More Letters of Charles Darwin — Volume 1

Referring to the classified list which I drew up of Mr. Darwin's scientific labours, ranging through the wide field of (1) Geology, (2) Physical Geography, (3) Zoology, (4) physiological Botany, (5) genetic Biology, and to the power with which he has investigated whatever subject he has taken up, — Nullum quod tetigit non ornavit, — I am of opinion that Mr. Darwin is not only one of the most eminent naturalists of his day, but that hereafter he will be regarded as one of the great naturalists of all countries and of all time. His early work on the structure and distribution of coral reefs constitutes an era in the investigation of the subject. As a monographic labour, it may be compared with Dr. Wells' "Essay upon Dew," as original, exhaustive, and complete — containing the closest observation with large and important generalisations.

Among the zoologists his monographs upon the Balanidae and Lepadidae, Fossil and Recent, in the Palaeontographical and Ray Societies' publications, are held to be models of their kind.

In physiological Botany, his recent researches upon the dimorphism of the genital organs in certain plants, embodied in his papers in the "Linnean Journal," on Primula, Linum, and Lythrum, are of the highest order of importance. They open a new mine of observation upon a field which had been barely struck upon before. The same remark applies to his researches on the structure and various adaptations of the orchideous flower to a definite object connected with impregnation of the plants through the agency of insects with foreign pollen. There has not yet been time for their due influence being felt in the advancement of the science. But in either subject they constitute an advance per saltum. I need not dwell upon the value of his geological researches, which won for him one of the earlier awards of the Wollaston Medal from the Geological Society, the best of judges on the point.

And lastly, Mr. Darwin's great essay on the "Origin of Species" by Natural Selection. This solemn and mysterious subject had been either so lightly or so grotesquely treated before, that it was hardly regarded as being within the bounds of legitimate philosophical investigation. Mr. Darwin, after twenty years of the closest study and research, published his views, and it is sufficient to say that they instantly fixed the attention of mankind throughout the civilised world. That the efforts of a single mind should have arrived at success on a subject of such vast scope, and encompassed with such difficulties, was more than could have been reasonably expected, and I am far from thinking that Charles Darwin has made out all his case. But he has treated it with such power and in such a philosophical and truth-seeking spirit, and illustrated it with such an amount of original and collated observation as fairly to have brought the subject within the bounds of rational scientific research. I consider this great essay on genetic Biology to constitute a strong additional claim on behalf of Mr. Darwin for the Copley Medal. (180/2. The following letter (December 3rd, 1864), from Mr. Huxley to Sir J.D. Hooker, is reprinted, by the kind permission of Mr. L. Huxley, from his father's "Life," I., page 255. Sabine's address (from the "Reader") is given in the "Life and Letters," III., page 28. In the "Proceedings of the Royal Society" the offending sentence is slightly modified. It is said, in Huxley's "Life" (loc. cit., note), that the sentence which follows it was introduced to mitigate the effect: —

"I wish you had been at the anniversary meeting and dinner, because the latter was very pleasant, and the former, to me, very disagreeable. My distrust of Sabine is, as you know, chronic; and I went determined to keep careful watch on his address, lest some crafty phrase injurious to Darwin should be introduced. My suspicions were justified, the only part of the address {relating} to Darwin written by Sabine himself containing the following passage:

"'Speaking generally and collectively, we have expressly omitted it {Darwin's theory} from the grounds of our award.'

"Of course this would be interpreted by everybody as meaning that after due discussion, the council had formally resolved not only to exclude Darwin's theory from the grounds of the award, but to give public notice through the president that they had done so, and, furthermore, that Darwin's friends had been base enough to accept an honour for him on the understanding that in receiving it he should be publicly insulted!

"I felt that this would never do, and therefore, when the resolution for printing the address was moved, I made a speech, which I took care to keep perfectly cool and temperate, disavowing all intention of interfering with the liberty of the president to say what he pleased, but exercising my constitutional right of requiring the minutes of council making the award to be read, in order that the Society might be informed whether the conditions implied by Sabine had been imposed or not.

