The Process of Breeding. 67 



lining is comparatively smooth, whereas in the cow the 

 mucous membrane lining the uterus shows rounded ele- 

 vations — buttons or cotyledons. The womb of the ewe is 

 similar to that of the cow, the horns being longer, as they 

 are also in the sow. The vagina is the passage connect- 

 ing the womb and the vulva; it is the organ of copula- 

 tion and permits the passage of the offspring. The vulva 

 is the external opening of the genito- urinary tract, ap- 

 pearing as a long ovoid slit below the anus; on the 

 floor of the vulva is the entrance to the bladder, and also 

 the clitoris (composed of erectile tissue). 



Reproduction is accomplished by the union of two indi- 

 viduals of the opposite sexes. 



Heat, Rut, Oestrum are all terms used to describe the 

 natural mating period, at which time the ovum (egg) is 

 developed in the ovary, and passed from thence to the 

 uterus, where if it meets the male element may become 

 fertilized and undergo development into the offspring. 

 This formation of the ovum does not occur until a certain 

 period, known as puberty, which is manifested by the 

 first appearance of heat, the signs of which are swelling 

 and reddening of the genitals, flow of reddish, peculiar 

 smelling discharge, frequent attempts to urinate, rest- 

 lessness, bellowing and seeking of the male, mounting 

 other animals, spasmodic movements of the clitoris are 

 evidenced during the erotic period. The condition of 

 rut or heat becomes more frequent with domestication. 



The time elapsing between the periods of heat varies 

 in the different animals, occurring in the mare at inter- 

 vals of eighteen to twenty- one days, in cattle about 

 every three weeks, ewes every sixteen to seventeen days, 



