wearing, and I am convinced
I can swear harder than you, therefore I am right. Q.E.D.

If the number of 1,000 pigeons were prevented increasing not by chance
killing, but by, say, all the shorter-beaked birds being killed, then
the WHOLE body would come to have longer beaks. Do you agree?

Thirdly, if 1,000 pigeons were kept in a hot country, and another
1,000 in a cold country, and fed on different food, and confined in
different-size aviary, and kept constant in number by chance killing,
then I should expect as rather probable that after 10,000 years the two
bodies would differ slightly in size, colour, and perhaps other trifling
characters; this I should call the direct action of physical conditions.
By this action I wish to imply that the innate vital forces are somehow
led to act rather 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 poin