1 6 MILK AND THE PUBLIC HEALTH chap, r 



an indication of the care which has been taken in the keeping 

 of the cows and in the collection and distribution of the 

 milk. 



He finds that although there is no constant relation between 

 the amount of dirt and the pathogenic properties of the milk 

 when individual cases are considered, there is a distinct avernge 

 correlation between the amount of dirt and the pathogenicity 

 of the milk. He records from his work that the reduction in the 

 amount of dirt found in the milk supplied to Manchester during 

 the past ten years has been associated with a marked diminu- 

 tion in the number of samples capable of producing disease in 

 inoculated animals. 



Del^pine, from laboratory observations, says that it appears 

 diflicult to obtain milk containing less than 7 grains of 

 sediment per gallon, and he accepts this as the irreducible 

 minimum. 



