H4 MILK BACTERIA AND HEALTH. 



of bacilli taken into the body, and hence this dilution of the 

 milk very much decreases the probability of distribution of 

 the disease by this means. 



The milk .used as food must pass through the digestive 

 organs and be subjected to the action of the digestive fluids. 

 These .will have a tendency to destroy the vitality of the 

 tubercle bacillus and thus still further reduce the danger of 

 infection. 



It is urged that the tubercle bacilli which came from milk 

 would find entrance most naturally through the intestines, but 

 that in mankind the intestine is not the most easy source of 

 entrance of this dread disease. For man the lungs furnish the 

 most ready entrance of this infection, and whereas the disease 

 may occasionally come through the intestine, this is com- 

 paratively unusual. The bacilli that are present in the milk 

 might lodge, of course, in the throat and possibly find entrance 

 into the lungs, but this would be a rare case, for the milk 

 is swallowed rapidly and most of the bacilli would pass to 

 the stomach. If, therefore, the milk were a source of tuber- 

 culosis it would naturally be expected that the disease would 

 start in the vicinity of the intestinal organs. The study of 

 human tuberculosis shows, however, that primary intestinal 

 tuberculosis is not common, and although it is by no means 

 sure, even if the. intestine was the means of entrance, that 

 the first traces of the disease would be in the vicinity of the 

 intestine, still the rarity of primary intestinal tuberculosis in 

 human adults is an indication that the intestine is not a 

 common source of infection. 



It is urged that statistics in regard to human tuberculosis 

 indicate pretty conclusively that, at least for adults, milk 

 cannot be looked upon as a very important source of 

 this disease. During the last quarter century the use of 

 milk has increased and a large amount of statistical evi- 

 dence has shown that the amount of bovine tuberculosis has 

 also rapidly increased. During that same period, however, 



