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Darwin Correspondence Project

From James Dixon   7 May 1880

Harrow Lands, | Dorking.

May 7. 1880.

Sir,—

May I take the liberty of drawing your attention to a trifling—very trifling—inaccuracy which occurs in your Descent of Man? (1871, i, 19)— You say “the platysma myoides … cannot be voluntarily brought into action.” In my own case this muscle is as much under control as any other in my body.1 I can use either lateral portion separately, or both portions together. The contraction influences the skin as far upwards as the angles of the mouth, both of which become slightly depressed; and in a downward direction the action extends far enough to move the nipples very slightly. I have known several persons who had the platysma under control, but I never met with anyone in whom this was the case to so great an extent as in myself.

I may observe that I know something about muscles inasmuch as I was Demonstrator of Anatomy at St Thomas’s Hospital during ten years.2 I was a standing wonder to my pupils, who were highly amused at my ability to use many muscles over which they had not the slightest control. I could—and can—move everyone of my facial muscles; and my palmaris brevis is as active now, when I am past 60, as it was 40 years ago.3

I hope these confessions will not cause you to regard me as the “missing link.”

Excuse my thus addressing you, and believe me to be very faithfully yrs. | James Dixon

Charles Darwin Esq. F.R.S. | &c &c

Footnotes

See Descent 1: 19. The platysma myoides is a sheet of muscle in the neck extending from the collar bone to the lower part of the cheek. CD did not change this passage in Descent 2d ed., but had noted in Expression, p. 298, that most people could voluntarily contract the muscle.
Dixon had trained at St Thomas’s Hospital, London, and served as assistant surgeon there from 1847 to 1851 (Plarr 1930).
The palmaris brevis is the muscle on the inner side of the palm below the little finger; it strengthens the grip of the hand on an object.

Bibliography

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.

Plarr, Victor Gustave. 1930. Plarr’s lives of the fellows of the Royal College of Surgeons of England. Revised by Sir D’Arcy Power. 2 vols. London: Simpkin Marshall.

Summary

Corrects CD’s statement [Descent 1: 19] that the platysma myoides muscle cannot be brought into voluntary action. He can move every one of his facial muscles.

Letter details

Letter no.
DCP-LETT-12598
From
James Dixon
To
Charles Robert Darwin
Sent from
Dorking
Source of text
DAR 162: 185
Physical description
ALS 4pp damaged

Please cite as

Darwin Correspondence Project, “Letter no. 12598,” accessed on 28 March 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-12598.xml

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