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Letter 2475

Darwin, C. R. to Hooker, J. D.

2 July [1859]
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    Summary Add

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    Returns JDH's proofs. He is so involved in Origin he cannot judge force of JDH's arguments. Some detailed comments.

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    Haldeman's old paper [see 2470] clever, but does not have natural selection. Explaining adaptation has always seemed turning point of theory of natural selection.

Transcription

Down.

July 2d

My dear Hooker.

I return by this Post your Proof.— Like all the rest, it has interested me much; but receiving them at intervals, & my head being confounded with my own book, I cannot judge of general force of argument.— I have marked a few passages which do not seem to me clear.—

p. XVII. Grand about diffusion from equable climate.—

p. XVIII. I do not see the bearing of Tropical orders having existed formerly in Europe, except to show that they have not recently been created, which as you afterwards truly say would be quite inadmissible.—

p. XVIII. Capital note about ranges of plants along Cordillera

p. XIX. I believe highest mountain in Borneo is granitic; as I believe are those of Sumatra: those of New Guinea unknown.—

p. XX.* Would it not be well to put Elater & Gryllus first in your list: it rather ryled me to meet first with a row of non-vegetable feeders.— Again wd it not be well to put Coniferæ last in second list; think of hosts of Hylurgus piniperda, Sirex, Rhagium &c— If I wanted to make myself disagreeable, I might ask who in native land has observed that Cycadeæ are free from insect attacks. Again do you know Lycopodiaceæ support fewer insects than Mosses or Lichens.?

XXII. End of paragraph 36. I do not doubt every word strictly true; but are you justified in leaving the impression which the last line will leave? And an impression so flagrantly in opposition to results from extinct animals. Do all Gymnosperms make one family; & if not, can you tell any more than that carboniferous fossils are gymnosperms.— You say you cannot assert that any carboniferous plants belong to new families; & it seems to me you ought to add that you cannot assert that several do belong to any old & known families.—

With respect to “intermediate” affinities (by which I suppose you do not mean exactly half-way intermediate), do think of some living plants, which may now be called nearly intermediate between existing families (not grand divisions) & fancy them in fossil condition like carboniferous plants, should you have detected their intermediate condition? Could you have told that Juglans connected the Cupuliferæ with another family? If so, all well & good: if not, I grieve to see this assertion, which would be a heavy blow to my doctrines.— It seems to me making, as Geologists often do, negative evidence which from its very nature cannot be of much value, appear to be valuable. I can see that you wd be justified in asserting that there were no intermediate forms between the grand primary divisions; but you apply remark to Families.

By the way the existence of Australian, American, Indian &c genera all at one time in Europe stretches my belief to the cracking point.—

XXIII. If you quote me about progressive development, I shd wish it to be added, that such notion only applies to all organic beings taken in mass: for I do not doubt that many whole groups have retrograded in one sense. The whole mass of fish are now lower. (ie less closely allied to the higher reptiles) than they were formerly; & so it seems with your Lycopodiaceæ.—

How I do wish my Book had been published first, what valuable criticisms I shd have received.—

I have been interested by your Geological summary on plants; & have been much impressed how poor the evidence is.—

So much for my poor & hasty criticisms.—

Many thanks for your last Sunday note. I have much idle curiosity on the Human tools, & am glad to hear that you think them certainly human: their number makes the case wonderfully curious.—

I read some years ago & abstracted Haldeman's paper, and thought it very clever: but it did not seem to me to give any idea, like natural selection— it did not attempt, I believe, to explain adaptations & this point has always seemed to me the turning point of the theory of Natural Selection. From my abstract I seem to have got very little from it.

I hardly know what to think about the medals, without talking over the subject with you.— The idea of giving medals to grown-up men has always seemed rather childish to me.—

I am sorry to hear that you are so much worked with many subjects & building.— Never mind about Goodneia: perhaps I cd get some species to flower in my greenhouse.— I thought the Acacias had been crossed.—

Farewell | My dear Hooker | Ever yours | C. Darwin

I most sincerely hope Miss Henslow's marriage will be in every way a happy one.—

I have found that Corydalis lutea does not let fly its pistil without aid, & yet sets plenty of pods, but what seems to me rather curious is that letting the pistil snap off, hastens in the most marked manner the formation of the pods; so that I could get a pod on any one flower on stem before the others.—

Again farewell.— I have been bad, having had two days of bad vomiting owing to the accursed Proofs— I shall have to go to Moor Park before long.—

    Footnotes Add

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    f1 2475.f1
    CD was reading the proof-sheets of Hooker 1859 at intervals during the summer.
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    f2 2475.f2
    Hooker stated: ‘I have, in the “Antarctic Flora,” shown that the distribution of tropical forms is extended into cold regions that are humid and equable further than into such as are dry and excessive; and, conversely, that temperate forms advance much further into humid and equable tropical regions than into dry and excessive ones’ (Hooker 1859, p. xvii).
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    f3 2475.f3
    In the published text, the reference to Europe was omitted.
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    f4 2475.f4
    Although no specimens of flowering plants had been found in the Lias, Hooker suggested that these comparatively advanced plants might have existed then; his suggestion was based on the fact that the plentiful insect remains from that period were mostly of genera that usually feed, or are parasitic, on flowering plants. The passage (Hooker 1859, p. xx n.) reads: These [fossil wood-boring and herb-devouring] insects include species of the existing common European genera, Elater, Gryllus, Hemerobius, Ephemera, Libellula, Panorpa, and Carabus. Of all conspicuous tribes of plants the Cycadeæ, Filices, Coniferæ, and Lycopodiaceæ perhaps support the fewest insects, and the association of the above-named insects with a vegetation consisting solely or mainly of plants of these Orders is quite inconceivable.
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    f5 2475.f5
    The section refers to the difficulty of seeing any evidence for progression in the plant fossil record. The sentence to which CD refers reads (Hooker 1859, p. xxiii): Regarded from the classificatory point of view, the geological history of plants is not altogether favourable to the theory of progressive development, both because the earliest ascertained types are of such high and complex organization, and because there are no known fossil plants which we can certainly assume to belong to a non-existing class or even family, nor that are ascertained to be intermediate in affinity between recent classes or families. Hooker added to this section several footnotes that addressed the points raised by CD in this letter. In CD's copy (Darwin Library–CUL), he marked the notes in pencil and wrote ‘good’ in the margin.
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    f6 2475.f6
    Although Hooker went on to discuss CD's and Alfred Russel Wallace's views on progressive development (Hooker 1859, p. xxiv), CD was not cited with regard to his point about retrograde development.
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    f7 2475.f7
    Hooker's note has not been found. It evidently discussed Joseph Prestwich's work on flint tools. See letter to J. D. Hooker, 22 [June 1859].
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    f8 2475.f8
    Haldeman 1843–4. See also letter to Charles Lyell, 21 June [1859].
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    f9 2475.f9
    The Copley and Royal Medals were awarded each November by the Royal Society. The final recommendations of the council were made in June or July. Hooker had retired from the council at the end of 1858.
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    f10 2475.f10
    See letter to J. D. Hooker, 6 May [1859].
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    f11 2475.f11
    Frances Harriet Hooker's younger sister Anne Henslow was to be married to R. Cary Barnard on2 August 1859 (Gentleman's Magazine n.s. 7 (1859): 303).
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    f12 2475.f12
    CD's experiments on the fertilisation of Corydalis lutea are recorded in his Experimental book, p. 43 (DAR 157a). The experiments were apparently undertaken to study fertility and sterility of plants in relation to visits by insects. CD moved the pistil in imitation of what would occur when a bee visited to collect the nectar.
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