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Darwin Correspondence Project

From William Yarrell   [c. 17 December 1838]

Extract from a letter written by Sir Robt. Heron to W.Y.

There is a breed of Pigs, size of the Chinese, with feet undivided—internally—: Like a horses foot some had them, and on crossing them, had some with two whole feet and two divided feet.

I have had Angora Rabbits for many years, at first only white ones, I then obtained a brown male, killed all the white males, and left him with 4 wives; the produce was white, black, brown and fawn colour’d the black in a few years prevailed to the exclusion of all the other colours.

I then obtained a pair of brown, and have now again all the colours except black, which I have no doubt will reappear, but the remarkable circumstance which appears to belong to this breed is that though I have frequently all the colours in one brood, there has never yet been two colours in any one Rabbit—1 Received Decr. 17th. 1838—

Lawrence’s example of the man with the scabrous skin. 2

CD annotations

‘like Piebald in colour’added ink
heavy scoring pencil and brown crayon
1.3 divided feet.] ‘(Dorkings feet. P. Chron)’3 added ink
2.4 other colours.] ‘2’ superimposed ink; circled ink
3.4 there has … Rabbit— ] scored pencil
‘Same as someone’s fact about Hamster & Bachman case of Squirrels — —’4 added pencil
Verso of last page: ‘Mr Yarrell tells me, he has seen several letters *from Ld. Western [interl] in the Morning Post from December 20th to January 4th about sheep & manner of breeding them bearing on his law:—look over them.—’5 ink; ‘Morning … sheep &’ ink over pencil; marked with large brace and‘1839?’ pencil ‘Appendixes to 2d Voyage of Parry. Richardson on wolves & dogs of N. America & Asia’6 ink over pencil, circled ink and pencil ‘Lawrence lectures of Man— | (Man with scaly skin)’ ink and pencil; partially underl


See Natural selection, p. 456, and Variation 2: 92 n. for CD’s use of this extract. He also refers to it in Notebook D (inside front cover): ‘Mem. for Eyton.— Sir. R. Heron’s case of breed of pigs with solid feet.—’ A passage in the manuscript of Variation (DAR 205.7), later cancelled, read: ‘In certain animals in a state of nature, when there has been no crossing, as with squirrels & hamsters, wholly white or black young appear far oftener than piebald or intermediate tints.’ (Natural selection, p. 456, R. Stauffer’s note).
Lawrence 1819, pp. 449–51 described a family in which the males had a thick horn-like covering to their skin, which was seemingly hereditary. The first case was described by Machin 1733.
CD refers here to a letter in The Poultry Chronicle for Wednesday, December 13, 1854, p. 355, which refers to crosses between Dorking and Spanish fowl. For CD’s use of this information see Natural Selection, p. 456, and Variation 2: 92 n.
Bachman 1838, p. 86.
Lord Western’s breeding of sheep is referred to in Variation 2: 198. William Yarrell’s law stated that the longer a character had been in the blood the more likely it was to be inherited (see Ospovat 1981, p. 46).
John Richardson’s zoological appendix to Parry 1824–5.


Bachman, John. 1838. Monograph of the species of squirrel inhabiting North America. Proceedings of the Zoological Society of London 6: 85–103.

Lawrence, William. 1819. Lectures on physiology, zoology, and the natural history of man, delivered at the Royal College of Surgeons. London: J. Callow.

Machin, John. 1733. An uncommon case of a distempered skin. Philosophical Transactions of the Royal Society of London 37: 299–301.

Notebook D. See de Beer 1960; de Beer and Rowlands 1961; de Beer, Rowlands, and Skramovsky 1967; Notebooks.

Ospovat, Dov. 1981. The development of Darwin’s theory. Natural history, natural theology, and natural selection, 1838–1859. Cambridge: Cambridge University Press.

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


Extract of a letter from Sir Robert Heron to WY, copied for CD, about the crossing of solid- and divided-hoofed pigs, and Angora rabbits of different colours.

Letter details

Letter no.
William Yarrell
Charles Robert Darwin
Sent from
Source of text
DAR 205.7: 287
Physical description
Amem 3pp †

Please cite as

Darwin Correspondence Project, “Letter no. 457,” accessed on 2 October 2023,

Also published in The Correspondence of Charles Darwin, vol. 2