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Darwin Correspondence Project

To T. H. Huxley   26 September [1857]1

Down Bromley Kent

Sept. 26th

My dear Huxley

Thanks for your very pleasant note.—2 It amuses me to see what a bug-bear I have made myself to you; when having written some very pungent & good sentences it must be very disagreeable to have my face rise up like an ugly ghost.— I have always suspected Agassiz of superficiality & wretched reasoning powers; but I think such men do immense good in their way.3 See how he stirred up all Europe about Glaciers.— By the way Lyell has been at the Glaciers, or rather their effects, & seems to have done good work in testing & judging what others have done.4

In regard to Blatta I have looked into Westwood,5 & see Marcel de Serres have written on anatomy of Orthoptera in Annal. du Museum. Tom. 12, 14, & 17.6

Audouin & Brullé in Hist. Nat. Ins. vol 9. 1836. but I do not know what work this is.—7

Duthiers in Annal. des Sc. Nat. 3d. series. Zoolog. Tom. 12th & 13th, has written good paper on homologies & structure of ovipositor in Orthoptera & Hymenoptera,8 but I cannot remember whether he attended to Male organs; Audouin, I know, has attended especially to male organs in Hymenoptera.—9 I do indeed pity the Hen-Cock-Roach from your description of the male apparatus.—10

I am very glad to hear how hearty you have returned from the Glaciers,11

Farewell | Yours very truly | C. Darwin

In regard to Classification, & all the endless disputes about the “Natural System which no two authors define in same way, I believe it ought, in accordance to my heteredox notions, to be simply genealogical.—12 But as we have no written pedigrees, you will, perhaps, say this will not help much; but I think it ultimately will, whenever heteredoxy becomes orthodoxy, for it will clear away an immense amount of rubbish about the value of characters &—will make the difference between analogy & homology, clear.—13 The time will come I believe, though I shall not live to see it, when we shall have very fairly true genealogical trees of each great kingdom of nature.—

I see Hummel has written on the development of Blattæ, (whether anatomical I know not) in his Essais Entomologique Nor. 1. St. Petersburgh 1821.14


The year is given by the reference to Huxley’s recent return ‘from the Glaciers’ (see n. 11, below) and to his criticisms of Louis Agassiz’s investigations of glacial phenomena (see n. 3, below).
The letter has not been found.
Huxley had evidently described to CD his forthcoming account of experiments and observations made on glaciers during his visit to the Swiss Alps in August 1857. In a published letter to John Tyndall (T. H. Huxley 1857b), Huxley criticized Agassiz’s earlier investigations of the same glaciers (Agassiz 1847).
Charles and Mary Lyell were making a tour of southern Europe. While in Switzerland, Lyell had studied glacial phenomena and had reported some of his observations in letters to Leonard Horner (K. M. Lyell ed. 1881, 2: 249–72).
Serres 1809b and 1811 both appeared in the Annales du Muséum d’Histoire Naturelle. Another earlier memoir on Orthoptera (Serres 1809a) was published in the Journal de Physique, de Chimie, et de l’Histoire Naturelle.
Volume 9 of Audouin and Brullé 1834–7. This series, Histoire naturelle des insectes, was intended to run to twelve volumes. Only four volumes, all by Gaspard Auguste Brullé, were published.
Lacaze-Duthiers 1852a and 1852b.
In a paper on Aphis, which he was preparing at that time, Huxley stated that the only other adult insect whose sexual anatomy he had studied with care was the common cockroach, Blatta orientalis (T. H. Huxley 1857–8, pp. 230–1).
Huxley had returned from the Swiss Alps by 3 September 1857 (L. Huxley ed. 1900, 1: 146).
CD explained his views on classification in chapter 13 of Origin, where he stated that ‘the natural system is founded on descent with modification; that the characters which naturalists consider as showing true affinity between any two or more species, are those which have been inherited from a common parent, and, in so far, all true classification is genealogical’ (Origin, p. 420).
Hummel 1821, cited in Westwood 1839–40, 1: 421 (see note 5, above).


Agassiz, Louis. 1847. Nouvelles études et expériences sur les glaciers actuels, leur structure, leur progression et leur action physique sur le sol. Paris: Victor Masson.

Audouin, Jean Victor. 1824. Recherches anatomiques sur la femelle du Drile jaunatre, et sur le mâle de cette espèce. Annales des Sciences Naturelles 2: 443–62.

Origin: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. By Charles Darwin. London: John Murray. 1859.

Westwood, John Obadiah. 1839–40. An introduction to the modern classification of insects; founded on the natural habits and corresponding organisation of the different families. 2 vols. London: Longman, Orme, Brown, Green, and Longman.


Agassiz’s superficiality and wretched reasoning powers. But he stirred up Europe on glaciers. Lyell has been working on their effects – testing work of others.

CD believes "Natural Systems" ought to be simply genealogical. "Time will come when we shall have true genealogical trees of each great kingdom of nature."

Letter details

Letter no.
Charles Robert Darwin
Thomas Henry Huxley
Sent from
Source of text
Imperial College of Science, Technology, and Medicine Archives (Huxley 5: 54)
Physical description
ALS 7pp

Please cite as

Darwin Correspondence Project, “Letter no. 2143,” accessed on 6 December 2022,

Also published in The Correspondence of Charles Darwin, vol. 6