More Letters of Charles Darwin Volume I Part 26

Geol. Soc." Volume XVIII., page 348, 1862.) with extreme interest, and I thank you for sending it, though I should certainly have carefully read it, or anything with your name, in the Journal. It seems to me a masterpiece of close reasoning: although, of course, not a judge of such subjects, I cannot feel any doubt that it is conclusive. Will Owen answer you? I expect that from his arrogant view of his own position he will not answer. Your paper is dreadfully severe on him, but perfectly courteous, and polished as the finest dagger. How kind you are towards me: your first sentence (145/2. "One of the most accurate observers and original thinkers of our time has discoursed with emphatic eloquence on the Imperfection of the Geological Record.") has pleased me more than perhaps it ought to do, if I had any modesty in my composition. By the way, after reading the first whole paragraph, I re-read it, not for matter, but for style; and then it suddenly occurred to me that a certain man once said to me, when I urged him to publish some of his miscellaneous wealth of knowledge, "Oh, he could not write,--he hated it," etc. You false man, never say that to me again. Your incidental remark on the remarkable specialisation of Plagiaulax (145/3. "If Plagiaulax be regarded through the medium of the view advocated with such power by Darwin, through what a number of intermediate forms must not the genus have pa.s.sed before it attained the specialised condition in which the fossils come before us!") (which has stuck in my gizzard ever since I read your first paper) as bearing on the number of preceding forms, is quite new to me, and, of course, is in accordance to my notions a most impressive argument. I was also glad to be reminded of teeth of camel and tarsal bones. (145/4. Op. cit. page 353. A reference to Cuvier's instance "of the secret relation between the upper canine-shaped incisors of the camel and the bones of the tarsus.") Descent from an intermediate form, Ahem!

Well, all I can say is that I have not been for a long time more interested with a paper than with yours. It gives me a demoniacal chuckle to think of Owen's pleasant countenance when he reads it.

I have not been in London since the end of September; when I do come I will beat up your quarters if I possibly can; but I do not know what has come over me. I am worse than ever in bearing any excitement. Even talking of an evening for less than two hours has twice recently brought on such violent vomiting and trembling that I dread coming up to London.

I hear that you came out strong at Cambridge (145/5. Prof. Owen, in a communication to the British a.s.sociation at Cambridge (1862) "On a tooth of Mastodon from the Tertiary marls, near Shanghai," brought forward the case of the Australian Mastodon as a proof of the remarkable geographical distribution of the Proboscidia. In a subsequent discussion he frankly abandoned it, in consequence of the doubts then urged regarding its authenticity. (See footnote, page 101, in Falconer's paper "On the American Fossil Elephant," "Nat. Hist. Review," 1863.)), and am heartily glad you attacked the Australian Mastodon. I never did or could believe in him. I wish you would read my little Primula paper in the "Linnean Journal," Volume VI. Botany (No. 22), page 77 (I have no copy which I can spare), as I think there is a good chance that you may have observed similar cases. This is my real hobby-horse at present. I have re-tested this summer the functional difference of the two forms in Primula, and find all strictly accurate. If you should know of any cases a.n.a.logous, pray inform me. Farewell, my good and kind friend.

LETTER 146. TO J.D. HOOKER.

(146/1. The following letter is interesting in connection with a letter addressed to Sir J.D. Hooker, March 26th, 1862, No. 136, where the value of Natural Selection is stated more strongly by Sir Joseph than by Darwin. It is unfortunate that Sir Joseph's letter, to which this is a reply, has not been found.)

Down, November 20th [1862].

Your last letter has interested me to an extraordinary degree, and your truly parsonic advice, "some other wise and discreet person," etc., etc., amused us not a little. I will put a concrete case to show what I think A. Gray believes about crossing and what I believe. If 1,000 pigeons were bred together in a cage for 10,000 years their number not being allowed to increase by chance killing, then from mutual intercrossing no varieties would arise; but, if each pigeon were a self-fertilising hermaphrodite, a mult.i.tude of varieties would arise. This, I believe, is the common effect of crossing, viz., the obliteration of incipient varieties. I do not deny that when two marked varieties have been produced, their crossing will produce a third or more intermediate varieties. Possibly, or probably, with domestic varieties, with a strong tendency to vary, the act of crossing tends to give rise to new characters; and thus a third or more races, not strictly intermediate, may be produced. But there is heavy evidence against new characters arising from crossing wild forms; only intermediate races are then produced. Now, do you agree thus far? if not, it is no use arguing; we must come to swearing, and I am convinced I can swear harder than you, therefore I am right. Q.E.D.

