THE GENERAL NATURE OF DIET 155 



bottle," that is, fed with cows' milk, usually, instead of its mother's 

 milk, the former should be modified so as to more closely resemble human 

 milk. As seen from the above figures, cows' milk has almost 50 per cent. 

 more proteid (largely in caseinogen) than woman's milk has. To reduce 

 this proportion water is added, at first considerable of it. The propor- 

 tion of water is gradually decreased, month by month. The caseinogen of 

 cows' milk coagulates in the child's stomach in small lumps, while that 

 of human milk solidifies in a flocculent mass easily permeated by the 

 digestive enzymes; this is a reason other than the proteid disproportion 

 why cows' milk used by infants needs diluting with water. To compen- 

 sate for the proportional reduction of fat by this dilution, cream is added. 

 To make up the deficiency of the cows' milk in the carbohydrate, lactose, 

 (milk-sugar) is added, or even cane-sugar. To insure its alkalinity 

 usually a small proportion of lime-water is used a saturated aqueous 

 solution of calcic hydrate. Provided it is fresh and free of disease germs, 

 warmed cows' milk so prepared (the proportions varying with the child's 



FIG. 75 



Pure milk and milk after standing in a warm room for a few hours in a dirty dish. 

 Many forms of bacteria are to be seen. (Moore.) 



age) is a very good imitation of woman's milk. To insure that it is free 

 of the germs of disease (tuberculosis especially, diphtheria, scarlatina, 

 typhoid, etc.), it is at present customary and necessary to pasteurize all 

 milk bought in the open market by heating it in a steam bath to 75 C. 

 (167 F.) for a few minutes. To insure average composition it is better 

 to have mixed milk rather than that from a single cow. Milk sterilized 

 by boiling is rather indigestible (some of the digestive enzymes contained 

 being thus destroyed) ; but it will keep in a cool place thus prepared for a 

 week or over, and is, therefore, at times a great convenience, for example, 

 in necessary travelling. 



Rotch recommends the following percentages for the composition of 

 cows' milk modified to suit various ages. It will be observed that the 

 proportion of each of the chief proximate principles of the prepared food 

 is less at first than in average human milk : 



