THE WAR 
WITH THE MICROBES. 
Address of the President before the Chemical 
Society of Washington, March 9, 1897. 
BY 
E. A. DE SCHWEINITZ. 
[Reprinted from SCIENCE, N. 8., Vol. V., No. 119, Pages 561-570, April 9, 1897.] [Reprinted from SCIENCE, N. S., Vol. V., No. 119, 
Pages 561-570, April 9, 1897. ] 
THE WAR WITH THE MICROBES* 
From the moment that man made his ap- 
pearance in the world there has been per- 
petual warfare between himself and every- 
thing animate and inanimate upon the 
earth. To a great extent this has been an 
aggressive strife, man's every effort being 
exerted to compel nature to contribute to 
his comfort, welfare and advancement by 
the subjugation of her materials and forces. 
It was many centuries, however, before he 
recognized that there were certain unknown 
insidious enemies, which often rendered 
fruitless his simple household occupations, 
defied his every effort at control and some- 
times menaced even his well-being and life. 
Though in 1675 Leeuwenhoeck discovered, 
with a powerful magnifying glass, certain 
minute organisms in decomposing animal 
matter, it was not until nearly two cen- 
turies later that their true significance was 
recognized, and Davaine first demonstrated 
the positive connection between these 
minute forms of life and disease. When 
animal and vegetable life ceased, in accord- 
ance with the laws of nature, they were 
supposed to be changed by purely chemical 
actions, so that their elements were again 
returned to the earth and air to supply food 
for other plants and animals. This destruc- 
tion was considered to be wrought simply 
by the oxygen of the air, and the process of 
fermentation was thought to be due to a 
similar cause. It had been known for ages 
* Address of the President before the Chemical So- 
ciety of Washington, March 9, 1897. 2 
that the juice of the grape, if allowed to 
stand, underwent changes by which its 
character was modified and wine was 
formed, or this change might be allowed 
to progress further until the juice had been 
converted into vinegar and finally carbon 
dioxide gas and water. These alterations, 
those which take place in the digestive 
tract of animals and are involved in the 
conversion of dead animal and plant matter 
into their simplest constituents, were classed 
under the general head of fermentations. 
The fermentations, especially that of wine, 
an Italian chemist, Fabroni, in 1822, sup- 
posed to be induced by a substance of vege- 
table origin, but closely allied to the white 
of egg. He considered this material iden- 
tical with the gluten of cereals and gave 
to it the name of the ' principle vegeto- 
animal.' For nearly forty years after- 
wards this theory was applied by chemists 
to all fermentations. It was supposed that 
the albuminoid substance present exposed 
to the oxygen of the air experienced a pro- 
gressively variable alteration, that diverse 
modifications of matter were produced 
which constituted the ferments of diverse 
nature. The fermentation was the result 
of the molecular movement thus commu- 
nicated. These theories were based upon an 
erroneous interpretation of what occurred 
under certain conditions. There exists in 
wine, when it is being converted into vine- 
gar, a substance which acts to bring about 
this modification, but this is not dead 
albuminoid matter, but a living plant. 
This fact the lamented chemist, Pasteur, 
demonstrated in his careful studies upon 
the production of wine and its conversion 
into vinegar. Before this time, it is true, 
there were many who failed to accept the 
theory of spontaneous oxidation, and en- 3 
deavored to show that if fermentable liquids 
were boiled in flasks which were then im- 
mediately sealed, the fermentation could 
not take place. But this did not fulfill the 
demands of one school of chemists, viz., 
that plenty of oxygen gas should always be 
present. When the liquid was boiled in con- 
tact with air which had previously been 
drawn through sulphuric acid, it was claimed 
that the air had undergone some chemical 
change, so it was not until 1854 that this 
objection was overcome by previously pass- 
ing the air in the presence of which boiling 
took place through cotton, and it was then 
that this school of chemists found their 
theories in danger. Pasteur demonstrated 
that the plant present in the preparation 
of vinegar was the simplest form of life, a 
cell which could be easily destroyed by 
heat. Its presence was absolutely neces- 
sary for fermentation, and without the liv- 
ing cell no amount of dead vegetable matter 
could cause the peculiar molecular disar- 
rangement which had been claimed. While 
Liebig had contended that as long as the 
juice of the grape remained away from con- 
tact with the oxygen of the air the neces- 
sary motion could not be imparted to the 
molecules, which movement subsequently 
caused the phenomena of fermentation. 
