128 EVOLUTION, OLD ANv NEW. 



animals, those which live with us have their perceptions 

 increased in range, while those that are wild have but 

 theii natural instinct, which is often more certain but 

 always more limited in range than is the intelligence 

 of domesticated animals." * 



" For perception to exist in its fullest development in 

 any animal body, that body must form a whoile — an 

 ensemble, which shall not only be capable of feeling in 

 all its parts, but shall be so arranged that all these 

 feeling parts shall have a close correspondence with 

 one another, and that no one of them can be disturbed 

 without communicating a portion of that disturbance to 

 every other part. There must also be a single chief 

 centre, with which all these different disturbances may 

 be connected, and from which, as from a common '^omt 

 d'appvd, the reactions against them may take their rise. 

 Hence man, and those animals whose organization most 

 resembles man's, will be the most capable of percep- 

 tions, while those whose unity is less complete, whose 

 parts have a less close correspondence with each other — 

 which have several centres of sensation, and which seem, 

 in consequence, less to envelope a single existence in a 

 single body than to contain many centres of existence 

 separated and different from one another — these will 

 have fewer and duller perceptions. The polypus, which 

 can be reproduced by fission; the wasp, whose head 

 even after separation from the body still moves, lives, 

 acte, and even eats as heretofore ; the lizard which we 

 deprive neither of sensation nor movement by cutting' 

 » Tom. vii. p. 9, 1758. 



