To J. D. Hooker 19 March 
Down near Bromley | Kent
My dear Hooker.
I presume that you are either returned home, or will soon return.— I have not sent back Wilkes,1 & your Pacific MS. as I did not like doing so till I could hear that it should arrive safely, so as to be able to make enquiries should it not arrive. When I hear from you I will send it by the first weekly opportunity: I have had the other volumes from the London Library, so need not trouble you. I seldom read a book with so little observation on anything except savage mankind, & as I do not much care about this, I find the work very tedious. I am reading Forbes Alps, which I find a wonderful contrast in style and spirit.2
I shall be very much obliged for a loan of d’Urville,3 whenever you can spare it, in the Autumn or summer.—& even more so, for the pamplet, you refer to, on, variation.—4 I am particularly anxious to collect all such stray facts as the hereditary simple-leaved strawberry. I thought Hinds Regions of Vegetation, which I presume you refer to, pompous & very poor.5
Your last letter interested me exceedingly; how high you appear to have been in favour with Humboldt; I wish you had had time to have gone to Berlin & seen the great men there: have you seen Ehrenberg’s statement of infusoria in certain pumice!6 How capitally it upsets the metallic-nucleus-oxidation theory,7 not to mention all other theories, or notions.—it is so extraordinary, that it is almost mesmeric, though I beg Ehrenberg’s pardon for comparing him in the remotest degree with the mildest mesmerist.
How I am to get my paper back from Ehrenberg now, I do not see.— I was very glad to hear Humboldts views on migrations & double creations: it is very presumptuous but I feel sure, that though one cannot prove extensive migration, the leading considerations, proper to the subject, are omitted, & I will venture to say, even by Humboldt.— I shd like sometime to put the case, like a lawyer, for your consideration, in the point of view, under which, I think it ought to be viewed: the conclusion, which I come to, is, that we cannot pretend, with our present knowledge, to put any limit to the possible & even probable migration of plants. If you can show that many of the Fuegian plants, common to Europe, are found in intermediate points, it will be grand argument in favour of the actuality of migration; but not finding them, will not in my eyes much diminish the probability of their having thus migrated.— My pen always runs away, when writing to you; & a most unsteady, vilely bad pace it goes.— What would I not give to write simple English, without having to rewrite & rewrite every sentence.
Ever yours | C. Darwin
When will you set off for the north?
I presume you are aware that Henslow has described a Galapagos Cactus.8
Would you tell me, what would be my best book in French or English on the morphology of plants; especially any book giving details on vegetable monsters & curious races of plants.
Would like to borrow the pamphlet on variation [Frédéric Gérard, "De l’espèce dans les corps organisés" (1844), extract from Dictionnaire universel d’histoire naturelle, ed. C. D. d’Orbigny].
Glad to hear Humboldt’s views on migration. CD believes we cannot "put any limit to the possible and even probable migration of plants".
Wants good book on plant morphology.
Please cite as
Darwin Correspondence Project, “Letter no. 842,” accessed on 25 July 2016, http://www.darwinproject.ac.uk/DCP-LETT-842