Thus was brought to an end the strife be- 
tween the two schools of vitalists and 
chemists; the one school of chemists de- 
manding the presence of ogygen only, the 
other the presence of a living plant cell in 
addition to oxygen. From this strife of 
the two schools was evolved in reality a 
new science and new theories, which have 
made the past thirty years marvelous in 
their explanations of many of the simplest 
phenomena of plant and animal life and 
death, placed the practice of medicine upon 4 
a scientific basis and rendered possible an 
intelligent system of agriculture and ani- 
mal husbandry. 
Pasteur's discoveries also served to explain 
the true cause of the poisonous properties of 
spoiled meats and other foods, stagnant 
water, and water from marshy countries. 
For more than half a century before this 
time a number of investigators had proved 
the dangerous character of Old sausage 
meats, bread and the like. Kerner con- 
cluded that they contained a fatty acid to 
which the poisonous action was due; others 
confirmed these ideas and came to similar 
conclusions in regard to poisonous cheese. 
In 1856 Panum asserted, as a result of his 
studies upon the poisons found in putrid 
animal matter, that these poisons might be 
formed by some active plant cell, but their 
injurious effect was independent of these 
cells. He demonstrated that fixed non-vol- 
atile poisons could be extracted from putrid 
matter which were soluble in water and 
alcohol, not destroyed by heat, and pro- 
duced the same effects after they had been 
submitted to a high temperature as before. 
These poisons he found to be intense in 
their action, 0.012 grams sufficing to cause 
the death of a small animal. In 1866 
Bence-Jones obtained from the liver a sub- 
stance which,- with dilute sulphuric acid, 
gave a bright blue fluorescence like .that 
noted in similar solutions of quinine. Prob- 
ably this was the product of what we now 
call fluorescing bacteria. 
The work of Pasteur threw light upon 
the origins of these poisons. As the ferment 
causes the alteration in the grape juice, so 
do microscopic forms of life bring about the 
changes which take place in dead animal and 
vegetable matter, and also those conditions 
in the living body which we call disease. 5 
Many of these microscopic forms of single- 
celled plants, the bacteria, have their natural 
habitat upon dead organic matter, but they 
may flourish in the living body and are 
almost unlimited in variety, appearance and 
behavior. It is possible also to cultivate 
them upon specially prepared solutions after 
their individual peculiarities have been 
studied. Some thrive best in light, others 
in darkness ; some like a goodly supply of 
oxygen, others prefer nitrogen ; some are 
very sensitive to changes of temperature, 
while others readily accustom themselves 
to vicissitudes. 
These different bacteria further are some- 
what eccentric within as well as without 
the animal body. Some, as the diphtheria 
germs, find their most comfortable habitat 
upon certain mucous membranes, others in 
the lungs, some in the digestive tract, still 
others in the blood, while others again con- 
fine themselves to certain external cells and 
membranes. In their artificial cultivation 
this eccentricity is equally apparent. While 
nearly all thrive upon a beef broth, some 
prefer the beef broth with an excess of acid, 
others with an excess of alkali. Some de- 
mand the addition of sugar or glycerine, 
others the addition of sugar together with 
acid, while some are satisfied with a diet 
of phosphates, salt and water. These pecu- 
liarities have to be studied for each germ, 
and while many can accommodate them- 
selves to their surroundings, and while the 
same germ grown upon different media pro- 
duces the same substances, the amount of each 
substance is a varying one, and in cultiva- 
ting them artificially we must find which 
diet gives rise to the largest amount of the 
most active products. 
