MILK ANALYSIS. 65 



concentrate can then be added to carbolic gelatine, 

 glucose broth fermentation tubes, and peptone tubes, as 

 before described. 



This method is particularly applicable when testing 

 for the Typhoid and Colon bacilli, and the Cholera 

 spirillum. 



Milk Analysis. 



The general principles of milk analysis are those al- 

 ready given under water analysis. As milk is such an 

 excellent medium for bacterial growth, it is usually 

 necessary to dilute the sample at least 10 times with 

 sterile water, before making plates. 



In milk analysis stress must be laid on the presence 

 or absence of the Tubercle bacillus, it being practically 

 the only bacterium transmitted directly from animals to 

 man via milk. We have two tests for Tubercle bacilli 

 in milk, (a) Microscopic examination of the sediment, 

 after sedimentation or centrifugation, at best an unreli- 

 able method. (6) The inoculation of guinea pigs. 5 to 

 10 cc. of the milk is thrown into the peritoneal cavity 

 of each of three or four guinea pigs. Three weeks 

 after, the animals are examined for developing tuber- 

 cular lesions. 



From a practical standpoint, the proper application 

 of the tuberculin test is a more ready and certain 

 method of detecting the presence, and danger from 

 Tuberculosis in cattle. 



