Life and Letters of Charles Darwin Volume II Part 16

[Dr. Gray wrote three articles in the 'Atlantic Monthly' for July, August, and October, which were reprinted as a pamphlet in 1861, and now form chapter iii. in 'Darwiniana' (1876), with the heading 'Natural Selection not inconsistent with Natural Theology.']

CHARLES DARWIN TO C. LYELL Down, September 12th [1860].

My dear Lyell,

I never thought of showing your letter to any one. I mentioned in a letter to Hooker that I had been much interested by a letter of yours with original objections, founded chiefly on Natural Selection not having done so much as might have been expected... In your letter just received, you have improved your case versus Natural Selection; and it would tell with the public (do not be tempted by its novelty to make it too strong); yet is seems to me, not REALLY very killing, though I cannot answer your case, especially, why Rodents have not become highly developed in Australia. You must a.s.sume that they have inhabited Australia for a very long period, and this may or may not be the case.

But I feel that our ignorance is so profound, why one form is preserved with nearly the same structure, or advances in organisation or even retrogrades, or becomes extinct, that I cannot put very great weight on the difficulty. Then, as you say often in your letter, we know not how many geological ages it may have taken to make any great advance in organisation. Remember monkeys in the Eocene formations: but I admit that you have made out an excellent objection and difficulty, and I can give only unsatisfactory and quite vague answers, such as you have yourself put; however, you hardly put weight enough on the absolute necessity of variations first arising in the right direction, videlicet, of seals beginning to feed on the sh.o.r.e.

I entirely agree with what you say about only one species of many becoming modified. I remember this struck me much when tabulating the varieties of plants, and I have a discussion somewhere on this point. It is absolutely implied in my ideas of cla.s.sification and divergence that only one or two species, of even large genera, give birth to new species; and many whole genera become WHOLLY extinct... Please see page 341 of the 'Origin.' But I cannot remember that I have stated in the 'Origin' the fact of only very few species in each genus varying. You have put the view much better in your letter. Instead of saying, as I often have, that very few species vary at the same time, I ought to have said, that very few species of a genus EVER vary so as to become modified; for this is the fundamental explanation of cla.s.sification, and is shown in my engraved diagram...

I quite agree with you on the strange and inexplicable fact of Ornithorhynchus having been preserved, and Australian Trigonia, or the Silurian Lingula. I always repeat to myself that we hardly know why any one single species is rare or common in the best-known countries. I have got a set of notes somewhere on the inhabitants of fresh water; and it is singular how many of these are ancient, or intermediate forms; which I think is explained by the compet.i.tion having been less severe, and the rate of change of organic forms having been slower in small confined areas, such as all the fresh waters make compared with sea or land.

I see that you do allude in the last page, as a difficulty, to Marsupials not having become Placentals in Australia; but this I think you have no right at all to expect; for we ought to look at Marsupials and Placentals as having descended from some intermediate and lower form. The argument of Rodents not having become highly developed in Australia (supposing that they have long existed there) is much stronger. I grieve to see you hint at the creation "of distinct successive types, as well as of a certain number of distinct aboriginal types." Remember, if you admit this, you give up the embryological argument (THE WEIGHTIEST OF ALL TO ME), and the morphological or h.o.m.ological argument. You cut my throat, and your own throat; and I believe will live to be sorry for it. So much for species.

The striking extract which E. copied was your own writing!! in a note to me, many long years ago--which she copied and sent to Mme. Sismondi; and lately my aunt, in sorting her letters, found E.'s and returned them to her... I have been of late shamefully idle, i.e. observing (Drosera) instead of writing, and how much better fun observing is than writing.

Yours affectionately, C. DARWIN.

CHARLES DARWIN TO C. LYELL. 15 Marine Parade, Eastbourne, Sunday [September 23rd, 1860].

My dear Lyell,

I got your letter of the 18th just before starting here. You speak of saving me trouble in answering. Never think of this, for I look at every letter of yours as an honour and pleasure, which is a pretty deal more than I can say of some of the letters which I receive. I have now one of 13 CLOSELY WRITTEN FOLIO PAGES to answer on species!...

I have a very decided opinion that all mammals must have descended from a SINGLE parent. Reflect on the mult.i.tude of details, very many of them of extremely little importance to their habits (as the number of bones of the head, etc., covering of hair, identical embryological development, etc. etc.). Now this large amount of similarity I must look at as certainly due to inheritance from a common stock. I am aware that some cases occur in which a similar or nearly similar organ has been acquired by independent acts of natural selection. But in most of such cases of these apparently so closely similar organs, some important h.o.m.ological difference may be detected. Please read page 193, beginning, "The electric organs," and trust me that the sentence, "In all these cases of two very distinct species," etc. etc., was not put in rashly, for I went carefully into every case. Apply this argument to the whole frame, internal and external, of mammifers, and you will see why I think so strongly that all have descended from one progenitor. I have just re-read your letter, and I am not perfectly sure that I understand your point.

