My dear Hooker

The following, I believe, are all the chief references on experiments on Cowslips &c. for Harvey.—²

H. C. Watson Loudon’s Mag of Nat. Hist. Vol. 3. 1830 p.217 p. 852. W. Herbert. Transact. Hort. Soc. Vol. IV. p. 19³ Henslow Loudon’s Mag. of Nat. Hist. Vol. 3. 1830. p. 409 He succeeded in getting primrose from cowslip⁴ H. C. Watson. Phytologist Vol. 2. p. 217 p. 852. Vol 3. p. 43.—⁵ Sidebotham Phytologist vol. 3. p. 703.⁶

Notwithstanding, the amount of evidence from witnesses who experimentised with hostile bias, I cannot avoid sometimes suspecting error.— No experiment is good unless plants protected by gauze or some other similar protection.—   I think M^r Sidebotham alone took such pains; yet for some unknown cause H. C. Watson sneers at his experiments.—   M^r Doubleday has often tried, & has found no variation.⁷ I reared lots of Primroses from manured primroses with no variation.—   I have now got cowslips under gauze, which I fertilize with care. Nevertheless looking through all the above accounts (& I have some loose corroborative facts) the evidence does seem overwhelming that they are varieties. The case does not half please me, as I remember saying to you, it does not work well in with nat. selection—it is rather too sudden a jump.—especially the adaption to different climatal ranges.— I am inclined by conjecture to look at cowslip as the modified descendant of Primrose; & that the seeds from the cowslip do not simply vary, but revert back in different degrees to primrose. Most of the experiments have been made on cowslips & oxlips.—   on this notion, the case would be more intelligible.

Yours affect | C. Darwin

I have received long copy of M.S. verses from some anonymous author, highly laudatory, yet partly quizzing the Origin.—   They are from some Botanist. I suspect D^r Boott.—⁸ Does he write verses?

Etty keeps just the same, poor little thing, now 3 week, wearing Fever. What a world it is—⁹