491 
per cent of the tuberculous cases examined. (Heller.) Evidence 
which must be considered conclusive has been obtained by the Bu- 
reau of Animal Industry, as well as by Ravenel 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 presence of pulmonary tuberculosis 
in infants without intestinal lesions is no indication that tlie disease 
was not transmitted by the food, and the statistics above referred to 
are thus shown to be below the true percentage of cases of tuberculosis 
of intestinal origin. 
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 
will be to study the lesions in the body of as many cases of human 
tuberculosis as is possible. Already we have sufficient data to give 
iis some idea of the extent of tuberculosis of the bovine type in 
children without considering the numerous cases of direct transmis- 
sion recorded by many physicians, especially of instances of butchers 
and others receiving accidental infections of the skin with the bovine 
organism. Moreover, 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 is of intestinal 
origin, infection having occurred primarily through the intestinal 
tract by drinking tuberculous milk during infancy and having 
remained latent until adult life. 
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 
of a single group, were all derived from the bodies of children under 
7 years of age, being taken from tubercular ulcers in the intestines, the 
mesenteric glands, or from the lungs. 
In a similar series of tests conducted by the British Royal Commis- 
sion on Tuberculosis 60 cases of the disease in the human were tested, 
with the result that 14 cases were claimed by this commission to have 
