THE OEJGIN OF SENSIBILITY. 407 



(gills or lungs) in the more comj^lex organisms ; nor 

 should we have more difficulty in understanding how 

 Sensibility, from being common to the whole organism, 

 is handed over to a special structure, which then per- 

 forms that function exclusively, as the lungs perform 

 that of Eespiration, or the muscles that of Contraction. 

 Nay, more : just as animals possessing special organs 

 for Respiration, do also, in a minor degree, respire by 

 the general surface, so, according to my observations, 

 it is almost demonstrable that animals possessing a 

 special nervous system also manifest Sensibility in parts 

 far removed from any nervous filament. In the higher 

 animals this is probably not the case.* The division of 

 labour is more complete. The stomach digests, the 

 glands secrete, the muscles contract, and the nerves 

 feel. Of course, the power is greatly increased by this 

 division of labour ; the more complex the organism, 

 the more various and effective each function. In the 

 pregnant language of our most thoughtful poet, — 



" All Nature widens upward. Evermore 

 The simpler essence lower lies ; 

 More complex is more perfect, owning more 

 Discourse, more widely wise." i* 



* I say prohablif, because recent investigations have shown that parts 

 which, in the normal healthy condition, are absolutely insensible, such 

 as tendons, ligaments, the dura mater, and the periosteum, become 

 intensely sensitive in a state of inflammation, and this cannot be attri- 

 buted to the nerves. — See Floueens, in Annates des Sciences Naturelles, 

 1856, IV. Serie, vi. 282 ; and compare Dr Inman's work on Spinal 

 Irritation. Further, Mr Tomes has communicated to the Royal So- 

 ciety a paper on the " Soft Fibrils in the Dentinal Tubes," which shows 

 a sensitive structure, not nervous, in the teeth. 



+ Tennyson: The Palace of Art. 



