INNERVATION OF THE GENERATIVE ORGANS 561 



vulva and clitoris, (2) Dilatation of the vulva, and (3) Relaxation of 

 the skin muscles surrounding the vulva. The visceral motor effects 

 were the same as those produced by the lumbar set of nerves as 

 described above. Besides these effects, contraction was induced in 

 the external sphincter of the vagina and in the striated genital 

 muscles. ' 



The Innervation of the Ovakies 



The ovary is innervated from the sympathetic plexus accompany- 

 ing the ovarian artery and from the plexus associated with the 

 ovarian branch of the uterine artery. It is generally supposed that 

 the nerve fibres, which are non-medullated, are merely vascular in 

 function.^ The fact that ovulation in some animals only occurs as 

 a consequence of coition, and then takes place at a definite time 

 afterwards, points to the conclusion that the follicles discharge in 

 response to a stimulus conveyed to the ovary by its nerves (see 

 p. 129). It has been suggested that the rupture is due to the 

 stimulation of erectile tissue.^ Nerve fibres have been described in 

 the tissue immediately surrounding the follicles, and have even been 

 traced as far as the follicular epithelium. 



The Innervation of the Uterus and Vagina and. the 

 Mechanism of Uterine Contraction 



It is well known that the onset of parturition is manifested by 

 rhythmically repeated contractions of the uterus which constitute 

 the "labour pains." But although the contractions are most pro- 

 nounced at this period, observations on animals have shown that 

 even in a virgin uterus rhythmical movements may occur. 



Kehrer ^ showed long ago that a uterus separated from the body 

 is capable of undergoing contractions if kept moist, and at the 

 normal body temperature. More recently Helme,* Kurdinowski,^ 



' Von Herff, "TJeber den feineren Verlauf der Nerven im Eierstocke des 

 Menschens," Zdtsch. f. Gebwt 11. Gynak, vol. xxiv., 1892. Gawronsky, 

 " Ueber Verbreitung und Endigungen der Nerven in den weiblichen Geni- 

 talien," Aroh. f. Oyniih., vol. xlvii., 1894. Kallius, " Nerven digungen in 

 Driisen d. EierstOcke," Merkel and Bonnet's Ergeb. d. Anat. u. Entwick., 

 vol. iv., 1895. Mandl, "Ueber Anordnung und Endigungaweise der Nerven 

 im Ovarium," Arch. f. Gynak, vol. xlviii., 1894-95. Vallet, " Nerfs d'Ovarie, 

 etc.," Tliesis, Paris, 1900. Abel and Mcllroy, "Nerves of the Ovary," Phys. 

 Soc, 5th June 1909. See also references on p. 358. 



2 Eouget, "Eecherches sur les Organea iferectiles de la Femme," Jour, de la 

 Phys., vol. i., 1858. 



^ Kehrer, " Zusammenziehungen der glatten Genitalmuskelatur, etc.," 

 Beiirage zur Vergl. u. Exper. Geburtskunde, 1867. ' 



* Helme, "Contributions to the Physiology of the Uterus and the Physio- 

 logical Action of Drugs upon it," Reports of the Lahoratwy of the Royal College 

 of Physidcms, Edinburgh, vol. iii., 1891. 



5 Kurdinowski, " Physiologische und pharmakologische Versuche an der 

 isolirten Gebarmutter," Arch.f. Anat. v,. Phys., Phys. Abth. (supplement), 1904. 



