[The letters given in the present chapter tell their story with sufficient clearness, and need but a few words of explanation. Mr. Wallace's Essay, referred to in the first letter, bore the title, ‘On the Tendency of Varieties to depart indefinitely from the Original Type,’ and was published in the Linnean Society's ‘Journal’ (1858, vol. iii. p. 53) as part of the joint paper of “Messrs. C. Darwin and A. Wallace,” of which the full title was ‘On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection.’

My father's contribution of the paper consisted of (1) Extracts from the sketch of 1844; (2) part of a letter addressed to Dr. Asa Gray, dated September 5, 1857, and which is given at p. 120. The paper was “communicated” to the Society by Sir Charles Lyell and Sir Joseph Hooker, in whose prefatory letter, a clear account of the circumstances of the case is given.

Referring to Mr. Wallace's Essay, they wrote:—

“So highly did Mr. Darwin appreciate the value of the views therein set forth, that he proposed, in a letter to Sir Charles Lyell, to obtain Mr. Wallace's consent to allow the Essay to be published as soon as possible.