skip to content

Darwin Correspondence Project

To J. D. Hooker   10 May 1848

Down Farnborough Kent

May 10/48/

My dear Hooker

I was indeed delighted to see your hand-writing; but I felt almost sorry when I beheld how long a letter you had written:1 I know that you are indomitable in work, but remember how precious your time is & do not waste it on your friends, however much pleasure you may give them. Such a letter would have cost me half a day’s work. How capitally you seem going on: I do envy you the sight of all the glorious vegetation. I am much pleased & surprised that you have been able to observe so much in the animal world. No doubt you keep a Journal, & an excellent one it will be, I am sure, when published.2 All these animal facts will tell capitally in it. I can quite comprehend the difficulty, you mention, about not knowing what is known zoologically in India: but facts observed, as you will observe them, are none the worse for reiterating.

Did you see Mr Blyth3 in Calcutta; he would be a capital man to tell you what is known about Indian zoology, at least in the Vertebrata: he is a very clever, odd, wild fellow, who will never do, what he could do, from not sticking to any one subject. By the way, if you should see him at any time, try not to forget to to remember me very kindly to him: I liked all I saw of him.—

Your letter was the very one to charm me, with all its facts for my species-Book, & truly obliged, I am, for so kind a remembrance of me. Do not forget to make enquiries about origin, even if only traditionally known of any vars. of domestic quadrupeds, birds, silkworms &c.— (Are there domestic Bees? if so hive ought to brough home.)

Of all the facts you mention, that of the wild Bhil, when breeding with the domestic, producing offspring, somewhat sterile, is the most surprising; surely they must be different species. Most zoologists would absolutely disbelieve such a statement & consider the result as a proof that they were distinct species: I do not go so far as that, but the case seems highly improbable: Blyth has studied the Indian Ruminantia.—

I have been much struck about what you say of lowland plants asending mountains, but the Alpine not descending. How I do hope you will get up some mountains in Borneo; how curious the result will be. By the way I never heard from you, what affinity the Maldiva flora has, which is cruel, as you tempted me by making me guess.4 I sometimes groan over your Indian Journey, when I think over all your locked up riches: when shall I see a memoir on insular Floras, & on the Pacific.5 What a grand subject, Alpine Floras of the world would be, as far as known: and then you have never given a coup d’œil on the similarity & dissimilarity of Arctic & Antarctic floras. Well thank Heavens, when you do come back, you will be nolens-volens a fixture.— I am particularly glad you have been at the Coal: I have often since you went gone on maundering on the subject,6 & I shall never rest easy in Down church-yard, without the problem be solved by someone before I die.

Talking of dying makes me tell you that my confounded stomach is much the same; indeed of late has been rather worse, but for the last year, I think, I have been able to do more work. I have done nothing besides the Barnacles, except indeed a little theoretical paper on Erratic Boulders, & Scientific Geological Instructions for the Admiralty Volume,7 which cost me some trouble. This work, which is edited by Sir J. Herschel is a very good job, in as much as, the Captains of Men of War, will now see that the Admiralty care for science & so will favour naturalists on board. As for a man, who is not scientific by nature, I do not believe Instructions will do him any good; & if he be scientific & good for anything the Instructions will be superfluous: I do not know who does the Botany;8 Owen does the zoology & I have sent him an account of my new simple microscope, which I consider perfect, even better than your’s of Chevalier’s.9 N.B. I have got a 18 object glass, & it is grand.— I have been getting on well with my beloved cirripedia, & got more skilful in dissection: I have worked out the nervous system pretty well in several genera, & made out their ears & nostrils,10 which were quite unknown. I have lately got a bisexual cirripede, the male being microscopically small & parasitic within the sack of the female;11 I tell you this to boast of my species theory, for the nearest & closely allied genus to it is, as usual, hermaphrodite, but I had observed some minute parasites adhering to it, & these parasites, I now can show, are supplemental males, the male organs in the hermaphrodite being unusually small, though perfect & containing zoosperms: so we have almost a polygamous animal, simple females alone being wanting.12 I never shd. have made this out, had not my species theory convinced me, that an hermaphrodite species must pass into a bisexual species by insensibly small stages, & here we have it, for the male organs in the hermaphrodite are beginning to fail, & independent males ready formed. But I can hardly explain what I mean, & you will perhaps wish my Barnacles & Species theory al Diabolo together. But I don’t care what you say, my species theory is all gospel.—

We have had only one party here viz of the Lyells, Forbes, Owen & Ramsay, & we both missed you & Falconer very much.13 I do not much think we shall have another for my poor dear wife will be employed in July in bringing into the world, under the influence of Chloriform, a sixth little (d) as Henslow calls my children.14 I know more of your history than you will suppose, for Miss Henslow most goodnaturedly sent me a packet of your letters, & she wrote me so nice a little note that it made me quite proud.—

I have not heard of anything in the scientific line which wd. interest you. Sir. H. Delabeche gave a very long & rather dull address:15 the most interesting part was from Sir J. Ross.16 Mr Beete Jukes figured in it very prominently; it really is a very nice quality in Sir Henry, the manner in which he pushes forward his subordinates.17 Jukes has since read, what was considered a very valuable paper:18 the man not content with moustaches, now sports an entire beard, & I am sure thinks himself like Jupiter tonans. There was a short time since, a not very creditable discussion at meeting of Royal Soc. where Owen fell foul of Mantell with fury & contempt about Belemnites.19 What wretched doings come from the ardor of fame; the love of truth alone would never make one man attack another bitterly.

