To Alphonse de Candolle 14 January 1
Down. | Bromley. | Kent. S.E.
My dear Sir
I thank you most sincerely for sending me your Memoir.—2 I have read it with the liveliest interest, as is natural for me; but you have the art of making subjects, which might be dry, run easily. I have been fairly astonished at the amount of individual variability in the oaks.3 I never saw before the subject in any department of nature worked out so carefully. I noted with delight case of achenia &c &c.—4 What labour it must have cost you! You spoke in one letter of advancing years; but I am very sure that no one would have suspected that you felt this.—5 I have been interested with every part; though I am so unfortunate as to differ from most of my contemporaries in thinking the the vast continental extensions of Forbes, Heer & others are not only advanced without sufficient evidence, but are opposed to much weighty evidence.—6
You refer to my work in the kindest & most generous spirit.— I am fully satisfied at the length in belief to which you go, & not at all surprised at the prudent reservations which you make.7 I remember well how many years it cost me to go round from old beliefs. It is encouraging to me to observe that everyone who has gone an inch with me; after a period goes a few more inches or even feet.— But the great point, as it seems to me, is to give up the immutability of specific forms; as long as they are thought immutable, there can be no real progress in ‘epiontology”.8 It matters very little to anyone except myself, whether I am a little more or less wrong on this or that point; in fact I am sure to be proved wrong in many points. But the subject will have, I am convinced, a grand future.—
Considering that Birds are the most isolated group in the animal kingdom, what a splendid case is this Solenhofen bird-creature with its long tail & fingers to its wings!9 I have lately been daily & hourly using & quoting your Geograph. Bot., in my book on “Variation under Domestication”.10
with cordial thanks & sincere respect | I remain Dear Sir | Yours very faithfully | Ch. Darwin
Thanks AdeC for his memoir ["Étude sur l’espèce", Ann. Sci. Nat. (Bot.) 4th ser. 18 (1862): 59–110].
CD astonished at the amount of variability in the oaks.
CD differs from most contemporaries in thinking that the vast continental extensions of Forbes, Heer, and others are not only advanced without sufficient evidence but are opposed to much weighty evidence.
AdeC’s comment on CD’s work [Origin] is generous.
CD is satisfied at the length AdeC goes with him and is not surprised at his prudent reservations. He remembers how many years it took him to change his old beliefs. The great point is to give up immutability. So long as species are thought immutable there can be no progress in "epiontology" [see ML 1: 234 n.]. CD is sure to be proved wrong in many points but the subject will have "a grand future".