264 NATURE AND MAN. 



is difficult, however, to ascertain precisely the real meaning of 

 Descartes, as of many writers who succeeded him ; for the Latin 

 sentire and its derivations obviously cover a very wide range of 

 mental affections, from simple consciousness up to the highest 

 forms of thought and feeling ; and it is clear from the illustrations 

 given by Descartes, that he sometimes meant rather sdf-zow- 

 scioasness — that is, the consciousness of one's consciousness — 

 than those simple states of feeling, which, though they can be 

 shown to have originally guided our movements, in consequence 

 of their habitual recurrence cease to excite our notice and are not 

 remembered. To this distinction I shall presently have occasion 

 to return. 



The next important stage in the progress of neurological 

 inquiry, consisted in the determination and general recognition of 

 the independent endowments of the spinal cord. To those who 

 have been brought up in modern neurological doctrine, it seems 

 scarcely credible that the grossest ignorance should have pre- 

 vailed up to the end of the first third of the present century, in 

 regard to the centric character of this organ ; even Bell regarding 

 it as a bundle of nerves — a conductor that brings the nerve-trunks 

 issuing from it into continuity with the brain, which was assumed 

 to be (with the exception of the sympathetic ganglia) the sole 

 centre of the nervous system of Vertebrate animals generally, 

 and of man in particular. And in like manner the knotted ventral 

 nerve-cord of articulated animals was represented by Bell's 

 disciple, George Ne\vport (and also by Professor Grant), as a 

 mere conductor between the cephalic ganglia and the nerve-trunks. 

 Yet Prochaska and Legallois had long before experimentally 

 proved, not only that the spinal cord as a whole is a centre of 

 reflex action quite independent of the brain, but that separated 

 segments of the spinal cord may so act independently of each 

 other. So, in the case of articulated animals, any one who had 

 cut a worm or a centipede into pieces, and had witnessed the 

 continued movements of each segment, might have drawn the 

 inference that these movements were sustained by the inde- 

 pendent endowments of the ganglionic centres which the seg- 

 ments severally contained. It had been further proved by Legal- 

 lois that the respiratory movements continue after the removal of 



