ways. Forming no zoogloe, but often felted in dense clusters. 
Differs from Spirillum by the long, narrowly-wound, flexible threads. 
S. plicatilis. Ehrb. 
Synonym: Spirillum plicatile. Duj. (Infs. p. 225, T. I, Fitf. 10). 
Spirulina plicatilis, Cohn. (Nova Acta Acad, Caes. Leopold; Carroll, XXIV, I, p. 125, T. XV, 
Fig. 10,11). 
Filaments very short and slender, with numerous narrow spiral 
turns; jointed, obtuse at the ends, .00440 to .00900 in. long (accord- 
ing to Rabenhorst); diameter, .00009 in. (according to Ehrenberg). 
In swamp water, among algae. 
This species differs, according to Koch, from the others, by the double spiral formed by 
the filaments. Yet threads wound in a continuous spiral are very common. 
S. Obermeieri, Cohn. 
Very similar to Spirochata plicatilis in form, only differing by the 
filaments being sharply pointed at both ends. 
In the blood of the sick with recurrent fever, and apparently the 
cause of the sickness. 57 
The filaments of Spirochceta Obermeieri are either extended and regularly spirally 
wound, or they are bent, so that the spirals appear irregular, especially in the parts most 
crooked, rapidly moving in various ways. This species is found in the blood of persons 
having recurrent fever, and really only during the returning access (onset) of the fever 
or a short time thereafter. They disappear in the periods between the paroxsms of the 
fever, [The former investigations have been confirmed by extensive. observations in 
India, where relapsing fever is now very common. See volume on “Spirillum Fever,” by. 
Dr. Vandyke Carter, London, 1882.] 
... .. > .. ." - 
S. Cohnii, Winter. 
Very similar to both the foregoing species, but always shorter and 
usually also more slender, like Spiroclueta Obermeieri sharply pointed 
at both ends. 
In mucus on the teeth; discovered by Cohn, figured by Koch 
(Beitr. z. Biol. II, Bd. 3, Heft., T. XIV, Fig. 8). 
S. gi«yantea, Warming. 
Filaments cylindrical, obtuse at both ends, about .00012 in. thick, 
with numerous spiral turns of a diameter of .00028 to .0J036 in. 
and length of each .001 in.; flexible; the articulations are not ap- 
parent, but the threads sometimes separate into joints. The longest 
have sixteen spiral turns; cilia have not been found. 
In sea water. 
SPIROMONAS, Peety. 
(Zur Kenntniss der Kleinsten Lebensformen. p, 171.) 
Cells leaf-like (flat), compressed, twisted around an ideal longi- 
tudinal axis; multiplying by transverse division. 
S. volubilis, Perty. 
Colorless, pellucid, polished, without in any part special differen- 
tiation ; movements quite rapid, turning upon the axis upon which 
the leaf-like body is wound. Body often very little twisted, never 
forming more than one spiral turn; length .00060 to .00070 in. 
In stagnant swamp water and foul infusions. 
i 
S. Co'inii, Warming. 
Cells flattened, but sometimes scarcely angular, sharply pointed 
at both ends and always furnished with a cilium, having one and 
a fourth (rarely more) spiral turns; these six to nine times as high 
as their diameter; height .00036 to .00080 in., diameter .00005 to 
.00014 in. Thickness of the cells .00005 to .00016 in.; colorless, 
often with one or two longitudinal stripes. 
In ill-scented, very strongly fermenting water. 58 
SPIRILLUM, Ehrb. 
(Abhand. d. Berl. Akad. 1830, p. 38). 
Vibrio, Cohn. (Boitr. z Biol. I, Bd. 2, Heft, p. 178.) 
Ophidomonas, Ehrb. (Infs. p. 43.) 
Cells cylindrical or somewhat compressed, with a single arch-form 
curve or spirally wound; rigid; furnished at each end with a cilium 
(not certainly observed in all the species); multiplying by trans- 
verse division, the parts soon separating from each other. The 
formation of zooglcea and of spores as in the species of Bacillus some- 
times occurs. 
