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Darwin Correspondence Project

To W. T. Preyer   17 February [1870]1

Down. | Beckenham | Kent. S.E.

Feb. 17

My dear Sir

I am very much obliged for your extremely kind letter & for your several presents.2 Although your appreciation of my work is certainly too high, yet it is very encouraging to me, especially as yesterday I read two pamphets, just published in England, in which every form of abuse is heaped on me.3 I am called, for instance, a “filthy dreamer”.— You seem to be doing splendid work in physiology, the noblest of sciences, as I have long thought it. What you say about the differences of the blood-crystals is truly astonishing.4 I am also much interested by what you say of the different effect of Prussic acid on different individuals of the same species: I remember some years ago wishing in vain for information on this head. I think it arose from observing how differently in quickness (whether due to rate of respiration or to direct action of the poison I could not tell) the vapour acted on different insects. I remember Bees died instantly, but (I think,) it was a Longicorn beetle which resisted all effects for an astonishing time.—5

R. W. Darwin is my Father, but I believe he was greatly aided in his paper on optics by his Father Erasmus D.6

I have really nothing of interest about myself, but as you desire it, I will scribble whatever occurs to me.— I derived no advantage from the Lectures at Edinburgh, for they were infinitely dull & cured me of any taste for Geology for 3 years. Dr Grant7 was not a Professor, but worked at zoology out of pure love, & his Society was a great encouragement. I used to amuse myself with examining marine animals, but I did so solely for amusement. I believe I was the first person who ever saw the earliest locomotive egg-like state of a Bryozoon: I showed it to Grant, who stated so at the meeting of the Wernerian Nat. Hist. Soc. & this little discovery was an immense encouragement.—8 I was disgusted at anatomy & attended only 2 or 3 Lectures & this has been ever since an irreparable loss to me.— When I went to Cambridge, I became a most enthusiastic collector of Coleoptera; but again only for amusement. If any one told me the name of a Beetle, I thought I knew all that anyone could desire; & I believe I never ever looked even at the oral organs of any insect! Yet I worked like a slave at collecting. Henslow’s Society was a great charm & benefit to me, & I liked much his Lecture on Botany.9 All my early life I was mad for collecting, minerals, shells, plants, Bird-skins have all had their turn. Near the end of my Cambridge life Henslow persuaded me to begin Geology. I was always very fond of observing the habits of Birds, & White’s Nat. Hist. of Selborne,10 thus had much influence on my mind. But of all books, Humboldt’s Travels had by far the greatest influence—11 I read large parts over & over again.— I had nearly managed to get a party to go to the Canary Islds, when the offer of joining the Beagle was made to me & joyfully accepted.12 I suppose, however, no ever started worse prepared than I was except as a mere collector. I knew nothing of anatomy, & had never read any systematic work on Zoology— I had never touched a compound microscope & had begun Geology for only about 6 months. But I took out plenty of Books13 & worked as hard as I could & dissected roughly all sorts of the lower marine animals. Here I felt fearfully the want of practice & knowledge. My education in fact began on board the Beagle. I remember nothing previously which deserved to be called education except some experimental work at chemistry when a school-boy with my Brother.—14 No doubt collecting largely in so many branches had improved my powers of observation.—

I never wrote so much about myself in my life, & I hope it may be worth your reading, but I doubt.—

Believe me, my dear Sir | Yours sincerely | Ch. Darwin

I do not know whether you will care to see extracts from my letters printed by Prof. Henslow, but I send a copy by this Post.—15


The year is established by the relationship between material in this letter and Preyer’s article on CD in Ausland, published on 2 April 1870 (Preyer 1870b). See also Correspondence vol. 17, letter to W. T. Preyer, [before 21 March 1869], and letter from W. T. Preyer, 21 March 1869.
See letter from W. T. Preyer, [before 17 February 1870]. Preyer enclosed a copy of Preyer 1868, of which there is a copy in the Darwin Pamphlet Collection–CUL, and possibly also Preyer 1869.
The pamphlets have not been identified.
See Preyer 1868.
See Preyer 1869. CD had used prussic acid gas to kill pigeons and insects (see Correspondence vol. 5, letter to W. D. Fox, 22 [July 1855]). He had also been interested in the effects of prussic acid (also known as hydrocyanic acid) on the insectivorous plant Drosera (see Correspondence vol. 10, letter to J. D. Hooker, 26 September [1862], and Insectivorous plants, pp. 195–6).
See letter from W. T. Preyer, [before 17 February 1870]. CD refers to Robert Waring Darwin, Erasmus Darwin, and R. W. Darwin 1786.
Robert Edmond Grant.
CD identified the organs of motion of the ova of Flustra; his observations were read by Grant at meetings of the Plinian and Wernerian Societies in Edinburgh in 1827 (see DAR 118 (Collected papers 2: 285–91); see also Correspondence vol. 1, Appendix I n. 14).
John Stevens Henslow had been professor of botany at Cambridge. On their relationship, see Walters and Stow 2001.
CD refers to Gilbert White’s Natural history of Selborne (White 1825).
CD refers to Alexander von Humboldt and to Humboldt 1814–29.
See Correspondence vol. 1.
For the books CD took on the Beagle, see Correspondence vol. 1, Appendix IV.
CD refers to Erasmus Alvey Darwin (see Correspondence vol. 1).
CD refers to [J. S. Henslow ed.] 1835.


Comments on effects of prussic acid on different individuals of the same species and other physiological research by WP.

Provides information about his studies in Edinburgh and Cambridge and qualifications he had for Beagle voyage. Describes influence of R. E. Grant and J. S. Henslow.

Letter details

Letter no.
Charles Robert Darwin
William Thierry (William) Preyer
Sent from
Source of text
Ralph Colp Jr (private collection)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 7112,” accessed on 16 January 2019,

Also published in The Correspondence of Charles Darwin, vol. 18