If the number of 1,000 pigeons were prevented increasing not by chance killing, but by, say, all the shorter-beaked birds being killed, then the WHOLE body would come to have longer beaks. Do you agree?

Thirdly, if 1,000 pigeons were kept in a hot country, and another 1,000 in a cold country, and fed on different food, and confined in different-size aviary, and kept constant in number by chance killing, then I should expect as rather probable that after 10,000 years the two bodies would differ slightly in size, colour, and perhaps other trifling characters; this I should call the direct action of physical conditions.

By this action I wish to imply that the innate vital forces are somehow led to act rather differently in the two cases, just as heat will allow or cause two elements to combine, which otherwise would not have combined. I should be especially obliged if you would tell me what you think on this head.

But the part of your letter which fairly pitched me head over heels with astonishment, is that where you state that every single difference which we see might have occurred without any selection. I do and have always fully agreed; but you have got right round the subject, and viewed it from an entirely opposite and new side, and when you took me there I was astounded. When I say I agree, I must make the proviso, that under your view, as now, each form long remains adapted to certain fixed conditions, and that the conditions of life are in the long run changeable; and second, which is more important, that each individual form is a self-fertilising hermaphrodite, so that each hair-breadth variation is not lost by intercrossing. Your manner of putting the case would be even more striking than it is if the mind could grapple with such numbers--it is grappling with eternity--think of each of a thousand seeds bringing forth its plant, and then each a thousand. A globe stretching to the furthest fixed star would very soon be covered. I cannot even grapple with the idea, even with races of dogs, cattle, pigeons, or fowls; and here all admit and see the accurate strictness of your ill.u.s.tration.

Such men as you and Lyell thinking that I make too much of a Deus of Natural Selection is a conclusive argument against me. Yet I hardly know how I could have put in, in all parts of my book, stronger sentences.

The t.i.tle, as you once pointed out, might have been better. No one ever objects to agriculturalists using the strongest language about their selection, yet every breeder knows that he does not produce the modification which he selects. My enormous difficulty for years was to understand adaptation, and this made me, I cannot but think, rightly, insist so much on Natural Selection. G.o.d forgive me for writing at such length; but you cannot tell how much your letter has interested me, and how important it is for me with my present book in hand to try and get clear ideas. Do think a bit about what is meant by direct action of physical conditions. I do not mean whether they act; my facts will throw some light on this. I am collecting all cases of bud-variations, in contradistinction to seed-variations (do you like this term, for what some gardeners call "sports"?); these eliminate all effects of crossing.

Pray remember how much I value your opinion as the clearest and most original I ever get.

I see plainly that Welwitschia (146/2. Sir Joseph's great paper on Welwitschia mirabilis was published in the "Linn. Soc. Trans." 1863.) will be a case of Barnacles.

I have another plant to beg, but I write on separate paper as more convenient for you to keep. I meant to have said before, as an excuse for asking for so much from Kew, that I have now lost TWO seasons, by accursed nurserymen not having right plants, and sending me the wrong instead of saying that they did not possess.

LETTER 147. TO J.D. HOOKER. Down, 24th [November, 1862].

I have just received enclosed for you, and I have thought that you would like to read the latter half of A. Gray's letter to me, as it is political and nearly as mad as ever in our English eyes. You will see how the loss of the power of bullying is in fact the sore loss to the men of the North from disunion.

I return with thanks Bates' letter, which I was glad to see. It was very good of you writing to him, for he is evidently a man who wants encouragement. I have now finished his paper (but have read nothing else in the volume); it seems to me admirable. To my mind the act of segregation of varieties into species was never so plainly brought forward, and there are heaps of capital miscellaneous observations.

I hardly know why I am a little sorry, but my present work is leading me to believe rather more in the direct action of physical conditions. I presume I regret it, because it lessens the glory of Natural Selection, and is so confoundedly doubtful. Perhaps I shall change again when I get all my facts under one point of view, and a pretty hard job this will be. (147/1. This paragraph was published in "Life and Letters," II., page 390. It is not clear why a belief in "direct action" should diminish the glory of Natural Selection, since the changes so produced must, like any other variations, pa.s.s through the ordeal of the survival of the fittest. On the whole question of direct action see Mr. Adam Sedgwick's "Presidential Address to the Zoological Section of the British a.s.sociation," 1899.)

LETTER 148. TO H.W. BATES. Down, November 25th [1862?].

I should think it was not necessary to get a written agreement. (148/1.

