REPRODUCTIVE SYSTEM GENERALLY. 251 



sensation of lust, called, in quadrupeds, heat. The desire of 

 the mare is vulgarly called horsing, and is known by vascular 

 changes in the generative organs, and by some nervous ex- 

 citement in the system generally : the vulva swell, and are 

 highly reddened ; staling is excited more frequently, and is 

 followed by the ejection of a whitish mucous matter from 

 the vagina, in stable language called the heats : sometimes 

 it is slightly bloody. The usual period of the heat in the 

 mare is between April and July ; it occasionally appears in 

 the former month, but in healthy subjects is seldom pro- 

 tracted until the latter. It is sometimes scarcely marked in 

 aged, hard-worked, or emaciated mares ; and it often con- 

 tinues the whole summer in barren mares, who will, some 

 of them, admit the horse whenever he is put to them. 



The male appetite is constant, but not uniform : low feed- 

 ing, cold weather, and absence from the effluvia of mares, 

 greatly mitigates it ; but during the season of female oestrum 

 it rages with uncontrolled force. The irritability of the 

 stallion at this time is well known, and his impatience of 

 restraint bespeaks the ungovernable nature of his desires : 

 even the ass, which proverbially dislikes to touch water, will 

 swim wide rivers to prosecute his amours. These effects 

 are, without doubt, produced by the absorption of the semen, 

 which produces its peculiar influence on the sensorium, and 

 thence is transmitted to the sexual organs. The generative 

 functions of the horse, therefore, consist in elaborating a 

 fecundating fluid, called semen. The generative functions 

 of the mare impose on her the necessity of receiving the 

 generating male secretion. 



Copulation is the immediate act by wiiich the generative 

 functions are mutually accomphshed. By a peculiar sym- 

 pathy present in the male system, the erectile substances 

 of the penis become distended with blood poured in from 

 the pudic vessels, and retained there by spasmodic con- 

 striction, aided probably by pressure of the excited muscles. 

 In this state it enters the vagina ; the testicles, drawn up by 

 the crem asters ; the acceleratores and levatores are alike 

 spasmodically and sympathetically convulsed ; and an emis- 

 sion of semen follows. The mare is also affected by a 

 venereal orgasm, but of less manifest intensity : and although 

 her frame is agitated, her actions are rather passive than 



