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Darwin Correspondence Project

To Henry Denny   28 January [1865]1

Down. | Bromley. | Kent. S.E.

Jan. 28th

Dear Sir

I thank you very sincerely for your interesting note & answers to my queries.2 I am also much obliged for Mr Murray’s paper;3 (returned by this Post) but the interest of this paper to my mind is much enhanced or rather almost wholly depends on a sentence in your note, viz. “Yet the same species of Lice infest the different varieties of Fowl, pigeon & dog.” Now as I understand this, you have never observed distinct varieties of the same species of Pediculus on different domestic varieties.— If, as is probable, I allude to this subject, I shd. like to quote on your authority this statement.4 But then (though I am ashamed to give so much trouble) I shd be glad to know whether you have often looked to the vars. of our domestic mammals & birds. It is not probable, but if you have ever received pediculi from the domesticated animals inhabiting distant lands, or recently brought from such lands & have found them the same, this wd. add immensely to the value of the statement, I presume you have not attended to the domestic vars. of other animals, besides Fowls, Pigeons & Dogs.5 I fear that you will think me very troublesome; pray excuse me & believe me—

Yours very faithfully | Ch. Darwin


The year is established by the relationship between this letter and the letter from Henry Denny, 23 January 1865.
Murray 1860. See letter from Henry Denny, 23 January 1865 and n. 3.
Denny’s statement is cited in Descent 1: 219.


Returns [Andrew] Murray’s paper;

especially values HD’s note that the same species of lice infect the different varieties of fowl, pigeon, and dog. Further queries about the relationship of the same species of pediculi to different domestic varieties.

Letter details

Letter no.
Charles Robert Darwin
Henry Denny
Sent from
Source of text
Alfred Denny Museum, University of Sheffield
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 4756F,” accessed on 20 August 2017,

Also published in The Correspondence of Charles Darwin, vol. 13