GENESIS OF MAN, INTELLECTUALLY 



with the Duke of Argyll, that the eleven cubic 

 inches of brain space by which the aboriginal 

 Hindu surpasses the gorilla have a higher value, 

 for purposes of classification, than the sixty- 

 eight cubic inches by which the modern English- 

 man surpasses the Hindu. We now see what 

 kind of a Rubicon it was which was crossed 

 when those eleven cubic inches of brain — or 

 even when four or five of them — had been 

 gained. The crossing of the Rubicon was the 

 point at which natural selection began to con- 

 fine itself chiefly to variations in psychical mani- 

 festation. The ape-like progenitor of man, in 

 whom physical and psychical changes had gone 

 on pari passu for countless aeons, until he had 

 reached the grade of intelligence implied by the 

 possession of a brain four or five inches more 

 capacious than that of the gorilla, had now, as 

 we may suppose, obtained a brain upon which 

 could be devolved, to a greater and greater ex- 

 tent, the task of maintaining relations with the 

 environment. Then began a new chapter in the 

 history of the evolution of life. Henceforward 

 the survival of the fittest, in man's immediate 

 ancestry, was the survival of the cerebrums best 

 able to form representative combinations. The 

 agencies which had hitherto been at work in 

 producing an organic form endowed with rare 

 physical capacities now began steadfastly to la- 



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