12 Diseases of the Genital Organs 



inches in length, one to one and a quarter inches in width, 

 and approximately one half inch in diameter from above 

 to below. They are readily palpated per rectum, by which 

 means they are recognized as oblong bodies meeting poster- 

 iorly on the median line where their ducts empty into the 

 urethra, while anteriorly they diverge and drop down upon 

 a level with the urethra. They can be partially picked up 

 and give to the examiner a sensation of a nodular, acinous 

 gland. In swine the seminal vesicles are very large and 

 similar in character to those of the bull. The structures 

 are absent in the dog. 



Physiologically they appear to be of fundamental im- 

 portance in those animals where present since they ap- 

 parently furnish a thin, mucoid secretion which contributes 

 the greater volume of the seminal fluid. In those animals 

 where it is not present, its place appears to be taken by an 

 increased volume and activity of the prostate gland. 



The prostate glands, lying across the urethra just behind 

 the posterior ends of the seminal vesicles, are small in the 

 horse. 



The prostate of the bull is of about the same volume as 

 either of the seminal vesicles. The body of the prostate is 

 a small, yellowish, transverse band lying across the urethra 

 just behind the termination of the seminal vesicles and in 

 front of the anterior end of Wilson's muscle, as shown in 

 Fig. 6. Posteriorly, it extends to the vicinity of Cowper's 

 glands. It surrounds, but lies chiefly above, the urethra. 

 On cross section it shows a U-shaped structure with the 

 urethral canal lying in the bottom of the U. Below and 

 at the sides, it is heavily covered by Wilson's muscle, and 

 above, the aponeurosis of the muscle stretches across from 

 side to side so that this, the more voluminous and important 

 portion of the gland, is completely hidden from sight and 

 touch. Only the body, or that portion not covered by 

 Wilson's muscle, is palpable per rectum. 



The gland is of moderate size in the boar. In carnivora 

 the prostate glands are large and apparently perform the 

 functions of the absent vesiculae seminales. It is virtually 



