ANATOMY OF THE MALE ORGANS OF GENERATION 65 



The Board might even have gone further, and have directed that all 

 horses should be at once destroyed, and compensation paid to the extent 

 of three-fourths of their value at the time when they became infected. 



10. THE ORGANS OF REPRODUCTION^ 



ANATOMY OF THE MALE ORGANS OF GENERATION 



The principal organs which subserve the function of reproduction in 

 the male are: (1) the testis, (2) the excretory ducts which convey the 

 spermatic fluid to the urethra, (3) the urethra, (4) the penis. 



The testis in the foetus first appears behind the kidneys (see Plate 

 XXXIV) on the under surftxce of the loins, from which it hangs suspended 

 in a pouch of peritoneum (the mesorchium). At this time it is connected 

 with the scrotum by a band of unstriated muscle (gubernaculum testis), the 

 gradual contraction of which draws the organ through the inguinal canal 

 into the scrotum or purse, which it reaches about the time of birth. 



Coverings of the Testicle.— In its descent the testis becomes invested 

 with two coverings of peritoneum — one, the tunica vaginalis, derived from 

 the roof of the abdomen, is closely adherent to its outer surface; the other, 

 the tunica vaginalis reflexa, forms a loose pouch in which it is enclosed. 

 This membrane is derived from the floor of the belly being pushed before 

 the testicle as it enters the inguinal canal on its way to the scrotum. The 

 two opposing surfaces of these coverings possess the power of secreting a 

 watery fluid, so that, being constantly in a moist condition and perfectly 

 smooth in themselves, the movements of the organ within its sac are 

 permitted to take place with the least possible friction. 



The Inguinal Canal, about 4 to 6 inches in length, is a passage 

 through the alxlominal wall. Before birth it is occupied, as we have 

 already stated, by the gubernaculum testis (see Plate), which, on the descent 

 of the testicle into the scrotum, gives place to the spermatic cord. It has 

 two openings — one above : the internal abdominal ring, by which the testis 

 enters; and another, much larger, below: the external abdominal ring, by 

 which it emerges into the scrotum. 



Testis. — The testis (fig. 223) in the horse weighs approximately about 

 8 ounces. It is oval in shape, with somewhat flattened sides, ancl hangs 

 suspended by the spermatic cord in the scrotum. The testicle is a gland 

 made up of a number of tortuous tubes enclosed in a somewhat thick, dense, 

 fibrous capsule. A long narrow body termed the eindidymis runs along 



