MILK SECRETION 



may be noted by examining the under side of the udder, where 

 the furrow separating them will be found. Each gland ordina- 

 rily has two teats on its lower side through which the milk may 

 be drawn from that particular gland. Each of the four teats 

 draws the milk from what is usually termed a "quarter" of the 

 udder. The two teats on the same side of the udder are from 

 the same gland. As the glands are distinct from each other, 

 so in a measure are the quarters. For example, it frequently 

 occurs that cows have garget in one quarter while the other 

 teat from the same gland milks freely and appears healthy. 



If an udder be dissected, it appears somewhat spongy and 

 pinkish, having numerous holes, or canals, much like a sponge. 

 When cut, milk escapes from the incision. Within each teat 

 is a cavity from which the milk is drawn. At the lower end of 

 each teat a small muscle encircles the outlet to prevent the es- 



FIG. 1. Section through alveoli of the mammary gland of the dog in first and 

 second stages of secretion. 



cape of the milk. Each of the glands of the udder is composed 

 of a quantity of structure somewhat resembling a bunch of 

 grapes. That which may be considered to represent the bunch 

 is called the lobe; the lobule corresponds to one grape, and 