"The resolution was read, and of course nothing of the kind appeared. Sabine didn't exactly like it, I believe. Both Busk and Falconer remonstrated against the passage to him, and I hope it will be withdrawn when the address is printed. If not, there will be an awful row, and I for one will show no mercy.")

In forming an estimate of the value and extent of Mr. Darwin's researches, due regard ought to be had to the circumstances under which they have been carried out — a pressure of unremitting disease, which has latterly left him not more than one or two hours of the day which he could call his own.

LETTER 181. TO HUGH FALCONER. Down, November 4th {1864}.

What a good kind friend you are! I know well that this medal must have cost you a deal of trouble. It is a very great honour to me, but I declare the knowledge that you and a few other friends have interested themselves on the subject is the real cream of the enjoyment to me; indeed, it is to me worth far more than many medals. So accept my true and cordial thanks. I hope that I may yet have strength to do a little more work in Natural Science, shaky and old though I be. I have chuckled and triumphed over your postscript about poor M. Brulle and his young pupils (181/1. The following is the postscript in a letter from Falconer to Darwin November 3rd {1864}: "I returned last night from Spain via France. On Monday I was at Dijon, where, while in the Museum, M. Brulle, Professor of Zoology, asked me what was my frank opinion of Charles Darwin's doctrine? He told me in despair that he could not get his pupils to listen to anything from him except a la Darwin! He, poor man, could not comprehend it, and was still unconvinced, but that all young Frenchmen would hear or believe nothing else.") About a week ago I had a nearly similar account from Germany, and at the same time I heard of some splendid converts in such men as Leuckart, Gegenbauer, etc. You may say what you like about yourself, but I look at a man who treats natural history in the same spirit with which you do, exactly as good, for what I believe to be the truth, as a convert.

LETTER 182. TO HUGH FALCONER. Down, November 8th {1864}.

Your remark on the relation of the award of the medal and the present outburst of bigotry had not occurred to me. It seems very true, and makes me the more gratified to receive it. General Sabine (182/1. See "Life and Letters," III., page 28.) wrote to me and asked me to attend at the anniversary, but I told him it was really impossible. I have never been able to conjecture the cause; but I find that on my good days, when I can write for a couple of hours, that anything which stirs me up like talking for half or even a quarter of an hour, generally quite prostrates me, sometimes even for a long time afterwards. I believe attending the anniversary would possibly make me seriously ill. I should enjoy attending and shaking you and a few of my other friends by the hand, but it would be folly even if I did not break down at the time. I told Sabine that I did not know who had proposed and seconded me for the medal, but that I presumed it was you, or Hooker or Busk, and that I felt sure, if you attended, you would receive the medal for me; and that if none of you attended, that Lyell or Huxley would receive it for me. Will you receive it, and it could be left at my brother's?

Again accept my cordial and enduring thanks for all your kindness and sympathy.

LETTER 183. TO B.D. WALSH. Down, December 4th {1864}.

I have been greatly interested by your account of your American life. What an extraordinary and self-contained life you have led! and what vigour of mind you must possess to follow science with so much ardour after all that you have undergone! I am very much obliged to you for your pamphlet on Geographical Distribution, on Agassiz, etc. (183/1. Mr. Walsh's paper "On certain Entomological Speculations of the New England School of Entomologists" was published in the "Proc. Entomolog. Soc. of Philadelphia," September 1864, page 207.) I am delighted at the manner in which you have bearded this lion in his den. I agree most entirely with all that you have written. What I meant when I wrote to Agassiz to thank him for a bundle of his publications, was exactly what you suppose. (183/2. Namely, that Mr. Darwin, having been abused as an atheist, etc., by other writers, probably felt grateful to a writer who was willing to allow him "a spirit as reverential as his own." ("Methods of Study," Preface, page iv.) I confess, however, I did not fully perceive how he had misstated my views; but I only skimmed through his "Methods of Study," and thought it a very poor book. I am so much accustomed to be utterly misrepresented that it hardly excites my attention. But you really have hit the nail on the head capitally. All the younger good naturalists whom I know think of Agassiz as you do; but he did grand service about glaciers and fish. About the succession of forms, Pictet has given up his whole views, and no geologist now agrees with Agassiz. I am glad that you have attacked Dana's wild notions; {though} I have a great respect for Dana...If you have an opportunity, read in "Trans. Linn. Soc." Bates on "Mimetic Lepidoptera of Amazons." I was delighted with his paper.