Mr. Bates' book, "A Naturalist on the Amazons," was published in 1863.) I have never had one from Murray. I suppose you have a letter with terms; if not, I should think you had better ask for one to prevent misunderstandings. I think Sir C. Lyell told me he had not any formal agreements. I am heartily glad to hear that your book is progressing.

Could you find me some place, even a footnote (though these are in nine cases out of ten objectionable), where you could state, as fully as your materials permit, all the facts about similar varieties pairing,--at a guess how many you caught, and how many now in your collection? I look at this fact as very important; if not in your book, put it somewhere else, or let me have cases.

I entirely agree with you on the enormous advantage of thoroughly studying one group.

I really have no criticism to make. (148/2. Mr. Bates' paper on mimetic b.u.t.terflies was read before the Linnean Society, November 21st, 1861, and published in the "Linn. Soc. Trans." XXIII., 1862, page 495, under the t.i.tle of "Contributions to an Insect Fauna of the Amazon Valley.") Style seems to me very good and clear; but I much regret that in the t.i.tle or opening pa.s.sage you did not blow a loud trumpet about what you were going to show. Perhaps the paper would have been better more divided into sections with headings. Perhaps you might have given somewhere rather more of a summary on the progress of segregation of varieties, and not referred your readers to the descriptive part, excepting such readers as wanted minute detail. But these are trifles: I consider your paper as a most admirable production in every way.

Whenever I come to variation under natural conditions (my head for months has been exclusively occupied with domestic varieties), I shall have to study and re-study your paper, and no doubt shall then have to plague you with questions. I am heartily glad to hear that you are well.

I have been compelled to write in a hurry; so excuse me.

LETTER 149. TO T.H. HUXLEY. Down, December 7th [1862].

I was on the point of adding to an order to Williams & Norgate for your Lectures (149/1. "A Course of Six Lectures to Working Men," published in six pamphlets by Hardwicke, and later as a book. See Letter 156.) when they arrived, and much obliged I am. I have read them with interest, and they seem to me very good for this purpose and capitally written, as is everything which you write. I suppose every book nowadays requires some pushing, so that if you do not wish these lectures to be extensively circulated, I suppose they will not; otherwise I should think they would do good and spread a taste for the natural sciences. Anyhow, I have liked them; but I get more and more, I am sorry to say, to care for nothing but Natural History; and chiefly, as you once said, for the mere species question. I think I liked No. III. the best of all. I have often said and thought that the process of scientific discovery was identical with everyday thought, only with more care; but I never succeeded in putting the case to myself with one-tenth of the clearness with which you have done. I think your second geological section will puzzle your non-scientific readers; anyhow, it has puzzled me, and with the strong middle line, which must represent either a line of stratification or some great mineralogical change, I cannot conceive how your statement can hold good.

I am very glad to hear of your "three-year-old" vigour [?]; but I fear, with all your multifarious work, that your book on Man will necessarily be delayed. You bad man; you say not a word about Mrs. Huxley, of whom my wife and self are always truly anxious to hear.

P.S. I see in the "Cornhill Magazine" a notice of a work by Cohn, which apparently is important, on the contractile tissue of plants. (149/2.

"Ueber contractile Gewebe im Pflanzenreiche." "Abhand. der Schlesischen Gesellschaft fur vaterlandische Cultur," Heft I., 1861.) You ought to have it reviewed. I have ordered it, and must try and make out, if I can, some of the accursed german, for I am much interested in the subject, and experimented a little on it this summer, and came to the conclusion that plants must contain some substance most closely a.n.a.logous to the supposed diffused nervous matter in the lower animals; or as, I presume, it would be more accurate to say with Cohn, that they have contractile tissue.

Lecture VI., page 151, line 7 from top--wetting FEET or bodies? (Miss Henrietta Darwin's criticism.) (149/3. Lecture VI., page 151: Lamarck "said, for example, that the short-legged birds, which live on fish, had been converted into the long-legged waders by desiring to get the fish without wetting their feet."

Their criticisms on Lectures IV. and VI. are on a separate piece of undated paper, and must belong to a letter of later date; only three lectures were published by December 7th, 1862.)

Lecture IV., page 89--Atavism.

You here and there use atavism = inheritance. d.u.c.h.esne, who, I believe, invented the word, in his Strawberry book confined it, as every one has since done, to resemblance to grandfather or more remote ancestor, in contradistinction to resemblance to parents.

LETTER 150. TO JOHN SCOTT.

(150/1. The following is the first of a series of letters addressed to the late John Scott, of which the major part is given in our Botanical chapters. We have been tempted to give this correspondence fully not only because of its intrinsic scientific interest, but also because they are almost the only letters which show Darwin in personal relation with a younger man engaged in research under his supervision.)

