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Letter 1983

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

9 Nov 1856
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    Summary Add

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    JDH approves MS section on geographical distribution.

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    Never felt so shaky about species before.

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    His objections to some mechanisms of distribution that CD proposes.

Transcription

Kew

Nov 9th/56

Dear Darwin

I have finished the reading of your mss. & have been very much delighted & instructed. Your case is a most strong one & gives me a much higher idea of change than I had previously entertained; &, though, as you know, never very stubborn about unalterability of specific type, I never felt so shaky about species before. The first half you will be able to put more clearly when you polish up, I have in several cases made pencil alterations in details as to words &c, to enable myself to follow better—some of it is rather stiff reading. I have a page or two of notes for discussion, many of which were answered as I got further on with the mss., more or less fully.

Your doctrine of the cooling of the tropics is a startling one, when carried to the length of supporting plants of cold-temperate regions, & I must confess that, much as I should like it, I can hardly stomach keeping the Tropical genera alive in so very cool a greenhouse. Still I must confess that all your arguments pro may be much stronger put than you have

I am more reconciled to Iceberg transport than I was also, the more especially as I will give you any length of time to keep vitality in ice, & more than that will let you transport roots that way also— Many of these subjects which I never myself studied for myself, I wanted put in the systematic form you have put them, for proper appreciation—

I think that you might support your cause by making more use of gulf streams & oblique lines of transport—you appear to dwell too much upon meridional lines of migration This mode of handling at once suggested the Query are the Arctic & Antarctic American genera more allied than the Tasmanian & Siberian—the former offering every possible facility in continuous land,—the latter none.— It also makes you appear to shirk the question of transport from E to W. or vice versa.— you offer no explanation of the vegetation (not littoral) of Abyssinia & Indian Penins. being so similar; of the Carnatic, Ava, & N.W. Australia being in so many points alike—of the curious parallels or representatives between Madagasca, Ceylon & the Sunda Islands. In short Meridional migration alone occupies you. Nor do I like putting Iceland, Ferroe, & Spitzbergen out of the Category of the glacially peopled countries, & leaving Shetlands Orkneys Scotland in it. This is however a trifle.

Ch. Martins arguments seem to apply no more to these islands than to any other area Continental or insular— If they presented any anomalies as the presence of Lapland plants or Greenland ones I might then believe them to be peopled by accidental migration, but if Icebergs are to be so powerful why did they bring no Greenland, American or other plants to these Islands, which are so well situated for the purpose.

Thanks for your note received this morning— We shall hope (if not look) for you on Wednesday to meet Lindley & Henslow.—or on Friday to meet Tyndall & Henslow.

Owen I hear committed a cutting telling & flaying alive assault on Huxleys adaptation views at the Geolog. Soc. & read it with the cool deliberation & emphasis & pointed tone & look of an implacable foe.—& H. I fear did not defend himself well (though with temper) & perhaps had not a popular champion in Carpenter who barbed him— These embroglios are very bad indeed & must insensibly have a bad effect upon Huxley—the best natures insensibly deteriorate under such trials.

I shall bring your mss to the Club in the Club box so you need not come on purpose. I shall be really glad of more.

Ever most sincerely yrs | Jos D Hooker

P.S. Was it not with you? that I argued that Lyell had assumed as demonstrable a change in the temp of the whole globe to be producable by altered condition of surface see Principles 9th Ed. 103, 104

[Memorandum]

Note I. Would Forbes suppose that the presence of the South Shetland Aira Antarctica on the Falklands was due to Iceberg transportation North? Is it not more natural to suppose that A. Ant. was produced by creation or variation on the American continent & thence either transported South to S. Shetland or that it inhabited an intermediate sunk area. I am against making arctic regions centres of creation either by variation or by specific creation.

I think it would facilitate our researches much not to look beyond the epoch of the existence of those continents having the required climate for the existence of the scattered productions whose migrations we seek to account for. It is enough to admit a glacial land & sea over central Europe & do not let us speculate on the origin of its species. Never wander further back into Geological time than is necessary—it bewilders.

