THE MALE SEXUAL ORGANS 693 



zoa: they produce a secretion of their own,, which has led Owen to describe 

 them as the vesicular glands. When they are extirpated either alone or in 

 conjunction with the prostate body, sexual desire remains unimpaired, and 

 copulation takes place in the same way as in the normal animal and with the 

 usual frequency. 



The fecundity of the animal, however, is very much reduced by the extir- 

 pation of the vesicular glands (in white rats) and if the prostate body be 

 removed along with them, the procreative power is entirely lost. The acces- 

 sory sexual glands therefore are absolutely necessary for the full fruition of 

 the male sexual functions (Steinach). 



Probably their most important purpose is to provide for the dilution of the 

 testicular secretion a condition which is indispensable for the motility of 

 the spermatozoa. In the testis itself and in the epididymis where the fluid is 

 thick the spermatozoa are not motile; but when semen from the testes is mixed 

 with physiological salt solution, active movements appear wherever an actual 

 mixing takes place (Iwanoff). The ova of rabbits, guinea pigs and dogs can 

 be successfully fertilized by injecting into the vagina a mixture of sperm from 

 the epididymis and physiological salt solution (Walker). 



On the other hand it was found in Steinach's experiments that the sperma- 

 tozoa remain motile in the prostate secretion from seven to ten times longer 

 than they do in the physiological salt solution. This shows that the secretion 

 contains other substances which have a favorable action upon the spermatozoa. 

 Since acids are very harmful to the spermatozoa, it is possible that the secre- 

 tion has the additional function of neutralizing any acid that may chance to 

 be present in the vaginal mucus. 



In the guinea pig and other rodents, the secretion of the vesicular gland 

 coagulates in the vagina so as to form a plug which prevents the escape of the 

 seminal fluid. This coagulation is caused by the action of an enzyme occurring 

 in the secretion of the prostate (Camus and Gley). 



The vasa deferentia in the cat receive their motor nerves from the (second) 

 third to fourth (fifth) lumbar roots ; these nerves have about the same peripheral 

 course as the lumbar nerves to the bladder (Langley and Anderson; cf. page 393). 



The vesicular glands of the guinea pig receive motor as well as secretory 

 fibers by the hypogastric nerves; they leave the spinal cord in the second to the 

 fourth lumbar nerves (Akutsu). 



Mislawsky and Bormann state that the secretory fibers of the prostate run 

 in the hypogastric nerves and that its muscles are supplied also with fibers from 

 the nervi erigentes. 



C. ERECTION AND EJACULATION 



Just previous to the act of copulation the penis becomes rigid and erect, 

 thus fitted to be introduced into the vagina. Friction of the glans against 

 the walls of the vagina sets up a reflex by which the seminal fluid containing 

 all the secretions of the accessory glands is discharged into the female organ 

 (ejaculation). The rigidity of the male organ then passes off and the act 

 of copulation is ended. 



Erection is due to an in-rush of blood into the three cavernous bodies 

 of the penis, caused by dilatation of its arteries under the influence of vaso- 

 dilator nerves. These nerves (nervi erigentes) discovered by Eckhard and 



