TUBERCULOSIS. 113 



disease in man. This has been proved by a number of in- 

 stances which have been collected where men have been acci- 

 dentally inoculated directly from animals. For instance, 

 butchers have become inoculated with tuberculosis through 

 cuts in the skin which were infected with material from 

 tuberculous animals that they were dissecting. Direct experi- 

 ments of inoculation of human beings have also been made in 

 the last few months with positive results. Enough instances 

 of this sort have been collected though they are really few 

 to prove beyond question that bovine tuberculosis may give 

 rise to an infection in man. The question whether tubercu- 

 losis in mankind may come from the use of milk as food has 

 not as yet been directly proved, although a number of 

 instances have been advanced which indicate pretty strongly 

 that such may be the case. 



The facts thus outlined will probably be recognized by all 

 as demonstrated. But beyond this point the question of 

 the distribution of tuberculosis from cattle to man by 

 means of milk is subject to dispute. It is quite uncertain 

 to what extent the milk of tuberculous cattle is dan- 

 gerous to mankind .when used as an article of food. That it 

 is a possible source of danger seems quite sure, and enough 

 instances have been advanced to suggest that it is some- 

 times an actual source of the disease; but it is still quite 

 vigorously denied that the extent of the danger is any- 

 thing more than extremely slight. Tfte reasons for doubting 

 the magnitude of this danger are as follows : 



The tubercle bacillus does not multiply in milk. Since 

 market milk is usually mixed milk, the milk from a tuber- 

 culous cow, even though at the outset quite highly con- 

 taminated with tubercle bacilli, will be diluted by milk from 

 many other cows before it reaches the customer. The result 

 of this would be that each individual who used the milk 

 would take into his body only a small number of tubercle 

 bacilli. The danger of infection increases with the number 

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