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Darwin Correspondence Project

From Francis Darwin   [before 22 August 1872]1

6 QA

Dear Father

Sutton says that the monkeys are often sick but he cannot say whether they do it voluntarily or not—2 But as they often do it when it good health it looks as if they could I think

Yrs affec | F Darwin

CD note:

This suspicion receives some slight support from the fact, of which I am assured by Mr S. that the m. in the z. Gardens often vomit [‘; & that [interl and del] they do so’ del] when in good health, which looks as if [‘this was effected’ del above del ‘they could vomit’] it was done voluntarily, [‘they’ del] we can see that with [mankind] owing to *his power of teaching [pencil, after del pencil ‘handing down’, above del ‘the acquisition of language & the [interl] tradition’] knowledge, *by [communicating] [pencil, above del ‘the power of voluntarily throwing up of’] what food to avoid there would be less occasion *than with *some of [interl] the [inferior] [del & restored] [animals] to use the faculty [above del ‘power’] of voluntarily throwing up food from the [stomach]; so that the power wd tend *through disuse [interl] to be lost.—3


The date is based on the day on which CD completed the proofs for Expression, 22 August 1872 (CD’s ‘Journal’ (Appendix II)). This was the last day on which he could have added the information contained in the letter.
Seth Sutton was a keeper at the zoological gardens in Regent’s Park, London (Archives of the Zoological Society of London, Freeman 1978).
CD used this information, with almost the same wording, in Expression, p. 259. He argued that the tendency to retch or vomit involuntarily at the thought of having eaten a particular food suggested that human ancestors once had the ability to vomit voluntarily. This suspicion receives support from the fact, of which I am assured by Mr. Sutton, that the monkeys in the Zoological Gardens often vomit whilst in perfect health, which looks as if the act were voluntary. We can see that as man is able to communicate by language to his children and others, the knowledge of the kinds of food to be avoided, he would have little occasion to use the faculty of voluntary rejection; so that this power would tend to be lost through disuse.


Expression: The expression of the emotions in man and animals. By Charles Darwin. London: John Murray. 1872.

Freeman, Richard Broke. 1978. Charles Darwin: a companion. Folkestone, Kent: William Dawson & Sons. Hamden, Conn.: Archon Books, Shoe String Press.


Sutton says monkeys often vomit, but cannot say whether they do it voluntarily.

Letter details

Letter no.
Francis Darwin
Charles Robert Darwin
Sent from
London, Queen Anne St, 6
Source of text
DAR 195.3: 67
Physical description
ALS 1p, CD note 1p

Please cite as

Darwin Correspondence Project, “Letter no. 5556,” accessed on 12 August 2022,

Also published in The Correspondence of Charles Darwin, vol. 20