On the whole then I would perhaps confine this part of the discussion to the migration North & vertical ascent of species inhabiting a cold country.

Note B. Might not much of this difficulty be got over by supposing the E & W. parts of the glacial continent differently heated, & that currents flowed East & West or NE & NW.

Thus the connecting land of Europe & America might be much warmer than those parts of either continent in the same latitude where the mountains were [DIAGRAM HERE] isotherm 50o 40 p 40o 50o 40o 50o America Europe White Mts 50o limit of glacial sea Amer 50o Alps

Note C. I cannot see why the colonization of Iceland Ferroe & Spitzbergen should come under a different category from other lands—this is most unphilosophical Surely a theoretical inflexion of the isothermals should not be wholly lost sight of, during the glacial epoch, as it manifestly is after it. The gradual accession of the Gulf Stream influence would warm all that part of the glacial sea coast or chain of Islands that included Iceland Ferroe &c before any other part of the glacial region & induce migration along that line, however cold the preexisting arctic desert in which they were situated may be assumed to be

Note D. I cannot understand this. Why do the Gentians not go North? these not being more Alpine than the Arctic species— Why should they have spread over the intervening country?

Note E. Then why no peculiar species or varieties in Iceland, Spitzbergen &c.

Note F The same argument must hold for the Arctic & Antarctic representative Crustacea—on which Ross was always insisting & swearing that some were identical with what he had described in Capt. Parry Voy &c

Note G In fact the Flora of analogous elevations of Ceylon, Nilghiri, Khasia & Himal is to great extent specifically the same

Note H. After which why did not any ascend the Himalaya?

An argument in favor of alteration induced by isolation afforded by fact that so many well known species when found isolated have as much differences as to deceive botanists & then when dried lose all distinguishing characters

Change of Tropical Climate demanded is far too great Where were many tropical genera & orders— Also migration not always N. & S. but across continents obliquely— Also all this leaves longitudinal distribution unaccounted for as Abyssinia & India—W. Austral & Carnatic.

Ordinary laws of reproduction includes modif. of specific forms.

But it is improbable that similar forms be generated from specifically different parents in different places

Hence will propagation account for presence of identical forms in all parts of globe

Plants, insects—common to Alps & Scandinavia Steinbock, variable Hare, Chamois.

Forbes glacial epoch accounts for this

Help may be got by introducing humidity as an element—quote very different levels on Himal. Khasia & Ceylon for same species. [DIAGRAM HERE]