[1862?]

To the best of my judgment, no subject is so important in relation to theoretical natural science, in several respects, and likewise in itself deserving investigation, as the effects of changed or unnatural conditions, or of changed structure on the reproductive system. Under this point of view the relation of well-marked but undoubted varieties in fertilising each other requires far more experiments than have been tried. See in the "Origin" the brief abstract of Gartner on Verbasc.u.m and Zea. Mr. W. Crocker, lately foreman at Kew and a very good observer, is going at my suggestion to work varieties of hollyhock. (150/2.

Altheae species. These experiments seem not to have been carried out.) The climate would be too cold, I suppose, for varieties of tobacco. I began on cabbages, but immediately stopped from early shedding of their pollen causing too much trouble. Your knowledge would suggest some [plants]. On the same principle it would be well to test peloric flowers with their own pollen, and with pollen of regular flowers, and try pollen of peloric on regular flowers--seeds being counted in each case.

I have now got one seedling from many crosses of a peloric Pelargonium by peloric pollen; I have two or three seedlings from a peloric flower by pollen of regular flower. I have ordered a peloric Antirrhinum (150/3. See "Variation of Animals and Plants," Edition I., Volume II., page 70.) and the peloric Gloxinia, but I much fear I shall never have time to try them. The Pa.s.siflora cases are truly wonderful, like the Crinum cases (see "Origin"). (150/4. "Origin," Edition VI., page 238.) I have read in a German paper that some varieties of potatoes (name not given) cannot be fertilised by [their] own pollen, but can by pollen of other varieties: well worth trying. Again, fertility of any monster flower, which is pretty regularly produced; I have got the wonderful Begonia frigida (150/5. The species on which Sir J.D. Hooker wrote in the "Gardeners' Chronicle," February 25th, 1860. See "Life and Letters,"

II., page 275.) from Kew, but doubt whether I have heat to set its seeds. If an unmodified Celosia could be got, it would be well to test with the modified c.o.c.ks...o...b.. There is a variation of columbine [Aquilegia] with simple petals without nectaries, etc., etc. I never could think what to try; but if one could get hold of a long-cultivated plant which crossed with a distinct species and yielded a very small number of seeds, then it would be highly good to test comparatively the wild parent-form and its varying offspring with this third species: for instance, if a polyanthus would cross with some species of Primula, then to try a wild cowslip with it. I believe hardly any primulas have ever been crossed. If we knew and could get the parent of the carnation (150/6. Dianthus caryophyllus, garden variety.), it would be very good for this end. Any member of the Lythraceae raised from seed ought to be well looked after for dimorphism. I have wonderful facts, the result of experiment, on Lythrum salicaria.

LETTER 151. TO JOHN SCOTT. Down, December 11th [1862].

I have read your paper with much interest. (151/1. "On the Nature and Peculiarities of the Fern-spore." "Bot. Soc. Edin." Read June 12th, 1862.) You ask for remarks on the matter, which is alone really important. Shall you think me impertinent (I am sure I do not mean to be so) if I hazard a remark on the style, which is of more importance than some think? In my opinion (whether or no worth much) your paper would have been much better if written more simply and less elaborated--more like your letters. It is a golden rule always to use, if possible, a short old Saxon word. Such a sentence as "so purely dependent is the incipient plant on the specific morphological tendency" does not sound to my ears like good mother-English--it wants translating. Here and there you might, I think, have condensed some sentences. I go on the plan of thinking every single word which can be omitted without actual loss of sense as a decided gain. Now perhaps you will think me a meddling intruder: anyhow, it is the advice of an old hackneyed writer who sincerely wishes you well. Your remark on the two s.e.xes counteracting variability in product of the one is new to me. (151/2.