Shortly after the work of Panum just re- 
ferred to, the Italian chemist Selmi out- 6 
lined methods of extracting poisonous prin- 
ciples from dead animal matter, and gave 
to these substances the name ptomaines, on 
account of their origin. Later, in 1876, the 
first analysis of a ptomaine was made by 
Nencki and its formula determined. Fur- 
ther experiments showed that volatile and 
non-volatile substances, alkaline in charac- 
ter, could be obtained from various portions 
of the animal body, often from fresh mate- 
rial and also from the cultures of bacteria. 
These ptomaines were found to resemble 
the alkaloids in their chemical reactions. 
In 1882-83 Brieger succeeded in separa- 
ting and determining a number of these 
ptomaines, from the brain, from fish musca- 
rin, from decomposed glue, neuridine and 
dimethyl amine, muscarin, etc. From pure 
cultures of the typhoid germ he obtained a 
substance, typhotoxin, which produced ty- 
phoid symptoms, and from cultures of the 
tetanus germ tetanin, which caused convul- 
sions. The presence of similar poisonous 
bases was demonstrated in cultures of the 
cholera^ hog cholera, anthrax, pyogenes 
aureus and like active bodies were isolated 
from cheese, milk, ice cream, sausage and 
other foods which had caused sickness. 
The isolation of these poisons from bac- 
terial cultures gave rise to the belief that 
they were the bodies which caused the 
fatal effects of disease. But while in 
many instances they produced the charac- 
teristic symptoms, in others they were not 
sufficient to account for all the phenomena. 
For example, from cultures of the tetanus 
germ it was possible to isolate a base that 
had but slight poisonous properties, while 
the culture liquid from which this was ob- 
tained after all the germs had been removed 
was ten thousand times more poisonous 
than the base secured. Non-poisonous pto- 7 
maines were also obtained from cultures of 
disease-producing bacteria, and, in fact, the 
majority of ptomaines were found to be 
non-poisonous. 
The next question was, if in the culture 
liquids freed from bacteria, poisonous sub- 
stances are obtained, and if they do not be- 
long to the class of ptomaines, how shall 
they be identified and classified? In 1886 
Mitchell and Reichert, while studying the 
venoms of serpents, noted that these poisons 
belonged to a class of bodies different from 
the ptomaines, viz., to the group called 
proteids. Shortly after, Roux and Yersin, 
in their studies upon the diphtheria poison, 
demonstrated that this was a substance 
which resembled the ferments and led them 
to think that an enzyme, as it is called, 
a substance like pepsin, was the active poi- 
son, and that this enzyme was in some way 
elaborated by the germ. Other investiga- 
tors had found a similar substance in 
tetanus and hog cholera cultures, and a re- 
investigation by Brieger of a number of 
bacterial cultures showed that by precipita- 
tion with ammonium sulphate and alcohol 
very poisonous substances giving proteid 
reactions could be obtained. Proteids of 
various characters belonging to different 
classes were obtained from cultures of 
many bacteria. About this time it was 
shown that certain plants of a higher order 
contained poisonous bodies of a like proteid 
character. An albumose abrin was ob- 
tained from the Jequirity seeds and ricin 
from the castor-oil bean. These were in- 
tensely poisonous, of a grain of 
abrin being sufficient to kill an animal 
weighing one kilogram, or the of a 
grain should be a fatal dose for a man 
weighing about 130 pounds. 
A relationship was thus established be- 8 
tween the poisons from higher plants and 
from the lowest plants and certain animals. 
