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Darwin Correspondence Project

From William Preyer   27 April 1871


April 27, 1871

Dear Sir—

I am not sure whether you have received my thanks, my most sincere thanks, for the fifth edition of your “Origin of species” a copy of which you had the great kindness to send me some time ago.1 I have again and again read this wonderful book with intense interest.

I hope the very severe review of your new work in the “Times” which, I hear, was written by the Duke of Argyll has not spoilt your good humour for a minute.2 Although it rather struck me at first on account of the scientific clothing I soon found out that the critic is easily refutable. Wallace’s review in the Academy is by far superior and perhaps his suggestion to publish the “Sexual selection” in a separate book, which might be done in the second edition is particularly acceptable because many who refrain even from thinking on the descent of man would with pleasure stand up for your splendid deductions on sexual selection.3 This part of your imposing investigations being free from arbitrary opinions (which it is impossible to avoid in any treatise on the origin of mankind) is sure, I think, to extend and to confirm Darwinism in the scientific world. Besides Jena there is no University in Germany where your theory is so openly confessed and publicly taught by so many professors. Häckel, Gegenbaur, Dohrn, Strasburger, W. Müller, myself: we are true Darwinians, in our lectures and writings.4

Professor Müller begged me to send you his book on the development of the brain in the animal series. But I must postpone this because the editor has not yet sent a single early copy even to the author.5 I believe it contains many facts in support of your views.

I hope in a few weeks to send you my book on the blood-crystals. It is rather voluminous for a monography containing between 250 and 300 pages and three plates, but it was necessary to collect all the facts relating to this remarkable substance—the colouring matter of the blood—which is different in different species and only in some points the same in all.6

I shall also I hope soon have the pleasure of sending you a paper on the physiological functions of the external ear, wh⁠⟨⁠ich⁠⟩⁠ are nearly naught, contrary to what many physiologists believe. This result is in accordance with your remarks on the rudimentary nature of the concha. But how is it to be explained that only the human ear has an ear-lap? And the ears of the negroes have none.7

I remain, dear Sir, ever yours | truly Preyer

In your Variations etc II, 301 you state: the guinea-pig in Germany has dependent ears.8 I beg permission to state that this positively is not the case. I am occupied with rearing guinea-pigs since 6 years and have not seen a single individual with dependent ears.

CD annotations

1.1 I am … easily refutable. 2.4] crossed pencil
2.4 Wallace’s … book, 2.5] double scored blue crayon; ‘[slow printer]blue crayon
2.11 Besides Jena … the same in all. 4.5] crossed pencil
3.1 Professor Müller … animal series. 3.2] scored blue crayon
5.1 a paper … external ear, 5.2] scored blue crayon
5.5 And … none.] double scored blue crayon
7.1 In … dependent ears 7.2] scored blue crayon
End of last page: ‘Mivart Gorilla | use of’9blue crayon


Origin 5th ed. was published in 1869.
An anonymous review of Descent appeared in The Times, 7 April 1871, p. 3, and 8 April 1871, p. 5. George Douglas Campbell, the duke of Argyll, was known to be opposed to CD’s theory of natural selection.
Alfred Russel Wallace made this suggestion in Wallace 1871c, p. 180.
Preyer refers to Ernst Haeckel, Carl Gegenbaur, Anton Dohrn, Adolf Strasburger, and Wilhelm Müller, all of whom were at the University of Jena.
Preyer refers to Beiträge zur pathologischen Anatomie und Physiologie des menschlichen Rückenmarks (Contributions on pathological anatomy and physiology of the human spinal cord; W. Müller 1871). Müller’s editor has not been identified.
There is a copy of Preyer’s Blutkrystalle (Blood-crystals; Preyer 1871) in the Darwin Library–Down. The published volume is 263 pages long with three colour plates. He devotes a chapter to the colouring agents in the blood of humans and other animals (pp. 108–15).
In Descent 1: 21, CD wrote, ‘The whole external shell of the ear may be considered a rudiment.’ Preyer’s paper has not been identified, but his observations on the earlobe are cited in Descent 2d ed., pp. 14–15.
In Variation 2d ed., 2: 291, the phrase is changed to ‘the guinea-pig formerly in Germany’.
In Descent 2d ed., p. 15, CD cited Preyer’s observations of the human earlobe along with St George Jackson Mivart’s observations of gorilla ears.


Descent 2d ed.: The descent of man, and selection in relation to sex. By Charles Darwin. 2d edition. London: John Murray. 1874.

Descent: The descent of man, and selection in relation to sex. By Charles Darwin. 2 vols. London: John Murray. 1871.

Müller, Wilhelm. 1871. Beiträge zur pathologischen Anatomie und Physiologie des menschlichen Rückenmarks. Leipzig: Voss.

Origin 5th ed.: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. 5th edition, with additions and corrections. By Charles Darwin. London: John Murray. 1869.

Preyer, William Thierry. 1871. Die Blutkrystalle. Jena: Mauke’s Verlag.

Variation 2d ed.: The variation of animals and plants under domestication. By Charles Darwin. 2d edition. 2 vols. London: John Murray. 1875.


Thanks CD for Origin, 5th ed.

Comments on reviews of Descent by the Duke of Argyll and A. R. Wallace.

Lists the Darwinian professors at Jena.

WP’s work shows external ear to have no physiological functions.

W. Müller’s book not yet arrived. Will send Müller’s next works.

Letter details

Letter no.
William Thierry (William) Preyer
Charles Robert Darwin
Sent from
Source of text
DAR 87: 52, DAR 174: 69
Physical description
ALS 4pp

Please cite as

Darwin Correspondence Project, “Letter no. 7721,” accessed on 23 May 2024,

Also published in The Correspondence of Charles Darwin, vol. 19