I unite with Spirillum the genera Vibrio, Cohn, Ophidomonas, 
Ehrb. The genus Vibrio does not indeed permit of sharp definition 
since their cilia have been found. Cohn himself has united Ophido- 
mas with Spirilltan. Warming also shows that all three genera are 
the same. Although the name Vibrio has the priority, I have 
chosen Spirillum because with the first, aside from its being non- 
botanical, misuse has been practiced, so that it is better to drop it 
altogether. 
S. rugula, Winter. 
8ynonyms: Vibrio rugula, Muller (Infs. p. 44, T. VI, Fig. 2.) Melanella flexuosa, Bory 
(Encycl. method, 1824.) 
Cells .00024 to .00064 in. long, .00002 to .00010 in. thick; 
either only one curve or one flattened spiral turn, bearing a cilium 
at each end, actively rotating around their long axis; the cells 
often felted into dense swarms; height of a spiral mostly .00024 to 
.00040 in., diameter .00004 to .00008 in.; globular spores always 
formed at the ends of the cells. 
In swamp water and various infusions; also in the slimy material 
on the teeth, &c. 
According to Warming some specimens attain a height of single spiral of .000.10 to .00080 
in., and diameter of .00010 to .00020 in. 
S. serpens, Winter. 
Synonym: Vibrio serpen*, Muller (Infs. T. VI, Fig. 7 and 8.) 
Cells half as thick as the preceding species, .00045 to .00112 in. 
long (according to Rabenhorst) .00003 to .000045 in. thick, with 
more usually three to four spiral turns; often joined in long chains; 
furnished with a cilium at each end; also often collected in swarms; 
height of a single spiral .00030 to .00050 in.; diameter, .00005 to 
.00012 in. 
In various infusions. 
Rabenhorst’s measurement of the length, .00092 to .00112 In., probably applies to the 
whole filament consisting of several cells. According to Warming the height of a single 
spiral sometimes attains .00088 in. 
S. tenue. Ehrb. (Infs. p. 84, T. V, Fig. 11). 
Cells very slender, .00016 to .00060 in. long, .00010 in. thick (ac- 
cording to Ehrenberg), with at least one and a half, usually two, 59 
three, four or five spiral turns; height of a single turn of the spiral, 
.00006 to .00316 in.; diameter, from one-half to the same; move- 
ments very active, but also without motion; collected in dense 
swarms or masses, or forming zoogloea. 
In various infusions. 
According to Warming only .00004 in. thick, and the distance of the turns of the spiral 
sometimes .00032 to .00040 in.; their diameter only one-eighth to one-tenth this measure- 
ment. A confusion appears to prevail in respect to Spirillum tenue and Sp. undula. 
S. undula, Ehrb. 
Synonvms: Vibrio undula, Muller (Vermium historia, p. 43). Vibrio prolifer, Ehrb. (Infs, 
p. 81. T. V. Fig. 8.) 
Cells .00032 to .00018 in. long, .000044 to .000056 in. thick (Ra- 
benhorst; spiral wider than the preceding; turns .00016 to .00020 
in. distant; each cell usuallv having only one-half or one, rarely 
two or three spiral turns; furnished at each end with a cilium; 
motions very active; sometimes also forming zoogloea. 
In swamp water and in various infusions. 
Ehrenberg gave for Spirillum tenue a thickness of 1-1000 of a Prussian line, and for 
Sp. undula only 1-1680 of a line; he also said in the description: “Sp. fibris valde tortuosis 
brevibus, validioribus." 
According to Warming, Spirillum tenue is more variable than has been hitherto sup- 
posed. The turns of the spiral are often very long, so that the cell appears almost 
straight, therefore the distance between them varies from .00012 to .00042 in., with a diame- 
ter from one-tenth to three-fourths of this measurement; the thickness of the cell is from 
.000024 to .00005. 
Var. litorale, Warming. 
Attains .00012 in. thick, length of one turn of the spiral form 
.00020 to .00040 in., and diameter from one-sixth to one-fourth as 
much. 
On the coast of the Baltic sea. 
