To J. S. Henslow 8 May 
Down Bromley Kent
My dear Henslow
Very many thanks about the Elodea,—which case interests me much. I wrote to Mr Marshall at Ely & in due time he says he will send me whatever information he can procure.—1
Owen is indeed very spiteful. He misrepresents & alters what I say very unfairly. But I think his conduct towards Hooker most ungenerous, viz to allude to his Essay, & not to notice the magnificent results on geographical distribution.2
The Londoners says he is mad with envy because my book has been talked about: what a strange man to be envious of a naturalist like myself, immeasurably his inferior! From one conversation with him I really suspect he goes at the bottom of his hidden soul as far as I do!—
I wonder whether Sedgwick noticed in the Edinburgh Review, about the “Sacerdotal revilers”3—so the revilers are tearing each other to pieces.— I suppose Sedgwick will be very fierce against me at the Phil. Soc.—4 Judging from his notice in the Spectator he will misrepresent me, but it will certainly be unintentionally done.—5 In a letter to me & in the above notice he talks much about my departing from the spirit of inductive philosophy.—6 I wish, if you ever talk on subject to him, you would ask him whether it was not allowable (& a great step) to invent the undulatory theory of Light—ie hypothetical undulations in a hypothetical substance the ether. And if this be so, why may I not invent hypothesis of natural selection (which from analogy of domestic productions, & from what we know of the struggle of existence & of the variability of organic beings, is in some very slight degree in itself probable) & try whether this hypothesis of natural selection does not explain (as I think it does) a large number of facts in geographical distribution—geological succession—classification—morphology, embryology &c. &c.— I shd really much like to know why such an hypothesis as the undulation of the ether may be invented, & why I may not invent (not that I did invent it, for I was led to it by studying domestic varieties) any hypothesis, such as natural selection.
Pray forgive me & my pen for running away with me & scribbling on at such length.—
My dear old Master | Yours affectly | C. Darwin
I can perfectly understand Sedgwick or any one saying that nat. selection does not explain large classes of facts; but that is very different from saying that I depart from right principles of scientific investigation.—
Comments on Richard Owen’s review of the Origin [in Edinburgh Rev. 111 (1860): 487–532]. Considers Owen unfair to CD and most ungenerous toward Hooker.
Expects Sedgwick to be fierce against him. Sedgwick also misrepresented CD in his Spectator review [24 Mar and 7 Apr 1860].
Compares natural selection to the undulatory theory of light as a hypothesis explaining a large number of facts.