My paper is full, so I must wish you with all my heart farewell. Heaven grant that your health may keep good: I sincerely grieve that your chest yet troubles you: pray do not work too hard, my dear Hooker, Your affectionate friend | C. Darwin.—


Letter from J. D. Hooker, 20 February – 16 [March] 1848.
Hooker’s Himalayan journals were eventually published in two volumes (J. D. Hooker 1854).
Edward Blyth had gone to India in 1841 to become curator of the museum of the Asiatic Society of Bengal. CD’s notes on Blyth’s articles in the Annals and Magazine of Natural History and the use to which they were put in the Origin are discussed in Sheets-Pyenson 1981.
Hooker eventually made insular floras the subject of a lecture at the British Association meeting of 1866 (J. D. Hooker 1867). He had ‘long intended to pay particular attention to the Pacific Isld. flora’ (Correspondence vol. 3, letter from J. D. Hooker, 9 March 1844), but no work on Pacific floras in general was published, although one of his papers dealt with the vegetation of the Galápagos as compared with other tropical islands (J. D. Hooker 1851b).
See letter to J. D. Hooker, [1 May 1847], and subsequent correspondence with Hooker during May 1847.
‘On the transportal of erratic boulders from a lower to a higher level’ (Collected papers 1: 218–27) and the chapter on geology in Herschel ed. 1849 (Collected papers 1: 227–50).
The chapter on botany in Herschel ed. 1849 was written by William Jackson Hooker, J. D. Hooker’s father.
See Living Cirripedia (1851): 49–55.
CD here uses the term ‘bisexual’ to mean that the species has separate males and females. For his usual use of the term, see letter to J. S. Henslow, [1 April 1848], n. 6.
This is the first description of CD’s discovery in the genus Scalpellum of what he later called ‘complemental males’, those which appeared to supplement a hermaphrodite rather than pairing with a true female. In letter to J. S. Henslow, [1 April 1848], CD mentioned finding little larva-like males parasitic on true females in Ibla, and in letter to J. D. Hooker, 6 October [1848], he mentioned a ‘far more curious case’ which he said he would refrain from describing until he was more certain of its nature. CD related the history of this discovery in Living Cirripedia (1851): 231–2: When first dissecting Scalpellum vulgare, I was surprised at the almost constant presence of one or more very minute parasites, on the margins of both scuta … I carelessly dissected one or two specimens, and concluded that they belonged to some new class or order amongst the Articulata; but did not at that time even conjecture, that they were Cirripedes. Many months afterwards, when I had seen in Ibla, that an hermaphrodite could have a complemental male, I … resolved to look with care at these parasites; on doing so, I soon discovered that they were Cirripedes … These facts, together with those given under Ibla (and had it not been for this latter genus, I never probably should have even struck on the right track in my investigation,) appear sufficient to justify me, in provisionally considering the truly wonderful parasites of the several species of Scalpellum, as Males and Complemental Males. This discovery greatly interested him as a case in nature which illustrated his earlier theory of the development of separate sexes from an ancestral hermaphrodite (see Notebook D, p. 162 (Notebooks)). There he proposed that the organs of either one or the other sex gradually became abortive until there were two distinct sexes in different individuals.
The weekend party took place on 12–13 February (see letter to A. C. Ramsay, 4 February [1848], and ‘Journal’ (Correspondence vol. 4, Appendix I)).
Henry Thomas De la Beche was president of the Geological Society, and the reference is to his anniversary address (De la Beche 1848).
James Clark Ross, captain of the Antarctic expedition of 1839–43, on which Hooker served as assistant-surgeon (see De la Beche 1848, pp. lxxxiii).
Joseph Beete Jukes, who was employed in North Wales by the Geological Survey, of which De la Beche was director-general (see De la Beche 1848, pp. xxxviii, xlv, lxiv, xc).
Jukes and Selwyn 1848, read on 5 April 1848 at a meeting of the Geological Society. CD, however, did not attend (Council Minute Books, Geological Society Archives). See also letter to H. T. De la Beche, 19 August [1847], n. 2.
Gideon Algernon Mantell, who produced evidence at a meeting of the Royal Society on 23 March 1848 that Richard Owen had misunderstood the structure of belemnites (Mantell 1848). Owen defended his work, for which he had received the Royal Medal in 1846, in a ‘virulent attack’ on Mantell (Curwen ed. 1940, p. 221; Spokes 1927, pp. 205–6).


Confident of species theory as result of applying it to cirripede sexual systems.

CD’s opinion of E. Blyth. JDH should meet Blyth, inquire about domesticated varieties, study insular flora, solve coal-plant problem.

Letter details

Letter no.
Charles Robert Darwin
Joseph Dalton Hooker
Sent from
Source of text
DAR 114: 112
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 1174,” accessed on 23 June 2017,

Also published in The Correspondence of Charles Darwin, vol. 4