WAYS OF NATURE 



and exceptional endowments that are often claimed 

 for them. The law of variation, as I have said, 

 would give rise to differences, but not to a sudden 

 reversal of race habits, or to animal geniuses. 



The law of variation is everywhere operative — 

 less so now, no doubt, than in the earlier history of 

 organic life on the globe. Yet Nature is still ex- 

 perimenting in her blind way, and hits upon many 

 curious differences and departures. But I suppose 

 if the race of man were exterminated, man would 

 never arise again. I doubt if the law of evolution 

 could ever again produce him, or any other species 

 of animal. 



This principle of variation was no doubt much 

 more active back in geologic time, during the early 

 history of animal life upon the globe, than it is in this 

 late age. And for the reason that animal life was 

 less adapted to its environment than it is now, the 

 struggle for life was sharper. Perfect adaptation of 

 any form of life to the conditions surrounding it 

 seems to check variability. Animal and plant life 

 seem to vary more in this country than in England 

 because the conditions of life are harder. The ex- 

 tremes of heat and cold, of wet and dry, are much 

 greater. It has been found that the eggs of the Eng- 

 lish sparrow vary in form and color more in the 

 United States than in Great Britain. Certain Ameri- 

 can shells are said to be more variable than the Eng- 

 lish. Among our own birds it has been found that 

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