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Darwin Correspondence Project

From J. T. Moggridge   22 July 1873

2 Montague Villas | Richmond | (Surrey)

22 July | 1873

My dear Sir

I am greatly obliged to you for your valued letter of the 14th. inst., & especially for the account you give in it of your suggestive experiments on seeds with Formic acid.1

I have purchased a small bottle of this acid, & hope to make a few experiments on my return to Mentone.2

I gather from your letter that the vapour of pure formic acid (not contact with the liquid) sufficed to kill the seeds outright, & this without allowing them to sprout. If I understand right I might try to repeat this curious & novel experience by placing seeds of a dozen sorts on damp sand under a tumbler, with a glass tube (say a homæopathic bottle), partly filled with acid, planted in the middle.—

Then I should propose to vary the quantity of formic acid, diluting measured amounts with water, & noting the results—

This is a kind of experiment with which I am quite unacquainted, & I do not feel at all sure that I shall get any reliable results, but I hope to amuse myself by trying—

I do hope, however, that you will be able yourself to carry on this enquiry, which is surely one of great practical importance; for, even though my small attempts should prove tolerably successful, my want of experience & many other wants must make my results worthless by the side of yours.—

Lindley Theory & Practice of Horticulture Ed. 2 (1855) p. 136 etc.) gives some account of experiments made with various acids (not formic acid) on seeds.— Soaking in Oxalic acid is stated to hasten germination! but the general results appear conflicting & dubious.3

I am glad that you were pleased with the Ophrys drawings—4

I must however tell you that variation is really not uncommon in the English apifera, though it sometimes happens that one form, whether aurita or apifera proper, predominates.5

I was myself much interested by the fact of the variation of the English plant, & I have, since the writing of this paper, made a tabulated series of observations shewing the variation in different parts of the flower in large numbers of specimens obtained from several distant parts of England.

In most cases in England the possibility of intercrossing is excluded, & it is surely important to observe that under these conditions many characters vary, & often do so to a marked degree—

Since the writing of my paper the curious & submonstrous variety Trollii” has been found near Reigate!—6

I should be very glad to furnish you with a condensed account of these observations if they could be of service to you— —

Believe me yrs. very sincerely | J. Traherne Moggridge.


The letter from CD has not been found; see, however, the letter to J. T. Moggridge, 10 March 1873.
Mentone (now Menton) is a town in south-eastern France on the French Riviera near the the border with Italy; Moggridge spent most winters there owing to his chronic ill health (R. Desmond 1994).
For the discussion of seeds soaked in oxalic acid and other substances to promote germination, see Lindley 1855, pp. 236–7.
Moggridge had sent CD copy of his German paper on Ophrys insectifera (Moggridge 1869) with his letter of 12 July 1873.
Ophrys apifera and O. apifera var. aurita are bee orchids. CD discussed the adaptations of this species for self-fertilisation in Orchids 2d ed., pp. 52–9. He noted that in Britain the forms were more differentiated than on the Continent, where cross-fertilisation might have taken place.
Moggridge refers to the wasp orchid (Ophrys apifera var. trollii). Reigate is in Surrey.


Desmond, Ray. 1994. Dictionary of British and Irish botanists and horticulturists including plant collectors, flower painters and garden designers. New edition, revised with the assistance of Christine Ellwood. London: Taylor & Francis and the Natural History Museum. Bristol, Pa.: Taylor & Francis.

Lindley, John. 1855. The theory and practice of horticulture; or an attempt to explain the chief operations of gardening upon physiological grounds. 2d edition. London: Longman, Brown, Green, & Longmans.

Moggridge, John Traherne. 1869. Ueber Ophrys insectifera L. (part.) Dresden: E. Blochmann & Sohn. [Verhandlungen der Kaiserlichen Leopoldino-Carolinischen deutschen Akademie der Naturforscher 35 (1870): (3d paper) 1–16.]

Orchids 2d ed.: The various contrivances by which orchids are fertilised by insects. By Charles Darwin. 2d edition, revised. London: John Murray. 1877.


He will repeat the experiments in which CD found that formic acid vapour killed seeds [see 8866]. John Lindley describes effects of other acids on germination.

He has tabulated the large amount of variation in English Ophrys apifera.

Letter details

Letter no.
John Traherne Moggridge
Charles Robert Darwin
Sent from
Source of text
DAR 171: 219
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 8984,” accessed on 19 January 2021,

Also published in The Correspondence of Charles Darwin, vol. 21