56 Proceedings oj 



crefc and snpply a nervous fluid, and 

 the nerves to be the conduit-pipes for 

 it* conveyance. In every age the 

 brain has been considered a common 

 sensoriuin, and ail tlie nerves to Le 

 capable of convejinji; sensation, unless 

 when tiicy iiad ganglia. If ganglia in- 

 tervened, then the nerves were said 

 to be cut oft" from tiie brain ; and those 

 so distinguished were called vital 

 nerves, neitl)er serving the purpose of 

 jfoverning the muscles nor of convey- 

 ing sensation. With all tliis apparent 

 simplicity of doctrine, there never has 

 been j)rcscnted such a crude heap of 

 errors in the history of any depart- 

 ment of science. 



These notions were obviously 

 founded on the mistake, tiiat the same 

 jierve served diii'erent purposes, and 

 that a fluid moved in the same tube 

 outwards to stimulate the muscles, and 

 inwards to convey sensation of exter- 

 nal impressions. So inconsistent are 

 those opiaions with the .structure of the 

 frame, that the simplest dissection 

 proves tlfcni false. 



So far is it from being true that 

 ganglia cut olf sensation, that I have 

 ascertained, and proved by experi- 

 ment, that all the nerves, without a 

 single exception, which bestow sensi- 

 "bility from the top of the head to the 

 toe, have ganglia on their roots ; and 

 those which have no ganglia arc not 

 nerves of sensation, but are for the 

 purpose of ordering the muscular 

 frame. 



This notion of a fluid moving back- 

 wards and forwards in the tubes of the 

 nerves, equally adapted to produce 

 niotion and sensation, has perpetuated 

 the error, that tlie diHereut nerves of 

 sensation are appropriated to their 

 offices by the texturcof their extremi- 

 ties, "that there exists a certain rela- 

 tion between the softness of the ncr- 

 ■vous extremities, and the uatureijf the 

 bodies which produce an impression 

 on them." On the contrnry, every 

 nerve of sense is limited in its exer- 

 cise, and can minister to certain per- 

 ceptions only. Whatever may be the 

 nature of the imi)ulse communicated to 

 a nerve, pressure, vibration, heat, elce- 

 tricily, the perception excited in the 

 mind will have reference to the organ 

 exercised, not to the impression made 

 upon it. Fire will not give the sensa- 

 tion of heat to any ner\e but that ap- 

 |iro])rialed to the surface. However 

 deliiatc the retina be, it <loes not feci 

 like the sUiu. The p<iiut whieji pricks 



Public Societies. [Feb. I,' 



the skin being thrust' against the 

 retina, will cause a spark oi- tire or a 

 flash of light. The tongue enjoys two 

 senses, touch and taste ; but by select- 

 ing the extremity of a paiticular 

 nerve, or, what is the same thing, a 

 particular papilla, we can exercise 

 either the one or the other sense sepa- 

 rately. If we press a needle against 

 a nerve of touch, we shall feci the 

 sharpness, and know the part of the 

 tongue in contact with the point ; but, 

 if we touch a nerve of taste, we shall 

 have no perception of form or of- 

 place, we shall experience a metallic 

 taste. 



The innovations of the celebrated 

 continental authority Eichat, did not 

 bring us a step nearer the truth. 

 When he at once threw oft' respect for 

 his contemporaries, and for the autho- 

 rity of those who had preceded him, 

 he equally disregarded the facts of 

 anatomy. There may be merit in 

 taking new views of a subject; but 

 Bichat was continually holding a 

 thing up by the wrong end, and pre- 

 senting it in an aspect so singular, as 

 to puzzle any one to say whether or 

 not it was that with which he had 

 been long familiar ; accordingly, what 

 had been termed tlie sympathetic 

 system of nerves, he called the ganglio- 

 nic system ; although they are not 

 more distinguishable by ganglia than 

 the other nerves, upon which indeed 

 the ganglia are remarkable for their 

 size, number, and regidarity. These 

 ganglia must not be thrown out of the 

 system altogether, n)erely because they 

 are contained within the skull and 

 vertebras, which circumstance should 

 rather mark their impoitauce. 



Bichat persuaded himself that his 

 ganglionic system was isolated, and a 

 thing by itself; when, on the contrary, 

 the connections of this part of the 

 nervous System are universal. 'Ihe 

 wide-spreading fifth pair, and the 

 thirty spinal nerves, give large and 

 conspicuous roots to this system. It 

 exhibits a tissue extending uni- 

 versally. 



It was a still more unfortunate mis- 

 take of this ingenious physiologist, to 

 suppose the S3mpathetic nerve to be 

 the same with that, which in the lower 

 animals (the vermes) is seen coursing 

 from one extremity of the body to the 

 other. In the leech, or worm, those 

 nerves produce union and concatena- 

 tion of all the voluntary motions, and 

 bcstoM' sensibility as well as motion ; 



vet 



