To Chauncey Wright   13 March 1875

Down, | Beckenham, Kent. | Railway Station | Orpington. S.E.R.

March 13. 75

My dear Mr Wright

I write today so that there shall be no delay this time in thanking you for your interesting & long letter received this morning.1 I am sure that you will excuse brevity when I tell you that I am half killing myself in trying to get a book ready for the press.2 I quite agree with what you say about advantages of various degrees of importance being co-selected, & aided by the effects of use &c. The subject seems to me well worth further developement.3 I do not think I have any where noticed the use of the eyebrows, but have long known that they protected the eyes from sweat. During the voyage of the Beagle4 one of the men ascended a lofty hill during a very hot day; he had small eyebrows & his eyes became fearfully inflamed from the sweat running into them

The Portuguese inhabitants were familiar with this evil as I well remember from a ridiculous incident; they immediately brought a woman who was suckling a baby to squirt milk from her breast into his eyes; but he “skedaddled” in dismay. I think you allude to the transverse furrows on the forhead as a protection against sweat; but remember that these incessantly appear on the forheads of Baboons.5

With many thanks believe me to be Yours sincerely | Charles Darwin

P.S. I have been greatly pleased by the notices in the Nation6

CD was making corrections to the manuscript of Insectivorous plants until 29 March 1875 (see CD’s ‘Journal’ (Appendix II)).
In his letter of 24 February 1875, Wright suggested that adaptations could have several functions, and that the principal use or benefit might change over time.
CD spent five years on the Beagle voyage, from 1831 to 1836 (see Journal of researches and Correspondence vol. 1).
In Expression, p. 139, CD described the incessant movement of the eyebrows and ridges of the foreheads of baboons when they were excited or angered. In his letter of 24 February 1875, Wright described how William James suffered from irritated eyes when fishing in the Amazon. Wright also noted that the furrows of the brow were useful as drains or watercourses.
See letter from Chauncey Wright, 24 February 1875 and n. 11. Wright sent CD a copy of his article on books about evolution; it was published in Nation, 18 February 1875, pp. 113–14.

Please cite as “DCP-LETT-9886,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-9886