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Darwin Correspondence Project

To Henry Denny   17 January [1865]1

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

Jan 17th

Dear Sir

I am much obliged for the M.S. which I had quite forgotten & for your note.2 I am glad to hear that you have resumed your long discontinued labour on the Anoplura,3 for I always thought that they would lead to valuable & curious results.

Will you excuse me asking you to inform me whether the Chiloe pediculi4 form a distinct species or well-marked variety? Is it the case that the Lice differ on different races of man; & can you believe, from any other evidence which you may possess, the statement by Mr Marshall about the Polynesian lice not living on a distinct race of man?5 I shd. be grateful for any information on this head, especially if you would permit me to quote you as my authority.6 But perhaps you will not have spare time to write to me on this head.—

Pray believe me | Dear Sir | Yours very faithfully | Ch. Darwin


The year is established by the relationship of this letter to the letter from Henry Denny, 23 January 1865.
Denny’s letter has not been found. The manuscript referred to was a portion of CD’s Beagle zoology notes (DAR 30 and 31; see also R. D. Keynes ed. 2000). In 1844, Denny had initiated a correspondence with CD on the occurrence of lice on animals and on humans while pursuing research on Anoplura (lice; see Correspondence vol. 3, letter to Henry Denny, 20 January [1844], and Denny 1844). CD had provided Denny with Beagle lice specimens and, apparently, a page of notes on Pediculus, a genus of Anoplura, from his Beagle zoology notes (see Correspondence vol. 3, Correspondence vol. 4, letter to Henry Denny, 21 July [1847], and this volume, Supplement, letter to Henry Denny, [27 July – 10 August 1844]). The page of notes, clearly folded for enclosure in an envelope, is in DAR 31: 315 (see also R. D. Keynes ed. 2000, p. 283, and n. 4, below).
Following the publication of his account of the British Anoplura (Denny 1842), Denny received a grant from the British Association for the Advancement of Science to report on exotic Anoplura (Report of the 14th meeting of the British Association for the Advancement of Science, held at York in 1844, p. 392). The report was never published.
CD’s ‘Catalogue for specimens in spirits of wine’ (Down House MS, Notebook 63.2, entry 1185) lists a Pediculus collected from the island of Chiloé, Chile; however, this specimen has not been found (see R. D. Keynes ed. 2000, pp. 283, 358, 410). The Denny collection at the University Museum, Oxford, contains four unidentified lice that may also have been collected by CD in Chiloé (see K. G. V. Smith 1987, pp. 29, 88).
Marshall (or Martial) was a surgeon on a British whaling vessel whom CD met in 1834 while on Chiloé during the Beagle voyage (see Correspondence vol. 3, letter to Henry Denny, 3 June [1844]). He has not been further identified. Marshall reported that lice found on the Sandwich islanders were unable to survive on the bodies of English sailors. His information was recorded in CD’s Beagle zoology notes (DAR 31: 315 and R. D. Keynes ed. 2000, p. 283), and later published in Descent 1: 219–20 in a discussion of the unity of the human species. In his ‘Catalogue of animals in spirits and wine’ (Down House MS, Notebook 63.1, entry 646, R. D. Keynes ed. 2000, p. 340), CD noted: it would be interesting to compare these parasites with those inhabiting an European individual to observe whether they have been altered by transportation & domestication: It would be curious to make analogous observation with respect to various tribes of men.
See letter from Henry Denny, 23 January 1865 and n. 2.


Pleased to learn that HD has resumed research on Anoplura.

Are Chiloe pediculi a distinct species?

Do lice differ on different races of humans?

Is there evidence supporting Mr Marshall’s statement about Polynesian lice?

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. 4747F,” accessed on 26 April 2017,

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