134 ANNUAL REPORT OF THE Off. Doc. 



In general the derermiuatiou of the primary lesion is based on the 

 belief that the lymphatic glands in children give evidence of the du- 

 ration and extent of tuberculous diseases in the organs with which 

 they are in relation. Consetiuently if the bronchial glands show more 

 advanced caseation than the mesenteric the infection is put down as 

 being through the respiratory tract. The fallacy of this has, 1 thiuk, 

 been demonstrated as regards infection through the tonsils, and that 

 it is correct, even when the absorption takes place through the in- 

 testinal mucosa is open to (juestioii. During intestinal digestion 

 there is a constant current from the intestine to the mesenteric 

 glands, and thence up the thoracic duct into the venous circulation. 

 Any tubercle bacilli which may have gained entrance into the stream 

 are carried almost immediately into the lung, and deposited there 

 by election. 



It has been shown by Dobroklonski, working under Cornil, that 

 the tubercle bacillus can penetrate the wall of the intestine in the 

 absence of any demonstrable lesion, and that the contact does not 

 need to be prolonged. As the result of carefully conducted experi- 

 ments on animals he says; "Tuberculosis can certainly invade the 

 body through the digestive tract. For this invasion to occur it is 

 not necessary that there should be either a lesion of the intestinal 

 wall, a desquamation of the epithelium, or any local modification 

 whatever, or an anterior inflammatory process. The tuberculous 

 virus (bacilli as well as spores) can easily pass through the epithelial 

 lining of the intestine when it is entirely normal. This penetration 

 is particularly easy at those points where the contact of the virus 

 with the intestinal wall is prolonged, but it is not necessary that 

 there should be prolonged contact or that it should be any longer 

 than what occurs normally." 



In our work at the laboratory of the State Live Stock (Sanitary 

 Board we have often been struck by the extensive involvement of the 

 lungs in animals infected by feeding, and the slight injury of the in- 

 testines. Indeed, in some animals it has been impossible to detect 

 any involvement of the intestines at all. 



I ask your attention to specimens from two animals illustrating 

 these points. The first is from a cow (No. 26435) which was fed with 

 bovine tuberculous material. Both lungs were involved and had 

 cavities in them. The bronchial glands were enlarged, and showed 

 small nodules. The mediastinal glands were enlarged and softened, 

 but showed no nodules. The mesenteric glands were normal, and 

 no lesion of the intestinal wall could be found. 



The second is from a monkey fed with a pure culture obtained 

 from the mesenteric gland of a child (Culture BB). Both lungs are 

 involved throughout and to a much greater extent than the ab- 

 dominal organs. The bronchial glands are enlarged and caseous. 



