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Darwin Correspondence Project

From John Wood   6 April 1871

68, Wimpole Street, | Cavendish Square. W.

April 6th. 1871

Dear Sir

You will, I am sure, excuse the liberty I take in pointing out in your last very valuable work “On the descent of Man” a slight inaccuracy.

At p. 19 it runs.—“The platysma myoides which is well developed in the neck (of man) belongs to this system, but cannot voluntarily be brought into action”.1 Now, like its congener, the “occipito-frontalis” this human muscle can usually be voluntarily brought into action, and in some individuals and families remarkably so.

In the lower orders of the Irish and especially in women of that class whose necks are less bound & covered up than in men, the muscle can be seen in bawling & angry gesticulation to raise folds of skin in the neck eminently expressive of disgust & contempt.2 A portion of it passing over the jaw to the angle of the mouth is called the “risorius Santorini” from being first described by that famous old anatomist3

It gives rise to the “risus sardonicus” or laughing “at the wrong side of the mouth” as the saying goes,—causing a “ricanante”4 & lugubrious expression to the mouth, spasmodically affected in tetanus & hydrophobia & which is also to be found remarkably characteristic in horses & dogs.

I have found both largely developed in the bodies of Negroes & low caste Lascars whom I have dissected, & in one Chinaman. Both are supplied liberally by the great nerve of expression to the cutaneous muscles of the face,—“the portio dura”5

I have also found them well developed in monkeys, the Orang & the Chimpanzee

I have more readily taken upon myself to set right this little mistake in that you have done me the honor to speak favorably, in your book in question, of my researches upon “muscular variations in the human subject.6 And I beg to forward you, with this, a copy of my last paper in the “Philosophical Transactions, in which I have marked several passages bearing in an important manner upon your renowned philosophical views as to the derivation of man.7

The two more remarkable developements I wish to call your attention to are those described at pp 92. 93. 94 84. 85 & 80; 103 & 108. viz the occipito scapular;—the scapulo-clavicular & the supra costal which I was the first to describe in the Human Subject8

The second named has been since found also by Dr. Pye Smith of Guys hospital; and the last by my friend professor Turner, with whose views of the homology of the “sternalis brutorum” mentioned in your book I quite agree9

In my M.S. yet unpublished I have many notes of specimens which tend very much to bear out your views in the same direction and which I hope, when leisure permits from my surgical avocations, to expound at the Royal Society.10

I remain Dear Sir | Yours most truly | John Wood

Chas. Darwin Esqre FRS.

Down. Beckenham | Kent

CD annotations

1.1 You … of man. 7.6] crossed pencil
3.1 In … anatomist 3.5] ‘Hence to act on Pl. first draw back corners of mouth’ pencil
6.1 I have … Chimpanzee] double scored red crayon
8.1 The two … scapular;—8.2] scored blue crayon; ‘102 self’ after ‘80;’11 pencil
8.1 The two … agree 9.3] ‘It will be enough to allude generally.—’ pencil
10.1 In my … Society. 10.3] crossed pencil
Top of letter: ‘Descent of man’ red crayon
Top of third page: ‘Descent of Man’ blue crayon


Descent 1: 19. The emphasis was added by Wood. See letter from Hubert Airy, 3 April 1871, n. 1.
CD cited these remarks in Expression, p. 302.
Ricanante: mocking, sneering (French).
Portio dura: part of the seventh cranial nerve.
See Descent 1: 109 n. 5.
Wood refers to ‘On a group of varieties of the muscles of the human neck, shoulder, and chest, with their transitional forms and homologies in mammalia’ in the Philosophical Transactions of the Royal Society of London (J. Wood 1869). CD’s annotated copy is in the Darwin Pamphlet Collection–CUL.
CD marked these pages in his copy; see n. 7, above.
Wood did not deliver a paper at the Royal Society of London.
CD refers to Descent, but the numbers are page numbers referring to J. Wood 1869.


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.

Pye-Smith, Philip Henry. 1868. Ein zweiter Fall von Musculus supracostalis anterior anomalus. Archiv für pathologische Anatomie und Physiologie und für klinische Medicin 43: 142.

Turner, William. 1867. On the musculus sternalis. [Read 21 January 1867.] Proceedings of the Royal Society of Edinburgh 6 (1866–9): 65–6.

Wood, John. 1869. On a group of varieties of the muscles of the human neck, shoulder, and chest, with their transitional forms and homologies in mammalia. [Read 17 June 1869.] Philosophical Transactions of the Royal Society 160 (1870): 83–116.


Corrects CD on his assertion that the platysma myoides "cannot voluntarily be brought into action" [Descent 1: 19].

Letter details

Letter no.
John Wood
Charles Robert Darwin
Sent from
London, Wimpole St, 68
Source of text
DAR 87: 145–6
Physical description
ALS 4pp †

Please cite as

Darwin Correspondence Project, “Letter no. 7661,” accessed on 12 April 2024,

Also published in The Correspondence of Charles Darwin, vol. 19