CHAPTER III 

 MILK SECEETION 



It is very essential that the dairyman should 

 understand the fundamental principles connected 

 with his work. Not the least of these is the secre- 

 tion of milk. In this brief work we can discuss 

 only in a general way the various theories and 

 opinions advanced in regard to the secretion of 

 milk. 



Milk a secretion of the mammary glands. Milk 

 may be briefly defined as a characteristic secre- 

 tion of the mammary glands. Its primary func- 

 tion, naturally, is for the nutrition of the young. 

 As a food for young animals it cannot be excelled, 

 for it contains the elements that are necessary for 

 the building up of the tissues of the body, and 

 it contains these elements in the proper propor- 

 tion. The class of animals that suckle their 

 young are termed "mammals" and are nearly 

 all four-footed animals. To this order, however, 

 belong some animals that live in the sea, such 

 as porpoises and whales, which secrete a fluid 

 very similar to that of the milk of land animals; 

 with but a few exceptions, however, all mammals 

 are land animals. We shall confine our discussion 



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