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Darwin Correspondence Project

From H. W. Jackson   20 June 1874

15 Limes Terrace | Lewisham, S.E.

20 June 1874

Dear Sir,

I beg to call your attention to an instance of correlation in colour which I have, for some months past, observed as invariable. It is that a cat with a white throat, or with a white spot on the throat, has always four white feet.1

Black & white, or coloured & white cattle have usually from what I have observed of late, white tails.

I noticed last year when I was in Auvergne that the extremities of the tails of the black & white sheep were invariably white.

That dogs which have any white about their bodies usually have white-tipped tails has been remarked by yourself—2 the exceptions are I think most frequent in curly-haired dogs.

I trust that you will not give yourself the trouble to reply to this letter, & I beg to remain, with the profoundest respect, | Yours faithfully | H. W. Jackson

Charles Darwin, Esqre | F.R.S. &c &c.

CD annotations

Top of letter: ‘Correlation’ ink


CD had discussed correlation in the colouring of various parts of the bodies of birds and animals in Variation (see especially Variation 2: 324); he cited Jackson for this information in Variation 2d ed., p. 316.
See Variation 1: 29 and n. 40.


Variation 2d ed.: The variation of animals and plants under domestication. By Charles Darwin. 2d edition. 2 vols. London: John Murray. 1875.

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


Cites instances of invariable correlations of colour he has observed in cats, dogs, and sheep. [See Variation, 2d ed., 2: 316.]

Letter details

Letter no.
Henry William Jackson
Charles Robert Darwin
Sent from
Source of text
DAR 47: 203–4
Physical description
3pp †

Please cite as

Darwin Correspondence Project, “Letter no. 9503,” accessed on 19 September 2021,

Also published in The Correspondence of Charles Darwin, vol. 22