My dear Sir

I am greatly obliged to you for your valued letter of the 14^th. in^st., & 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 et^c.) 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 y^rs. very sincerely | J. Traherne Moggridge.