63 



EXERCISE XXII 



EFFECT OF FEEDING HAY, JUST BEFORE MILKING, ON THE GERM 

 CONTENT OF MILK 



1 . Sterilize two small top pails and select two cows whose udders 

 and flanks are alike as regards the amount of visible dirt on them. 



2 . Milk one of the cows and take in a sterile bottle a sample of the 

 milk for plating. 



3. Before milking the second cow, shake two or three forkfuls of 

 hay near where she stands. Milk the cow and take in a sterile bottle 

 a sample of the milk for plating. 



4. Compare the number of bacteria found in the milk drawn 

 before and after the hay was shaken. 



