546 
1 
infection occurs through the intestines, most frequently with bacilli 
contained in cow’s milk. He claims to have established this as a 
fact with experiments made at Berne, and published in Virchow’s 
Archives in the early seventies of last century. He says that he has 
found no reason to change his views, and calls attention to the con- 
clusive manner in which they have been proven by the unimpeachable 
experiments of Orth, Yon Behring, and Calmette. 
Gorter ® adds his testimony to show that the intestinal mode of in- i 
fection is not rare, and Bongert^ showed with rats, as was shown by 
the experiment station of the Bureau of Animal Industry with hogs 
and cattle, that the injection of pure cultures of tubercle bacilli into 
portions of the body as remote as possible to the thorax caused pul- 
monary tuberculosis without intermediate lesions to connect the loca- 
tion of the disease in the lung with the portal at which the infecting 
bacilli were introduced. 
Baumgarten'^ concluded after experimental studies and a review 
of the literature that for practical, prophylactic purposes we must 
consider not only the inhalation theory and ingestion as modes of 
infection, but all possible ways in which tubercle bacilli may enter 
the body. 
It is not intended to give a complete summary of all the investi- 
gations that have sui^plied evidence to support the fact that tubercle 
bacilli can and do penetrate the wall of the digestive tract without 
affecting it and pass to the lung and there cause lesions. It has been 
amply shown that the intestinal mode of infection for pulmonary and 
other forms of tuberculosis, unlike the inhalation of tubercle bacilli 
directly into the lung tissue, is not merely a theory, but a well-estab- 
lished truth, which has forced its way to recognition in the face of 
considerable opposition. Hence, the frequency with which tubercu- 
losis is a pulmonary disease can not be used as an argument to en- 
courage an undervaluation of tubercle bacilli in dairy products ; on . 
the contrary, the mode of infection with tuberculosis, the certainty 
with which tubercle bacilli may enter one portion of the body and 
leave it unaffected and cause disease in other portions, condemns 
dairy products infected with tubercle bacilli as a serious menace to 
public health. 
The relative virulence of tubercle bacilli in moist, opaque sub- 
stances like milk, cream, butter, and cheese; in dry dust from tuber- 
culous material ; in translucent substances like sputum ; and in 
® Zeitschrift fiir Tuberkulose, Yol XI, No. 3, 1907 ; also Intern. Centralb. fiir 
die ges. Tuber. Forscb., YoL II, No. 1, 1907. 
® Tierarz. Wochens., Yol. XY, No. 29, 1907. 
^ Bureau of Animal Industry Bulletin 93, 1906. 
^ Inter, Centralb. fur die ges. Tuber. Forscb., Yol. II, No. 1, 1907. 
