To F. C. Donders   18 March 1871

Down. Beckenham | Kent

Mar 18. 1871

My dear Professor Donders.

Very many thanks for your kind letter. I have been interested by what you tell me about your views published in 1848, & I wish I could read your Essay.1 It is clear to me that you were as near as possible in preceeding me on the subject of natural Selection. You will find very little that is new to you in my last book; whatever merit it may possess consists in the grouping of the facts & in deductions from them. I am now at work on my Essay on Expression.2

My last book fatigued me much & I have had much correspondence, otherwise I shd. have written to you long ago, as I often intended, to tell you in how high a degree your Essay published in Beale’s Archives interested me.3 I have heard others express their admiration at the complete manner in which you have treated the subject. Your confirmation of Sir C Bell’s rather loose statement has been of paramount importance for my work—4

You told me that I might make further enquiries of you. When a person is lost in meditation, his eyes often appear as if fixed on a distant object & the lower eyelids may be seen to contract & become wrinkled. I suppose the idea is quite fanciful, but as you say that the eyeball advances in adaptation for vision for close objects, would the eyeball have to be pushed backwards in adaptation for distant objects? If so can the wrinkling of the lower eyelids, which has often perplexed me, act in pushing back the eyeball? But as I have said I daresay this is quite fanciful. Gratiolet says that the pupil contracts in rage, and dilates enormously in terror.5 I have not found this great anatomist quite trustworthy on such points, & am making enquiries on this subject. But I am inclined to believe him, as the old Scotch anatomist Munro says that the iris of parrots contract & dilate under passions, independently of the amount of light.6 Can you give any explanation of this statement?

When the heart beats hard & quick, & the head becomes somewhat congested with blood in any illness, does the pupil contract? Does the pupil dilate in incipient faintness, or in utter prostration, as when after a severe race a man is pallid, bathed in perspiration, with all his muscles quivering? Or in extreme prostration from any illness?

With cordial thanks for all your kindness and invaluable assistance, | believe me yours very sincerely | Charles Darwin

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2
Expression.
3
CD refers to Donders 1870 (‘On the action of the eye-lids in determination of blood from expiratory effort’). It was published in Archives of Medicine, which was edited by Lionel Smith Beale.
4
See Expression, pp. 158–62, for CD’s discussion of the contraction of muscles around the eye during violent expiration. CD referred to Donders’s confirmation of Charles Bell’s assertion that the contraction was to prevent injury to the eye (Expression, p. 162).
5
Louis Pierre Gratiolet noted these movements of the pupil in Gratiolet [1865], p. 346.
6
CD refers to Alexander Monro (secundus); the statement about the parrot’s eye is in Monro 1783, p. 96. CD referred to Monro’s statement in Expression, p. 304.

Please cite as “DCP-LETT-7595,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-7595