THE SCIENCE OF HAPPINESS 



rule, he has passed his climax of muscular efficiency. 

 His muscular system may at best seem almost to "hold 

 its own" for another decade. 



But meantime the organism is entering on what might 

 be termed the cerebral epoch : the muscles have had 

 their day, it is now the brain's turn. That too must 

 pass on to a climactic in due course ; but it was the 

 chief thesis of our text to suggest that, for the average 

 man and woman, the period of up-grade might be 

 prolonged, and the declining slope made less pre- 

 cipitous. 



IV 



THE LESSON OF HEREDITY 



[Amplifying the text of the chapters on Life-Companionship, 

 and The Coming Generation, pp. 210-240.] 



The scientific shibboleth of our time is heredity. 

 The word is on everyone's tongue. Viewing a fallen 

 fellow-mortal, it is quite the fashion to shake one's head 

 and say, "Oh, heredity accounts for him; blood will 

 tell." And with this formula we are accustomed to 

 measure our fellows, much as a clerk measures cloth. 

 And lest there should be any doubts about the method, 

 the man of science comes to our aid. 



"Yes," he says, "you are quite right. Your formula 

 expresses the universal principle of heredity. We word 

 it a little differently, but the idea is the same. 'Like 

 begets like' is the way we put it. It applies to every 

 living thing in the world. Notice this bacillus, for 



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