The Origin of Bacteria in Milk. 27 



tively answered by the assertion that the glands of a" 

 healthy cow give off milk absolutely free from such 

 organisms. We call such milk sterile. Germs enter, , 

 manifestly, from the outside and may therefore be 

 termed a pollution of the milk. These decomposing 

 germs are encountered in great abundance where or- 

 ganic matter is in the act of disintegrating into its- 

 composing elements, and of such decomposing matter 

 there is enough around the premises where we draw 

 milk the stable ; there is, in fact, generally more 

 than necessary, and this is easily brought into contact 

 with the outer cover of the milk glands the udder.. 

 The location of the udder of our domestic animals- 

 involves a continual exposure to its being soiled by 

 the excrements, urine, dust from the bedding, and' 

 even our most scrupulous cleanliness and precaution 

 cannot prevent, during milking, a quantity of dirt,, 

 particles of straw and fodder, dust, hair and excoria- 

 tions from finding their way into the milk. It may, 

 therefore, be taken for granted that the greater part 

 of dirt, and, therefore, the greatest mass of spores, is 

 derived from the udder, as well from the external 

 part of it as from the openings in the teats, and even, 

 from the interior milk cisterns. Dairymen know 

 \vell that the first stoppings when commencing to 

 milk are by no means favorable for the making of 

 cheese, and in many dairies I have found it customary 

 to milk the first few strippings into the bedding. 

 Many of the germs possess very active motion and 

 from a soiled teat find their way into the interior of 



