differently in the two cases, just as heat will allow or cause two elements
to combine, which otherwise would not have combined. I should be
especially obliged if you would tell me what you think on this head.

But the part of your letter which fairly pitched me head over heels with
astonishment, is that where you state that every single difference which we
see might have occurred without any selection. I do and have always fully
agreed; but you have got right round the subject, and viewed it from an
entirely opposite and new side, and when you took me there I was astounded.
When I say I agree, I must make the proviso, that under your view, as now,
each form long remains adapted to certain fixed conditions, and that the
conditions of life are in the long run changeable; and second, which is
more important, that each individual form is a self-fertilising
hermaphrodite, so that each hair-breadth variation is not lost by
intercrossing. Your manner of putting the case would be even more striking
than it is if the mind could grapple with such numbers--it is grappling
with eternity--think of each of a thousand seeds bringing forth its plant,
and then each a thousand. A globe stretching to the furthest fixed star
would very soon be covered. I cannot even grapple with the idea, even with
races of dogs, cattle, pigeons, or fowls; and here all admit and see the
accurate strictness of your illustration.

Such men as you and Lyell thinking that I make too much of a Deus of
Natural Selection is a conclusive argument against me. Yet I hardly know
how I could have put in, in all parts of my book, stronger sentences. The
title, as you once pointed out, might have been better. No one ever
objects to agriculturalists using the strongest language about their
selection, yet every breeder knows that he does not produce the
modification which he selects. My enormous difficulty for years was to
understand adaptation, and this made me, I cannot but think, rightly,