Was this poisonous property of these bac- 
terial substances due to a true proteid, or 
was there an admixture of an active fer- 
ment-like substance with the proteid, and 
are these poisons mechanically carried down 
in the process of precipitation of the albu- 
minoid matter in the culture liquids ? Ex- 
periments show that while the poisons may 
be proteids, it is more than probable that they 
are simply carried down with proteid matter 
as indicated. Brieger in 1893, in view of 
the results so far obtained, endeavored to 
isolate the pure poison from cultures of 
the tetanus bacillus. The cultures were 
first filtered through porous porcelain, a 
Chamberland or Monroe filter tube, for in- 
stance, and the liquid which passed through 
was treated with a concentrated solution of 
ammonium sulphate. This preciptated the 
poisons and a number of other substances 
which gave proteid reactions. After puri- 
fication and dialysis the poison was ob- 
tained as yellow soluble flakes which no 
longer gave proteid reactions. It was a 
substance in which there was no noticeable 
phosphorus nor sulphur. It was thus 
proved that the tetanus poison belonged 
neither to the ptomaines before referred to, 
nor to the proteids. The poison, while not 
perfectly pure, was purer than any ever 
before obtained, and was so poisonous that 
a mouse weighing oz. was killed by 
1,128.000 Part of a §rain> while m of a 
grain should kill a man weighing 150 lbs. 
It is not difficult to understand how if the 
tetanus bacillus outside of the body can 
produce such powerful poisons, it can give 
rise in the animal organism to serious 
troubles. The diphtheria bacillus is an- 
other germ which forms very powerful poi- 9 
sons in the solutions upon which it feeds. 
As already mentioned, some authors, Roux 
and Yersin, believe that this poison also 
belongs to the ferments like trypsin and 
pepsin, while Briegerand Fraenkel thought 
it was a toxalbumin. We find after the 
germ has been removed from the culture 
liquid by filtration, that the poison can be 
separated by calcium phosphate or am- 
monium sulphate, just like the tetanus poi- 
son. In the purest condition in which it 
has been so far obtained it fails to give the 
proteid reaction, and of a grain will kill 
a guinea pig. It dialyses readily. Bodies 
of a similar kind have been obtained from 
cholera, glanders, swine plague, tubercu- 
losis, and anthrax cultures, while many 
other bacteria produce soluble intensely 
poisonous substances in artificial cultures 
as well as inside the animal body. 
These products are all characteristic of 
the individual organism. The conditions 
under which the most poisonous ones are 
formed seem to be dependent partly, we 
may say, upon the humor of the germ and 
also upon the food offered for its use. It 
appears, for example, in connection with 
the diphtheria germ that, if there happens 
to be present in the beef broth upon which 
it is being cultivated, an undue amount of 
glucose and an insufficient supply of alkali, 
that, instead of producing a very active 
poison, the substance secreted is much less 
harmful. This is accounted for by the sup- 
position that the glucoseis decomposed into 
acid which, in its turn, neutralizes or de- 
composes the poison ordinarily produced 
by the germ. These poisons, it was origi- 
nally supposed, resulted from the decompo- 
sition of the food of the germ, just as 
soluble and assimilable albuminoids are 
produced by the acids and ferments of the 10 
animal body from the insoluble albuminoids 
that are ingested as food. It has been 
found, however, that in most instances the 
poison of the germ is in solution in quan- 
tity only after the germs themselves have 
become partially disintegrated. In other 
words, the active bacterial poisons seem to 
be products of the cell and retained within 
the cell until the latter dies and the cell 
membrane is broken, permitting the passage 
into the surrounding liquid of the poison. 
What then is the true nature of these poi- 
sons if they belong neither to the bases nor 
to the proteids or toxalbumins ? That, un- 
fortunately, is one of the problems to 
which, up to the present time, chemical re- 
search has not been able to give a definite 
answer; and this, because, as we have al- 
ready noted, the poisons of these bacteria 
are so tremendously active and conse- 
quently produced in proportionately small 
amount, even when a large quantity of the 
culture media is used, that it has so far been 
a matter almost of impossibility to separate 
a sufficient quantity of these poisonous 
principles to purify them perfectly for 
chemical analysis. Perhaps this object has 
been attained more nearly than ever before 
by some workers in the Biochemic Labora- 
tory in this city, who have succeeded in 
separating from cultures of the tuberculosis 
germ a crystalline poison with constant 
melting point and a constant composition. 
