fcaAPTER X. 

 THE DAIRY. 



Milk is a valuable agricultural product, and both it and the 

 substances obtained from it are of considerable commercial and 

 industrial importance. 



Milk is the secretion of special glands in the mammalian 

 female, adapted to the nourishment of the newly born 

 animal. 



The milk of different animals differs considerably in com- 

 position and properties. That of the cow is the most 

 important. 



The constituents of milk may be divided into the follow- 

 ing : 



The Fat of Milk resembles in chemical constitution the 

 animal and vegetable oils and fats already described in 

 chap. y. — i.e., it consists of the glyceryl compounds of 

 fatty acids. It differs chiefly in containing acid radicals of 

 low molecular weight in addition to the heavy acids — oleic, 

 stearic, palmitic, &c, — which are present in other oils and fats. 

 Butter fat, like all natural oils and fats, is a complex mixture 

 of glyceryl salts of various acids. 



According to recent investigations, 100 grammes of butter 

 fat yield 92*73 grammes of fatty acids, containing : 



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