MILK AND ITS PRODUCTS, 



CHAPTER I. 



THE SECRETION OF MILK. 



The females of all animals that suckle their 

 young (class Mammalia) secrete for this purpose a 

 special fluid which is known as milk. It is an 

 opaque yellowish white fluid, with a slight alkaline 

 reaction and a faintly sweetish taste. It consists 

 of an emulsion of fats in a watery solution of 

 alkaline salts, casein and sugar. It is secreted in 

 two special glands situated without the body cavity 

 on either side of the median line, and known as 

 the mammary glands or mammae. 



Mammarij glands. — While, strictly speaking, there 

 are but two glands, each gland may be divided 

 into two or more lobes, each having a separate open- 

 ing.; thus, while thei^e are ordinarily but two simple 

 glands in the ewe, mare and goat, in the cow there 

 are four or six, in the cat and bitch six to ten, and 

 in the sow ten to fourteen. In animals having 

 multiple glands, the mammse occupy nearl}^ the whole 

 of the lower part of the chest and abdomen. In 

 other animals the glands are confined either to the 

 chest or abdomen. In many animals each gland 



