Dated by the reference to ‘Asa Gray’ (see n. 4, below).

The reference is to the recently published Explorations & adventures in equatorial Africa by the French-born American explorer Paul Belloni Du Chaillu (Du Chaillu 1861). Upon his arrival in London, Du Chaillu, who had become a celebrity in the United States through his lectures and through newspaper accounts of his adventures, was invited by Roderick Impey Murchison to give a lecture at the annual meeting of the Royal Geographical Society on 25 February 1861. Du Chaillu spoke before a large and distinguished audience, attracted by the first public exhibition of the gorilla skins and skulls he had collected. Du Chaillu offered a first-hand account of the fierce nature of the beasts themselves and of the tribes of cannibals he had encountered. See Vaucaire 1930, pp. 125–30. However, the accuracy of Du Chaillu’s account of his travels and the identification and description of the animals he collected was challenged by John Edward Gray, keeper of the zoological department of the British Museum, and several others in a series of letters published in the Athenæum late in May and in June 1861. This exchange sparked a public controversy that spilled over into the pages of The Times and other periodicals.

Du Chaillu’s lecture at the Geographical Society was preceded by remarks by Richard Owen, who gave a brief account of the anatomical structure of the gorilla and pointed out its similarity to human skeletons (see R. S. Owen ed. 1894, 2: 115–16). On 18 March, Du Chaillu spoke before the Royal Institution of Great Britain, followed the next day by a formal lecture by Owen, who gave a more detailed description of the anatomical structure of the skulls and brains of gorillas. Owen maintained that the skeleton of gorillas more nearly approximated that of humans than did those of orang-utans or chimpanzees. Nevertheless he stated that the structure of their brain was strikingly dissimilar to that of man. See Athenæum, 11 May 1861, pp. 621–3, and 23 March 1861, pp. 395–6; and Du Chaillu 1861, pp. 363–82. See also letter to T. H. Huxley, 1 April [1861].

A. Gray 1861a. CD had recommended Asa Gray’s articles on Origin to Cresy as by far ‘the best Review’ of the book (Correspondence vol. 8, letter to Edward Cresy, 12 December [1860]).

The reference is to Hutton 1861. See letter to F. W. Hutton, 20 April 1861.

John Frederick William Herschel had recently sent CD a copy of Herschel 1861 (see letter to J. F. W. Herschel, 23 May [1861]).

The Darwins did not actually leave for Torquay until 1 July 1861 (‘Journal’; Appendix II).