BACTERIA COMMONLY FOUND IN COWS* MILK. 85 



The milk was kept in the hauling-can in the stable dur- 

 ing the 1J hours after the milking. The mouth of the 

 can was covered by a clean, thin linen cloth thrown loosely 

 over it, which did not exclude the air, but to a large extent 

 prevented possible new infection from bacteria in the air.* 



It was found in these experiments that immediately 

 after the milking a very varying number of bacteria was 

 found in the different layers of the rnilk. I was of the 

 opinion that since the milk in the pail is under constant 



* Sedgwick and Batchelder (Boston Ned. and Surg. Journal, Jan. 

 14, 1892) in studying the Boston milk supply made the following 

 experiments : " Milk was drawn from a clean and well-kept Hoi- 

 stein cow in an unusually decent stable. The normal milk of this 

 cow had already been repeatedly proved to be sterile. Milk drawn 

 by hand from this cow with great care into sterilized bottles, and 

 planted quickly, yielded as an average of several trials 530 bacteria 

 per cubic centimeter. When, however, the milkman used the ordi- 

 nary milk-pail of flaring form, seated himself with more or less dis- 

 turbance of the bedding, and vigorously shook the udder over the 

 pail during the usual process of milking, we found that the numbers 

 were very much higher, namely, an average of 30,500 per cubic 

 centimeter at the end of the milking. When such milk is found 

 upon the tables of country families a few hours later it naturally 

 shows still more bacteria, doubtless because those with which it was 

 seeded have had time to multiply, The average of fifteen such sam- 

 ples from the tables of families in Jamaica Plain, Cambridge, and 

 Auburndale was 69,143 per cubic centimeter. In these cases, 

 moreover, the conditions of the cows and of the stables were excep- 

 tionally good, while the milkmen were much more than ordinarily 

 clean and careful." W. 



