PROSTATE. 321 



spermatozoids are the true fecundating elements of the male, 

 and that these are developed in the testicles, shows that the 

 spermatozoids found in the seminal vesicles pass into their 

 cavity from the vasa def erentia. 



The ejaculatory ducts are formed by the union of the 

 vasa def erentia with the ducts of the vesiculse seminales on 

 either side, and open into the prostatic portion of the ure- 

 thra. Except that their coats are much thinner, they have 

 essentially the same structure as the vasa def erentia. 



Prostate. Surrounding the commencement of the ure- 

 thra, including what is known as its prostatic portion, is the 

 prostate gland or body. This organ, except as it secretes a 

 fluid which forms a part of the ejaculated semen, has chiefly 

 a surgical interest, so that it is unnecessary to describe mi- 

 nutely its form and relations. It is enveloped in an exceed- 

 ingly dense, fibrous coat, contains numerous glandular struct- 

 ures 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 penetrating its substance 

 and surrounding the glands. 1 



The glands of the prostate are most distinct at that por- 

 tion 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, branching 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 cubical, becoming tesselated 

 near their openings, and sometimes laminated. 



The prostatic fluid, according to Eobin, is secreted only 

 at the moment of ejaculation. 2 Its characters will be consid- 



1 KLEIN, in STRICKER, Manual of Human and Comparative Histology, The 

 New Sydenham Society, London, 1872, vol. ii., p. 297. 



2 ROBIN, Lemons sur les hwneurs, Paris, 1867, p. 353. 



