CHAPTEE I 



The Structure of the Coiu's Udder, and the Secretion 

 of Milk 



Definition of Milk. Milk may be described as the 

 secretion of the mammary glands of the female 

 mammal. It is a fluid which is secreted for a longer 

 or shorter period after giving birth. 



Before dealing with the nature, composition, and 

 properties of milk, it will be well to say a word or 

 two on the mode in which milk is secreted, and on 

 the structure of the mammary glands. As we are 

 here concerned almost entirely with cows' milk, it 

 will be sufficient for our purpose to deal with the 

 structure of the cow's udder. 



Structure of the Udder. The cow's udder, of 

 which a diagram is given as the frontispiece of this 

 book, consists of two milk-glands, a right and a left, 

 rwhich, in the adult cow, vary from about 9 to 12 

 inches in length, 6 to 12 inches in breadth, and 4 to 



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