BACTERIA IN MILK 187 



bovine bacillus, and is most commonly located in the cervical 

 and abdominal glands and in the meninges. If a cow has 

 tuberculosis of the udder, tubercle bacilli are usually found 

 in great numbers in the milk. If she has lesions elsewhere 

 she may still excrete the bacilli in the milk, but it is impos- 

 sible to determine when or in what numbers. The obvious 

 indication is not to use milk from a tuberculous animal. 

 Tuberculin tests are now being required almost everywhere 

 when permission to register a milch cow is asked. No cow 

 giving a tuberculin test should be used for a milk supply. 

 Bacilli are also excreted in feces of infected animals, and are 

 easily carried into the milkings by the swishing tail. Tubercle 

 bacilli of human sources may, of course, be in milk if handled 

 by a consumptive. Pasteurization does not surely kill the 

 tubercle bacillus, especially if surrounded by a bit of mucus. 



Septic sore-throat is an epidemic condition due to strepto- 

 cocci of human origin that get into the milk by handling or, 

 quite as often if not more so, from the cow. While the strepto- 

 cocci concerned are not pathogenic for the cow, they get into 

 the udder or teat ducts, live there without causing inflamma- 

 tion but pass out to be distributed with the milk. The dis- 

 ease may be very severe, be gravely complicated and at 

 times has a considerable mortality among feeble children 

 and old persons. It seems not to be easily transmitted from 

 person to person. 



Examination of Milk. Milk is examined for the presence 

 of colon bacilli, and the whole number of bacteria just as in 

 the case of water. For the demonstration of tubercle bacilli 

 by stain a special technic is necessary. We usually inject 

 some of the milk, cream, or sediment into guinea-pigs, and 

 expect lesions in them. The chemical examination of milk 

 usually shows its food value, which may be affected by 

 bacteria. 



