QUANTITATIVE BACTERIAL ANALYSIS 249 



milk to them in a direct individual manner impossible to large mun- 

 icipalities. 



Another application, and one likely to develop rapidly in the 

 future, is the establishment of bacteriological laboratories at the 

 dairies themselves, so that each dairy may control its own product 

 in the first place. Naturally this is only likely to be done where 

 the dairy is a large one, and is devoted to the production of clean 

 milk as a business. 



Standard Counts for Milk. — Experience and experiment have 

 crystallized the opinions held by most sanitarians into a set of 

 standards voiced by A. D. Melvin, Chief of the Department of 

 Agriculture, as follows: for certified milk, a limit of 10,000 per 

 c.c. when delivered to the consumer; for inspected milk, a limit of 

 100,000 per c.c. when delivered to the consumer. All milk above 

 this point should be pasteurized before sale is permitted, according 

 to some authorities. This at present is an academic requirement, 

 especially in large cities. Hence Boston and some other cities and 

 the State of Minnesota permit 500,000 per c.c. in market milk. 



EXAMINATIONS FOR " PUS " IN MILK. 



This subject has been so much discussed and so many methods 

 and objections to methods have been proposed that only a much 

 more extended account than is possible here could adequately treat 

 the subject. At present writing the tendency is to consider the test 

 of chief value for municipal milk inspection and analysis, where 

 the actual routine veterinary examination of all cows cannot be done. 

 The finding of an unusually high cellular content by any method 

 should lead to investigation of the dairy supplying the milk in 

 •question. Often cows suffering from mammitis or garget are 

 found in this way. On the other hand, it has apparently been well 

 -established that cows giving unusually high cellular content have 

 been found in which no veterinary examination, however careful, 