I enclose two diagrams showing the sort of manner I CONJECTURE that mammals have been developed. I thought a little on this when writing page 429, beginning, "Mr. Waterhouse." (Please read the paragraph.) I have not knowledge enough to choose between these two diagrams. If the brain of Marsupials in embryo closely resembles that of Placentals, I should strongly prefer No.2, and this agrees with the antiquity of Microlestes. As a general rule I should prefer No.1 diagram; whether or not Marsupials have gone on being developed, or rising in rank, from a very early period would depend on circ.u.mstances too complex for even a conjecture. Lingula has not risen since the Silurian epoch, whereas other molluscs may have risen.

Here appear two diagrams.

Diagram I.

A - Mammals, not true Marsupials nor true Placentals. - 2 branches - Branch I, True Placental, from which branch off Rodents, Insectivora, a branch terminating in Ruminants and Pachyderms, Canidae and terminates in Quadrumana. - Branch II, True Marsupial, from which branches off Kangaroo family an unnamed branch terminating in 2 unnamed branches and terminates in Didelphys Family.

Diagram II.

A - True Marsupials, lowly developed. - True Marsupials, highly developed. - 2 branches - Branch I, Placentals, from which branch off Rodents, Insectivora, a branch terminating in Ruminants and Pachyderms, Canidae and terminates in Quadrumana. - Branch II, Present Marsupials, splitting into two branches terminating in Kangaroo family (with 2 unnamed branches) and Didelphys family.

A, in the two diagrams, represents an unknown form, probably intermediate between Mammals, Reptiles, and Birds, as intermediate as Lepidosiren now is between Fish and Batrachians. This unknown form is probably more closely related to Ornithorhynchus than to any other known form.

I do not think that the multiple origin of dogs goes against the single origin of man... All the races of man are so infinitely closer together than to any ape, that (as in the case of descent of all mammals from one progenitor), I should look at all races of men as having certainly descended from one parent. I should look at it as probable that the races of men were less numerous and less divergent formerly than now, unless, indeed, some lower and more aberrant race even than the Hottentot has become extinct. Supposing, as I do for one believe, that our dogs have descended from two or three wolves, jackals, etc., yet these have, on OUR VIEW, descended from a single remote unknown progenitor. With domestic dogs the question is simply whether the whole amount of difference has been produced since man domesticated a single species; or whether part of the difference arises in the state of nature. Aga.s.siz and Co. think the negro and Caucasian are now distinct species, and it is a mere vain discussion whether, when they were rather less distinct, they would, on this standard of specific value, deserve to be called species.

I agree with your answer which you give to yourself on this point; and the simile of man now keeping down any new man which might be developed, strikes me as good and new. The white man is "improving off the face of the earth" even races nearly his equals. With respect to islands, I think I would trust to want of time alone, and not to bats and Rodents.

N.B.--I know of no rodents on oceanic islands (except my Galapagos mouse, which MAY have been introduced by man) keeping down the development of other cla.s.ses. Still MUCH more weight I should attribute to there being now, neither in islands nor elsewhere, [any] known animals of a grade of organisation intermediate between mammals, fish, reptiles, etc., whence a new mammal could be developed. If every vertebrate were destroyed throughout the world, except our NOW WELL-ESTABLISHED reptiles, millions of ages might elapse before reptiles could become highly developed on a scale equal to mammals; and, on the principle of inheritance, they would make some quite NEW CLa.s.s, and not mammals; though POSSIBLY more intellectual! I have not an idea that you will care for this letter, so speculative.

Most truly yours, C. DARWIN.

CHARLES DARWIN TO ASA GRAY. Down, September 26 [1860].

... I have had a letter of fourteen folio pages from Harvey against my book, with some ingenious and new remarks; but it is an extraordinary fact that he does not understand at all what I mean by Natural Selection. I have begged him to read the Dialogue in next 'Silliman,' as you never touch the subject without making it clearer. I look at it as even more extraordinary that you never say a word or use an epithet which does not express fully my meaning. Now Lyell, Hooker, and others, who perfectly understand my book, yet sometimes use expressions to which I demur. Well, your extraordinary labour is over; if there is any fair amount of truth in my view, I am well a.s.sured that your great labour has not been thrown away...

I yet hope and almost believe, that the time will come when you will go further, in believing a very large amount of modification of species, than you did at first or do now. Can you tell me whether you believe further or more firmly than you did at first? I should really like to know this. I can perceive in my immense correspondence with Lyell, who objected to much at first, that he has, perhaps unconsciousnessly to himself, converted himself very much during the last six months, and I think this is the case even with Hooker. This fact gives me far more confidence than any other fact.

CHARLES DARWIN TO C. LYELL. 15 Marine Parade, Eastbourne, Friday evening [September 28th, 1860].

