68 Historical Notices i?i regard to the Distinction of Nerves 



centre, than Erasistratus proceeded to appropriate to different parts of 

 that organism the functions which, along witli Herophilus, he had dis- 

 tinguished, of sensibility and voluntary motion. He placed the source 

 — of the former in the meninges or membranes, of the latter in the sub- 

 stance, of the encephalos in general, that is, of the Brain-proper and 

 After-brain or Cerebellum. And while the nerves were, mediately or 

 immediately, the prolongations of these, he viewed the nervous mem- 

 branes as the vehicle of sensation, the nervous substance as the vehicle 

 of motion. (Rufus Ephesius, L. i. c. 22 ; L. ii. cc- 2, 17.) This theory, 

 which is remarkable, if for nothing else, as manifesting the tendency 

 from an early period to refer the phenomena of motion and sensation to 

 distinct parts of the nervous organism, has not obtained the attention 

 which it even intrinsically merits. In modern times, indeed, the same 

 opinion has been hazarded, even to my fortuitous knowledge, at least 

 thrice. Firstly by Fernelius (1550, Physiologia, L.v. cc. 10, 14 ;) secondly 

 by Rosetti (1722, Raccolta d'Opuscoli, &c., t. v. p. 272 sq. ;) thirdly by 

 Le Cat (1740, Traite' des Sensations, GEuv. Phys. t. i. p. 124, and Diss, 

 sur la Sensibilite' des Meninges, § i.) By each of these the hypothesis is 

 advanced as original. In the two last this is not to be marvelled at ; 

 but it is surprising how the opinion of Erasistratus could have escaped 

 the erudition of the first. I may observe, that Erasistratus also antici- 

 pated many recent physiologists in the doctrine, that the intelligence of 

 man, and of animals in general, is always in proportion to the depth 

 and number of the cerebral convolutions, that is, in the ratio of the ex- 

 tent of cerebral surface, not of cerebral mass. 



The second alternative was adopted by Galen, who, while he refutes, 

 apparently misrepresents, the doctrine of Erasistratus ; for Erasistratus 

 did not, if we may credit Rufus, an older authority than Galen, derive 

 the nerves from the membranes of the encephalos, to the exclusion of 

 its substance ; or if Galen be herein correct, this is perhaps the early 

 doctrine which Erasistratus is by him said in his maturer years to have 

 abandoned; — a doctrine, however, which, under modifications, has in 

 modern times found supporters in Rondeletius and others. (Laurentii 

 Hist. Anat. L. iv. qu. 13.) — Recognising, what has always indeed been 

 done, the contrast of the two phenomena of sensibility and motion, 

 Galen did not, however, regard them as necessarily the products of dis- 

 tinct parts of the nervous system, although, de facto, different parts of 

 that system were often subservient to their manifestation. As to the 

 problem — Do the nerves perform their double function by the convey- 

 ance of a corporeal fluid, or through the irradiation of an immaterial 

 power .'* — Galen seems to vacillate ; for texts may be adduced in favour 

 of each alternative. He is not always consistent in the shares which 

 he assigns to the heart and to the brain, in the elaboration of the animal 

 spirits ; nor is he even uniform in maintaining a discrimination of origin, 

 between the animal spirits and the vital. Degrading the membranes to 

 mere envelopments, he limits every peculiar function of the nervous or- 



