109 



"An invertebrate animal, possessing no consciousness, would 

 be precisely in the same condition as the body of the man, 

 Colbourne, whose case has been detailed; when irritated, it 

 would exhibit all the appearances of suffering, but would not 

 be aware of it. It would be, in fact, like an actor who exhibits 

 to an admiring audience all the phases of love, anger, jealousy, 

 despair, and madness ; and yet is perfectly innocent of feeling 

 the emotions he pourtrays. 



"But as the psychological development of the lower ani- 

 mals is such, that many candid enquirers have been induced 

 to accord to them a considerable amount of rationabty, it will 

 not be advisable to stretch this point too far. 



" I will be perfectly content, if it be allowed that the seat of 

 the mental powers presumed to exist, be in the analogue to the 

 brain, i. e., the cephalic, or supraesophageal ganglion. 



"If this be granted, it will follow, that if we cut an 

 animal possessed of such a ganglion into two parts, through 

 the middle, the one will be a sensitive, the other an insensible 

 portion ; the former answering to our head, the latter to our 

 body. 



" It will be further necessary to presume that both of these 

 parts shall be possessed of life ; that they shall neither have 

 been destroyed by the process. 



" Now, if these two parts act at all differently under the 

 influence of any irritating cause, should we not be justified in 

 asserting that they did so in consequence of their different sen- 

 sitive endowments; and if they act precisely in the same 

 way — if the same cause produce precisely analogous pheno- 

 mena in each — should we not be equally justified in affirming 

 that there was no real difference between the two ? 



"We have an animal that possesses all the characters 

 thought necessary — the common earth worm. It possesses 

 a head and tail, a supraesophageal or a cephalic ganglion, and 

 if cut across is not deprived of vitality. Yet if the two seg- 

 ments are irritated, do not each present the same phenomena ? 



