NORMAL MILK AND ITS PRODUCTS AS FOOD 9 



manner. The casein, of human milk is separated and more 

 flocculent when curdled. In this condition the digestive 

 juices attack it with greater ease. 



Pasteurized cows' milk coagulates into a more flocculent 

 or separated curd than does raw milk. 



Raw vs. Heated Milk. — The effect of heat upon the 

 digestibility of milk is a matter that the best authori- 

 ties do not agree upon, though it has been the subject of 

 considerable investigation. Heating milk to a temperature 

 sufficiently high for efi&cient pasteurization partly renders 

 the calcium salts insoluble and may partly coagulate the 

 lactalbumin. But since investigators obtain different 

 results in their work, it seems evident that the ease of 

 digestibility of heated milk cannot differ greatly from that 

 of raw milk. And, as will be shown later, the pasteur- 

 ization of average city milk is beneficial. 



Use of Milk with Other Foods. — In a series of digestion 

 experiments conducted by Professor Harry Snyder at the 

 Minnesota Experiment Station, various foods were used 

 at different times, milk constituting in many cases a con- 

 siderable part of the diet. One fact of great practical 

 importance brought out by this work was that the various 

 foods showed a higher digestibiUty when milk was included 

 in the diet than when fed alone. 



The food components may undergo many different 

 changes in the digestive tract, depending upon the person 

 and the conditions and demands of the person's system. 

 The complex cleavage and synthetic changes of digestion 

 and assimilation, especially during the end processes, are 

 imperfectly understood. 



When the digestibihty of the components of milk is 

 compared with that of other food substances, milk ranks 

 among the most digestible of all foods. 



