MILK SECRETION 25 



of milk in this work to that produced by cows, 

 although the milk of other animals, such as sheep 

 and goats, is used as food in different parts of 

 the world, especially in various parts of Euro- 

 pean countries. 



Milk glands. The glands which secrete the 

 milk are only two in number. There may be 

 one lobe to each gland, or, as in the case of the 

 dog or swine, several. In cows these lobes are 

 termed "quarters," and there are two to each 

 gland. These four quarters form what is termed 

 the udder. 



The udder. These glands are separated from 

 each other by a membrane. There is, therefore, 

 no connection between the right and left sides 

 of the udder. Each teat has practically its own 

 system of cisterns, channels and cells. But there 

 is more or less connection between the smaller 

 ducts in the upper parts of the lobes on the same 

 side. It is therefore possible to get more than 

 half as much milk from one teat, if milked by 

 itself, as can be obtained when both teats are 

 milked at the same time. 



Milk cisterns. Just above each teat we find a 

 small cavity from which there lead many small 

 channels; these in turn lead to other but smaller 

 cavities. All these cavities are termed "cis- 

 terns. ' ' These small channels, with their cisterns, 

 ramify the udder, becoming smaller and smaller, 



