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Darwin Correspondence Project

To C. S. Bate   30 August [1853]

Down Bromley Kent

Aug 30th

My dear Sir

I feel much obliged for your never-tiring exertions in obliging me. The last specimen has been quite satisfactory:1 Verruca acts on the rock in two ways, round the margin & under the middle of the basis: this latter action was unequivocally plain, & suffices in my mind, with all the previous facts known to me, to prove that Verruca acts only on calcareous substances.—2 Will you oblige me, by taking the trouble to give me a reference to any book, in which your view of carbonic acid has been given:3 you stated, I think, that this was published, but I have mislaid your letter.

I am glad to perceive that you are progressing in your researches on the metamorphoses of the spider-like Crustacea.—4 Mr. Lubbock mentioned to me, when I told him what you had done, that he had seen somewhere (I forget where) something published on this subject; I imagine it probably must have been in some of the late numbers of the Annales des Sciences Naturelles.5

With my very sincere thanks for your valuable assistance in regard to Verruca— | Believe me | My dear Sir | Yours sincerely | C. Darwin


CD had asked Bate to find specimens of Verruca adhering to rocks (letters to C. S. Bate, 10 January [1853] and 7 July [1853]). Bate had apparently supplied CD with specimens adhering to limestone which provided the evidence CD sought for his view of the non-mechanical excavating power of Verruca (see Living Cirripedia (1854): 514).
Bate had also found specimens of Verruca adhering to slaty rocks that showed no sign of excavation.
As a response to Albany Hancock’s view of the mechanical means of boring of certain molluscs (A. Hancock 1848), Bate reported to the 1849 meeting of the British Association for the Advancement of Science his view that the boring mechanism was chemical. He suggested that carbonic acid in sea-water, directed by respiratory and ciliary currents, acted as the solvent (Bate 1849, pp. 73–4). CD referred to Bate’s view but stated that it could not be applicable to cirripedes, which lack the respiratory currents and the ciliary action Bate’s theory required (Living Cirripedia (1854): 518 and n.). He favoured an internal chemical boring mechanism: a solvent emitted by the cement ducts of Verruca (ibid., pp. 512–18).
Pycnogonida, the sea-spiders, were probably being investigated by Bate in order to further his work on the anatomy of crabs and other Crustacea, eventually published as Bate 1855.
Probably a reference to Quatrefages de Bréau 1842 (see letter to John Lubbock, 10 [September 1853], n. 2).


Bate, Charles Spence. 1849. Notes on the boring of marine animals. Report of the 19th meeting of the British Association for the Advancement of Science held at Birmingham, Transactions of the sections, pp. 73–5.

Bate, Charles Spence. 1855. On the homologies of the carapace and on the structure and function of the antennæ in Crustacea. Annals and Magazine of Natural History 2d ser. 16: 36–46.

Hancock, Albany. 1848. On the boring of the Mollusca into rocks, &c.; and on the removal of portions of their shells. Annals and Magazine of Natural History 2d ser. 2: 225– 48.

Living Cirripedia (1854): A monograph of the sub-class Cirripedia, with figures of all the species. The Balanidæ (or sessile cirripedes); the Verrucidæ, etc. By Charles Darwin. London: Ray Society. 1854.


Sends thanks for recent specimen, which gave him conclusive evidence that Verruca acts only on calcareous rocks.

Asks for a reference on carbonic acid.

Is glad CSB progresses in research on spider-like Crustacea.

Letter details

Letter no.
Charles Robert Darwin
Charles Spence Bate
Sent from
Source of text
American Philosophical Society (Mss.B.D25.)
Physical description
ALS 4pp

Please cite as

Darwin Correspondence Project, “Letter no. 1528,” accessed on 25 March 2023,

Also published in The Correspondence of Charles Darwin, vol. 5