S. volutans, Ehrb. 
Synonyms: Vibrio spirillum, Muller (Infs. p. 49, T. VI, Fig. 9j. Melanella spirillum, Bory 
(Encycl. method.) 
Cells somewhat tapering at the ends, gradually rounded, .00100 
to .00120 in. long, .00006 to .00008 in. thick; each cell with two 
and a half to three and a half spiral turns, each of which is .00036 
to .00050 in. high, .00026 in. in diameter; furnished with a cilium 
at each end. 
In various infusions as well as in swamp water among algae. 
According to Warming, the spiral is often elongated so that the 
cell appears almost straight, the diameter then becoming only .00006 
to .00016 in. 
Var. robustum, Warming. 
Thickness .00008 to .00018 in.; height of spiral .00040 to .00080 
in.; diameter .00004 to .00012 in.; mostly one and a half turns; 
sometimes two cilia at one end. 
In sea water. 
S. sang’uineum, Cohn. 
Synonym: Ophidomas sanguinea, Ehrb (Monatsber, d. Berl. Akad. 1840, p. 201). 60 
Cells cylindrical, only rarely tapering at the end, .00012 in. 
and more thick, of various lengths, with mo.stly two, seldom only 
one-half or two and a half spiral turns; distance of the latter 
.00036 to .00048 in.; diameter two-thirds as great; furnished at 
each end with a cilium. Cell-contents colored by numerous reddish 
granules with many granules of sulphur. 
In foul brackish water. 
Accordingto Warming the longest specimens reach a length of .00200 in., the distance of 
the turns of the spiral .000f>0 to .00150 in., diameter one-half to two-thirds, or with the 
smallest one-fourteenth to one-seventh as much. 
S. violaceum. Warming. 
Cells either crescent-form (without a complete spiral winding) or 
with one or one and a fourth spiral turns; abruptly rounded at 
the ends and furnished with a cilium. Cell-contents violet, contain- 
ing little granules of sulphur. Distance of the turns of the spiral 
.00033 to .00040 in., diameter .000J4 to .00006 in., thickness of the 
cell .00012 to .00016 in. 
In brackish water. 
S. Rosenberg’ii, Warming. 
With one or one and a half turns of the spiral, cells .00016 to .00050 
long, .00006 to .00010 in. thick; colorless, but with numerous, 
highly refractive, sulphur granules. Distance of a turn of the spiral 
.00024 to .00030 in., diameter very different, highest half as much. 
Active and moving in various ways, but without cilia as it ap- 
pears. 
In brackish water. 
S. attenuatum, Warming. 
Cells tapering to the ends, usually with three spiral turns, the 
middle one is .00044 in. high and .00024 in. in diameter, the end 
ones .00040 in. high, and .00080 in. in diameter; thickness of the 
cell .00005 to .00008 in.. 
In sea water. 
S. jenense, Winter. 
Synonym: Qphidornonas jenensis, Ehrb (Infs. p. 44). 
Cells obtuse at both ends, furnished with a cilium, olive-brown, 
.00160 in. long, .000132 in. thick, with one-half to two and a half 
spiral turns. 
Whether this is really a distinct species is hard to say so long as it is not again 
found in the original locality. Possibly it is identical with Spirillum volutang. 
APPENDIX. 
We connect with the Schizomycetes some genera which are united 
with them on the part of others without question; but which show 
so many peculiarities that I may provisionally separate them. 61 
SPILEROTILUS, Kutzing. 
(Linnaea YIII, 1833, p, 385, T. IX.) 
Cells roundish, angular, or oblong, rounded on the angles, in the 
greater number united end to end in a colorless, slimy sheath, into 
long filaments which form cue-like, interlaced and entangled float- 
ing flocks. Multiplying by isolating vegetative cells which produce, 
through continued division, new filaments; propagation by spores, 
which form within the vegetative cells. 
S. natans, Kutzing, (l.c.; also 54 Jahresb. d. Schles. Ges. f. vaterl, Cultur. 1876, p.133.) 
Flocks in the vegetative stage, in the old parts yellowish-brown, 
in the younger colorless, much branched, very slippery. In those 
producing spores, a part milk-white and a part colored red. Cells 
.00016 to .00036 in. long, .00012 in. thick. 
