MIXING MORNING'S AND NIGHT'S MILK 125 



may smell or taste and is more difficult to re- 

 move from milk than stove heat. The fact is 

 that animal heat is just heat. Animal heat is 

 removed from milk by cooling of any kind. Ani- 

 mal heat will all escape from milk through the 

 sides of a can or bottle when standing in cold 

 water. 



MIXING MORNING'S AND NIGHT'S MILK 



There is supposed to be some mysterious chem- 

 ical action that takes place between morning's 

 milk and night's milk when they are mixed, which 

 results in the rapid souring of the mixture. The 

 mixture is supposed to sour much more rapidly 

 than either the night's milk or the morning's 

 milk would if left alone, consequently, dairymen 

 keep morning's milk and night's milk separate. 

 The truth is that souring of milk is the result 

 of the growth of bacteria which produce lactic 

 acid out of the milk sugar. If night's milk has 

 been kept cold it stays sweet, because the bac- 

 teria do not grow in the cold. Warm morning's 

 milk is sweet because it is fresh. Morning's 

 milk will sour in a few hours if not cooled. If 

 morning's milk is mixed with night's milk it 



