Volume Ii Part 12 (1/2)

I am much obliged for your kind note, and especially for your offer of sending me some time corrections, for which I shall be truly grateful. I know that there are many blunders to which I am very liable. There is a terrible one confusing the supra-condyloid foramen with another one.

(471/1. In the first edition of the ”Descent of Man,” I., page 28, in quoting Mr. Busk ”On the Caves of Gibraltar,” Mr. Darwin confuses together the inter-condyloid foramen in the humerus with the supra-condyloid foramen. His attention was called to the mistake by Sir William Turner, to whom he had been previously indebted for other information on the anatomy of man. The error is one, as Sir William Turner points out in a letter, ”which might easily arise where the writer is not minutely acquainted with human anatomy.” In speaking of his correspondence with Darwin, Sir William remarks on a characteristic of Darwin's method of asking for information, namely, his care in avoiding leading questions.) This, however, I have corrected in all the copies struck off after the first lot of 2500. I daresay there will be a new edition in the course of nine months or a year, and this I will correct as well as I can. As yet the publishers have kept up type, and grumble dreadfully if I make heavy corrections. I am very far from surprised that ”you have not committed yourself to full acceptation” of the evolution of man. Difficulties and objections there undoubtedly are, enough and to spare, to stagger any cautious man who has much knowledge like yourself.

I am now at work at my hobby-horse essay on Expression, and I have been reading some old notes of yours. In one you say it is easy to see that the spines of the hedgehog are moved by the voluntary panniculus. Now, can you tell me whether each spine has likewise an oblique unstriped or striped muscle, as figured by Lister? (472/2. ”Expression of the Emotions,” page 101.) Do you know whether the tail-coverts of peac.o.c.k or tail of turkey are erected by unstriped or striped muscles, and whether these are h.o.m.ologous with the panniculus or with the single oblique unstriped muscles going to each separate hair in man and many animals? I wrote some time ago to Kolliker to ask this question (and in relation to quills of porcupine), and I received a long and interesting letter, but he could not answer these questions. If I do not receive any answer (for I know how busy you must be), I will understand you cannot aid me.

I heard yesterday that Paget was very ill; I hope this is not true. What a loss he would be; he is so charming a man.

P.S.--As I am writing I will trouble you with one other question. Have you seen anything or read of any facts which could induce you to think that the mind being intently and long directed to any portion of the skin (or, indeed, any organ) would influence the action of the capillaries, causing them either to contract or dilate? Any information on this head would be of great value to me, as bearing on blus.h.i.+ng.

If I remember right, Paget seems to be a great believer in the influence of the mind in the nutrition of parts, and even in causing disease. It is awfully audacious on my part, but I remember thinking (with respect to the latter a.s.sertion on disease) when I read the pa.s.sage that it seemed rather fanciful, though I should like to believe in it. Sir H.

Holland alludes to this subject of the influence of the mind on local circulation frequently, but gives no clear evidence. (472/3. Ibid., pages 339 et seq.)

LETTER 472. TO W. TURNER. Down, March 29th [1871].

Forgive me for troubling you with one line. Since writing my P.S. I have read the part on the influence of the nervous system on the nutrition of parts in your last edition of Paget's ”Lectures.” (472/1. ”Lectures on Surgical Pathology,” Edition III., revised by Professor Turner, 1870.) I had not read before this part in this edition, and I see how foolish I was. But still, I should be extremely grateful for any hint or evidence of the influence of mental attention on the capillary or local circulation of the skin, or of any part to which the mind may be intently and long directed. For instance, if thinking intently about a local eruption on the skin (not on the face, for shame might possibly intervene) caused it temporarily to redden, or thinking of a tumour caused it to throb, independently of increased heart action.

LETTER 473. TO HUBERT AIRY.

(473/1. Dr. Airy had written to Mr. Darwin on April 3rd:--

”With regard to the loss of voluntary movement of the ears in man and monkey, may I ask if you do not think it might have been caused, as it is certainly compensated, by the facility and quickness in turning the head, possessed by them in virtue of their more erect stature, and the freedom of the atlanto-axial articulation? (in birds the same end is gained by the length and flexibility of the neck.) The importance, in case of danger, of bringing the eyes to help the ears would call for a quick turn of the head whenever a new sound was heard, and so would tend to make superfluous any special means of moving the ears, except in the case of quadrupeds and the like, that have great trouble (comparatively speaking) in making a horizontal turn of the head--can only do it by a slow bend of the whole neck.” (473/2. We are indebted to Dr. Airy for furnis.h.i.+ng us with a copy of his letter to Mr. Darwin, the original of which had been mislaid.)

Down, April 5th [1871].

I am greatly obliged for your letter. Your idea about the easy turning of the head instead of the ears themselves strikes me as very good, and quite new to me, and I will keep it in mind; but I fear that there are some cases opposed to the notion.

If I remember right the hedgehog has very human ears, but birds support your view, though lizards are opposed to it.

Several persons have pointed out my error about the platysma. (473/3.

The error in question occurs on page 19 of the ”Descent of Man,” Edition I., where it is stated that the Platysma myoides cannot be voluntarily brought into action. In the ”Expression of the Emotions” Darwin remarks that this muscle is sometimes said not to be under voluntary control, and he shows that this is not universally true.) Nor can I remember how I was misled. I find I can act on this muscle myself, now that I know the corners of the mouth have to be drawn back. I know of the case of a man who can act on this muscle on one side, but not on the other; yet he a.s.serts positively that both contract when he is startled. And this leads me to ask you to be so kind as to observe, if any opportunity should occur, whether the platysma contracts during extreme terror, as before an operation; and secondly, whether it contracts during a s.h.i.+vering fit. Several persons are observing for me, but I receive most discordant results.

I beg you to present my most respectful and kind compliments to your honoured father [Sir G.B. Airy].

LETTER 474. TO FRANCIS GALTON.

(474/1. Mr. Galton had written on November 7th, 1872, offering to send to various parts of Africa Darwin's printed list of questions intended to guide observers on expression. Mr. Galton goes on: ”You do not, I think, mention in ”Expression” what I thought was universal among blubbering children (when not trying to see if harm or help was coming out of the corner of one eye) of pressing the knuckles against the eyeb.a.l.l.s, thereby reinforcing the orbicularis.”)

Down, November 8th [1872].

Many thanks for your note and offer to send out the queries; but my career is so nearly closed that I do not think it worth while. What little more I can do shall be chiefly new work. I ought to have thought of crying children rubbing their eyes with their knuckles, but I did not think of it, and cannot explain it. As far as my memory serves, they do not do so whilst roaring, in which case compression would be of use. I think it is at the close of the crying fit, as if they wished to stop their eyes crying, or possibly to relieve the irritation from the salt tears. I wish I knew more about the knuckles and crying.

What a tremendous stir-up your excellent article on prayer has made in England and America! (474/2. The article ent.i.tled ”Statistical Inquiries into the Efficacy of Prayer” appeared in the ”Fortnightly Review,” 1872.

In Mr. Francis Galton's book on ”Enquiries into Human Faculty and its Development,” London, 1883, a section (pages 277-94) is devoted to a discussion on the ”Objective Efficacy of Prayer.”)

LETTER 475. TO F.C. DONDERS.

(475/1. We have no means of knowing whether the observations suggested in the following letter were made--if not, the suggestion is worthy of record.)