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Darwin Correspondence Project

From Chauncey Wright   24 February 1875


Feb. 24 1875

Dear Mr Darwin

Your letter of last Sept. after its long wanderings reached me at length through Dr Gray in time to serve as a Valentine; and gave me much pleasure; of which not the least part was from the release it gave me from the discipline of a doubt whether my long letter of last summer was properly mailed, or ever reached you.1 It seemed to me,—and this was my chief motive in writing,—that a letter to one interested especially in some of the many points of investigation which lay loose in my mind would serve to give them a greater degree of coherency, with sufficient freedom, than the more rigorous requisites of an essay. I have found that writing in any other style is apt to crystallize one’s meditations into opinions too fixed for clear open thought. I was quite willing to submit them, however, as comparative crudities to so friendly a critic; and I am much gratified that you found so little to object to in the letter.2 I had thought a little upon the point you make that the two motions of the head,—that 〈o〉f denial and that of inspection,—are widely different, and had conceived of their grading into each other in the expression of the mixed mental states. I have since made a sort of geometrical analysis of them as extremes of a series of movements. Thus, placing and holding fixedly the tip of the forefinger on the top of the head, the head can only move on an axis through this point and the turning point in the neck. This is one extreme, the gesture of denial, refusal, warning, &c. By placing the finger successively on the forehead, the tip of the nose and the chin, the axis of rotation is successively brought forward by stages toward the horizontal direction it has in the most neutral of critical considerations. But already at the forehead there is a decided element of consideration introduced into the gesture, according to my instincts of interpretation. Prof. Lowell is unable to recall distinctly the character of the movement like our negative, which he saw in Southern Italy, and learned to understand as an affirmative one;3 but he is so far interested in the question that he has offered to make inquiries of Signore Monti, an Italian gentleman, a native of Sicily, who formerly taught the Italian language in this college.4 If, as I hope, he gets the true gesture from him, I will preserve and transmit to you as accurate a description of it as I can.

Very lately reading for the first time in my life the Memorabilia of Xenophon in translation I came to a passage near the beginning of Chap 4, Book I, where Socrates gives an interesting statement of the argument from the appearance of design for the existence of the gods; and I was struck with this sentence “Is it not,” he asks, “like the work of forethought” … “to make the eyelashes grow as a screen that the winds may not injure it, (the eye,)? To make a coping on the parts above the eyes with the eye-brows, that the perspiration from the head may not annoy them?”5 It was with the latter query that I was most struck for it was a new suggestion to me and seemed truer than the first. I found that the idea of this use was in the minds of several of my friends; but whence they derived it they could not tell; whether from literature or direct experience. One gentleman, formerly much devoted to athletic exercises, told me that in rowing the perspiration was often annoying from running into the outer corners of his eyes. His eyebrows are rather thin and short. Dr. W. James, Instructor in Physiology in the College, who went with Prof. Agassiz on his first expedition to South America,6 says that he spent several hours a-day in a part of the expedition fishing in the Amazon under a scorching sun; and that the sweat running from his forehead and drying into a brine irritated his eyes excessively, so that he was obliged to bathe them frequently in the river. Fishing under a broiling sun in a tropical stream seems not far removed from the conditions of existence of primeval man!

I thought that if you had referred to this use of the eyebrows I should have remembered it; but I made a cursory though fruitless search for it. I have lately read, by the way, the principal additions and corrections in your new edition of the “Descent of Man”; and your less qualified adoption of Mr. Wallace’s views on the use of the lay of the hair on the gorilla’s forearms gave me another hint toward the little speculation on uses, which I venture to propound at the risk of making another long letter.7 The surviva〈l〉 of the panniculus carnosus8 in the human forehead and scalp, (the latter partially rudimentary,) the development of the corrugator muscles, the survival or perhaps even the development of the eye-brows, and the length of the hair on the head, all seem to me related to the denuding of the forehead, which doubtless was by sexual selection, or for ornament. The arrangement of the hair on the foreheads of most hairy animals and in the eye-brows, as well as in the eyelashes, (which do not serve, as Socrates thought, for screens against the wind;) seems to be adapted to keep the rain and perspiration out of their eyes; or to serve for shedding water. Now the loss of this use in the hair on the forehead would have been a considerable expense for beauty, if the correlative adaptations made for it below and above, in the retention or increase, perhaps, of the hair on the brows, and the increase of length in the hair on the head (to serve as a parting thatch for shedding rain, in place of the old shingles,) had not taken its place and laid the foundations for later developments of beauty. The prototypes of the long hairs or vibrissae in the eyebrows of some families perhaps served the same use. (I have met with an instance of this occurring in three successive generations at least.) But the eyebrows are sometimes curly, and may serve, (as a friend suggests, who has curly ones, and is one of the three who have had vibrissae,) to catch the perspiration and rain; which strokes of the hand would remove from time to time. It occurred to me, that in the same way a negro’s woolly mat might serve to catch a tropical shower, and hold it till he has an opportunity to shake it out. Perhaps the panniculus of the scalp served for the latter purpose. The reversal of direction in the hair bordering the forehead in some monkeys may be for a similar service. (The above suggested use of the panniculus could be experimentally determined in this case)    The cowlicks on the foreheads of many children may be relics of, or reversions to a similar normal arrangement in the straight-haired varieties or races of primeval men.