This is not the only poison produced by the 
tuberculosis germ, but that it is one of the 
principles which is responsible for much of 
the trouble with this disease is beyond 
doubt. These special poisonous principles, 
which are so difficult to obtain pure, we 
designate by the name toxines, to distin- 
guish them from the ptomaines and proteid 
substances before mentioned. Another dif- 11 
Acuity which is always encountered in ex- 
tracting the poisons of bacteria is their in- 
stability. The material with which an ex- 
periment is begun may be very poisonous, 
but the processes of precipitation and ex- 
traction through which it must be passed in 
order to obtain a desired substance are such 
that often, long before the Anal stages have 
been reached, the nature of the poisons lias 
undergone an entire change due to the 
chemical processes which have necessarily 
been applied. 
We have said that the poisons of the 
germ were synthetic products which were 
built up within the cell wall. Some of 
these easily pass through the cell wall, due 
probably to the greater permeability of the 
living membrane; others are retained within 
the cell wall only to pass into solution when 
these walls are broken down. Tetanus, 
diphtheria and swine plague allow this dif- 
fusion to take place very rapidly, while 
with other germs, like typhoid fever, an- 
thrax, cholera, glanders, tuberculosis, the 
poison is produced and retained within the 
cell more Armly during the life of the latter. 
As the germs die, however, in artihcial cul- 
tures, the cell walls gradually disintegrate 
and the poison passes out into the surround- 
ing liquid. In the case of tuberculosis and 
glanders a strong solution of these cell 
poisons in the surrounding liquid upon 
which the germ has been feeding gives 
tuberculin and mallein, the two diagnostic 
agents which have been of inestimable value 
in detecting latent disease in men and ani- 
mals and thus preventing the spread of un- 
told evils. 
Thus the warfare Arst began by the 
chemist with the microbes in identifying 
their character and relation to disease has 
been prosecuted for little more than a 12 
decade in endeavoring to detect the true 
character of the insidious poisons with which 
their arrows are tipped. To a certain ex- 
tent, as we have seen, this warfare has 
been a successful one in so far that the 
poisons have been hunted and driven to 
their last stronghold, which, ere long, with 
the many workers in attack, must yield as 
heretofore to superior forces. But while 
this search for the pure poisons has been in 
progress the chemist has not been idle in 
endeavoring to counteract these poisons, 
the nature of which he did not thoroughly 
understand, but the evil effects of which 
were only too apparent. While Jenner in 
vaccination for small-pox, and Pasteur with 
his method of vaccination for anthrax, had 
shown that it was possible to protect ani- 
mals and men from a virulent attack of 
disease by giving them first a mild attack, 
(though, by the way, there are a few who 
contend even to-day that vaccination is use- 
less), it remained for Salmon, his assistant, 
and Smith in this city to demonstrate, in 
1882, that the poisons of germs could be 
used by men and animals to fortify them- 
selves against the attacks of these same 
bacteria. This could be accomplished by 
introducing into the circulation of the ani- 
mal a small quantity of the poison of the 
germ, so that when the germ itself was in- 
jected the poison which it produced was 
without effect. What had been found true 
for one disease of animals proved also to be 
true for many others, and chemical vaccina- 
tion was tried for diphtheria, tetanus, an- 
thrax, cholera, typhoid fever, tuberculosis, 
glanders and a number of other diseases. 
But this discovery led to another, important 
and far-reaching. Fodor showed that the 
blood serum of animals, made immune to a 
particular disease by injecting the animal 13 
with the poison which this germ formed, had 
the effect of destroying the germ of the dis- 
ease. This excited renewed interest in the 
study of the blood, and within a few years 
it was demonstrated by the work of many, 
some in this city in the laboratories before 
mentioned, that this serum from previously 
immunized animals, not only had the prop- 
erty of conferring immunity upon other 
animals, but also of checking the disease 
after it had once begun. How thoroughly 
this fact was demonstrated, first by Behring 
and subsequently by Roux and others in 
connection with diphtheria and tetanus, 
has been dwelt upon often, and we know of 
the many thousands of lives that have been 
saved by the use of antitoxic serums. 
