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mals we must study their past history, for geo- 

 logical and geographical distribution go hand 

 in hand. 



It is a familiar saying nowadays that steam 

 and electricity have made the world so small 

 that no portion of the globe may remain by it- 

 self. But it was not otherwise in the past, for 

 Europe and Asia contributed to the animal 

 population of North America. And if dis- 

 tances were great and opportunities few, time 

 was long ; the trail of the slow-moving mam- 

 moth reaches across three continents, from Eng- 

 land to New York, though we may only guess 

 at the number of centuries this journey re- 

 quired. 



Finally, the one thing that stands promi- 

 nently forth is that in the struggle for exist- 

 ence mere brute force avails nothing ; not size 

 nor strength, but adaptability to surroundings, 

 is the prime factor of success in life's race. 



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