146 



PHYSIOLOGY 



CHAP. 



greatest degree of intensity, even independently of coitus, that is 

 from strong reflex excitement caused by contact and friction of 

 the sensitive mucous covering of the glans with that of the vagina. 

 It is probable, but not demonstrable, that during the venereal ex- 

 citement which promotes erection of the penis there should be an 

 increase in the metabolic activity of all the secretory organs 

 which compose the male genital apparatus, which, augmenting the 

 filling and tension of the whole system of canals, increases in a 

 reflex way the nervous excitement, and promotes the erotic orgasm 

 which immediately precedes the spermatic ejaculation. But this 

 is essentially the mechanical effect of a series of movements 

 caused by muscular activity. 



FIG. 38. Prostatic urethra and membranous urethra, opened by a median incision in the 

 anterior wall. (Chiarugi.) 1, colliculus seminalis ; 2, urethral crest ; 3, frenum of urethral 

 crest ; 4, orifice of prostatic utricle ; 5, orifice of an ejaculatory duct ; 6, orifices of prostatic 

 glands ; 7, surface of section of the prostate. 



The contraction of the muscular fibres which are found in the 

 septa of the testicles, and specially the peristaltic contractions of 

 the walls of the vas deferens, and the simultaneous contractions of 

 the muscular fibres of the ampulla of the epididymis, and of the 

 vesiculae seminales, produce a propulsion of all the secretions 

 accumulated in these organs, impelling them along the ejacu- 

 latory ducts into the prostatic urethra, where the ejaculated 

 fluid mixes with the prostatic secretion which has been at the 

 same time expelled (into the urethra) by the contraction of the 

 muscular elements of the prostrate. In fact, the numerous 

 punctiform orifices of the prostate gland open in close proximity 

 to those of the ejaculatory ducts, below the colliculus seminalis 

 and at the sides of the urethral crest (Fig. 38). 



