It was evident that such facts as these, as well as many others, could
be explained only on the supposition that species gradually become
modified; and the subject haunted me. But it was equally evident that
neither the action of the surrounding conditions nor the will of the
organisms (especially in the case of plants) could account for the
innumerable cases in which organisms of every kind are beautifully
adapted to their habits of life--for instance, a woodpecker or a
tree-frog to climb trees, or a seed for dispersal by hooks or plumes. I
had always been much struck by such adaptations, and until these could
be explained it seemed to me almost useless to endeavor to prove by
indirect evidence that species have been modified.
After my return to England it appeared to me that by following the
example of Lyell in geology, and by collecting all facts which bore in
any way on the variation of animals and plants under domestication and
nature, some light might perhaps be thrown on the whole subject.
Pages:
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717