... I am very glad to hear about the Germans reading my book. No one will be converted who has not independently begun to doubt about species. Is not Krohn (There are two papers by Aug. Krohn, one on the Cement Glands, and the other on the development of Cirripedes, 'Wiegmann's Archiv,'

xxv. and xxvi. My father has remarked that he "blundered dreadfully about the cement glands," 'Autobiography.') a good fellow? I have long meant to write to him. He has been working at Cirripedes, and has detected two or three gigantic blunders,... about which, I thank Heaven, I spoke rather doubtfully. Such difficult dissection that even Huxley failed. It is chiefly the interpretation which I put on parts that is so wrong, and not the parts which I describe. But they were gigantic blunders, and why I say all this is because Krohn, instead of crowing at all, pointed out my errors with the utmost gentleness and pleasantness.

I have always meant to write to him and thank him. I suppose Dr. Krohn, Bonn, would reach him.

I cannot see yet how the multiple origin of dog can be properly brought as argument for the multiple origin of man. Is not your feeling a remnant of the deeply impressed one on all our minds, that a species is an ent.i.ty, something quite distinct from a variety? Is it not that the dog case injures the argument from fertility, so that one main argument that the races of man are varieties and not species--i.e., because they are fertile inter se, is much weakened?

I quite agree with what Hooker says, that whatever variation is possible under culture, is POSSIBLE under nature; not that the same form would ever be acc.u.mulated and arrived at by selection for man's pleasure, and by natural selection for the organism's own good.

Talking of "natural selection;" if I had to commence de novo, I would have used "natural preservation." For I find men like Harvey of Dublin cannot understand me, though he has read the book twice. Dr. Gray of the British Museum remarked to me that, "SELECTION was obviously impossible with plants! No one could tell him how it could be possible!" And he may now add that the author did not attempt it to him!

Yours ever affectionately, C. DARWIN.

CHARLES DARWIN TO C. LYELL. 15 Marine Parade, Eastbourne, October 8th [1860].

My dear Lyell,

I send the [English] translation of Bronn (A MS. translation of Bronn's chapter of objections at the end of his German translation of the 'Origin of Species.'), the first part of the chapter with generalities and praise is not translated. There are some good hits. He makes an apparently, and in part truly, telling case against me, says that I cannot explain why one rat has a longer tail and another longer ears, etc. But he seems to muddle in a.s.suming that these parts did not all vary together, or one part so insensibly before the other, as to be in fact contemporaneous. I might ask the creationist whether he thinks these differences in the two rats of any use, or as standing in some relation from laws of growth; and if he admits this, selection might come into play. He who thinks that G.o.d created animals unlike for mere sport or variety, as man fas.h.i.+ons his clothes, will not admit any force in my argumentum ad hominem.

Bronn blunders about my supposing several Glacial periods, whether or no such ever did occur.

He blunders about my supposing that development goes on at the same rate in all parts of the world. I presume that he has misunderstood this from the supposed migration into all regions of the more dominant forms.

I have ordered Dr. Bree ('Species not Trans.m.u.table,' by C.R. Bree, 1860.), and will lend it to you, if you like, and if it turns out good.

... I am very glad that I misunderstood you about species not having the capacity to vary, though in fact few do give birth to new species. It seems that I am very apt to misunderstand you; I suppose I am always fancying objections. Your case of the Red Indian shows me that we agree entirely...

I had a letter yesterday from Thwaites of Ceylon, who was much opposed to me. He now says, "I find that the more familiar I become with your views in connection with the various phenomena of nature, the more they commend themselves to my mind."

CHARLES DARWIN TO J.M. RODWELL. (Rev. J.M. Rodwell, who was at Cambridge with my father, remembers him saying:--"It strikes me that all our knowledge about the structure of our earth is very much like what an old hen would know of a hundred acre field, in a corner of which she is scratching.") 15 Marine Parade, Eastbourne. November 5th [1860].

My dear Sir,

I am extremely much obliged for your letter, which I can compare only to a plum-pudding, so full it is of good things. I have been rash about the cats ("Cats with blue eyes are invariably deaf," 'Origin of Species,'

edition i. page 12.): yet I spoke on what seemed to me, good authority.

The Rev. W.D. Fox gave me a list of cases of various foreign breeds in which he had observed the correlation, and for years he had vainly sought an exception. A French paper also gives numerous cases, and one very curious case of a kitten which GRADUALLY lost the blue colour in its eyes and as gradually acquired its power of hearing. I had not heard of your uncle, Mr. Kirby's case (William Kirby, joint author with Spence, of the well-known 'Introduction to Entomology,' 1818.) (whom I, for as long as I can remember, have venerated) of care in breeding cats.

I do not know whether Mr. Kirby was your uncle by marriage, but your letters show me that you ought to have Kirby blood in your veins, and that if you had not taken to languages you would have been a first-rate naturalist.