170 SPECIES NOT 



would be the height of absurdity to suppose that 

 an "acquired habit" could make the goldfinch, 

 the fan-tail warbler, the long- tailed tit, or any 

 other bird in fact, construct a nest in every par- 

 ticular the same as the species has done since 

 the creation, from other power than that of 

 a beautifully-adapted instinct. And so clearly 

 the song thrush of the old world and the new, 

 though belonging to a fauna essentially distinct, 

 have been created, and endowed, with the same 

 instinct, although it would be as absurd in us 

 to assume a knowledge of the reason, as it would 

 be to explain why the goldfinch and the redpole 

 should build nests so totally different. Each 

 member of the thrush family, as well as that of 

 every other bird, forms its nest from the power 

 of an instinct it cannot resist, just as the caged 

 nightingale obeys the inherited instinct of migra- 

 tion, by flying about its cage all night. But the 

 most admirable part of the nest-building of birds, 

 is their constant uniformity. They are always 

 made alike. If the birds were insensibly being 

 modified by natural selection, their nests ought 

 to be changing also, to meet their anticipated 

 new condition. 



Is there no foresight in natural selection? If 

 not, what on earth is the power or force which 

 elumges the body, but leaves the instincts un- 

 touched? If there is foresight, why then should 

 we not see some evidence of it in the operations 

 of the changing instinct? 



Mr. Darwin considers that the larva 1 <>f it-linen- 