I have got a notice of your views about the female Cynips inserted in the "Natural History Review" (183/3. "Nat. Hist. Review," January 1865, page 139. A notice by "J.L." (probably Lord Avebury) on Walsh's paper "On Dimorphism in the Hymenopterous Genus Cynips," in the "Proc. Entomolog. Soc. of Philadelphia," March, 1864.): whether the notice will be favourable, I do not know, but anyhow it will call attention to your views...

As you allude in your paper to the believers in change of species, you will be glad to hear that very many of the very best men are coming round in Germany. I have lately heard of Hackel, Gegenbauer, F. Muller, Leuckart, Claparede, Alex. Braun, Schleiden, etc. So it is, I hear, with the younger Frenchmen.

LETTER 184. TO J.D. HOOKER. Down, January 19th {1865}.

It is working hours, but I am trying to take a day's holiday, for I finished and despatched yesterday my Climbing paper. For the last ten days I have done nothing but correct refractory sentences, and I loathe the whole subject like tartar emetic. By the way, I am convinced that you want a holiday, and I think so because you took the devil's name in vain so often in your last note. Can you come here for Sunday? You know how I should like it, and you will be quiet and dull enough here to get plenty of rest. I have been thinking with regret about what you said in one of your later notes, about having neglected to make notes on the gradation of character in your genera; but would it be too late? Surely if you looked over names in series the facts would come back, and you might surely write a fine paper "On the gradation of important characters in the genera of plants." As for unimportant characters, I have made their perfect gradation a very prominent point with respect to the means of climbing, in my paper. I begin to think that one of the commonest means of transition is the same individual plant having the same part in different states: thus Corydalis claviculata, if you look to one leaf, may be called a tendril-bearer; if you look to another leaf it may be called a leaf-climber. Now I am sure I remember some cases with plants in which important parts such as the position of the ovule differ: differences in the spire of leaves on lateral and terminal branches, etc.

There was not much in last "Natural History Review" which interested me except colonial floras (184/1. "Nat. Hist. Review," 1865, page 46. A review of Grisebach's "Flora of the British West Indian Islands" and Thwaites' "Enumeratio Plantarum Zeylaniae." The point referred to is given at page 57: "More than half the Flowering Plants belong to eleven Orders in the case of the West Indies, and to ten in that of Ceylon, whilst with but one exception the Ceylon Orders are the same as the West Indian." The reviewer speculates on the meaning of the fact "in relation to the hypothesis of an intertropical cold epoch, such as Mr. Darwin demands for the migration of the Northern Flora to the Southern hemisphere.") and the report on the sexuality of cryptogams. I suppose the former was by Oliver; how extremely curious is the fact of similarity of Orders in the Tropics! I feel a conviction that it is somehow connected with Glacial destruction, but I cannot "wriggle" comfortably at all on the subject. I am nearly sure that Dana makes out that the greatest number of crustacean forms inhabit warmer temperate regions.

I have had an enormous letter from Leo Lesquereux (after doubts, I did not think it worth sending you) on Coal Flora: he wrote some excellent articles in "Silliman" again {my} "Origin" views; but he says now after repeated reading of the book he is a convert! But how funny men's minds are! he says he is chiefly converted because my books make the Birth of Christ, Redemption by Grace, etc., plain to him!

LETTER 185. TO J.D. HOOKER. Down, February 9th {1865}.

I quite agree how humiliating the slow progress of man is, but every one has his own pet horror, and this slow progress or even personal annihilation sinks in my mind into insignificance compared with the idea or rather I presume certainty of the sun some day cooling and we all freezing. To think of the progress of millions of years, with every continent swarming with good and enlightened men, all ending in this, and with probably no fresh start until this our planetary system has been again converted into red-hot gas. Sic transit gloria mundi, with a vengeance...

LETTER 186. TO B.D. WALSH. Down, March 27th {1865}.

