142 MAN AND THE LOWER ANIMALS. n 



and of a Chimpanzee of the same length, in order to show 

 the relative proportions of the parts: the former taken 

 from a specimen, which Mr. Flower, Conservator of the 

 Museum of the Royal College of Surgeons, was good 

 enough to dissect for me; the latter, from the photograph 

 of a similarly dissected Chimpanzee's brain, given in Mr. 

 Marshall's paper above referred to. a, posterior lobe; b, 

 lateral ventricle; c, posterior cornu; x, the hippocampus 

 minor. 



simple reason that, as may be concluded from what 

 has been already said respecting cranial capacity, 



niable axiom, objectors occasionally, and with much seem- 

 ing plausibility, argue that the vast intellectual chasm 

 between the Ape and Man implies a corresponding struc- 

 tural chasm in the organs of the intellectual functions; 

 so that, it is said, the non-discovery of such vast differ- 

 ences proves, not that they are absent, but that Science is 

 incompetent to detect them. A very little consideration, 

 however, will, I think, show the fallacy of this reasoning. 

 Its validity hangs upon the assumption, that intellectual 

 power depends altogether on the brain — whereas the brain 

 is only one condition out of many on which intellectual 

 manifestations depend; the others being, chiefly, the or- 

 gans of the senses and the motor apparatuses, especially 

 those which are concerned in prehension and in the pro- 

 duction of articulate speech. 



A man born dumb, notwithstanding his great cerebral 

 mass and his inheritance of strong intellectual instincts, 

 would be capable of few higher intellectual manifestations 

 than an Orang or a Chimpanzee, if he were confined to 

 the society of dumb associates. And yet there might not 

 be the slightest discernible difference between his brain 

 and that of a highly intelligent and cultivated person. 

 The dumbness might* be the result of a defective innerva- 

 tion of these parts; or it might result from congenital 

 deafness, caused by some minute defect of the internal 

 ear, which only a careful anatomist could discover. 



The argument, that because there is an immense dif- 

 ference between a Man's intelligence and an Ape's, there- 

 fore, there must be an equally immense difference between 

 their brains, appears to me to be about as well based as 

 the reasoning by which one should endeavour to prove 

 that, because there is a " great gulf " between a watch 



