TRANSMISSION OF TUBERCULOSIS THROUGH MEAT AND MILK. 715 
by side with bovine bacilli, the differences which Smith found 
might not be present. This seems to be a fertile field for in¬ 
vestigation. Koch 74 expresses (July 23, 1901 vaguely the 
possibility of differentiating between intestinal tuberculosis in 
man of animal and of human origin by inoculation of cattle. 
If of animal origin, the cattle, he leads us to infer, will be in¬ 
fected, and if of human origin the cattle will not be infected. 
He does not, however, offer the proof necessary to remove this 
from the realm of pure speculation. 
On the other hand, it is not unlikely that the bovine tuber¬ 
cle bacillus, by passing through the bodies of several persons, 
or even one, may be so modified as to present under study the 
characters which we ascribe to the human bacillus. Weight is 
added to this view by the experiments of Nocard 75 in which he 
succeeded by means of cultures in vivo transforming the human 
bacillus into one of the avian type. Also by the experiments 
of Dubard and Krai 76 in which it was shown that the tubercle 
bacillus derived from fish was at first pathogenic for cold-blooded 
animals only and grew only at a low temperature, but that by 
passage through a series of guinea-pigs and rabbits it became 
virulent for these animals, and that by frequent transplantation 
it was induced to grow at incubator temperature and produce a 
culture just like the human tubercle bacillus, from which it 
was supposed to have been at first derived. 
Neither the work of Smith, Pearson, nor Dinwiddie adds or 
pretends to add anything positive to our knowledge of the trans- 
missibility of tuberculosis from animal to man through the meat 
and milk. All evidence we have from this work is that afforded 
by an interpretation of the results and the use of them as a basis 
for reasoning about what the result would be if the terms of the 
experiment should be reversed and human beings were inocu¬ 
lated with bovine bacilli. By such an examination of these re¬ 
sults we find that they are rightfully interpreted as antagonistic 
to the idea that tuberculosis is not communicated from animal 
to man through the meat and milk. Smith’s experiments have, 
evidently, because of careless reading, been used by some writers 
