488 GENERAL REFLECTIONS ON 



that such animals are capable in some degree of sensibility. 

 The very reverse of unity is however visible in their irrita- 

 ble principles. Here, therefore, if the presence of an imma- 

 terial conscious being be admitted, it must be in infinite 

 number ; an idea so absurd, that we are forced to believe 

 that the Acrita, or those animals which possess not the life 

 of organification, have no sentient principle acting on their 

 nervous matter. Their irritability no more proves it, than 

 the convulsion by galvanism of the muscles of a dead frog 

 is sufficient testimony of its suffering pain. 



The latter notions with respect to the nature of the sen- 

 tient principle in animals, are in strict unison with zoolo- 

 gical phenomena. I am indeed ignorant of any better ex- 

 planation of these, than by such an hypothesis, which must 

 be acknowledged, however, to involve, as well as the other 

 theories, assumptions of the truth of which we cannot be 

 certain. Perhaps some opinion, preferable to any of the 

 preceding, may yet be devised, and the search for it must 

 give us an additional zest for that science, which affords 

 the only sure data upon which similar investigations can 

 ever be founded. I despair, indeed, of positive certainty on 

 the point being in this world ever attained ; but surely the 

 subject is one of the most interesting upon which the mind 

 can speculate, and must fully repay the trouble of thought. 

 At all events, we ought not on a philosophical question, 

 as it has most truly been said, to take assertion for proof, 

 obscurity for depth, or perplexity for argument. Neither 

 the authority of office, nor the weight of name; neither the 

 elegance of style, nor the purity of motive, can be any suf- 

 ficient reason for doing ourselves so little justice. Or, to 

 cite a passage of Ray which is most apposite, " Let it 

 not suffice us to be book-learned, to read what others have 



