ion, so please do not repeat them.

I quite agree about the extreme importance of such men as Cohn
[illegible] and Carter having observed apparent cases of heterogenesis.
At present I should prefer any mad hypothesis, such as that every
disintegrated molecule of the lowest forms can reproduce the
parent-form, and that the molecules are universally distributed, and
that they do not lose their vital power until heated to such a
temperature that they decompose like dead organic particles.

I am extremely grieved to hear about the Museum: it is a great
misfortune.--Yours most sincerely,

C. DARWIN.

I have taken up old botanical work and have given up all theories.

I quite agree about Howorth's paper: he wrote to me and I told him that
we differed so widely it was of no use our discussing any point.

As for Galton's paper, I have never yet been able to fully digest it: as
far as I have, it has not cleared my ideas, and has only aided in
bringing more prominently forward the large proportion of the latent
characters.

* * * * *

_Down, Beckenham, Kent. October 20, 1872._

My dear Wallace,--I have thought that you would perhaps like to see
enclosed specimen and extract from letter (translated from the German by
my son) from Dr. W. Marshall, Zoological Assistant to Schlegel at
Leyden. Neither the specimen nor extract need be returned; and you need
not acknowledge the receipt. The resemblance is not so close, now that
the fragments are gummed on card, as I at first thought. Your review of
Houzeau was very good: I skimmed through the whole gigantic book, but
you managed to pick out the plums much better than I did for myself. You
are a born critic. What an _admirable_ number that was of _Nature_.

I am writing this at Sevenoaks, where we have taken a house for three
weeks and have one more week to stay. We came here that I may get a
little rest, of which I stood in much need.--Ever yours very sincerely,

CH. DARWIN.

With respect to what you say about certain instincts of ants having been
acquired by experience or sense, have you kept in mind that the neuters
have no progeny? I wish I knew whether the fertile females, or queens,
do the same work (viz. placing the eggs in warm places, etc.) as the
neuters do afterwards; if so the case would be comparatively simple; but
I believe this is not the case, and I am driven to selection of varying
pre-existing instincts.

* *