My dear Wallace,—­I write a line to say that I understood—­but I may of course have been mistaken—­from Huxley that Bastian distinctly stated that he had watched the development of the scale of Sphagnum:  I was astonished, as I knew the appearance of Sphagnum under a high power, and asked a second time; but I repeat that I may have been mistaken.  Busk told me that Sharpey had noticed the appearance of numerous Infusoria in one of the solutions not containing any nitrogen; and I do not suppose that any physiologist would admit the possibility of Infusoria absorbing nitrogen gas.  Possibly I ought not to have mentioned statements made in private conversation, 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.