503 
well as by Eavenel and a number of French investigators, showing 
that tuberculous infection may take place through the intestinal tract 
without leaving any lesion in the abdominal cavity, the first alteration 
being found in the lungs or the thoracic glands. Therefore the pres- 
ence of pulmonary tuberculosis in infants without intestinal lesions is 
no indication that the disease was not transmitted by the food, and the 
statistics above referred to are thus shown to be below the true per- 
centage of cases of tuberculosis of intestinal origin. 
EVIDENCE OF TRANSMISSION FROM CATTLE TO PEOPLE. 
These figures, however, do not give any satisfactory idea as to 
whether the bacilli entering the intestines originated from human or 
bovine sources. Owing to this fact it follows that the only way of 
determining the infection of people by bacilli of the bovine type is to 
study the lesions in the bod}^ of as many cases of human tuberculosis 
as possible. Already we have sufficient data to give us some idea of 
the extent of tuberculosis of the bovine t}^pe in children without con- 
sidering the numerous cases of direct transmission recorded by many 
physicians, especially of instances of butchers and others receiving 
accidental infections of the skin with the bovine organism. More- 
over, according to Von Behring, the question of infection in man 
usually goes back to childhood, as he believes that many of the cases 
of pulmonary tuberculosis in adults are of intestinal origin, infection 
having occurred primarily through the intestinal tract b}- drinking 
tuberculous milk during infancy and having remained latent until 
adult life. As vital statistics show that 14 out of every 100 people 
that die succumb to tuberculosis, while of the remaining 86 more than 
one-half show lesions of tuberculosis on post-mortem, although dying 
from some other cause, the foregoing statement of Von Behring is 
also practically pertinent in regard to the relation of human tubercu- 
losis to the milk supply, especially in connection with the results of 
those investigators who have studied market milk and found from 2.7 
to 55 per cent of the samples examined to contain tubercle bacilli. 
Since direct experiments upon human beings are out of the ques- 
tion, the finding of the bovine type of tubercle bacillus in human 
lesions is the most direct and positive proof that tuberculosis of cattle 
is responsible for a certain amount of tuberculosis in the human 
family. Numerous experiments with this object in view have already 
proven this fact. Thus the German Commission on Tuberculosis 
examined 56 different cultures of tubercle bacilli of human origin and 
found 6 which were more virulent than is usual for human tubercle 
bacilli, causing marked lesions of tuberculosis in the cattle inoculated 
with them, and making over 10 per cent of the cases tested that were 
affected with a form of tuberculosis which, by Koch’s own method, 
must be classified as of bovine origin. The bacilli, with the exception 
