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Darwin Correspondence Project

From John Struthers   31 December 1864


Decr 31 1864.

Dear Sir

Allow me to ask your acceptance of Part II of my Anatomical Papers,1 on account especially of the last (on variation in the number of Fingers & Toes, and in the number of Phalanges, in Man) which may possibly interest you.2 The next last Paper may perhaps also interest you as indicating a physical cause for the preference of the right hand by all known races of Man.3

I have to thank you for your reference in April last4 to De Blainville’s notice of the Solid Hoofed Pig.5 It is also I find noticed by Otto in his great work on Monsters (page 314, Section 551—Figured in Table XXI Figs: 8 & 9, and the hoofs in Figs: 10. 11. 12).6 Also in his compendium of Comparative Anatomy (Translated by South), page 118.7 Prof Retzius of Stockholm8 informed me last year that there is not now there any specimen or knowledge of the variety, notwithstanding Otto’s reference to Stockholm.9

Otto also gives cases (cases 465, 466, 467—468 and 469—and Tab: XXVI Fig 1 of five or more toes in the Pig.10

I am desirous of drawing your attention to the occurrence of a supra-condyloid process in the human arm, a variety which early attracted my notice and which seems to me of much interest in relation to the subject of variation and Rudimentary Structures. I had kept the enclosed notice of it, from the Lancet with the view of asking your acceptance of it,11 but the many duties connected with my removing from Edinburgh to Aberdeen have caused delay.12

If at any time you would like to see some of my now numerous specimens of the supra-condyloid variety in Man, or my specimen (referred to on page 231 footnote) of Pig’s foot with five toes, it would afford me much pleasure to forward them for your inspection.13

With much respect I am | Yours faithfully | John Struthers

Charles Darwin Esq


Struthers 1854–64, vol. 2. CD’s annotated copy is in the Darwin Pamphlet Collection–CUL.
The reference is to ‘On variation in the number of fingers and toes, and in the number of phalanges in man’ (Struthers 1854–64, 2: 305–33). This paper had appeared in the July 1863 issue of the Edinburgh New Philosophical Journal, pp. 83–111. It is cited in Variation 2: 13. CD had sought information on polydactylism in January and February 1863, shortly after he began writing a draft of the chapters on inheritance for Variation (see Correspondence vol. 11, letter to F. T. Buckland, 26 January [1863], and letter to T. H. Huxley, 16 February [1863] and n. 3). In Variation 2: 17, CD argued that the possession of extra digits in mammals was a case of reversion to a remote progenitor.
‘On the relative weight of the viscera on the two sides of the body; and on the consequent position of the centre of gravity to the right side’ (Struthers 1854–64, 2: 283–304).
The letter to Struthers has not been found.
The reference is to Blainville 1841–55, 2: 128. Struthers’s paper on the solid-hoofed pig (Struthers 1863b) is cited, together with Blainville 1841–55, in Variation 1: 75. CD began revising the early chapters of Variation in mid-November (see letter to W. B. Tegetmeier, 21 December [1864] and n. 4).
The reference is to Monstrorum sexcentorum descriptio anatomica by Adolph Wilhelm Otto (Otto 1841).
The reference is to Otto’s Compendium of human & comparative pathological anatomy, translated by John Flint South (Otto 1831).
Magnus Christian Retzius.
Otto referred to three swine specimens with undivided hoofs that he had seen in the Veterinary School at Stockholm (Otto 1831, p. 118).
Otto 1841, pp. 273–4.
Struthers 1863a. The paper described cases in humans of a hook-like formation on the inner surface of the humerus, similar to the supra-condyloid foramen in many animals. CD cited Struthers 1863a in Descent 1: 28, referring to this structure as the homologue and rudiment of the supra-condyloid foramen in animals.
Struthers resigned his appointment as surgeon at the Royal Infirmary, Edinburgh, to take up a position as professor of anatomy at the University of Aberdeen in 1863 (DNB).
The specimen of the pig’s foot is mentioned in Struthers 1854–64, 2: 331, n. Struthers wrote ‘231’ in error.


Blainville, Henri Marie Ducrotay de. 1841–55. Ostéographie, ou description iconographique comparée du squelette et du système dentaire des cinq classes d’animaux vertébrés récents et fossiles pour servir de base à la zoologie et à la géologie. 3 vols. and atlas (2 vols.). Paris: Arthus Bertrand.

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

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

DNB: Dictionary of national biography. Edited by Leslie Stephen and Sidney Lee. 63 vols. and 2 supplements (6 vols.). London: Smith, Elder & Co. 1885–1912. Dictionary of national biography 1912–90. Edited by H. W. C. Davis et al. 9 vols. London: Oxford University Press. 1927–96.

Otto, Adolph Wilhelm. 1831. A compendium of human & comparative pathological anatomy. Translated from the German, with additional notes and references by John F. South. London: B. Fellowes.

Otto, Adolph Wilhelm. 1841. Monstrorum sexcentorum descriptio anatomica. Bratislava: sumptibus Ferdinandi Hirt.

Struthers, John. 1854–64. Anatomical and physiological observations. 2 vols. Edinburgh: Sutherland and Knox. Aberdeen: D. Wyllie & Son.

Variation: The variation of animals and plants under domestication. By Charles Darwin. 2 vols. London: John Murray. 1868.


Sends CD part two of his anatomical papers [Anatomical and physiological observations (1863) [part 1 (1854)]]; thinks CD may be interested in the paper dealing with variation in numbers of digits in man. Draws CD’s attention to another variation: the occurrence of a supra-condyloid process in the human arm.

Letter details

Letter no.
John Struthers
Charles Robert Darwin
Sent from
Source of text
DAR 177: 267
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 4725,” accessed on 20 October 2021,

Also published in The Correspondence of Charles Darwin, vol. 12