I have been much interested by your letter. I received your former paper on Phytophagic variety (186/1. For "Phytophagic Varieties and Phytophagic Species" see "Proc. Entomolog. Soc. Philadelphia," November 1864, page 403, also December 1865. The part on gradation is summarised at pages 427, 428. Walsh shows that a complete gradation exists between species which are absolutely unaffected by change of food and cases where "difference of food is accompanied by marked and constant differences, either colorational, or structural, or both, in the larva, pupa and imago states."), most of which was new to me. I have since received your paper on willow-galls; this has been very opportune, as I wanted to learn a little about galls. There was much in this paper which has interested me extremely, on gradations, etc., and on your "unity of coloration." (186/2. "Unity of coloration": this expression does not seem to occur in the paper of November 1864, but is discussed at length in that of December 1865, page 209.) This latter subject is nearly new to me, though I collected many years ago some such cases with birds; but what struck me most was when a bird genus inhabits two continents, the two sections sometimes display a somewhat different type of colouring. I should like to hear whether this does not occur with widely ranging insect-genera? You may like to hear that Wichura (186/3. Max Wichura's "Die Bastarde befruchtung im Pflanzenreich, etc: " Breslau 1865. A translation appeared in the "Bibliotheque Universelle," xxiii., page 129: Geneva 1865.) has lately published a book which has quite convinced me that in Europe there is a multitude of spontaneous hybrid willows. Would it not be very interesting to know how the gall-makers behaved with respect to these hybrids? Do you think it likely that the ancestor of Cecidomyia acquired its poison like gnats (which suck men) for no especial purpose (at least not for gall-making)? Such notions make me wish that some one would try the experiments suggested in my former letter. Is it not probable that guest-flies were aboriginally gall-makers, and bear the same relation to them which Apathus probably does to Bombus? (186/4. Apathus (= Psithyrus) lives in the nests of Bombus. These insects are said to be so like humble bees that "they were not distinguished from them by the early entomologists: " Dr. Sharp in "Cambridge Nat. Hist. (Insects," Part II.), page 59.) With respect to dimorphism, you may like to hear that Dr. Hooker tells me that a dioecious parasitic plant allied to Rafflesia has its two sexes parasitic on two distinct species of the same genus of plants; so look out for some such case in the two forms of Cynips. I have posted to you copies of my papers on dimorphism. Leersia (186/5. Leersia oryzoides was for a long time thought to produce only cleistogamic and therefore autogamous flowers. See "Variation of Animals and Plants," Edition II., Volume II., page 69.) does behave in a state of nature in the provoking manner described by me. With respect to Wagner's curious discovery my opinion is worth nothing; no doubt it is a great anomaly, but it does not appear to me nearly so incredible as to you. Remember how allied forms in the Hydrozoa differ in their so-called alternate generations; I follow those naturalists who look at all such cases as forms of gemmation; and a multitude of organisms have this power or traces of this power at all ages from the germ to maturity. With respect to Agassiz's views, there were many, and there are still not a few, who believe that the same species is created on many spots. I wrote to Bates, and he will send you his mimetic paper; and I dare say others: he is a first-rate man.

Your case of the wingless insects near the Rocky Mountains is extremely curious. I am sure I have heard of some such case in the Old World: I think on the Caucasus. Would not my argument about wingless insular insects perhaps apply to truly Alpine insects? for would it not be destruction to them to be blown from their proper home? I should like to write on many points at greater length to you, but I have no strength to spare.

LETTER 187. TO A.R. WALLACE. Down, September 22nd {1865}.

I am much obliged for your extract (187/1. Mr. Wallace had sent Darwin a note about a tufted cock-blackbird, which transmitted the character to some of its offspring.); I never heard of such a case, though such a variation is perhaps the most likely of any to occur in a state of nature, and to be inherited, inasmuch as all domesticated birds present races with a tuft or with reversed feathers on their heads. I have sometimes thought that the progenitor of the whole class must have been a crested animal.

