324 Diseases of the Genital Organs 



economic importance. Tuberculosis of the vesiculae semi- 

 nales or prostate would tend to interfere with urination and 

 copulation (ejaculation). The diagnosis of tuberculosis of 

 these parts would be based necessarily upon rectal palpation. 



Penial Tuberculosis. Penial tuberculosis is comparatively- 

 common in the bull. The corpus cavernosum, urethra, and 

 urethral mucosa are not involved as frequently as the sub- 

 mucosa of the glans, prepuce and sheath, and the adjacent 

 penial lymphatics. 



Tuberculosis invades any organ far more readily when 

 the protective epithelium is wounded. The anatomy of the 

 copulatory apparatus of the bull and the mechanism of copu- 

 lation render epithelial injuries more probable elsewhere 

 than in the mucosa of the glans penis itself. The penis of 

 the bull (and of ruminants generally) is very firm. The 

 transverse diameter and the rigidity of the penis are but 

 slightly modified by erection. The protrusion of the penis 

 during copulation is brought about almost wholly by the 

 elimination of the sigmoid flexure (See Fig. 99), the ac- 

 complishment of which requires the relaxation of the re- 

 tractor penis muscle. When at rest, the penis lies within 

 the prepuce, above the sheath. As a rule, no distinction is 

 drawn between the mucosa of the sheath and that of the 

 prepuce, although they have a wholly different embryologic 

 history. The sheath exists as a distinct structure at the 

 time of birth ; the prepuce does not. In the new-born rumi- 

 nant and porcine male, the sheath constitutes a compara- 

 tively short infundibulum, terminating at the bottom in the 

 meatus urinarius (Fig. 8, page 14, and Fig. 9, page 15). 

 No part of the glans penis is exposed. At the time of birth, 

 the two layers of mucosa, one of which is later to form the 

 mucosa of the glans penis and the other the mucous mem- 

 brane of the prepuce, are firmly adherent to each other. 

 Later, when sexual maturity approaches, the tissue between 

 the two layers of mucous membrane, which serves to bind 

 them together, slowly gives way, and the preputial sac 

 finally becomes established. In the abattoir, one may ob- 

 serve in veal calves every gradation of the development of 



