150 MILK HYGIENE 



general, to this difference. On the other hand, the fact 

 must be considered that the fats in tlie two kinds of milk 

 differ somewhat chemically, and that cow's milk contains 

 much more volatile fat (butyric acid) than human milk. 

 These other important conditions should be mentioned : 

 the decided different proportions of lactose which, 

 doubtless, is of value in the nourishment of the child, and 

 the small quantity of lecithin in cow's milk, to which 

 great importance is now ascribed in metabolism. It is 

 doubtful if the greater quantity of citric acid and of 

 inorganic salts in cow's milk has an unfavorable influ- 

 ence on the nourishment of the child. 



Many attempts have been made to correct the defects 

 of cow's milk and to make it a more appropriate food 

 for infants. 



By diluting cow's milk with water, the percentage 

 of salt is proportionately decreased so that the casein 

 coagulates in the stomach in flakes, just as the casein of 

 human milk, and at the same time there is a proportion- 

 ate diminution in the percentage of the total proteids. 

 But there is also a decrease in the quantity of albumin 

 as well as of the other ingredients of great nutri- 

 tive importance — lecithin, lactose and fat — which is 

 decidedly disadvantageous. In order to remedy this, 

 the milk is often diluted with barley- or oat-water or the 

 proper quantit}' of milk- or grape-sugar is added. 

 Others have used cream diluted with water; by this 

 means an appropriate quantity of protein and fat can 

 be had, and since fat may be substituted for lactose, the 

 deficiency of the latter makes little difference. 



To make cow's milk approach human milk more 

 closely, and to make it more easy of digestion many 

 methods of preparation, some of them rather complex, 

 have been proposed, and some have been used conuner- 

 cially. The following are examples of such preparations : 



