336 OP THE GENITAL FUNCTION IN MAN. 



of generation : thus the epileptic paroxysm is not unfrequently ac- 

 companied by an emission. Nocturnal emissions occur most 

 frequently after a person has been long in bed and supine, the 

 cerebellum the lowest part of the encephalon, if the occiput is, 

 as usually, raised by a pillow. They may, however, be explained 

 by the urine accumulating in the bladder during the continuance 

 of repose and stimulating the generative parts connected with 

 this receptacle the more readily in the supine posture, and this 

 view is countenanced by the large quantity of urine generally 

 made on waking after nature has been thus relieving the chaste 

 unmarried man. 



(L) The discharge of semen resembles the discharge of fluids 

 from all glands. It is excited by the abundance of the fluid, by 

 mental stimulus, or by mechanical irritation of the extremity of 

 the excretory duct, for in such a point of view must be regarded 

 the friction of the glans penis in copulation. The fluid is accu- 

 mulated in the bulb of the urethra, since it must be accumulated 

 somewhere to be emitted so copiously, and no other use can be 

 assigned to the bulb ; and if the vesiculse do not receive it, no 

 other part but the bulb can ; besides, it is upon the bulb 

 that the muscular contraction of the venereal paroxysm first 

 acts. " The semen acting as a stimulus to the cavity of the bulb 

 of the urethra, the muscles of that part of the canal are thrown 

 into action, the fibres nearest the bladder probably act first, and 

 those more forward in quick succession, and the semen is pro- 

 jected with some force. The blood in the bulb of the urethra 

 is by the same action squeezed forward, but requiring a greater 

 impulse to propel it, is rather later than the semen, on which it 

 presses from behind ; the corpus spongiosum being full of blood, 

 acts almost as quick as undulation, in which it is assisted by the 

 corresponding constriction of the urethra, and the semen is hur- 

 ried along with a considerable velocity."* 



(M) Zeno's practice was conformable to his principles. He 



* Hunter, Observations on the glands situated between the rectum and 

 llnddri', val/rd ri-yinila- xaninaha. 1. C. 45. 



