534 
that the large amount of feces passed by cows, about 30 pounds per 
day by a cow of ayerage size, introduces an enormous amount of infec- 
tious material into their enyiromnent when they are affected with 
tuberculosis, much more than can be safely and economically dis- 
posed of so as to make this enyiromnent a proper place for the 
exposure of human food. 
As the discoyery of- yirulent tubercle bacilli in the feces of tubercu- 
lous cattle is of comparatively recent date, and as some harmless 
bacilli closely resembling tubercle bacilli in appearance are of com- 
mon occurrence in and about stables and are supposed to be of com- 
mon occurrence in the feces of cattle, it is desirable to outline briefly 
the ewidenee on which the occurrence of yirulent tubercle bacilli in 
the feces of tuberculous cattle rests. 
First. The microscopic examinations of the feces of a cow that was 
being fed small amounts of tubercle bacilli, in the form of cultures 
added to her drinking water, reyealed germs precisely like tubercle 
bacilli. The cultures of tubercle bacilli fed to the cow were of a 
yirulence too low to cause tuberculosis in cattle. The test of the 
bacilli in the feces showed that they were yirulent for guinea pigs. 
This experiment proyed that tubercle bacilli can pass through the 
entire length of a cow's intestinal tract and out with her feces without 
losing their pathogenic yirulence. 
Second. Xumerous microscopic examinations made with the feces 
of tuberculous cows and with the feces of healthy cows, stabled, fed, 
and generally kept under precisely the same conditions, reyealed that 
the feces of the tuberculous cows contained bacilli like tubercle germs, 
and that the feces of the healthy cows did not contain such bacilli. 
TTith the exception of a few cases, the tubercle bacilli were not a con- 
stant factor in the feces of the tuberculous cows; their occurrence 
yaried from cases in which they were found with eyery examination 
to cases in which they were found with daily examinations only once 
eyery two to three weeks. This intermittent character of the expul- 
sion of tubercle bacilli in the feces is precisely what should be ex- 
pected, when we bear in mind that the bacilli liaye their origin in 
the lung; that tuberculosis in the lungs of cattle, because of the 
abundant interlobular connectiye tissue, is not accompanied by free 
cayity formation, and that cattle do not cough as freely or as yio- 
lently as persons affected with lung tuberculosis. 
Third. Guinea pigs inoculated with small masses of fresh feces 
from tuberculous cows that were passing bacilli like tubercle germs 
per rectum became affected with typical, generalized, fatal tuber- 
culosis. 
Fourth. Cultures made from the bodies of guinea pigs that suc- 
cumbed to tuberculosis induced by the inoculation of fresh feces 
from tuberculous cows were found to be pure cultures of tubercle 