Scott (op. cit., page 214): "The reproductive organs of phoenogams, as is well-known, are always products of two morphologically distinct organs, the stamens producing the pollen, the carpels producing the ovules...The embryo being in this case the modified resultant of two originally distinct organs, there will necessarily be a greater tendency to efface any individual peculiarities of these than would have been the case had the embryo been the product of a single organ." A different idea seems to have occurred to Mr. Darwin, for in an undated letter to Scott he wrote: "I hardly know what to say on your view of male and female organs and variability. I must think more over it. But I was amused by finding the other day in my portfolio devoted to bud-variation a slip of paper dated June, 1860, with some such words as these, 'May not permanence of grafted buds be due to the two s.e.xual elements derived from different parts not having come into play?' I had utterly forgotten, when I read your paper that any a.n.a.logous notion had ever pa.s.sed through my mind--nor can I now remember, but the slip shows me that it had." It is interesting that Huxley also came to a conclusion differing from Scott's; and, curiously enough, Darwin confused the two views, for he wrote to Scott (December 19th): "By an odd chance, reading last night some short lectures just published by Prof. Huxley, I find your observation, independently arrived at by him, on the confluence of the two s.e.xes causing variability." Professor Huxley's remarks are in his "Lectures to Working Men on our Knowledge, etc." No. 4, page 90: "And, indeed, I think that a certain amount of variation from the primitive stock is the necessary result of the method of s.e.xual propagation itself; for inasmuch as the thing propagated proceeds from two organisms of different s.e.xes and different makes and temperaments, and, as the offspring is to be either of one s.e.x or the other, it is quite clear that it cannot be an exact diagonal of the two, or it would be of no s.e.x at all; it cannot be an exact intermediate form between that of each of its parents--it must deviate to one side or the other.") But I cannot avoid thinking that there is something unknown and deeper in seminal generation. Reflect on the long succession of embryological changes in every animal. Does a bud ever produce cotyledons or embryonic leaves? I have been much interested by your remark on inheritance at corresponding ages; I hope you will, as you say, continue to attend to this. Is it true that female Primula plants always produce females by parthenogenesis? (151/3. It seems probable that Darwin here means vegetative reproduction.) If you can answer this I should be glad; it bears on my Primula work. I thought on the subject, but gave up investigating what had been observed, because the female bee by parthenogenesis produces males alone. Your paper has told me much that in my ignorance was quite new to me. Thanks about P. scotica. If any important criticisms are made on the Primula to the Botanical Society, I should be glad to hear them. If you think fit, you may state that I repeated the crossing experiments on P. sinensis and cowslip with the same result this spring as last year--indeed, with rather more marked difference in fertility of the two crosses. In fact, had I then proved the Linum case, I would not have wasted time in repet.i.tion. I am determined I will at once publish on Linum...

I was right to be cautious in supposing you in error about Siphocampylus (no flowers were enclosed). I hope that you will make out whether the pistil presents two definite lengths; I shall be astounded if it does. I do not fully understand your objections to Natural Selection; if I do, I presume they would apply with full force to, for instance, birds.

Reflect on modification of Arab-Turk horse into our English racehorse. I have had the satisfaction to tell my publisher to send my "Journal" and "Origin" to your address. I suspect, with your fertile mind, you will find it far better to experiment on your own choice; but if, on reflection, you would like to try some which interest me, I should be truly delighted, and in this case would write in some detail. If you have the means to repeat Gartner's experiments on variations of Verbasc.u.m or on maize (see the "Origin"), such experiments would be pre-eminently important. I could never get variations of Verbasc.u.m.

I could suggest an experiment on potatoes a.n.a.logous with the case of Pa.s.siflora; even the case of Pa.s.siflora, often as it has been repeated, might be with advantage repeated. I have worked like a slave (having counted about nine thousand seeds) on Melastoma, on the meaning of the two sets of very different stamens, and as yet have been shamefully beaten, and I now cry for aid. I could suggest what I believe a very good scheme (at least, Dr. Hooker thought so) for systematic degeneration of culinary plants, and so find out their origin; but this would be laborious and the work of years.

LETTER 152. TO J.D. HOOKER. Down, 12th [December, 1862].

My good old Friend--

How kind you have been to give me so much of your time! Your letter is of real use, and has been and shall be well considered. I am much pleased to find that we do not differ as much as I feared. I begin my book with saying that my chief object is to show the inordinate scale of variation; I have especially studied all sorts of variations of the individual. On crossing I cannot change; the more I think, the more reason I have to believe that my conclusion would be agreed to by all practised breeders. I also greatly doubt about variability and domestication being at all necessarily correlative, but I have touched on this in "Origin." Plants being identical under very different conditions has always seemed to me a very heavy argument against what I call direct action. I think perhaps I will take the case of 1,000 pigeons (152/1. See Letter 146.) to sum up my volume; I will not discuss other points, but, as I have said, I shall recur to your letter. But I must just say that if sterility be allowed to come into play, if long-beaked be in the least degree sterile with short-beaked, my whole case is altered. By the way, my notions on hybridity are becoming considerably altered by my dimorphic work. I am now strongly inclined to believe that sterility is at first a selected quality to keep incipient species distinct. If you have looked at Lythrum you will see how pollen can be modified merely to favour crossing; with equal readiness it could be modified to prevent crossing.