718 
JOHN J. REPP. 
numerous inoculations and feedings of cattle with human tu¬ 
bercle bacilli from sputum in which he has failed to infect them. 
At the same time cattle inoculated or fed in the same manner 
with bovine tubercle bacilli from the lungs became badly in¬ 
fected. He concludes : “ Considering all these facts, I feel justi¬ 
fied in maintaining that human tuberculosis differs from bovine 
and cannot be transmitted to cattle. It seems to me very desir¬ 
able, however, that these experiments should be repeated else¬ 
where, in order that all doubt as to the correctness of my asser¬ 
tion may be removed.” Koch has nowhere stated that because 
human tuberculosis cannot be transmitted to cattle neither can 
cattle tuberculosis be transmitted to man. Some critics of 
Koch’s paper have made it appear that Koch has given expres¬ 
sion to such a line of reasoning, but a careful reading of the 
paper will show that he has not done so. He does not use this 
argument at all when he comes to answer the question, u Is 
man susceptible to bovine tuberculosis? ” So far as the answer 
to this question is concerned he wisely leaves his cattle experi¬ 
ments out of the consideration. Second, he makes the following 
answer to the question “ Is man susceptible to bovine tuber¬ 
culosis?” “Though the important question whether man is 
susceptible to bovine tuberculosis at all is not yet absolutely 
decided, and will not admit of absolute decision to-day or 
to-morrow, one is nevertheless at liberty to say that, if such 
a susceptibility really exists, the infection of human beings 
is but a very rare occurrence. I should estimate the extent 
of the infection by the milk and flesh of tuberculous cattle 
and the butter made from their milk, as hardly greater than 
that of hereditary transmission, and I therefore do not deem 
it advisable to take any measures against it.” Ket us see 
what brings him to this conclusion. It is the result of his own 
observation and the observation of several other physicians, to 
wit, that primary tuberculosis of the human intestine is a very 
rare disease. His reasoning may be stated in this way: If 
tuberculosis were set up in the human being by ingesting meat 
and milk of tuberculous cattle the primary lesion would be in 