The vibrissae of the brows, especially in curly ones, would have served in former times as gargoyles; as in the nose they apparently ser〈v〉e for forming drops and extending the conducting and evaporating surfaces of the nasal passages (thus promoting the circulation of the lachrymal ducts.) Other features serving the same important end in vision of shedding water I have hinted at above; namely, the muscles which produce the transverse and vertical furrows of the forehead. Their non-appearance or slight development in childhood indicates the lateness of their acquisition by the race. That these furrows have been serviceable as drains or water courses, taking the place of arrangement in the hair formerly on the forehead, is not inconsistent with the uses of the grief-muscles which you seem to me to have fully made out.9 To compress the eye-ball in the more energetic action of the corrugators and to shade the eyes from excessive light by their lesser action seem to be unquestionable uses. That they should also serve this other use, and that their development has largely depended on this use, are to me none the less credible and even probable views. The inquiry as to which of several real uses is the one through which natural selection has acted for the development of any faculty or organ, or stands and has stood in the first rank of essential importance to an animal’s welfare in the struggle for life, has for several years seemed to me a somewhat less important question than it seemed formerly, and still appears to most thinkers on the subject. The reasons you give why sexual selection should have had much to do with several of the features, of which I have spoken, I still believe are perfectly valid. The uses of the rattling of the rattle-snake, as a protection by warning its enemies and as a sexual call, are not rival uses; neither are the high-reaching and the far-seeing uses of the giraff’s neck rivals; but are in the most intimate conspiracy to the same effects. Furthermore it seems to me presumable that in a long course of development, even in cases of highly specialized faculties, coexisting uses have risen in succession or alternately to the place of first importance, as in the various uses of the hand. This principle of a plurality of coexisting uses involves a very important influence in secondary uses, whether these are incidental and correlative acquisitions or are the more or less surpassed and superseded ones. They serve to connect in some cases the action of natural selection with the inherited effects of habit and exercise. An animal may for a comfort or convenience which bears but little reference to its essential welfare be indirectly furthering through exercise certain faculties, which though rarely called into exercise in functions of prime importance may nevertheless have, or may come to have such functions. Thus the constant or frequent use of the corrugators for forming vertical furrows and draining the forehead into the lachrymal ducts, or down the nose; or drawing the brows together for shading the eyes, may have been a preparation of them for their rarer but more important surgical service of quickly correcting the circulations of the eyes, and thus keeping the vision keen in conditions of exposure to danger. There is nothing in this principle which is really new or different from what you have set forth in your works, except the emphasis or prominence I am inclined to give it. The value of a plurality of coexisting uses in making the principle of natural selection and that of the inherited effects of habit cooperate in a larger number of cases and to a greater degree than could otherwise happen, ought to raise the principle from the rank of a scholium to that of a main theorem in the development doctrine. At least my present interest in one of its possible illustrations makes the matter seem so to me. It is, no doubt, a very interesting inquiry how any given organ or faculty is specially related to essential conditions of an animal’s existence; but it is not so important to the theory of natural selection as it would be if the efficacy of this process depended solely or generally on a single or permanent relation of this sort. The aid, too, which sexual selection gets and gives from such an association with habits and natural selection, or through a plurality of uses, is worthy of consideration. I do not conceive the question whether in a given case the coloring of an animal is protective or sexually attractive is a question of alternatives, of which only one can be true.

