5568 Reason and Instinct. 



faculties in that animal, but that those faculties must be, in their 

 essence or nature, strongly resembling, if not identical with, those 

 reasoning faculties we are so well acquainted with in ourselves. They 

 work on the same motives and by the same machinery, so far as we 

 can trace their influence or their operation ; and we have no more real 

 or valid reason, a priori, to dispute that the origin of the motive 

 power is the same in either case, than we have to question whether 

 the agency which propels the steam-ship, drives the intricate 

 machinery of the great factory, urges on the locomotive in its head- 

 long rush, or puts in motion the mechanism which wields the pon- 

 derous Nasmyth hammer, is one and the same in each case. But 

 more than this ; physiological researches, so far as they have been 

 already carried on, have shown that, in whatever way and degree the 

 brain of man is connected with his intellectual organization, develop- 

 ment or capacity, analogous observations on the brains of animals 

 tend to the establishment of similar theories as regards them. " It 

 being admitted that the brain is the material organ in connexion with 

 the mental principle, and it being also admitted that there is in the 

 different species of animals, on the one hand, a great difference as to 

 the extent of their moral and intellectual faculties, and, on the other 

 hand, a not less remarkable difference in the size and formation of the 

 brain ; so we cannot well avoid the conclusion that these two orders 

 of facts are, in a greater or less degree, connected with each other. 

 I do not mean to infer from this connexion that the mind is always 

 the same, and that the greater or less development of it depends 

 altogether on the greater or less perfection of the material organ. It 

 may well be supposed that the original difference is in the mind 

 itself, and that the Creator has so ordered it that the brain, in the 

 different species of animals, should be such as will meet the peculiar 

 requirements of the peculiar mind with which it is associated, — a view 

 of the subject, which, if I am not misinformed, derives no small 

 support from the researches of modern physiologists." (' Psychol. 

 Researches,' p. 170.) Again; "Is it possible, from any experience 

 that we have of the habits and character of a particular tribe of 

 animals, to predicate what kind of brain we should find them to have 

 on dissection ; or, from our observations on the latter, to form an 

 opinion as to their moral and intellectual capacities? To a limited 

 extent, this knowledge is within our reach. If two brains were placed 

 before me, in one of which the cerebral hemispheres were largely 

 developed, while, in the other, they were very little developed or 

 altogether absent, I should at once pronounce the former to indicate 



