534 
that the large amount of feces passed by cows, about 30 pounds per 
day by a cow of average size, introduces an enormous amount of infec- 
tious material into their en^uronment when they are affected with 
tuberculosis, much more than can be safely and economically dis- 
posed of so as to make this environment a proper place for the 
exposure of human food. 
As the discovery of virulent 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 evidence on which the occurrence of virulent 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, revealed germs precisely like tubercle 
bacilli. The cultures of tubercle bacilli fed to the cow were of a 
virulence too low to cause tuberculosis in cattle. The test of the ] 
bacilli in the feces showed that they Avere Aurulent for guinea pigs. i 
This experiment proA^ed that tubercle bacilli can pass through the 
entire length of a cow's intestinal tract and out with her feces without i 
losing their pathogenic Aurulence. 
Second. Xumerous microscopic examinations made Avith the feces 
of tuberculous coavs and Avith the feces of healthy cows, stabled, fed, 
and generally kept under precisely the same conditions, reA^ealed 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. I 
With the exception of a few cases, the tubercle bacilli Avere not a con- i 
stant factor in the feces of the tuberculous cows; their occurrence i 
varied from cases in Avhich they were found with eA^ry examination 
to cases in which they Avere found Avith daily examinations only once 
eA^ery tAvo to three weeks. This intermittent character of the expul- 
sion of tubercle bacilli in the feces is precisely Avhat should be ex- 
pected, when we bear in mind that the bacilli haA^e their origin in 
the lung; that tuberculosis in the lungs of cattle, because of the i 
abundant interlobular connectiAx tissue, is not accompanied by free i 
caAuty formation, and that cattle do not cough as freely or as auo- 
lently as persons affected with lung tuberculosis. 
Third. Guinea pigs inoculated with small masses of fresh feces 
from tuberculous coavs 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 ’ 
