MILK AS DRAWN FROM THE UDDER. 25 



In investigations concerning the original sterility of the 

 milk I have followed a somewhat different plan from the 

 one given. When the udder has been cleaned I have 

 drawn the milk by means of a sterilized silver milking- 

 tube, kept carefully protected from infection till it is used. 

 Following this method I have succeeded in obtaining good 

 results, even when the experiment was made in the barn. 

 Nearly all the samples of milk remained unchanged, al- 

 though they were kept for several days in an incubator 

 (thermostat) at a temperature of 86-90 F. (30-32 C.). 

 This speaks decidedly in favor of this simple method, which 

 doubtless is to be preferred to the older one, as the milk in 

 the latter is far more liable to infection. 



Since the milk when drawn from a sound udder is abso- 

 lutely sterile and will keep, i.e., does not contain any 

 micro-organisms, our efforts must be directed toward pro- 

 tecting it from infection in the handling and further manu- 

 facture in the dairy and creamery. We shall see in the 

 next chapter that infection of the milk by bacteria* is 

 inevitable, and shall learn the best means of protecting 

 the milk and its products from the same. 



^^ j^S^-SSSS^^k. 