Sexual selection may in one case take up what natural selection has laid down; as in lengthening the hair beyond its value as a thatch for keeping the rain from the forehead and eyes. Or this agency having perhaps elaborated, in another case, the woolly mat of the negro, the hair may then have curled still closer than taste demanded, from its value in holding water; and then, later, sexual selection would return to the artificial cultivation of the African savage’s coiffure.

Among the multitude of topics in my head last summer one, for which I had no space from the length of my letter, related to a class of gestures used in reflection, meditation and, I may add, continuous thought or speach under distracting circumstances. To some of these gestures you refer where you say, “Why the hand should be raised to the mouth or face in deep thought is far from clear”.10 I came to this question from the speculations of which I wrote; and I hope, since it would make this letter too long to do so now, to discuss it with you at some other time. But I may state here one general conclusion which I had reached. The service on which many gestures seem to be founded appears to be to prevent the attention from wandering by turning it to something upon which it can readily be kept, and from which it can as readily be recovered. This prevents its wandering too far or into the swamp of vague uncontrollable feelings such as those of self-attention, visceral sensations and the reflexes from involuntary movements. The great sensibility of the face, especially about the mouth, seems to me to explain the gesture to which you especially refer; and even the pressure of the hand 〈on〉 the forehead appears to relate rather to vague sensations in it, thus controlled by the hand, than to any direct effect of the pressure on the action of the brain. But the full justification of these conclusions is a long argument into which I will not here enter.

I send in the same mail with this letter a number of the “Nation”, which contains a couple of “Notes” by me about books on evolution. They begin at the foot of page 113.11

Very sincerely yours | Chauncey Wright.


See Correspondence vol. 22, letter to Chauncey Wright, 21 September 1874 and 29 January 1875. CD’s letter had been incorrectly addressed and was returned to him; he sent the letter again, care of Asa Gray.
CD had suggested that Wright should publish his views on head movements (see Correspondence vol. 22, letter to Chauncey Wright, 21 September 1874 and 29 January 1875).
James Russell Lowell had mentioned to Wright that he noticed, when in southern Italy, a shake of the head similar to a negative one expressed deliberative assent rather than simple affirmation. See Correspondence vol. 22, letter from Chauncey Wright, 3 September 1874.
Luigi Monti was an instructor in Italian at Harvard University from 1854 to 1859 (Appleton’s cyclopaedia of American biography).
The quotation is from Memorabilia 1.4.6.
William James accompanied Louis Agassiz on the Thayer Expedition to Brazil as a student volunteer. For more on James’s experience, see Machado ed. 2006.
In Descent 2d ed., pp. 151–2, CD expanded a discussion of the direction of hair in apes and humans, including for the first time remarks about gorillas made by David Livingstone. In his original discussion of the topic (Descent 1: 193), CD had referred to observations of Alfred Russel Wallace on the orang-utan, which suggested that the direction of hair growth could help in throwing off rain. Livingstone’s observations supported Wallace’s view.
The panniculus carnosus is a thin sheet of striated muscle embedded in the lowest skin layer of many mammals; it produces local movement of the skin. In humans, only vestigial remnants remain. See Landau ed. 1986. CD discussed the panniculus carnosus in Expression, pp. 101, 298.
CD discussed the muscles and expressions associated with grief in Expression, pp. 178–97.
Expression, p. 230.
CD’s annotated copy of the unsigned article in the Nation, 18 February 1875, pp. 113–14, is in DAR 226.2: 181. Wright divided books on evolution into two categories, the scientific and inductive, represented by CD’s own books, and the speculative and philosophical, such as the works of Herbert Spencer.


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 vols to date. Cambridge: Cambridge University Press. 1985–.

Descent 2d ed.: The descent of man, and selection in relation to sex. By Charles Darwin. 2d edition. London: John Murray. 1874.

Descent: The descent of man, and selection in relation to sex. By Charles Darwin. 2 vols. London: John Murray. 1871.

Expression: The expression of the emotions in man and animals. By Charles Darwin. London: John Murray. 1872.


Speculates on the function of eyebrows and of hair and the furrows of the forehead. Considers many features and faculties to serve, or to have served, more than one function, either simultaneously or successively. Determining the one function through which natural selection has acted in developing it is unrealistic and not worth while.

Letter details

Letter no.
Chauncey Wright
Charles Robert Darwin
Sent from
Cambridge Mass.
Source of text
DAR 181: 173 fos. 1–5
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 9871,” accessed on 1 August 2021,

Also published in The Correspondence of Charles Darwin, vol. 23