My dear Hooker

Many thanks for your long & pleasant letter & for the enclosures herewith returned.—   I am sorry Thomson does not budge an inch about permanence of species;¹ but how capitally he appreciates the Geographical part of your Essay,²—he ranks it as it deserves.—   I am pleased to observe that Thwaites advances a little.—³

I enclose two slips, with points on which I want observations; if you can persuade M^r Oliver kindly to observe;⁴ mind that I know that you are much too busy.—

Have you ever thought of getting that done, which you said you thought you could, viz a rough approximation of proportions of plants in some one greenhouse or Hot-house—or even out-of-doors, which set seeds.— This would be invaluable for me— In Gardeners Ch. I have said from sticky gland that I thought that pollen-masses of Bee-orchis would be sometimes removed by insects—⁵ I have now received account of numerous moths caught with pollen-masses on proboscis—(in one case 3 pair on one!) & the writer asserts that they were pollen-masses of Bee orchis; but I have written to know how he knew this.—⁶

Thank you for telling me about homologies of stigma &c of Leschenaultia & Scævola; I was curious on this head.—⁷

I have long meant to experimentise (as far as insects are concerned) on the imperfect flowers of Viola & certain Leguminosæ; but I do not know whether I shall have time.⁸

I am sorry to hear about bronchitis & your little boy;⁹ we know what that is with children.—

We were grievously disappointed yesterday by decided return of Fever-fit with Etty.—   It is extremely doubtful whether I shall get to Oxford.

Yours affect | C. Darwin

P.S. The following metaphor gives good view of my notion of relative importance of Variability & Selection.—   Squared stones, bricks or timber are indispensable for construction of a building; & their Nature will to certain extent influence character of building, but selection I look at, as the architect; & in admiring a well-contrived or splendid building one speaks of the architect alone & not of the brick-maker.—