CHAPTER XXI 



THE CROWN OF EVOLUTION 



When monsters lived and ruled the earth, it was bulk of bone 

 muscle, not size of brain 1 or keenness of wit, that counted. 



The creatures had eyes and ears and all five senses, but 

 not one among the number carried a brain so efficient as the 

 smallest normal man-brain that guides the life of the smallest 

 man to-day. 



Think, then, of the change that has come about. To-day it 

 is brain, not bone or muscle, that rules the world. The ele- 

 phant and the rhinoceros still live, but it is small man with 

 his active brain that masters them when he meets them. 



To understand how this has come to pass, recall the five- 

 linked chain of evolution, discussed in Chapter IX. Go back 

 far enough in history and apply the chain to the evolution of 

 brain in vertebrate animals. Recall the fact that in every 

 family of every generation there has been endless variation. 

 Also ask this question : Other things being equal, which 

 animals have the better chance to survive, those with quick 

 wit or those with slow wit ; those with an efficient or those 

 with an inefficient brain ? 



The question answers itself. As a rule, quicker wit means 

 better chance to find food and to keep it, to scent danger and 

 to escape it, to succeed in competition and to survive in the 

 struggle for existence. 



1 For description of the human brain and the work it does see " Control 

 of Body and Mind." 



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