COSMIC PHILOSOPHY 



now rank among the fleetest and most timid of 

 mammals. If all the lions and other swift car- 

 nivora of Africa were to become extinct, so that 

 antelopes would no longer have to run for their 

 lives, the slower and less easily alarmed indi- 

 viduals would begin to be preserved in as great 

 numbers as the swifter and more timid ones, so 

 that by and by the average speed and timidity 

 of the race would be diminished. In all this 

 we see merely the effects wrought by unaided 

 natural selection. But it is a fundamental law 

 of biology that functions are maintained at 

 their maximum only through constant exercise. 

 Freed from savage enemies, our antelopes 

 would less frequently use the muscles con- 

 cerned in running, and would less often exer- 

 cise the mental faculties concerned in the rapid 

 perception of approaching danger. Inevitably, 

 therefore, they would, after several generations, 

 diminish in speed, and become less alert and less 

 timid. Here we see the effects of what is called 

 the law of use and disuse. But to these we should 

 also have to add the effects of correlation of 

 growth. Decrease in speed involving decrease 

 in muscular tonicity, and rendering possible the 

 assimilation of less concentrated food, would 

 seriously modify the nutrition of the entire or- 

 ganism. The digestive tract would probably 

 be enlarged, and larger and lazier bodies could 

 not fail to be produced, both by |the direct in- 

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