To prepare these the solution of the 
toxins, which we have before described, are 
injected into different animals, preferably 
horses, and at the end of six to twelve 
weeks the blood of these animals is found 
to yield a serum containing substances 
possessing both immunizing and curative 
properties which we call antitoxines. The 
active principle of this serum is present in 
a comparatively small quantity, but its in- 
fluence is enormous. It does not appear to 
be a substance which directly chemically 
neutralizes the poison, but counteracts its 
effects within the animal in some unknown 
way. 
But some of our friends may ask: Were 
not these facts discovered first by the use 
of animals, and hence has not this knowl- 
edge, though of inestimable value to man- 
kind, been too dearly bought? Yes, per- 
haps, a score or two of guinea pigs and 
sweet, lovely rats and mice have sacri- 
ficed their lives for humanity's sake. But 
this knowledge could not have been gained 
in any other way unless by the sacrifice of 14 
human life. What mother would hesitate 
to sacrifice a thousand guinea pigs for the 
life of her child, or, on the other hand, 
would wish her child to serve as the subject 
of experiment for others ? 
I have often been asked if the horses 
placed under this treatment for the produc- 
tion of antitoxines suffer. I think not and, 
as an illustration, will relate an incident 
which has come under my own observation, 
in the study of the antitoxins of the dread 
disease, tuberculosis. A well-blooded horse, 
gentle in every particular, except that he 
would run away upon the slightest provo- 
cation, seemed to be a suitable subject for 
some work. Accordingly he received an 
injection of the poison of the tuberculosis 
germ with the expectation that so high 
strung an animal would rebel against these 
pleasant familiarities. But he was entirely 
too wise for this. He submitted quietly 
and seemed much interested while by means 
of a hypodermic, syringe a small quantity 
of the poison was ejected beneath his skin. 
A few days afterwards when the operation 
was repeated it would have been reasonable 
to expect that if there had been any dis- 
comfort the horse would have rebelled 
against the procedure. Did this happen? 
Not by any means. As soon as he observed 
the doctor appear with the syringe and 
bottle he trotted toward him with pleasure, 
stood quietly looking around with intelli- 
gence, while the injection was made and 
ever afterwards lent himself to the experi- 
ment with as much evident pleasure and 
interest as that of the investigators, appar- 
ently thoroughly appreciating its object. 
It would hardly be fair to say that this 
dumb animal was endowed with more in- 
telligence than some of our ill-informed but 
well-meaning friends, and yet would its ac- 15 
tions not seem to indicate a high regard for 
scientific work and disclaimer of suffer- 
ing? 
Is it that they are instigated by a desire 
to inflict torture that scores of investigators 
have sacrificed their lives in searching for 
the poisons of dangerous bacteria and their 
antitoxins ? Is it inhumanity which spurs 
them on at imminent personal risk in their 
efforts, which are daily yielding new and 
brilliant results to find means for control- 
ling a disease which annually causes one- 
seventh of the deaths of the population of 
the globe? 
