RELATED SYSTEMS OF NERVES. 659 



temperature in the limbs, on stimulating the posterior roots of the 

 nerves supplying the limbs. The experiments we consider elsewhere 

 (cf. p. 668), but the observations on degeneration in the posterior roots 

 after section, show that the increase of temperature observed cannot be 

 due to the presence in the posterior roots of efferent fibres arising from 

 the spinal cord. 



Budge l found in the rabbit that dilator ribres for the pupil run in the 

 anterior and not in the posterior roots of the first and second thoracic 

 nerves. In the following year he stated 2 that section of certain anterior 

 roots in the rabbit causes flushing of the ear, whilst section of the correspond- 

 ing posterior roots has little or no effect. Since that time numerous observa- 

 tions have been made, cf . Dastre and Morat 3 on vaso-dilator fibres to the bucco- 

 facial region ; Gaskell 4 on erector nerves of the penis ; Bradford 5 on vaso- 

 motor nerves to the kidney ; Langley 6 on pilo-motor nerves ; Langley and 

 Anderson 7 on nerve fibres running to the end of the intestine, the bladder, 

 the internal and external generative organs. 



In vertebrates other than mammals the matter is less clear. In the chick 

 the axons of nerve cells in the spinal cord have been traced into the posterior 

 roots, but the function of these axons has not been determined. There are 

 no satisfactory degenerative observations on any lower vertebrate. Ex- 

 perimental observations have been chiefly made on the frog, but the con- 

 clusions drawn from them are contradictory. 



Pfliiger 8 found that the vasomotor fibres to the mesentery and web of the 

 frog run in the anterior and not in the posterior roots of the spinal nerves. 



Steinach and Wiener 9 state that in Rana esculenta electrical and 

 mechanical stimulation of the posterior roots of the second to the ninth spinal 

 nerves causes movements in some part or other of the alimentary canal or in 

 the bladder. They find that the effect on the rectum and bladder is not 

 confined to the posterior roots, but occurs to a varying extent on stimulat- 

 ing the anterior roots. Horton Smith, 10 however, was unable to confirm these 

 results. He readily obtained contraction of the rectum and bladder on 

 stimulating the anterior roots of certain of the lower spinal nerves, but did 

 not obtain contraction from the posterior roots. 



Systems of Nerves related to the Sympathetic. 



Nomenclature. — The sympathetic system, as we have seen, sup- 

 plies nerve fibres to certain structures in all parts of the body. In 

 some parts of the body these structures receive nerve fibres from other 

 sources than the sympathetic. It is, in consequence, convenient to 

 have some term to include the whole nervous supply. The words 

 " organic," " vegetative," ganglionic," and " involuntary " have all been 

 used, but they have also been used in senses other than that we require. 

 The term " visceral nervous system " has been employed by Gaskell and 

 others, including myself. The word "visceral," however, is obviously 



1 Arch./, physiol. HeilL, Stuttgart, 1852, S. 773. 



2 C'ompt. rend. Acad. d. sc, Paris, 1853, tome xxx. p. 377. 



3 Arch, de, physiol. norm, etpath., Paris, 1882, p. 190. 



* " Proe. Physiol. Soc," 1887, p. iv., Jov/rn. Physiol., Cambridge and London, vol. viii. 



5 Ibid., 1889, volx. p. 363. 



6 Ibid., 1893, vol. xv. p. 181. 



7 Ibid., 1895, vols, xviii. and xix. 



8 Zfschr.f. rat. Med., 1857, III. Eeihe, Bd. i. S. 346. 



9 Arch. f. d. gen. Physiol., Bonn, 1895, Bd. lx. S. 593. 



10 Jowrn. Physiol., Cambridge and London, 1897, vol. xxi. p. 101. Steinach {Arch./. 

 d. ges. Physiol., Bonn, 1898, Bd. lxxi. S. 533), after renewed experiments, upholds the 

 conclusion lie had previously come to. 



