From H. C. Watson 10 May 1860
Thames Ditton | Kingston—S.W.
10 May 1860
My dear Sir
I return by same post the four notices of ‘Origin’ which you kindly sent.— Gradually, the various arguments, objections, cavils, etc. on the grand subject are growing into a sort of conglomerate in my recollections; who said this, & who said that, getting pretty much confused together. I hope you can keep them mentally distinct.
Pictet goes a good way,1—farther perhaps than he himself clearly knows,— on page 15, where you pencil the no. 12,2 your difficulty is & will be to lead zoologists & botanists, those who look to existing “species”, so far as Pictet “believes”. Until a faith in certain impassable barrier between existent species becomes thoroughly shaken, naturalists will resist your views, & hail difficulties as if conclusive arguments on the contra side.
Differently as these unseen barriers are traced or placed, they are believed in about as strongly by almost all. Let the subjoined numerals represent botanical forms, & the lines be the barriers as placed by different botanists;
Jordan3 1 2 3 4 5 6 7 8 9 0 Babington4 1 2 3 4 5 6 7 8 9 0 Bentham5 1 2 3 4 5 6 7 8 9 0 Hooker6 1 2 3 4 5 6 7 8 9 0 at any rate, previous to 1859.
This represents an approximate uniformity which is not always found; the differences lying only in the more numerous barriers of J e B, as compared with B e H.— But these transpositions sometimes occur;
Hooker 1 2 3 4 — One species Smith7 1 2 3 4 — Two species Babn. 1 4 2 3 — Two (other) species
Shall I bore you with a simple illustration of convergence?8 You have at any rate the option not to read it. Take two plants, nore or less unlike in all other respects than these three characters:—
1. Glabrous — Leaves linear — Flowers white. 2. Pubescent — Leaves oval — Flowers blue 1 varies with leaves lanceolate — Flowers pink. 2 varies with Leaves lanceolate — Flowers pink.
Then let one (1) become pubescent, or the other (2) glabrous; & the convergence is completed so far as the three characters go.—
Accumulate similar convergences, in your way of accumulating divergences, and though you may never actually change two distant species into each other, you still may counterpoise endless divergence. Now, as facts in nature, the changes from pubescent to glabrous,—from linear or oval to lanceolate,—from white or blue to pink,—are ordinary, & excite no surprize singly. And yet those three characters would be held (as a rule) amply sufficient to justify a separation of 1 e 2 as perfectly distinct species, tho‘ all other technical characters should agree.
I presume you would say that some ancestors of 1 e 2 had lanceolate leaves & pink flowers, which had diverged into linear & white, oval & blue. But you can at best only suppose this lanceolate & pink fore-parent. And if you try to account for all converging variations in the like manner, your original adam or dozen of adams must surely have combined every character in one? Unless you believe that diverging characters are novelties, while converging are restorations only?
Sincerely yours | Hewett Cl. Watson
C. Darwin | Esqe
CD annotations
Footnotes
Bibliography
Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 29 vols to date. Cambridge: Cambridge University Press. 1985–.
Origin: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. By Charles Darwin. London: John Murray. 1859.
Pictet de la Rive, François Jules. 1860. Sur l’origine de l’espèce par Charles Darwin. Bibliothèque universelle. Revue suisse et étrangère n.s. 7: 233–55.
Summary
Returns reviews of Origin.
F. J. Pictet [Arch. Sci. Phys. & Nat. n.s. 7 (1860): 231–55] goes further than he himself realises.
Naturalists will resist CD’s views until faith in certain "impassable" barriers between existent species is shaken.
Gives CD an instance of convergence.
Letter details
- Letter no.
- DCP-LETT-2793
- From
- Hewett Cottrell Watson
- To
- Charles Robert Darwin
- Sent from
- Thames Ditton
- Source of text
- DAR 47: 160–1
- Physical description
- ALS 4pp †
Please cite as
Darwin Correspondence Project, “Letter no. 2793,” accessed on 28 March 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-2793.xml
Also published in The Correspondence of Charles Darwin, vol. 8