Do you make any progress with your journal of travels? I am the more anxious that you should do so as I have lately read with much interest some papers by you on the ourang-outan, etc., in the "Annals," of which I have lately been reading the later volumes. I have always thought that journals of this nature do considerable good by advancing the taste for Natural History: I know in my own case that nothing ever stimulated my zeal so much as reading Humboldt's "Personal Narrative." I have not yet received the last part of the "Linnean Transactions," but your paper (187/2. Probably on the variability and distribution of the butterflies of the Malayan region: "Linn. Soc. Trans." XXV., 1866.) at present will be rather beyond my strength, for though somewhat better, I can as yet do hardly anything but lie on the sofa and be read aloud to. By the way, have you read Tylor and Lecky? (187/3. Tylor, "Early History of Mankind;" Lecky's "Rationalism.") Both these books have interested me much. I suppose you have read Lubbock. (187/4. Lubbock, "Prehistoric Times," page 479: "...the theory of Natural Selection, which with characteristic unselfishness he ascribes unreservedly to Mr. Darwin.") In the last chapter there is a note about you in which I most cordially concur. I see you were at the British Association but I have heard nothing of it except what I have picked up in the "Reader." I have heard a rumour that the "Reader" is sold to the Anthropological Society. If you do not begrudge the trouble of another note (for my sole channel of news through Hooker is closed by his illness) I should much like to hear whether the "Reader" is thus sold. I should be very sorry for it, as the paper would thus become sectional in its tendency. If you write, tell me what you are doing yourself. The only news which I have about the "Origin" is that Fritz Muller published a few months ago a remarkable book (187/5. "Fur Darwin.") in its favour, and secondly that a second French edition is just coming out.

LETTER 188. TO F. MULLER. Down, January 11th {1866}.

I received your interesting letter of November 5th some little time ago, and despatched immediately a copy of my "Journal of Researches." I fear you will think me troublesome in my offer; but have you the second German edition of the "Origin?" which is a translation, with additions, of the third English edition, and is, I think, considerably improved compared with the first edition. I have some spare copies which are of no use to me, and it would be a pleasure to me to send you one, if it would be of any use to you. You would never require to re-read the book, but you might wish to refer to some passage. I am particularly obliged for your photograph, for one likes to have a picture in one's mind of any one about whom one is interested. I have received and read with interest your paper on the sponge with horny spicula. (188/1. "Ueber Darwinella aurea, einen Schwamm mit sternformigen Hornnadeln." — "Archiv. Mikrosk. Anat." I., page 57, 1866.) Owing to ill-health, and being busy when formerly well, I have for some years neglected periodical scientific literature, and have lately been reading up, and have thus read translations of several of your papers; amongst which I have been particularly glad to read and see the drawings of the metamorphoses of Peneus. (188/2. "On the Metamorphoses of the Prawns," by Dr. Fritz Muller. — "Ann. Mag. Nat. Hist." Volume XIV., page 104 (with plate), 1864. Translated by W.S. Dallas from "Wiegmann's Archiv," 1863 (see also "Facts and Arguments for Darwin," passim, translated by W.S. Dallas: London, 1869).) This seems to me the most interesting discovery in embryology which has been made for years.

I am much obliged to you for telling me a little of your plans for the future; what a strange, but to my taste interesting life you will lead when you retire to your estate on the Itajahy!

You refer in your letter to the facts which Agassiz is collecting, against our views, on the Amazons. Though he has done so much for science, he seems to me so wild and paradoxical in all his views that I cannot regard his opinions as of any value.

LETTER 189. TO A.R. WALLACE. Down, January 22nd, 1866.

