268 THE PHYSIOLOGY OF REPRODUCTION 



the penis causes a reflex discharge of motor impulses in both the female 

 and the male. In the female the uterus undergoes a series of 

 peristaltic contractions, by means of which the semen is sucked into 

 its cavity (see p. 173). Moreover, Bartholini's glands show an increased 

 activity and pour out a viscid secretion. In the male, the sexual 

 impulses culminate in the emission of the semen. This is brought 

 about by a series of muscular contractions, which probably begin in 

 the walls of the vasa efferentia and pass to the canal of the epididymis, 

 and thence along the vas deferens on 'either side. The vesiculie 

 seminales contract simultaneously, expelling their contents into the 

 vasa, and the mixed fluid passes out through the ejaculatory ducts 

 into the prostatic portion of the urethra. The prostatic muscles also 

 contract, and probably assist in forcing the semen along the urethra, 

 while at the same time expelling the secretion of the prostate glands. 

 Entrance to the bladder is prevented by the erection of the crista 

 urethrse, assisted by the contraction of the sphincter of the bladcler, 

 as already mentioned. The final discharge is brought about by 

 the rhythmical contractions of the bulbo-cavernosus and ischio- 

 cavernosus muscles, which have the effect of emptying the canal 

 from behind forwards, and so ejecting the semen, mixed with 

 the various glandular secretions, into the vaginal passage of the 

 female. 



The innervation of the muscles of the penis has already been 

 described. 



The -secretory cells of Cowper's glands receive branches from the 

 pudic nerves. 



The prostate is innervated by fibres coming both from the nervi 

 erigentes and from the hypogastric nerves. The former are purely 

 motor, whereas the latter are both motor and secretory. Eckhard ^ 

 found that stimulation of the nervi erigentes in the dog caused the 

 expulsion of the prostatic secretion into the urethra. Loeb ^ obtained 

 contraction of the prostatic vesicles by excitation of the hypogastric 

 nerves. Mislawsky and Bormann ^ confirmed both these observa- 

 tions, and found also that stimulation of the hypogastrics, while 

 inducing the muscles to contract, at the same time promoted 

 secretory activity in the glandular cells, the secretion continuing 

 so long as the stimulation was kept up.* Eogge also states that 



' Eckhard, loc. cit. 



2 Loeb (M.), "Beitrage zur Bewegung des Samenleiters," iTiauq. Dissert, 

 Oiessen, 1866. 



3 Mislawsky and Bormann, "Di« Secretionsnerven der Prostata," Zentraihl 

 /. Phys., vol. xii., 1898. 



* Timofeew has described end-bulbs in the prostate, testis, and other male 

 genital organs. Some of these are of a peculiar kind, and are in connection 

 with, two nerve fibres ("Zur Kenntniss der Nervenendigungen in den 

 Mannlichen Geschlechtsorganen der Sanger," Anat. Anz., vol. ix., 1894). 