However, it is not only for protection 
against the two diseases, tetanus and diph- 
theria, just mentioned, that antitoxic serums 
can be prepared. Recent investigations 
have proved that typhoid fever, cholera, 
anthrax, the plague, etc., are amenable to 
similar treatment and in the same depart- 
ment in this city that chemical vaccina- 
tion received its first impetus, but by 
workers in the Biochemic laboratory it 
has been demonstrated that two diseases 
that cause such losses to the farmers of the 
country may be controlled by antitoxic se- 
rums. Investigators in this same labora- 
tory have shown also that a substance anti- 
toxic to tuberculosis can be produced in 
the serum of animals when they are prop- 
erly treated, which has undoubted and pro- 
nounced effect in checking experimental 
tuberculosis in small animals. When we 
inquire the character of these antitoxins we 
are almost as yet more in the dark than in 
our efforts to discover the exact nature of 
the poisons of germs. However, it has 
been possible to separate in a fairly pure 
form the antitoxic principle from diphtheria 
serum, a minute amount of which will con- 
fer immunity and the antitoxic principle of 16 
swine plague, .002 g. of which has been 
found to cure animals weighing 1 pound, 
and even a solid antitoxic-like substance 
for tuberculosis has been obtained in an im- 
pure form. All these solid antitoxic prin- 
ciples resemble each other very closely in 
their chemical tests and methods of separa- 
tion showing albuminoid reactions, but in 
their curative properties they are totally 
independent the one of the other. The 
diphtheria antitoxic serum does not cure 
tetanus; the swine plague serum does not 
cure the cholera. 
In the case of the venom of serpents it 
has been found that repeated injections will 
make the serum of an animal antitoxic and 
curative against other venoms. The anti- 
toxic serum produced by the cobra venom 
will protect animals and men against the bite 
of the rattlesnake as well as its own bite. It 
would seem from this that there is a very 
close relationship between the poisons of 
venomous snakes and that immunity to one 
also gives protection from the other. It ap- 
pears very probable also that the poisons of 
germs belonging to the same genus will be 
closely allied and that an antitoxin for one 
will also be an antitoxin for .the other. In 
fact, it has been demonstrated that the prod- 
ucts of the bacillus coli communis will 
protect animals from the typhoid germ to 
which it is closely allied. The same effect 
will probably be found with many other 
diseases where the germs are related. 
The difficulty of separating these anti- 
toxins completely from the other constitu- 
ents of the blood has made it impossible as 
yet to obtain positive information as to 
their true chemical character. 
As to their action in producing immunity 
one theory is that they directly neutralize 
the poisons which the germs produce, but 17 
this does not seem to be substantiated by 
experiment. 
Another theory proposed first by Stern- 
berg, then by Metchinkoff, ascribes im- 
munity to the action of the white blood 
corpuscles upon the bacteria, while the third 
theory, and the one which seems most ten- 
able in view of actual results, is that the 
antitoxic principle partakes of the nature of 
an unorganized ferment like diastase, and 
that its action in the body, with the aid of 
the leucocytes, suffices to render innocuous 
the poisons of the particular germs. 
There is little room for doubt that in the 
first instance the antitoxins are the result of 
cell activity upon the introduced poison. 
Just how the cell manages to convert the 
toxin into antitoxic ferment is not known, 
probably by absorption of the toxin and 
subsequent secretion of the antitoxin within 
the cell-wall. Every added dose of toxin 
finds not only the leucocytes but a ferment 
to aid in its decomposition, and so the 
change proceeds more rapidly and the im- 
munity is increased. Exactly what the 
chemical alteration in this instance is, has 
not been explained, but that there is oxida- 
tion, and molecular rearrangement of the 
toxin seems to be probable. 
Thus without taking into consideration 
the destruction of the causes of disease, 
viz., germs themselves, by means of such 
excellent disinfectants as formaldehyde, has 
the warfare against the microbes progressed. 
Although as we learn more of the proper- 
ties and uses of their toxins we are almost 
forced to confess that it is not a warfare, 
but rather that man is learning how to 
train and control these microscopic forms 
of life as centuries before he learned how 
to control the animals and higher plants. 
Our ideas of germs are so thoroughly 18 
associated with disease that we often forget 
that these germs are but the simplest forms 
of plant cells which are endowed with vari- 
ous functions. The majority of them are 
not injurious to man, but very useful fellow- 
workers if he has once learned how to 
manage them. The value of this cell life 
in the production of wines, beer and other 
fermented liquids is too well known to need 
more than passing mention. But you may 
not all know to what extent the aroma and 
flavor of butter and cheese are due to the 
products of micro-organisms. Now these 
products are frequently ethers and esters, 
sometimes acid and acid derivatives or 
amines, the latter a class of compounds to 
one of which smoked herring owes its par- 
ticular flavor and which is also formed by a 
number of bacteria. 
