Volume I Part 45 (1/2)

LETTER 295. TO E.S. MORSE. Down, October 21st, 1879.

Although you are so kind as to tell me not to write, I must just thank you for the proofs of your paper, which has interested me greatly.

(295/1. See ”The Sh.e.l.l Mounds of Omori” in the ”Memoirs of the Science Department of the Univ. of Tokio,” Volume I., Part I., 1879. The ridges on Arca are mentioned at page 25. In ”Nature,” April 15th, 1880, Mr.

Darwin published a letter by Mr. Morse relating to the review of the above paper, which appeared in ”Nature,” XXI., page 350. Mr. Darwin introduces Mr. Morse's letter with some prefatory remarks. The correspondence is republished in the ”American Naturalist,” September, 1880.) The increase in the number of ridges in the three species of Arca seems to be a very noteworthy fact, as does the increase of size in so many, yet not all, the species. What a constant state of fluctuation the whole organic world seems to be in! It is interesting to hear that everywhere the first change apparently is in the proportional numbers of the species. I was much struck with the fact in the upraised sh.e.l.ls of Coquimbo, in Chili, as mentioned in my ”Geological Observations on South America.”

Of all the wonders in the world, the progress of j.a.pan, in which you have been aiding, seems to me about the most wonderful.

LETTER 296. TO A.R. WALLACE. Down, January 5th 1880.

As this note requires no sort of answer, you must allow me to express my lively admiration of your paper in the ”Nineteenth Century.” (296/1.

”Nineteenth Century,” January 1880, page 93, ”On the Origin of Species and Genera.”) You certainly are a master in the difficult art of clear exposition. It is impossible to urge too often that the selection from a single varying individual or of a single varying organ will not suffice.

You have worked in capitally Allen's admirable researches. (296/2. J.A.

Allen, ”On the Mammals and Winter Birds of East Florida, etc.” (”Bull.

Mus. Comp. Zoolog. Harvard,” Volume II.) As usual, you delight to honour me more than I deserve. When I have written about the extreme slowness of Natural Selection (296/3. Mr. Wallace makes a calculation based on Allen's results as to the very short period in which the formation of a race of birds differing 10 to 20 per cent. from the average in length of wing and strength of beak might conceivably be effected. He thinks that the slowness of the action of Natural Selection really depends on the slowness of the changes naturally occurring in the physical conditions, etc.) (in which I hope I may be wrong), I have chiefly had in my mind the effects of intercrossing. I subscribe to almost everything you say excepting the last short sentence. (296/4. The pa.s.sage in question is as follows: ”I have also attempted to show that the causes which have produced the separate species of one genus, of one family, or perhaps of one order, from a common ancestor, are not necessarily the same as those which have produced the separate orders, cla.s.ses, and sub-kingdoms from more remote common ancestors. That all have been alike produced by 'descent with modification' from a few primitive types, the whole body of evidence clearly indicates; but while individual variation with Natural Selection is proved to be adequate for the production of the former, we have no proof and hardly any evidence that it is adequate to initiate those important divergences of type which characterise the latter.” In this pa.s.sage stress should be laid (as Mr. Wallace points out to us) on the word PROOF. He by no means a.s.serts that the causes which have produced the species of a genus are inadequate to produce greater differences. His object is rather to urge the difference between proof and probability.)

LETTER 297. TO J.H. FABRE.

(297/1. A letter to M. Fabre is given in ”Life and Letters,” III., page 220, in which the suggestion is made of rotating the insect before a ”homing” experiment occurs.)

Down, February 20th, 1880.

I thank you for your kind letter, and am delighted that you will try the experiment of rotation. It is very curious that such a belief should be held about cats in your country (297/2. M. Fabre had written from Serignan, Vaucluse: ”Parmi la population des paysans de mon village, l'habitude est de faire tourner dans un sac le chat que l'on se propose de porter ailleurs, et dont on veut empecher le retour. J'ignore si cette pratique obtient du succes.”), I never heard of anything of the kind in England. I was led, as I believe, to think of the experiment from having read in Wrangel's ”Travels in Siberia” (297/3. Admiral Ferdinand Petrovich von Wrangell, ”Le Nord de la Siberie, Voyage parmi les Peuplades de la Russie asiatique, etc.” Paris, 1843.) of the wonderful power which the Samoyedes possess of keeping their direction in a fog whilst travelling in a tortuous line through broken ice. With respect to cats, I have seen an account that in Belgium there is a society which gives prizes to the cat which can soonest find its way home, and for this purpose they are carried to distant parts of the city.

Here would be a capital opportunity for trying rotation.

I am extremely glad to hear that your book will probably be translated into English.

P.S.--I shall be much pleased to hear the result of your experiments.

LETTER 298. TO J.H. FABRE. Down, January 21st, 1881.

I am much obliged for your very interesting letter. Your results appear to me highly important, as they eliminate one means by which animals might perhaps recognise direction; and this, from what has been said about savages, and from our own consciousness, seemed the most probable means. If you think it worth while, you can of course mention my name in relation to this subject.

Should you succeed in eliminating a sense of the magnetic currents of the earth, you would leave the field of investigation quite open.

I suppose that even those who still believe that each species was separately created would admit that certain animals possess some sense by which they perceive direction, and which they use instinctively.

On mentioning the subject to my son George, who is a mathematician and knows something about magnetism, he suggested making a very thin needle into a magnet; then breaking it into very short pieces, which would still be magnetic, and fastening one of these pieces with some cement on the thorax of the insect to be experimented on.

He believes that such a little magnet, from its close proximity to the nervous system of the insect, would affect it more than would the terrestrial currents.

I have received your essay on Halictus (298/1. ”Sur les Moeurs et la Parthenogese des Halictes” (”Ann. Sc. Nat.” IX., 1879-80).), which I am sure that I shall read with much interest.

LETTER 299. TO T.H. HUXLEY.

(299/1. On April 9th, 1880, Mr. Huxley lectured at the Royal Inst.i.tution on ”The Coming of Age of the Origin of Species.” The lecture was published in ”Nature” and in Huxley's ”Collected Essays,” Volume II., page 227. Darwin's letter to Huxley on the subject is given in ”Life and Letters,” III., page 240; in Huxley's reply of May 10th (”Life and Letters of T.H. Huxley,” II., page 12) he writes: ”I hope you do not imagine because I had nothing to say about 'Natural Selection' that I am at all weak of faith on that article...But the first thing seems to me to be to drive the fact of evolution into people's heads; when that is once safe, the rest will come easy.”)

Down, May 11th, 1880.

I had no intention to make you write to me, or expectation of your doing so; but your note has been so far ”cheerier” (299/2. ”You are the cheeriest letter-writer I know”: Huxley to Darwin. See Huxley's ”Life,”