CHAPTER I. 

 MILK AND ITS PRESERVATION. 



Milk as it comes from a healthy cow fed on pure food is abso- 

 lutely pure and steril, that is, if we could secure it without admission 

 of air in a sterilized bottle, it would keep if not forever for a very 

 long time indeed. 



Practically this is of course impossible, and thousands of germs 

 (bacteria) float in the dust laden air, adheres to the udder the flanks 

 of the cow, the hands and the clothing of the milker. 



Even supposing that the utmost precaution is taken, that the 

 cows are carded and brushed that the udder, and the hands of the 

 milker are washed, that the barn is thoroughly ventilated just before 

 milking, even then remains the favorable breeding place for bacteria 

 the end of the milk duct in the teats of the cow where they find the 

 best temperature and the best nutrition in the few drops of milk 

 which remain from the previous milking. 



But it must not be supposed that all these bacteria are -undesir- 

 able, some of them do no harm, and some of them are useful, not 

 only in the manufacture of cheese and butter, but also in aiding us to 

 digest the milk. 



This explains why there is a difference of opinion among physi- 

 cians as to the desirability of giving infants sterilized milk . 



I am therefore of the opinion that wherever we are sure of getting 

 milk from a healthy cow under veterinary inspection and with the 

 above mentioned safeguards, as well as the additional one of using 

 only sterilized vessels, or at least those which have been exposed to 

 steam or boiling water for 10 or 15 minutes, we have done all that 

 can be expected even in this "antiseptic" age. 



But, when we come to the practical task of supplying large cities 

 like Chicago and New York with milk at a reasonable price, we meet 

 the difficulty of an effective control. In these cases I do not hesitate 

 to recommend pasteurization for. two reasons. (1) It will, without 

 perceptibly changing the taste and digestibility, kill a great many if 

 not all bacteria. (2) It will enable the milk producer and dealer, to 

 preserve the milk sweet for 36 or 48 hours longer without fear of 

 committing infanticide with preservatives. 



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