A472 REPORT OF TILE COMMISSIONER OF AGRICULTURE. 
course, I cannot answer. When Gerlach first pronounced pleuro-pneu- 
monia of cattle a pure contagion, that is, a disease propagated exclu- 
sively by means of infection, Professor Spinola asked pertly if Gerlach 
had imported pleuro-pneumonia from the moon, but failed utterly—and 
everybody else, too—to show a solitary case of an unmistakable and well- 
authenticated spontaneous development. If any one can show me a 
case of spontaneous glanders, not caused by infection, or give satisfac- 
tory and unmistakable proof that a protopathic or deuteropathic develop- 
ment of glanders has occurred, I will take back what I have said, but 
not before. 
The contagion—The contagion must be considered as the exclusive 
cause of glanders. When I lived.in Dixon, Lee county, Illinois, from 
the fall of 1865 to September, 1868, I had an opportunity of observing 
numerous cases of glanders. A friend of mine, D. W. McKinney, dealer 
in horses and proprietor of alivery-stable, knew nearly every horse in the 
whole county, and taking special interest in those cases of glanders, 
assisted me in inquiring into the history of every horse affected. Asa 
result, every case, without exception, was traced back to an infection by 
condemned United States army horses that had been sold to the farmers. 
The contagious prineiple is developed during the very first stages of 
the disease, and even before plain symptoms have made their appear- 
ance. It exists most concentrated in the immediate products of the 
morbid process, but especially in the discharges from the nose, and in 
the contents of the glanders and farcy ulcers. Itis present also in all the 
secretions and excretions of the affected animals, as has been proved by 
numerous direct experiments. Professor Gerlach, in order to ascertain . 
if the contagion is contained not only in the fluid animal humors and 
excretions, and in the fluid and solid products of the morbid process, 
but also in the pulmonal exhalation and in the perspiration, has made 
several interesting experiments, and has found that an inoculation of 
a healthy horse with artificially condensed exhalation and perspiration 
of a glandered animal produces the disease. He has, however, not suc- 
ceeded in communicating glanders by injecting defibrinated blood of 
glandered horses (100 and 200 grains respectively) into the veins of 
healthy animals. Still, the contagiousness of the blood has been estab- 
lished long ago by Abildgardt and Viborg in Copenhagen. 
The experiments of Gerlach and of others, and numerous clinical 
observations, too, have proved beyond a doubt that the contagion con- 
tained in the exhalation and perspiration clings, though only in small 
quantities, to the aqueous vapors exhaled by the respiratory organs and 
perspired by the skin. The contagious principle, therefore, is volatile 
only ina limited degree, and to produce an infection by means of the 
exhalation and perspiration at a distance of several feet requires usually 
some length of time. So it happens very often that’ a horse occupying 
with a glandered horse the same stable, but not the same stall, remains ex- 
empted. The more forcible and accelerated the breathing, and the more 
abundant the perspiration of the horse affected with glanders, the 
greater, it seems, is the danger of an infection of healthy horses that 
are near, or occupy the same stable. 
Another question not easily answered, and yet an object for investi- 
gation, may be asked; that is, Do organic forms constitute the conta- 
gion; is the contagious principle bound on, or inseparable from, organic 
forms; or is its action merely a chemical one? On this question the 
opinions of the best authorities differ. Professor Gerlach, in his suc- 
cessful experiments with condensed exhalation and perspiration, found 
no organic forms whatever in the perfectly limpid drops; further, he 
