GERMS IN RELATION TO MILK 9 



It may be positively affirmed, however, that American phy- 

 sicians having most experience and knowledge of feeding babies 

 are generally agreed that infants thrive best on clean, unheated 

 milk. 



The whole question of the comparative value of raw and 

 pasteurized milk for infants' food is still undecided. In either case 

 it is equally imperative that the milk be as clean as possible. 



The " ferments " of milk aid digestion of milk, and even that of 

 other food taken with the milk. Different ferments occur in the 

 milk of different animals. Similar ferments occur in the milk of 

 women and bitches ; also there are like ferments in the milk of cows 

 and goats. 



Besides the ferments in fresh milk, there is also a body which is 

 destructive to germs.* It is probable that both the ferments and 

 this germicidal substance disappear spontaneously in 24 hours, and 

 both are weakened or destroyed by high degrees of heat. The chief 

 ferments in cows' milk are the following: 1. Galactose. This is a 

 proteolytic ferment, or that digesting proteids, as casein of milk. 

 Other proteids in the stomach may be digested to some slight extent 

 by it in new milk. Galactase occurs in the milk of most animals and 

 is not destroyed except by heat near the boiling point. Galactase 

 consists of galactase proper and two other ferments (catalase and 

 peroxidase), which do not affect the digestion of milk. 2. Lipase. 

 This is a fat-splitting or fat digesting ferment. It is weakened by 

 a temperature of 145 ° F., and destroyed by 149° F. 3. Lactokinase. 

 This digests proteids similarly to galactase, but acts especially in 

 the small intestines of animals consuming milk. It is destroyed by 



* It should be stated, however, that Stocking denies that there is any germi- 

 cidal substance in milk. From his experiments he concludes that the primary 

 •decrease in bacterial content in fresh milk is simply due to dying out of those 

 varieties of bacteria which do not readily flourish in milk. If bacteria— which find 

 in milk their natural habitat— predominate in fresh milk, then there is a constant 

 increase from the time the milk is drawn. These bacteria natural to milk include 

 the B. lactis acidi and B. lactis aerogenes. 



