Relation of Disease-Bacteria to Milk. 89 



many and Denmark, 1 and the frequently reported cases of 

 intestinal infection of young stock also attest the presence 

 of the organism in milk. 



The tubercle bacillus is so markedly parasitic in its hab- 

 its, that, under ordinary conditions, it is incapable of grow- 

 ing at normal air temperatures. There is, therefore, no 

 danger of the germ developing in milk after it is drawn 

 from the animal, unless the same is kept at practically blood 

 heat. 



Even though the milk of some reacting animals may not 

 contain the dangerous organism at the time of making the 

 test, it is quite impossible to foretell how long it will re- 

 main free. As the disease becomes more generalized, or if 

 tuberculous lesions should develop in the udder, the milk 

 may pass from a healthy to an infectious state. 



This fact makes it advisable to exclude from milk sup- 

 plies intended for human use, all milk of animals that re- 

 spond to the tuberculin test; or at least to treat it in a 

 manner so as to render it safe. Whether it is necessary to 

 do this or not if the milk is made into butter or cheese is a 

 somewhat different question. Exclusion or treatment is 

 rendered more imperative in milk supplies, because the 

 danger is greater* with children with whom milk is often a 

 prominent constituent of their diet, and also for the reason 

 that the child is more susceptible to intestinal infection 

 than the adult. 



The danger of infection is much lessened in butter or 

 cheese, because the processes of manufacture tend to dimin- 

 ish the number of organisms originally present in the milk, 

 and inasmuch as no growth can ordinarily take place in these 

 products the danger is minimized. Moreover, the fact that 



i Ostertag, Milch Zeit., 22:672. 