The flocks consist of an enormous mass of long, variously collected threads, which are 
formed of cells in rows, surrounded by a slimy, refractive sheath. These threads often 
form shrubby, branchy structures, which become attached to aquatic plants, or float in a 
thin stratum on the water. In the thread-cells forming spores the protoplasm separates 
in numerous small, highly refractive portions, which become the globular spores colored; 
when ripe, red; later, brown. These become free when the membrane of the mother cell 
dissolves. They germinate very soon and grow into tnreads, which are either isolate or 
attached to the mother or other threads. These daughter threads, formed from the germ- 
inating spore, are at first undivided, and only later become the typical row of cells. 
Sometimes the spores develop into threads inside the mother cell. 
CRENOTHRIX, Cohn. 
(Beitr z. Biol, I, Bd. 12, Heft, p. 130). 
Filaments cylindrical, slightly club-form, thickened above, jointed, 
furnished with a sheath; multiplying by the escape of the joint-like 
cells from the sheath and their growth into filaments. Propagation 
by spores, which are formed within the sheath by the further di- 
vision of the cells. The spores either grow directly into threads, or 
form, by continued division, gelatinous colonies of round cells, which 
afterward produce threads. 
C. Kuhniana, Zopf. 
. Synonyms: Leptothrix Kuhniana, Rabh. (Algen Sachsens, No. 284;) Kypheotlirix Kuhn- 
tana Rabh. (Flora Europ. Alg. II, p. 88): Crenothrix polyspora, Cohn, Beitr. z. Biol. I, Bd. 
12, Heft, p. 13b; ? Palmellina floculosa, Radlkofer. (Zeitschrift f. Biol. Bd I) 
Exsiccata: Rabenhorst’s Algen, 284. 
Filaments in whitish or brownish webs (Raschen), .00003 to .00020 
in. thick, widened near the ends to .00024 to .00036 in.; joints of 
very different lengths. Spores .00004 to .00024 in. in diameter. 
In springs and drainage tile, etc. 
Often a very troublesome fungus since it pollutes the water and stops up small pipes. 
The cylindrical filaments slightly thickened towards the end are evidently articulated; 
the joints after a while separate from each other, but are then inclosed by a sheath, 
which, originally colorless, becomes yellow or yellowish brown by imbibing iron. The 
sheath, at first ctosed, is finally burst by the continued division of the joints and these 
escape. Eachjoint candevelop into a new filament. Butin other cases the thread re- 
mams enclosed in the sheath; its joints are divided by numerous close cross-partitions- 
into thin disks, which then by vertical divisions separate into little globular cells; these 
may be considered as the spores of the fungus. They often develop inside the sheath 62 
nto new filaments which grow through the swelling gelatinous sheath; or they leave the 
sheath in order to further develop outside. They either grow in filaments or form by 
repeated bi-partition little colonies of rounded cells, which are held together by the 
membranes, now become gelatinous. These colonies are assigned to the I’almellix 
(perhaps Pahnellina flocculosa. Rad.); eachof their cells can again form a filament. 
SACCHAROMYCETES. 
Saccharomycetes, or yeast fungi, are one-celled plants which mul- 
tiply by budding and propagate themselves by spores produced 
within the cells. They live isolated or joined in sprouting chains 
(sprossverbanden), chiefly in liquids containing sugar in which they 
induce alcoholic fermentation. 
In most Saccharomycetes the cells are globular, oval or elliptical, 
only rarely do they elongate into cylindrical tubes, which become 
jointed by transverse partitions, and may then be considered the 
earliest imitation of hyphse or mycelium formation. For the pur- 
pose of multiplication the cell pushes out a little rounded protuber- 
ance (Austulpung) which becomes filled with a part of the contents 
of the mother cell, whose form and size it gradually acquires, and 
is cut off by a partition wall. Both cells can, in like manner, pro- 
duce daughter cells, which frequently remain attached for a time 
and after their separation continue to vegetate independently. 
A damp solid substance is especially favorable for the formation 
of spores. Typically the whole cell contents divides into two to 
four rounded portions, or contracts into a single globular body. 
