226 PATHOGENIC BACTERIA IN MILK 



and a half the surviving swine were all killed and examined. 

 Among the animals that had been fed with sputum no trace of 

 tuberculosis was found, except here and there little nodules in the 

 lymphatic glands of the neck, and in one case a few grey nodules 

 in the lungs. The animals, on the other hand, which had eaten 

 bacilli of bovine tuberculosis had, without exception (just as in the 

 cattle experiment), severe tubercular disease, especially tubercular 

 infiltration of the greatly enlarged lymphatic glands of the neck 

 and of the mesenteric glands, and also extensive tuberculosis of the 

 lungs and the spleen. The difference between human and bovine 

 tuberculosis appeared not less strikingly in a similar experiment with 

 asses, sheep, and goats, into whose vascular system the two kinds of 

 tubercle bacilli were injected. Dr Koch also stated that other experi- 

 ments in former times, and recently in America, had led to the 

 same result. 



In support of his second contention, namely, that bovine tuber- 

 culosis is not transmissible to man, Dr Koch points out that the 

 direct experiment upon human beings is, of course, out of the ques- 

 tion, and hence it is necessary to rely upon indirect evidence. 

 Dr Koch, therefore, reasons as follows : Tuberculosis, caused by 

 meat or milk, can be assumed with certainty only when the intestine 

 suffers first, i.e. when a so-called " primary tuberculosis " of the 

 intestine is found. If bovine tubercle bacilli are capable of causing 

 disease in man there are abundant opportunities for the transfer- 

 ence of the bacilli from one species to the other, and cases of 

 primary intestinal tuberculosis from consumption of tuberculous 

 milk ought therefore to be of common occurrence. " But such 

 cases," he maintains, "are extremely rare." In support of this view 

 Dr Koch stated that he had only seen two cases ; that only ten 

 cases had been met with in the Charite Hospital in Berlin ; and 

 that out of 3104 post-mortems of tubercular children, Biedert 

 observed only 16 cases.^ Reference was also made to other 

 similar evidence. 



At the end of 1902, Dr Koch again referred at length to his 

 views on the transference of bovine tuberculosis to man at the 



1 The statistics set forth by Dr Koch with regard to primary intestinal 

 tuberculosis cannot be accepted as representing universal experience. For 

 example, in two separate reports from children's hospitals in London and 

 Edinburgh dealing with 547 cases of death from tuberculosis in children, it 

 appears that in 29-1 per cent, and 28-1 per cent, of the cases respectively, 

 primary infection appeared to have taken place through the intestine {see 

 also p. 244). 



