origin of the various animal species: he said, for example, that the
short-legged birds which live on fish had been converted into the
long-legged waders by desiring to get the fish without wetting their
bodies, and so stretching their legs more and more through successive
generations. If Lamarck could have shown experimentally, that even
races of animals could be produced in this way, there might have been
some ground for his speculations. But he could show nothing of the
kind, and his hypothesis has pretty well dropped into oblivion, as it
deserved to do. I said in an earlier lecture that there are hypotheses
and hypotheses, and when people tell you that Mr. Darwin's
strongly-based hypothesis is nothing but a mere modification of
Lamarck's, you will know what to think of their capacity for forming a
judgment on this subject.

But you must recollect that when I say I think it is either Mr. Darwin's
hypothesis or nothing; that either we must take his view, or look upon
the whole of organic nature as an enigma, the meaning of which is
wholly hidden from us; you must understand that I mean that I accept it
provisionally, in exactly the same way as I accept any other hypothesis.
Men of science do not pledge themselves to creeds; they are bound by
articles of no sort; there is not a single belief that it is not a
bounden duty with them to hold with a light hand and to part with it
cheerfully, the moment it is really proved to be contrary to any fact,
great or small. And if, in course of time I see good reasons for such
a proceeding, I shall have no hesitation in coming before you, and
pointing out any change in my opinion without finding the slightest
occasion to blush for so doing. So I say that we accept this view as
we accept any other, so long as it will help us, and we feel bound to
retain it only so long as it will serve our great purpose--the
improvement of Man's estate and the widening of his knowledge. The