484 URO-GEN1TAL APPARATUS. 



simplest form of erection, or turgescence, would not suffice for 

 those more complicated forms, as the erection of the bulb, 

 ovary, and uterus; we must consider that the smooth mus- 

 cular trabeculaa assist in the compression of the venous 

 trunks ; and it is equally certain that at the period of men- 

 struation this permanent contraction of the uterine muscles, 

 and those of the Fallopian tube, coincide with the application 

 of the tube to the ovary, and accomplish this phenomenon. 

 It is also true that the muscular trabeculaB of the spongy and 

 cavernous tissue of the penis contract, after the dilatation of 

 the small arteries. When this latter contraction does not 

 occur, as in the dead subject, the size of the penis may be 

 made enormous, and yet its rigidity be relatively incom- 

 plete. 



Finally, in the erection of the organs of copulation of both 

 sexes, the action of the extrinsic muscles is brought in play 

 in order to complete its development ; and in fact we know 

 that an injection by the most forcible pressure will not pro- 

 duce a true erection unless preceded by ligation or compres- 

 sion of the large veins in the pelvis. 



The centrifugal nerves which share in the function of erec- 

 tion have been classified in two groups, whose action is dis- 

 tinct and antagonistic (Rouge t). 



1. The cavernous and spongy nerves (branches of the large 

 cavernous nerve given off from the prostatic plexus) are sup- 

 plied from the grand sympathetic, and belong to that class of 

 nerves which are provided with ganglionic corpuscles, whose 

 irritation results in the paralysis of those arterial coats inner- 

 vated by these nerve fibres (nervi erigentes ot'Eckhard). 



2. Those nerves which go, without traversing the gangli- 

 onic corpuscles, to the muscles of the trabecula?, and whose 

 irritation is followed by contraction of the muscles which 

 they supply (nerfs urethro-peniens, plexus lateral] i; so also 

 an irritation of the direct nerves (and without ganglia) which 

 innervate the erector penis, accelerator urince, and the in- 

 ferior transverse muscles, is followed by contraction of these 

 muscles. 



The erector penis and accelerator urince muscles may be 

 called, from their functions, true peripheral hearts ; their func- 

 tion consists in chasing the blood from the base to the free 

 extremity of the penis. The former of these two muscles 

 encircles the root of the corpus cavernosum, the latter the 

 bulb of the urethra, and by their rhythmical contractions 

 cause the erection of the penis from the base to its summit. 



