My dear Hooker

I sh^d. very much like to borrow Heer at some future time, for I want to read nothing perplexing at present, till my abstract is done.—² Your last very instructive letter shall make me very cautious, on the hyper-speculative points we have been discussing.—³

When you say you cannot master the train of thoughts I know well enough they are too doubtful & obscure to be mastered.— I have often experienced what you call the humiliating feeling of getting more & more involved in doubt, the more one thinks of the facts & reasoning on doubtful points. But I always comfort myself with thinking of the future & in the full belief that the problems, which we are just entering on, will some day be solved; & if we just break the ground, we shall have done some service, even if we reap no harvest.—

I quite agree that we only differ in degree about means of dispersal, & that I think a satisfactory amount of accordance.— You put in very striking manner the mutations of our continents, & I quite agree; I doubt only about our oceans.—⁴

I, also, agree (I am in very agreeing frame of mind) with your argumentum ad hominem, about highness of Australian Flora from number of species & genera; but here comes in a superlative bothering element of doubt, viz the effects of isolation.—⁵

The only point in which I presumptously rather demur is about the status of the naturalised plants in Australia. I think Müller speaks of them having spread largely beyond cultivated ground;⁶ & I can hardly believe that our Europæan plants would occupy stations so barren that the native plants could not live there: I sh^d require much evidence to make me believe this.—

I have written this note merely to thank you, as you will see it requires no answer.—

I have heard to my amazement this morning from Phillips that Geolog. Council have given me the Wollaston medal!!!⁷

Ever yours | C. Darwin