Each of these surrounds itself with a cell-wall, and thus becomes a 
spore which can bud like the vegetative cells. 
To the yeast fungi (in the narrower sense) belongs the ability to 
decompose the sugar of a solution, for example of wine must, into 
alcohol and carbonic acid, that is, to set up alcoholic fermentation. 
The carbonic acid escapes in rapid streams, while the alcohol, as 
well as some subordinate elements of sugar, e. g. succinic acid, 
remains behind. The fermentation proceeds with special energy 
with a small supply of air; but by long continued exclusion of air 
the yeast cells perish. 
The validity of the Saccharomycetes species from a botanical stand- 
point, is similar to that of the Schizomycetes. As with the latter, it 
is also necessary here to make a limitation to the leading species, 
and to leave out of consideration only those species established by 
reliable investigators. Even then there remains much doubt, for 
the majority of accepted species at present are probably only differ- 
ent forms of one and the same kind, which have become differen- 
tiated under changed conditions of growth. 
SACCHAROMYCES, Me yen. 
One-celled fungi with vegetative multiplication by budding; prop- 
agation by spores which (usually) form by the division of the con- 
tents of the mother cell. 63 
[This is the only genus, hence has the general characteristics of 
the group. The relation to the Schizomycetes is certainly quite close 
and apparently nearer than usually supposed by excellent authori- 
ties. The so-called budding is, after all, only a peculiar mode of 
self-division by elongation and the formation of transverse parti- 
tions, and the production of spores is entirely similar in the one to 
the other, while the physiological processes and effects are not more 
distinct than the existing difference in these respects between true 
species of Schizomycetes. For these reasons, as well as the fact that 
the two kinds of organisms are very commonly associated in nature, 
I have appended this account of the Saccharomyces without intend- 
ing to imply that the species belong among the bacteria.] 
S. cerevisiae, Meyen. 
Synonyms: Torula crevisice, Turpin (Compt. Rend. VIII, 1838, p. 379); Cryptococcus fer- 
mentum, Ktz. (Species Algarum, p. 146); Hormiscium cerevisiae. Bail, (Flora, 1867, p. 417.) 
Exsiccata: Rabenhorst’s Algen, 121; Fungi Europ., 1999; ThumenMycotheca Universa- 
is, 800; Kryptogamen Badens, 141. 
Cells mostly globular or oval, .00032 to .00036 in. long; isolated 
or joined in little colonies; spore-forming cells isolated, .00044 to 
.00058 in. long; spores usually three or four in a mother cell, 
.00016 to .00020 in. in diameter. 
In beer, in both the surface and bottom fermentation. 
This peculiar beer yeast is found in the various kinds of beer, in 
both kinds of fermentation. It is cultivated in quantity and fur- 
nishes then the so-called compressed yeast—a mass consisting of 
yeast cells and water. 
S. ellipsoideus, Reess, (Bot. Unters, ub. d. Alkoholgahrungpilze, p. 82.) 
Exsiccata: Rabenhorst’s Fungi Europ. 2000. 
Cells elliptical, usually .00024 in. long; isolated, or united in 
little branched colonies. Spore-forming cells mostly isolated; spores 
in the mother cell two to four, .00012 to .00014 in. in diameter. 
In wine must, spontaneously fermenting. 
S. conglomeratus, Reess, (1. c. p. 82). 
Cells almost globular, .00020 to .00024 in. in diameter, united in 
skeins which consist of numerous budding cells from one or a few 
mother cells; spore-forming cells often to one or two vegetative 
cells united; spores two to four in a mother cell. 
In wine must at the beginning of the fermentation and on decay- 
ing grapes. 
S. exiguus, Reess, (1. c. p. 83). 
Cells conical or top-form .00020 in. long, .00010 in. wide, united 
in little branched colonies; spore forming cells isolated with always 
two to three spores in a row. 
Among the yeast of the secondary fermentation of beer. 64 
S. Pastorianus, Reess. (1. c. p. 83.) 
Exsiecata: Thumen Fungi Austriaca 101*9 (vnr. Rubi-Id&i.) und 1199 (var. Ribis). 
