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CHAPTER XIV. 

 MILK AND MILK PRODUCTS. 



MILK is the natural secretion of the special glands of a 

 female, intended for the nourishment of the new-born. The 

 mammary glands are, in general, only developed in the female 

 and are active in producing their secretion for a certain period 

 after parturition. In certain abnormal instances, however, 

 males have been known to produce milk ; but such cases are 

 rare. 



The milks of different animals differ considerably both in 

 the constituents present and in the proportions of the con- 

 stituents. 



The milk of the cow is the most important and has been 

 studied in greatest detail. 



The constituents of milk are usually divided into 

 Water, 

 Fat, 



Albuminoids, 

 Sugar, 

 Ash. 



A short account of the chemical nature of these constituents 

 (excluding water) may be here given. 



Fat. The fat present in milk resembles in general constitu- 

 tion the true animal and vegetable fats already described (see 

 p. 202). Like them it consists of a mixture or compound of 

 the glyceryl salts of fatty acids. 



It differs, however, from other oily substances in the 

 character of the fatty acids present. 



In milk fat considerable quantities of acid radicals of low 

 molecular weight are present, besides the stearic, oleic, and 

 other heavy acids found in other fats. 



In common with most natural fats it is probably a mixture, 

 though whether each acid radical is present as a distinct 



