Th€ Mammae or Udder 39 



nivora possess no milk cisterns, each of several large milk canals 

 opening separately at the apex of the teat. 



Rudimentary mammary glands occur in male animals in har- 

 mony with the general rule that the sexual organs of each sex 

 tend to be repeated or to possess an analogy in the other. In 

 rare cases, the mammse of males become functional and he-goats 

 and bulls have been known to yield milk. 



In the female the secretion of milk normally becomes estab- 

 lished only as a result of pregnancy and the milk appears ordi- 

 narily onlj' near its termination, within a few days of the birth 

 of the young, and reaches its greatest activity generally shortly 

 after giving birth. This is not constant. If abortion is threat- 

 ened in a pregnant animal, especially a mare, when the normal 

 period of pregnancy is not nearing its close, the secretion of milk 

 is liable to become suddenly established. In some animals the 

 mammse become excited, swollen and even function during 

 estrum. Such was the case with a mule observed by the author, 

 from which there was a very profuse and annoying flow of milk, 

 keeping the legs constantly wet during the spring of the year, 

 when she was in estrum much of the time. 



If a fetus perishes within the uterus of a uniparous animal 

 without decomposition, its continued presence in the uterus fails 

 to excite lactation and tends to prevent by its presence the occur- 

 rence of estrum. 