I thank you for your paper on pigeons (189/1. "On the Pigeons of the Malay Archipelago" (The "Ibis," October, 1865). Mr. Wallace points out (page 366) that "the most striking superabundance of pigeons, as well as of parrots, is confined to the Australo-Malayan sub-region in which...the forest-haunting and fruit-eating mammals, such as monkeys and squirrels, are totally absent." He points out also that monkeys are "exceedingly destructive to eggs and young birds."), which interested me, as everything that you write does. Who would ever have dreamed that monkeys influenced the distribution of pigeons and parrots! But I have had a still higher satisfaction, for I finished your paper yesterday in the "Linnean Transactions." (189/2. "Linn. Soc. Trans." XXV.: a paper on the geographical distribution and variability of the Malayan Papilionidae.) It is admirably done. I cannot conceive that the most firm believer in species could read it without being staggered. Such papers will make many more converts among naturalists than long-winded books such as I shall write if I have strength. I have been particularly struck with your remarks on dimorphism; but I cannot quite understand one point (page 22), (189/3. The passage referred to in this letter as needing further explanation is the following: "The last six cases of mimicry are especially instructive, because they seem to indicate one of the processes by which dimorphic forms have been produced. When, as in these cases, one sex differs much from the other, and varies greatly itself, it may happen that individual variations will occasionally occur, having a distant resemblance to groups which are the objects of mimicry, and which it is therefore advantageous to resemble. Such a variety will have a better chance of preservation; the individuals possessing it will be multiplied; and their accidental likeness to the favoured group will be rendered permanent by hereditary transmission, and each successive variation which increases the resemblance being preserved, and all variations departing from the favoured type having less chance of preservation, there will in time result those singular cases of two or more isolated and fixed forms bound together by that intimate relationship which constitutes them the sexes of a single species. The reason why the females are more subject to this kind of modification than the males is, probably, that their slower flight, when laden with eggs, and their exposure to attack while in the act of depositing their eggs upon leaves, render it especially advantageous for them to have some additional protection. This they at once obtain by acquiring a resemblance to other species which, from whatever cause, enjoy a comparative immunity from persecution." Mr. Wallace has been good enough to give us the following note on the above passage: "The above quotation deals solely with the question of how certain females of the polymorphic species (Papilio Memnon, P. Pammon, and others) have been so modified as to mimic species of a quite distinct section of the genus; but it does not attempt to explain why or how the other very variable types of female arose, and this was Darwin's difficulty. As the letter I wrote in reply is lost, and as it is rather difficult to explain the matter clearly without reference to the coloured figures, I must go into some little detail, and give now what was probably the explanation I gave at the time. The male of Papilio Memnon is a large black butterfly with the nervures towards the margins of the wings bordered with bluish gray dots. It is a forest insect, and the very dark colour renders it conspicuous; but it is a strong flier, and thus survives. To the female, however, this conspicuous mass of colour would be dangerous, owing to her slower flight, and the necessity for continually resting while depositing her eggs on the leaves of the food-plant of the larva. She has accordingly acquired lighter and more varied tints. The marginal gray-dotted stripes of the male have become of a brownish ash and much wider on the fore wings, while the margin of the hind wings is yellowish, with a more defined spot near the anal angle. This is the form most nearly like the male, but it is comparatively rare, the more common being much lighter in colour, the bluish gray of the hind wings being often entirely replaced by a broad band of yellowish white. The anal angle is orange-yellow, and there is a bright red spot at the base of the fore wings. Between these two extremes there is every possible variation. Now, it is quite certain that this varying mixture of brown, black, white, yellow, and red is far less conspicuous amid the ever-changing hues of the forest with their glints of sunshine everywhere penetrating so as to form strong contrasts and patches of light and shade. Hence ALL the females — one at one time and one at another — get SOME protection, and that is sufficient to enable them to live long enough to lay their eggs, when their work is finished. Still, under bad conditions they only just managed to survive, and as the colouring of some of these varying females very much resembled that of the protected butterflies of the P. coon group (perhaps at a time when the tails of the latter were not fully developed) any rudiments of a prolongation of the wing into a tail added to the protective resemblance, and was therefore preserved. The woodcuts of some of these forms in my "Malay Archipelago" (i., page 200) will enable those who have this book at hand better to understand the foregoing explanation."), and should be grateful for an explanation, for I want fully to understand you. How can one female form be selected and the intermediate forms die out, without also the other extreme form also dying out from not having the advantages of the first selected form? for, as I understand, both female forms occur on the same island. I quite agree with your distinction between dimorphic forms and varieties; but I doubt whether your criterion of dimorphic forms not producing intermediate offspring will suffice, for I know of a good many varieties which must be so called that will not blend or intermix, but produce offspring quite like either parent.