To J. D. Hooker 31 December 1
Down. | Bromley Kent
My dear Hooker
I have had this copied to save you trouble, as it was vilely written & is now vilely expressed.—2
Your letter has interested me greatly; but how inextricable are the subjects, which we are discussing.— I do not think I said that I thought the productions of Asia were higher than those of Australia.3 I intend carefully to avoid this expression, for I do not think that any one has a definite idea what is meant by higher, except in classes which can loosely be compared with man. On our theory of Nat: Selection, if the organisms of any area belonging to the Eocene or Secondary periods, were put into competition with those now existing in the same area (or probably in any part of world) they (i.e. the old one) would be beaten hollow and be exterminated; if the theory be true, this must be so. In same manner I believe a greater number of the productions of Asia, the largest territory in the world, would beat those of Australia, than conversely.4 So it seems to be between Europe and N. America, for I can hardly believe in the difference of stream of commerce, causing so great a difference in proportions of immigrants.
But this sort of highness (I wish I could invent some expression, and must try to do so) is different from highness in the common acceptation of word.5 It might be connected with degradation of organisation; thus the blind degraded worm-like snake (Typhlops) might supplant the true earth-worm; here then would be degradation in the class, but certainly increase in the scale of organisation in the general inhabitants of the country: on the other hand it would be quite as easy to believe that true earth-worms might beat out the Typhlops.— I do not see how this “competitive highness” can be tested in any way by us. And this is a comfort to me when mentally comparing the Silurian and Recent organisms.—6
Not that I doubt a long course of “competitive highness” will ultimately make the organisation higher in every sense of the word; but it seems most difficult to test it. Look at the Erigeron Canadensis on one hand, and Anacharis on the other; these plants must have some advantage over European productions to spread as they have; yet who could discover it? Monkeys can co-exist with Sloths and Opossums, orders at the bottom of scale; and the opossums might well be beaten by placental insectivores coming from a country, where there were no monkeys &c, &c.— I should be sorry to be forced to give up view that an old and very large continuous territory would generally produce organisms higher in the competitive sense than a smaller territory. I may of course be quite wrong about plants of Australia (and your facts are of course quite new to me on their highness) but when I read the accounts of immense spreading of European plants in Australia, and think of the wool and corn brought thence to Europe, and not one plant naturalised, I can hardly avoid suspicion that Europe beats Australia in its productions.7 If many (i.e. if more than 1 or 2) Australian plants are truly naturalised in India (N.B Naturalisation on Indian mountains hardly quite fair, as mountains are small islands in the land) I must strike my colours. I should be glad to hear whether what I have written very obscurely on this point produces any effect on you: for I want to clear8 my mind, as perhaps I should put a sentence or two in my abstract on this subject.—9
I have always been willing to strike my colours on former immense tracts of land in oceans, if any case required it in an eminent degree: perhaps yours may be a case, but at present I greatly prefer land in the Antarctic regions, where now there is only ice and snow, but which before glacial period might well have been clothed by vegetations. You have thus to invent far less land, and that more central; & aid is got by floating ice for transporting seed.
I hope I shall not weary you by scribbling my notions at this length. After writing last to you, I began to think that the Malay Land might have existed through part of the Glacial epoch; why I at first doubted, was from difference of existing mammals in different islands; but many are very close and some identical in the islands; and I am constantly deceiving myself from thinking of little change which the shells and plants, whilst all co-existing in their own N. hemisphere, have undergone since glacial epoch; but I am convinced that this is most false reasoning, for the relations of organism to new organisms, when thrown together, are by far the most important.
When you speak of plants having undergone more change since old geological periods, than animals, are you not rather comparing plants with higher animals; think how little some, indeed many, mollusca have changed; remember Silurian Nautilus and Lingula, and other Brachiopods and Nucula & amongst Echinoderms, the Silurian Asterias &c. &c.
What you say about lowness of Brackish water plants interests me:10 I re-member that they are apt to be social (i.e. many individuals in comparison to specific forms) and I should be tempted to look at this as case of very small area and consequently of very few individuals in comparison with those on the land or in pure Fresh water; and hence less development (odious word!) than on land or Fresh water. But here comes in your two-edged sword! I should like much to see any paper on plants of brackish water or on edge of sea; but I suppose such has never been published.
Thanks about Nelumbium, for I think this was very plant, which from size of seed astonished me and which A. Decandolle adduced as marvellous case of almost impossible transport.11 I now find to my surprise that Herons do feed sometimes on other fruit; and Grebes on seeds of Compositæ!
Many thanks for offer of help about Grant for Abstract; but I should hope it would sell enough to pay expenses.—
I am very glad to hear of your observation on Mimosa and Eucalyptus; but I should have much more confidence if made in fruiting season, when things would go on more normally: Gärtner shows that period of maturity of pollen and stigmatic surface is easily affected.12
I am reading your letter and scribbling as I go on.
Your oak and chestnut case seem very curious: is it not the more so as Beeches have gone to, or come from, the South? But I vehemently protest against your or anyone making such cases especial marvels; without you are prepared to say why each species in any Flora is twice or thrice, &c rarer than each other species which grows in same soil. The more I think the more evident is it to me how utterly ignorant we are of the thousand contingencies on which range frequency and extinction of each species depend.—
I have sometimes thought from Edentata and Marsupialia that Australia retains a remnant of former and ancient state of Fauna of World; and I suppose that you are coming to some such conclusion for plants; but is not the relation between Cape and Australia too special for such views: I infer from your writings that the relation is too special between Fuegia and Australia to allow us to look at the resemblances in certain plants as the relics of mundane resemblances: on other hand has not Sandwich Islands in the northern hemisphere some odd relations to Australia? When we are dead and gone what a noble subject will be Geographical Distribution!
You may say what you like, but you will never convince me that I do not owe you ten times as much as you can owe me. Farewell my dear Hooker. I am sorry to hear that you are both unwell with influenza. Do not bother yourself in answering anything in this, except your general impression on the battle between N. and S.
Ever yours | C. Darwin
Replies at length to JDH’s worried reaction to his comments on lowness of Australian plants. CD distinguishes between "competitive highness", i.e., which fauna would be exterminated and which survive if two faunas were placed in competition, and ordinary "highness" of classification.