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Letter 7112

Darwin, C. R. to Preyer, T. W.

17 Feb [1870]


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.


Down. | Beckenham | Kent. S.E.

Feb. 17

My dear Sir

I am very much obliged for your extremely kind letter & for yourseveral presents.f2 Although your appreciation of my work is certainlytoo high, yet it is very encouraging to me, especially as yesterdayI read two pamphets, just published in England, in which every formof abuse is heaped on me.f3 I am called, for instance, a “filthydreamer”.— You seem to be doing splendid work in physiology, thenoblest of sciences, as I have long thought it. What you sayabout the differences of the blood-crystals is truly astonishing.f4I am also much interested by what you say of the different effectof Prussic acid on different individuals of the same species:I remember some years ago wishing in vain for information on thishead. I think it arose from observing how differently in quickness(whether due to rate of respiration or to direct action of the poisonI could not tell) the vapour acted on different insects. I rememberBees died instantly, but (I think,) it was a Longicorn beetle whichresisted all effects for an astonishing time.—f5

R. W. Darwin is my Father, but I believe he was greatly aidedin his paper on optics by his Father Erasmus D.f6

I have really nothing of interest about myself, but as you desire it,I will scribble whatever occurs to me.— I derived no advantagefrom the Lectures at Edinburgh, for they were infinitely dull & curedme of any taste for Geology for 3 years. Dr Grantf7 was not aProfessor, but worked at zoology out of pure love, & his Society wasa great encouragement. I used to amuse myself with examining marineanimals, but I did so solely for amusement. I believe I was the firstperson who ever saw the earliest locomotive egg-like state of aBryozoon: I showed it to Grant, who stated so at the meeting of theWernerian Nat. Hist. Soc. & this little discovery was an immenseencouragement.—f8 I was disgusted at anatomy & attended only2 or 3 Lectures & this has been ever since an irreparable loss to me.—When I went to Cambridge, I became a most enthusiastic collectorof Coleoptera; but again only for amusement. If any one told me thename 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 greatcharm & benefit to me, & I liked much his Lecture on Botany.f9 Allmy early life I was mad for collecting, minerals, shells, plants,Bird-skins have all had their turn. Near the end of my Cambridgelife Henslow persuaded me to begin Geology. I was always very fondof observing the habits of Birds, & White’s Nat. Hist. of Selborne,f10thus had much influence on my mind. But of all books, Humboldt’sTravels had by far the greatest influence—f11 I read large parts over& over again.— I had nearly managed to get a party to go to theCanary Islds, when the offer of joining the Beagle was made tome & joyfully accepted.f12 I suppose, however, no ever started worse preparedthan I was except as a mere collector. I knew nothing of anatomy,& had never read any systematic work on Zoology— I had nevertouched a compound microscope & had begun Geology for only about 6 months.But I took out plenty of Booksf13 & worked as hard as I could & dissectedroughly all sorts of the lower marine animals. Here I felt fearfullythe want of practice & knowledge. My education in fact began on boardthe Beagle. I remember nothing previously which deserved to becalled education except some experimental work at chemistry when aschool-boy with my Brother.—f14 No doubt collecting largely in so many brancheshad improved my powers of observation.—

I never wrote so much about myself in my life, & I hope it may beworth 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 lettersprinted by Prof. Henslow, but I send a copy by this Post.—f15

Ralph Colp, Jr (private collection)



The year is established by the relationship between material inthis letter and Preyer’s article on CD in Ausland, published on2 April 1870 (Preyer 1870b). See also Correspondence vol. 17, letterto 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]. Preyerenclosed a copy of Preyer 1868, of which there is a copy inthe 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 andinsects (see Correspondence vol. 5, letter to W. D. Fox, 22 [July1855]). 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 refersto Robert Waring Darwin, Erasmus Darwin, and R. W. Darwin 1786.
Robert Edmond Grant.
CD identified the organs of motion of the ova of Flustra; hisobservations were read by Grant at meetings of the Plinian andWernerian 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. Ontheir relationship, see Walters and Stow 2001.
CD refers to Gilbert White’s Natural history of Selborne (White1825).
CD refers to Alexander von Humboldt and to Humboldt 1814–29.
See Correspondence vol. 1.
For the books CD took on the Beagle, see Correspondencevol. 1, Appendix IV.
CD refers to Erasmus Alvey Darwin (see Correspondence vol. 1).
CD refers to [J. S. Henslow ed.] 1835.
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