When milk is first collected from healthy 
animals it is almost free from germs, but ex- 
posed to the air it soon becomes filled with 
those forms ,of life which are perfectly 
harmless. If placed under suitable condi- 
tions with regard to temperature they will 
multiply very readily and the milk becomes 
sour, due to the formation of lactic acid 
produced from the sugar in the milk by one 
or more of these germs. If the germs 
present happen to be those giving an ether 
and ester which have a pleasant flavor and 
aroma, good butter can be made, but if 
they give rise to the formation of disagree- 
able thio, ethers and esters or some amines, 
the butter is poor and bad. 
Now, by isolating different germs found 
in the milk and cultivating them separately, 
so as to discover their own peculiar product, 
it is possible to always make butter of the 
same sort and flavor by first destroying the 
other, germs present by Pasteurization and 
then inoculating the cream with the par- 19 
ticular germs desired. A number of germs 
have been isolated from milk which will 
produce good butter, and any one of them 
is, perhaps, as satisfactory as the other, the 
etheral product being slightly different and 
more palatable to different individuals. 
Of course, a great many germs have been 
found in milk which produce disagreeable 
compounds and it is not possible to tell 
from their appearance simply, which will 
be desirable plants, but it is easy to culti- 
vate them in a small quantity of milk, note 
the results and select the desirable plant 
cells. 
Fortunately or unfortunately the use of 
these germs has been patented, so that in 
the near future we may see branded upon 
particularly fine butter and cheese patented 
in 1893, amended 1896, reissued 1908, etc. 
May we expect soon a patented process for 
sterilized breathing, eating and sleeping ? 
Recently it has been found that malt if in- 
oculated with a particular ferment from the 
skin of the grape will be converted into 
wine, the ferment used giving rise to the for- 
mation of characteristic ethers, so it is cer- 
tainly not beyond the limits of possibilities 
that in the near future American beer after 
a voyage to France may return as excellent 
champagne. When we discover too a germ 
(as had been done recently) that converts 
starch into cellulose, we are almost led to 
wonder if it might not be possible to pro- 
duce cotton in a culture flask if the parti- 
cular germs were supplied with nutritious 
food and a sufficient amount of carbon di- 
oxide, oxygen and water. 
The flavor of many lucious fruits and 
foods is due to the products either directly 
or indirectly of one or more of these useful 
bacteria, and on the other hand similar 
germs play an important and as yet un- 20 
known role in the formation of poisonous 
alkaloids. 
Many bacteria form beautifully colored 
substances, reds, yellows, blues, greens and 
delicate shades which the art of man has 
not been able to imitate and the nature of 
which he has not yet learned. These, too, 
are only hiding their secrets with a thin veil 
which investigation will soon withdraw. 
But it is not only in simple industrial 
processes that the products of germs are 
important. Man's very existence, while 
menaced on the one hand by a few germs, 
is on the other dependent upon their activ- 
ity. The germs which in the soil produce 
nitrous and nitric acid and ammonia, and 
aid their assimilation by the plants, those 
which facilitate the decomposition of phos- 
phates and bring the phosphorous, a so nec- 
essary constituent for the life of plants and 
animals into an available form, and those 
which aid in the destruction of dead vege- 
table and apimal matter, play a very valu- 
able and but little appreciated part in the 
continuance of the life and well-being of 
man. 
There are many other ways in which the 
products of these dreaded microscopic cells 
are useful, but all, a very insignificant num- 
ber of which we have mentioned, are only 
waiting man's bidding to become valuable 
subjects, and to show that, as has been in- 
stanced in the history of nations, conquered 
people often make the best and wisest citi- 
zens. 
E. A. DE SCHWEINITZ. 
Washington, D. C.