504 
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 Com- 
mission 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 been infected from bovine sources. Ravenel reports that of 
5 cases of tuberculosis in children 2 received their infection from 
cattle. Theobald Smith has estimated that from 25 to 50 per cent of 
the cases of human tuberculosis starting in the cervical and mesenteric 
lymph glands are bovine in origin, while Park has recently found 4 
cases of bovine infection out of 11 cases of generalized tuberculosis of 
infants, and 3 cases due to the bovine type of bacillus out of 16 cases 
of tubercular adenitis. Of 4 cases of generalized tuberculosis in chil- 
dren examined in the Biochemic Division of the Bureau of Animal 
Industry 2 were found to be affected with very virulent organisms, 
which warranted the conclusion that such children had been infected 
from a bovine source. The Pathological Division of the same Bureau 
has likewise, out of the 9 cases of infantile tuberculosis examined, 
obtained two cultures of tubercle bacilli that could not be differen- 
tiated from bovine cultures. In Europe so many similar instances of 
bovine tubercle bacilli having been recovered from human tissues are 
on record that it appears entirely proven that man is susceptible to 
tuberculosis caused by animal infections, and while the proportion of 
such cases can not be decided with even approximate accuracy, it is 
nevertheless incumbent upon us to recommend such measures as will 
guard against these sources of danger.® 
MILK AS A CARRIER OF TUBERCULAR INFECTION. 
The two principal sources of infection from cattle, and the only 
ones necessary to be considered, are the meat and milk of tuberculous 
animals. The fact that most of the cases of bovine tuberculosis 
above enumerated Avhich occurred in the human occurred in infants 
points with grave suspicion to the milk rather than the meat supply. 
This naturally leads to the question of how and under what condi- 
tion does the milk become dangerous, since Bang, Rabinowitsch and 
Kempner, Ernst, Ravenel, Smith, MacWeeney, Moussu, Gehrmann 
and Evans, Mohler. and many others have definitely determined the 
infectiveness of milk from tuberculous cows. 
That milk coming from a tuberculous udder is capable of trans- 
mitting the infectious j^rinciple is conceded by all who have given 
o Ravenel lias collected the number of cases of human tuberculosis which have 
been studied with special reference to the type of bacillus causing them, whether 
human or bovine, and states that of the 306 cases reported, 63, or approximately 
20 per cent, were due to the bovine tubercle bacillus. 
