68 SCIENCE PROGRESS. 



circular fibres. Bernheim ^ in frogs and salamanders found 

 fibres for the bladder in the eighth and ninth nerves, some- 

 times in the tenth as well. Steinach" found nerves for the 

 bladder of the frog not only in the anterior roots of the 

 seventh, eighth and ninth nerves, but also in the posterior 

 roots of those same nerves. He confirms their presence 

 in these posterior roots, by obtaining a retiex contraction of 

 the bladder after all the anterior roots of these nerves had 

 been cut on both sides, and the posterior as well on one 

 side. 



Very few, if any, vaso-niotor nerves are contained in the 

 lumbar set of nerves ^ to the bladder, nor were Langley 

 and Anderson able to show their presence in the sacral set 

 of fibres.'* 



External genital organs. — Langley and Anderson ^ have 

 examined the lumbar and sacral nerves with especial 

 reference to these organs. 



Here again the nerves arise in two sets, an upper and 

 a lower. The upper set of nerves in the male cause when 

 stimulated a powerful contraction of the retractor muscle of 

 the penis, contraction of the intrinsic muscles of the penis, 

 of the unstriated muscles of the genital skin, and of the 

 dartos and cremaster muscles. Stimulation of the lower 

 set of fibres causes very marked inhibition of the retractor 

 muscle, of the non-striated muscles of the penis and of the 

 skin, with contraction of the striated erector muscles, viz., 

 the recto-cavernosus, the ischio cavernosus, the bulbo- 

 cavernosus, Houston's muscle and the striated muscle of the 

 urethra. In the female, the upper set cause contraction of 

 the vulva and of the skin muscles, with slight retraction of 

 the clitoris ; the effects sometimes are very slight especially 

 in the cat and doer. The lower set cause dilatation of the 

 vulva, relaxation of the skin muscles around the vulva 

 and contraction of the muscles which correspond to the 



"^ Arch. f. i^Atiat. u.') Fhys-^^^M^xA., p. ii, 1892. 



"^ Pfliiger's Archiv, vol. Ix., p. 593, 1895. 



°Journ. 0/ Fhys., vol. xix., p. 75, 1895. 



* Loc. cit., p. 79. 



^ Journ. of Physiol.^ vol. xix., p. 85, 1895. 



