18 ANATOMY. 



When the udder becomes charged with milk, it flows into 

 the teat and distends it. Suction is apparently an operation 

 purely mechanical. The teat is seized and closely com- 

 pressed by the lips of the foal ; and the imbibing effort which 

 follows has a tendency to produce a vacuum, or raise the 

 valve at the upper part of the teat, and the milk passes from 

 the reservoirs into the mouth. 



ON THE PHYSIOLOGY OF THE ORGANS OF GENERATION, MALE 



AND FEMALE. 



The common object in the male and female organs of 

 generation, is the development and reproduction of new 

 beings. The copulative act is the essential first cause that 

 therein the action of the organs is mutual and sympathetic, 

 and that the result is the generation of a new animal, bearing 

 a likeness to one or both parents, the office of the testicles 

 being to furnish the fecundating liquor, called semen. This 

 is the most important part of the male apparatus. These 

 organs do not descend into the scrotum for some time after 

 birth, and do not carry on their glandular functions until the 

 period of puberty. This epoch is marked in animals by luxu- 

 riant growth of hair, particularly in the mane and tail, a 

 peculiar odor of the body, and lustful passions. 



The semen is secreted from the blood, &nd is a white 

 viscous fluid, having a peculiar faint odour, and Mr. Percivall 

 found it to contain myriads of animalculas, or vermiculi. To 

 chemical analysis, according to Girard, the horse's semen 

 yields four fifths of a peculiar animal matter ; the remaining 

 ingredients being mucus, muriate of potass and soda, and 

 carbonate and phosphate of lime. Castration operates in 

 horses, not only by depriving stallions of their amorous fury, but 

 converting the most outrageous into meek and even spiritless 

 geldings. But the loss of one testicle does not take away 

 either the procreative faculty, or the sexual appetite ; for rigs, 

 as they are then called, appear to get foals as well as stallions. 



In the covering season animals are found to grow restless 

 and unruly, and unless permitted to seek their mates they 