    Footnotes Add

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    f1 1983.f1
    Hooker refers to the manuscript on geographical distribution (a section of chapter 11 of Natural selection), which CD gave to him for his comments in October (see letter to J. D. Hooker, [16 October 1856]). The manuscript is now in DAR 14.
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    f2 1983.f2
    Hooker's comments are on the fair copy in DAR 14. They have also been transcribed as footnotes in the published version of Natural selection.
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    f3 1983.f3
    See the memorandum transcribed following the letter.
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    f4 1983.f4
    Martins 1849, in which Charles Frédéric Martins claimed that the number of European plants decreased on northern islands as the distance from Europe increased. See Natural selection, p. 541.
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    f5 1983.f5
    CD visited London on 13 November 1856 to attend a meeting of the Philosophical Club (Royal Society Philosophical Club minutes) but did not dine with Hooker.
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    f6 1983.f6
    Richard Owen had read a paper on a much-debated fossil mammal, named by him Stereognathus ooliticus, at a meeting of the Geological Society on 5 November 1856. In the paper (Owen 1857a), Owen made it clear that he was using the case as an example of how a single fossil tooth could legitimately lead to the determination of affinities and organisation, a point sharply criticised by Thomas Henry Huxley in T. H. Huxley 1856b.
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    f7 1983.f7
    The Philosophical Club of the Royal Society (see n. 5, above).
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    f8 1983.f8
    In C. Lyell 1853, pp. 103–4, Charles Lyell used information on soundings given to him by James Clark Ross and Hooker after the voyage of the Erebus and Terror (1839–43) to establish the point that the movement of large segments of the earth's crust, up and down relative to the sea, could produce great changes in climate.
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    f9 1983.f9
    Hooker's notes on CD's manuscript on geographical distribution were probably given to CD at a later date, but they have been transcribed here for clarity. They had been received by CD by 15 November 1856 (see letter to J. D. Hooker, 15 November [1856]). The notes are in DAR 100: 109–10.
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    f10 1983.f10
    Note A was presumably intended. On the manuscript, Hooker wrote: ‘It is difficult to believe that during glacial epoch the northern land was warm enough for any plants at all. See Note A.’ He refers to CD's point that the seeds of northern plants were transported via icebergs to the mountains of southern Europe during a former cold period (see Natural selection, p. 536).
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    f11 1983.f11
    Aira antarctica was described in J. D. Hooker 1844–7, 2: 377. He called it an ‘elegant grass’.
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    f12 1983.f12
    On the manuscript, Hooker wrote: ‘Certainly J. D. H. Note B’. He refers to CD's proposal that there was a connection between Arctic regions before the former cold period began (see Natural selection, p. 538).
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    f13 1983.f13
    Hooker refers to CD's discussion of the colonisation of northern islands such as Iceland and Greenland. CD believed that they were covered by snow and ice during a former cold period and their flora and fauna were introduced at a later time. He cited Martins 1849 in his discussion (see n. 4, above). Hooker also made reference to Martins's work in his letter.
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    f14 1983.f14
    CD explained that exclusively alpine species, such as gentians, would have extended their range in the glacial period and ‘on the returning warmth … would together with the arctic species have reascended the mountains’ (Natural selection, p. 542). He did not explain why they would not also have migrated northwards with the Arctic plants.
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    f15 1983.f15
    CD's manuscript reads: ‘we might have expected that there would have been many representative species & strongly marked varieties, on the several alpine summits of Europe, when compared one with another & with the arctic regions’ (Natural selection, p. 542). Beside this passage, CD wrote:‘Dr. Hooker: I wish I knew whether this was so: Forbes thought so, but I do not know whether heis to be trusted.’ Hooker added the note: ‘Certainly true J. D. H’, but indicated the further queryin note E.
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    f16 1983.f16
    Note F refers to CD's discussion of the existence of species in the two hemispheres that ‘represented’ each other in the sense that they were very closely similar. Hooker's point relates to CD's concluding sentence: ‘Some of the fish, also, from Madeira, as I am informed by the Rev: R. B. Lowe represent those of Japan.—’ (Natural selection, p. 543).
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    f17 1983.f17
    James Clark Ross in Ross 1826, Appendix, pp. 116–20. Hooker had accompanied Ross on the Antarctic expedition of 1839–43.
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    f18 1983.f18
    Hooker refers to CD's statement: ‘Dr. Hooker believes abundance of plants on the Nilghiri are common with those on the mountains of Ceylon & the Himalaya.’ (Natural selection, pp. 545–6).
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    f19 1983.f19
    Hooker refers to CD's description of the flora and fauna of the Far East and India during a former cold period (Natural selection, p. 552). He wondered why the ‘woolly-covered Rhinoceros tichorinus and Elephas primigenius’ did not ascend the mountain heights with the plants at the end of the cold period.
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    f20 1983.f20
    CD subsequently responded to Hooker's criticisms in a note now in DAR 50 (ser. 5): 40 that reads: The way to put the question is,—cool Tropics, & imagine all plants killed, then wd they migrate over bare land, if so they wd have some chance [illeg del] with distressed Tropical productions. If come to this how much do you attribute S. range to other productions & how much to temperature. Your objection to meridional migration is because whole discussion an offset of Alpine distribution & so connected with cold.— Following this, CD added in pencil: ‘Not more temperate plants S. than almost arctic | Effects of damp on Khasia.—’ He then deleted ‘Effects … Khasia.—’ in pencil.
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