BACTERIA OF MILK AND ITS PRODUCTS 315 



cattle appear in perfect health. When cattle are suffering from 

 tuberculosis the bacilli appear in the faeces, so that not only 

 are diseased cattle likely to have tubercle bacilli in their milk, 

 but other cattle in the same herd, from particles of manure 

 which are very likely to get in during milking process. 



A number of bacteriologists, headed by Koch, have denied 

 the intertransmissibility of this disease. The works of recent 

 years, especially that of Ravenel, and more recently by the 

 English and German Commissions, and by Park, have shown 

 that a considerable portion of tuberculosis in children is due 

 to bovine infection. And the question at the present time is 

 not whether the disease is intertransmissible or not, but 

 what proportion of human tuberculosis comes from bovine 

 sources. It is certainly incumbent on those responsible for 

 the rearing of children to use milk from cattle free from 

 tuberculosis when this is possible. If not, it would seem better 

 to use milk from a herd rather than from a single untested 

 cow, " for Bellinger and Gebhardt showed milk which pro- 

 duced disease in guinea pigs was innocuous when diluted with 

 healthy milk fifty to one hundred times its volume. There- 

 fore, there is less danger in mixed herd milk than that of a single 

 cow, unless it is positively known that she is unaffected with 

 the disease." 



The detection of tuberculosis is so easily and accurately done 

 by the use of tuberculin that there is no excuse for having 

 milk contaminated with the tubercle bacilli. All that is 

 needed is an aroused public sentiment. 



