MALE ORGANS OF GENERATION 781 



what convoluted, in the natural state, into an ovoid mass that is firmly 

 bound to the vesical wall. The structure of the seminal vesicles is not 

 unlike that of the sacculated portion of the vasa deferentia. They have 

 an external fibrous coat, a middle coat of muscular fibres and a mucous 

 lining. Muscular fibres pass over these vesicles from the bladder, both in 

 a longitudinal and in a circular direction, and serve as compressors, by 

 the action of which their contents may be discharged. The mucous coat 

 is pale, finely reticulated, and covered with cells of polygonal epithelium 

 which are nucleated and contain brownish granules. The vesiculae 

 seminales undoubtedly serve, in part at least, as receptacles for the 

 semen, as their contents often present a greater or less number of 

 spermatozoids. Although the membrane of the vesicles seems to 

 produce an independent secretion, the presence of mucous glands has 

 not been demonstrated. 



The ejaculatory ducts are formed by the union of the vasa deferentia 

 with the ducts of the vesiculae seminales on either side, and they open 

 into the prostatic portion of the urethra. Except that their coats are 

 much thinner, they have essentially the same structure as the vasa 

 deferentia. 



Prostate. Surrounding the vesical extremity of the urethra, includ- 

 ing what is known as its prostatic portion, is the prostate gland, or 

 body. This organ, except as it secretes a liquid that forms a part of the 

 ejaculated semen, has chiefly a surgical interest, so that it is unnecessary 

 to describe minutely its form and relations. It is enveloped in a dense 

 fibrous coat, contains many glandular structures opening into the 

 urethra, and presents a great number of non-striated, with a few striated 

 muscular fibres, some just beneath the fibrous coat and others penetra- 

 ting its substance and surrounding the glands. 



The glands of the prostate are most distinct in that portion which 

 lies behind the urethra. In the posterior portion of this canal are found 

 about twenty openings, which lead to tubes ramifying in the glandular 

 substance. These tubes are formed of a structureless membrane branch- 

 ing as it penetrates the gland. They present hemispherical diverticula 

 in their course and terminate in dilated extremities which are looped and 

 coiled. In the deeper portions of the tubes, the epithelium is columnar 

 or cuboidal, becoming tessellated near their openings, and sometimes 

 laminated. 



The prostatic secretion probably is produced only at the moment of 

 ejaculation. Its characters will be considered in connection with the 

 composition of the semen. According to Kraus it has an important 

 office in maintaining the vitality of the spermatozoids. "The sper- 

 matozoa, in the absence of the prostatic fluid, can not live in the mucous 



