THE MIND OF MAN 273 



stimulus for growth. At the basis of man's mental acquire- 

 ments lie his memory and his instincts his capacity for 

 making acquirements and his incitements to making them. 

 But instinct has so shrunken in him that, unaided by ac- 

 quirements, it cannot prolong his life nor enable him to 

 perpetuate his race. At birth he cries when in pain and 

 sucks when hungry, but there is little besides that he can 

 do. His deferred instincts the sporting, the sexual, the 

 parental though they incite him to necessary actions, are 

 dependent for usefulness on previous acquirements, without 

 which they would prompt in vain. In effect he has become 

 a creature with a vast memory and with incitements to use 

 his memory in such definite ways that presently, when grown, 

 he shall in body and mind fit his environment whatever that 

 may be. The rest of his physical and mental characters are 

 as much overshadowed by his memory and its corollary in- 

 telligence as the structures of some internal parasites are 

 dominated by their reproductive organs. The parasite has 

 become a mere bag of eggs; man has become almost as 

 completely a manufactory of thought, owing his persistence 

 as much to his intelligence as the parasite to its fecundity. 

 439. His bodily structures have been modified in accord- 

 ance with this dominant character. The great hemispheres 

 of his brain, to which consciousness has transferred its seat 

 from lower centres, have arisen. His hands have become 

 the strong but delicate instruments of his intelligence. To 

 free his hands for their peculiar functions he has assumed 

 the erect attitude. As a consequence his whole skeleton 

 has undergone a change. Structures and capabilities, a 

 high development of which was formerly essential to the 

 survival of his less intelligent ancestors, have become less 

 essential and have undergone regression. Thus his senses 

 of smell and hearing are now less keen than those of the 

 animals nearest to him. Intelligence enabled him to dis- 

 cover and perpetuate the art of making fire, and so of warm- 

 ing himself, and of cooking, softening, and partially pre- 

 digesting his food; but, as a consequence, his jaws have 



brain be mechanically prevented from growing, as by an early coalescence 

 of the cranial bones, the mental development is checked, and idiotcy 

 results. The individual is unable to make those mental acquirements 

 which would enable him to move " rationally " through his world. 

 Idiotcy also follows a lack of opportunity to make acquirements, as in 

 the case of prisoners closely confined from infancy in Eastern prisons. 

 Races that make comparatively few mental acquirements (i. e. the lower 

 savages) are usually small-brained. 



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