EXCURSIONS OF AN EVOLUTIONIST 



thus travel over vast fields of thought with an 

 ease of which they are themselves unaware. Dr. 

 Nathaniel Bowditch once said that in translating 

 the " Mecanique Celeste," he had come upon 

 formulas which Laplace introduced with the 

 word " obviously," where it took nevertheless 

 many days of hard study to supply the inter- 

 mediate steps through which that transcendent 

 mind had passed with one huge leap of infer- 

 ence. At some time in his youth no doubt La- 

 place had to think of these things, just as Ru- 

 binstein had once to think how his fingers 

 should be placed on the keys of the piano ; but 

 what was once the object of conscious attention 

 comes at last to be well-nigh automatic, while 

 the flight of the conscious mind goes on ever 

 to higher and vaster themes. 



Let us now take a long leap from the high- 

 est level of human intelligence to the mental 

 life of a turtle or a codfish. In what does the 

 mental life of such creatures consist? It con- 

 sists of a few simple acts mostly concerned with 

 the securing of food and the avoiding of danger, 

 and these few simple acts are repeated with un- 

 varying monotony during the whole lifetime 

 of these creatures. Consequently these acts are 

 performed with great ease and are attended with 

 very little consciousness, and moreover the 

 capacity to perform them is transmitted from 

 parent to offspring as completely as the capacity 

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