Cells roundish-oval or elongate-clavate, of various dimensions; 
colonies branched, consisting of primarily club-shaped joints .00072 
to .00088 in. long, which form secondary roundish or oval, angular 
cells .00020 to .00024 in. long. Spore-forming cells roundish or 
oval; spores two to four .00008 in. in diameter. 
In the yeast of the secondary fermentation of wine, ciders and 
self-fermenting beer. 
S. apiculatus, Reess, (1. c. p. 84.) 
Exsiecata: Thiimen Fungi Austriaca, 263. 
Cells lemon-shaped, with a little short point at each end; .00024 
to .00002 in. long, .00008 to .00012 in. wide, sometimes a little 
longer; daughter cells only from the ends of the mother cell, 
usually soon isolated, rarely joined in little scarcely branched 
colonies. Spores not known. 
In the principal fermentation of wine and other spontaneous 
fermentations. 
S. Sphsericus. Saccardo (Michelia I, p. 89. et Fungi Ital. Autogr. del. No. 76.) 
Exslccata: Thumen Mycotheca Universalis, 91)0. 
Cells of different forms; the basal one (of a colony) oblong or 
cylindrical, .00040 to .00060 in. long, .00020 in. wide; the rest globu- 
lar, .00020 to .00024 in. in diameter, united in crooked, branched, 
often skein-like families; spore formation not known. 
In the fermenting juice of Lycopersicum esculentiun (Tomato.) 
S. glutOnus, Cohn (1. c. p. 187.) 
Synonym: Cryptococcun glutinus, Fresenius, (Beitr. z. Mycol. 2 Heft, p 77.) 
Cells globular, oval, oblong, elliptical or short cylindrical, .00020 
to .00044 in. long, .00010 wide, isolated, or two, rarely more, united; 
cell wall and contents in a fresh condition, colorless, after drying 
and again moistened a slightly reddish nucleus in the middle; 
spore formation unknown. 
On starch paste, slices of potato, etc., forming rose-red slimy 
spots which at the beginning have a diameter of .02 to .04 in., but 
gradually spreading and uniting they cover a surface of more than 
.4 in. square. The coloring matter is not changed by acids or 
alkalies. ,Rtr> 
liO O’ . 
S. Mycoderma, Reess (1. c. p. 83). 
Synonyms: Mycoderma cerevisice and .1/. vini, Demaz. (Ann. Scienc. Natur. I 8erie. 
Tome x, p. 59et65). Hormiscium vini and cerevinitv, Bonord. (Hundbuch p. 33, T. I. fig. i 
und 2. 
Exsiecata: Thumen Fungi Austr. 1299.1300. 
Cells oval, elliptical or cylindrical, .00024 to .00028 in. long, 
.00008 to .00012 in. wide, united in richly branched colonies. Fre- 
quently the cells are elongated, mycelium-like; spore-forming cells 
reaching a length of .00080 in.; spores one to four in each mother 
cell. 
On fermented liquids, sauer-kraut, juices of fruits, etc. On wine 
and beer, forming the so-called mold. Til BACTERIA. 
An Illustrated Monograph by T. J. B URRILL, PH. D., Professor of 
Botany, Illinois University. 
CONTENTS. 
Introduction. 
PART I.—Nature and Organization of Bacteria, 
(1) Existence, (2) Color, Shape, Size, (3) Movement, (4) Structure, 
(5) Reproduction and Development, (6) Vitality and Endurance, (7) Nu- 
trition, (8) Origin, (9) Place in Nature. 
PART II,—Effects of Bacteria, 
(1) Fermentations and Putrefactions, (2) Diseases, (3) Benefits. 
PART III,—Classification of Bacteria, 
Sixteen Genera (with artificial key) and over one hundred Species 
systematically arranged and described. 
EXTRACTS, 
“ Tt is the object of this paper to present, in language freed as far as possible from technical 
terms, the principal and most interesting facts now known about these silent-working denizens of 
the earth, the air, and the water.” 
