468 POPULAR SCIENCE MONTHLY. 



But, now, how is it with the susceptibility of man to bovine tuber- 

 culosis? This question is far more important to us than that of the 

 susceptibility of cattle to human tuberculosis, highly important as that 

 is too. It is impossible to give this question a direct answer, because, 

 of course, the experimental investigation of it with human beings is 

 out of the question. Indirectly, however, we can try to approach it. It 

 i"- well known that the milk and butter consumed in great cities very 

 often contain large quantities of the bacilli of bovine tuberculosis in a 

 living condition, as the numerous infection-experiments with such dairy 

 products on animals have proved. Most of the inhabitants of such 

 cities daily consume such living and perfectly virulent bacilli of bovine 

 tuberculosis, and unintentionally carry out the experiment which we 

 are not at liberty to make. If the bacilli of bovine tuberculosis were 

 able to infect human beings, many cases of tuberculosis caused by the 

 consumption of alimenta containing tubercle bacilli could not but occur 

 among the inhabitants of great cities, especially the children. And most 

 medical men believe that this is actually the case. 



In reality, however, it is not so. That a case of tuberculosis has 

 been caused by alimenta can be assumed with certainty only when 

 the intestine suffers first — i. e., when a so-called primary tuberculosis 

 of the intestines is found. But such cases are extremely rare. Among 

 many cases of tuberculosis examined after death I myself remember 

 having seen primary tuberculosis of the intestine only twice. Among 

 the great post-mortem material of the Charite Hospital in Berlin 10 

 cases of primary tuberculosis of the intestine occurred in five years. 

 Among 933 cases of tuberculosis in children at the Emperor Frederick's 

 Hospital for Children Baginsky never found tuberculosis of the in- 

 testine without simultaneous disease of the lungs and the bronchial 

 glands. Among 3,104 post-mortem examinations of tuberculous chil- 

 dren Biedert observed only 16 cases of primary tuberculosis of the 

 intestine. I could cite from the literature of the subject many more 

 statistics of the same kind, all indubitably showing that primary 

 tuberculosis of the intestine, especially among children, is a compara- 

 tively rare disease, and of the few cases that have been enumerated it 

 is by no means certain that they were due to infection by bovine tuber- 

 culosis. It is just as likely that they were caused by the widely- 

 propagated bacilli of human tuberculosis, which may have got into 

 the digestive canal in some way or other — for instance, by swallowing 

 saliva of the mouth. Hitherto nobody could decide with certainty in 

 such a case whether the tuberculosis of the intestine was of human or 

 of animal origin. Now we can diagnose the two. All that is necessary 

 is to cultivate in pure culture the tubercle bacilli found in the tuber- 

 culous material and to ascertain whether they belong to bovine 

 tiiberculosis by inoculating cattle with them. For this purpose I recom- 



