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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