“ We swallow them with our food, and at least some kinds sometimes retain their activity in 
the stomach and intestinal tube It now seems certain that the latter is always inhabited by spe- 
cial kinds which have to do with the activities there in operation. In health the blood is usually 
quite free from them, but in certain diseases this too, as it rapidly courses through the arteries and 
veins, sweeps along in the current myriads of the minute but living and developing, ever active 
things, inappropriately called “germs.” 
“There is now in certain cases just as good evidence that bacteria cause diseases as there 
is that hawks destroy chickens, and the evidence is as inductively rigid in the one case as in the 
other.” 
Octavo. (55 pages, paper, 50 cents. Ten or more copies by express, 35 cents 
each. For sale by the author, Champaign, Illinois. 65 
This and the following species reach in their development the highest rank in the 
Saccharomycetes. The cells often form especially in aqueous solutions elongated tubes, 
which become articulated by the growth of cross partitions and from these separate into 
single cells. The latter bud on their part in a similar manner. 
While the proper yeast fungus vegetates submerged, in the upper strata of liquids and 
here sets up very active alcoholic fermentation, the mold fungus grows on the surface 
without exciting fermentation. Artificially forced to grow submerged there is a small 
quantity of alcohol formed, but the fungus soon perishes. 
Although the growth of the mold-layer goes hand in hand with the souring of wine and 
beer, yet this Saccharomyces is not the cause of the latter phenomenon, several other 
fungi whose systematic position is not certain, produce this vinegar out of the alcohol of 
wine. etc. According to some it is a Vibrio (spirillum) species which excites this decom- 
position. 
S. Albicans, Reess (Sitzungsber der physic, Med. Soc. Erlangen, 9 Juli, 1877). 
Synonym: Oidium albicans, Robin (Hist. Nat. d. Yeget, Paras, p. 488, PI. I, Fig. 3 to 7). 
Cells in part globular, in part oval, or elongated to cylindrical, 
.00014 to .00020 in. wide, the globular ones .00016 in. in diameter, 
the cylindrical ones ten to twenty times as long as thick. Budding 
colonies usually consisting of rows of cylindrical cells, from the ends 
of which rows of oval or globular cells are produced by budding. 
Spores single, formed in roundish joints. 
On the mucous membrane of the mouth, especially of nursing in- 
fants, producing the disease known as Thrush (“Soor”). Also in 
animals. 
This fungus appears in the form of less or greater grayish-white masses which, how- 
ever, do not consist entirely of Saccharomyces, but also contain Schizomycetes and the 
mycelium of mold fungi. When cultivated the fungus forms abundant long-jointed, 
richly branched threads; at the upper end of each joint is usually found a crown 
or tuft of short cells which have an oval or globular form and these bud again in 
their turn. In other cases all the cells of a colony remain short and take the 
globular form. The fungus excites alcoholic fermentation only in a slight degree. 
According to Grawitz (Virchow’s Archiv. f. pathol. Anat. und Physiol. 70 Bd. p. 557), 
Saccharomyces albicans is identical with S. mycoderma. 
S. guttulatus, Winter. (Doubtful species.) 
Synonym: Cryptococcus guttulatus, Robin (1. c. p. 327, PI. IV, Fig. 2.) 
Cells elliptical or elongated oval, .0CC60 to .00C96 in. long, .00020 
to .00032 in. wide; brown, opaque, with two to four colorless 
vacuoles, isolated or two to five united. Spore-formation unknown. 
In the sesophagus and intestines of mammals, birds and reptiles. ERRATA. 
Page i, second line from bottom, for Geneva read Genera. 
Page i 2, 3d paragraph, 5th line, for are read is. 
Page 16, 1 st paragraph, next to last line, strike out original. 
Page 37, deduct 92 from 149, 130, 137, &c. 
Page 41, 3d paragraph, for .000004 read .00004. 
Page 41, remove bracket from M. bombycis. 
Page 41, below latter strike out umlaut W. 
Page 42, insert bracket before M. of croupous pneumonia. 
Page 42, under M. amylovorus for .000012 read .00012. 
Page 42, under M. insectorum for lencopterus read leucopterus.