Darwin's notes on Wallace's Island life (1880)
Alfred Russel Wallace's Island Life: or, The phenomena and causes of insular faunas and floras, including a revision and attempted solution of the problem of geological climates. London: Macmillan & Co. (1880) was one of Wallace’s most successful books. It surveyed the problems of the dispersal and speciation of plants and animals on islands which he categorized, following Darwin, as oceanic or continental. The latter type Wallace subdivided into "continental islands of recent origin", like Great Britain, and ancient continental islands, such as Madagascar. Unlike Darwin’s theories of erratic spread to account for the discontinuous distribution of types, Wallace favoured theories of continuous spread followed by selective extinctions thus creating the appearance of gaps. Wallace had a copy of the book sent to Darwin, presumably by 11 October 1880. (See Wallace's letter to Darwin of that date Darwin Correspondence Letter 12752.) By 3 November Darwin had finished the book and taken notes for suggestions, at Wallace's request, while reading. On 3 November 1880 Darwin wrote to Wallace and included these notes. Wallace told the story well in his autobiography:
On November 3, 1880, [Darwin] wrote me the following very kind letter upon my "Island Life," on which I had asked for his criticism:—
"I have now read your book, and it has interested me deeply. It is quite excellent, and seems to me the best book which you have ever published; but this may be merely because I have read it last. As I went on I made a few notes, chiefly where I differed slightly from you; but God knows whether they are worth your reading. You will be disappointed with many of them; but it will show that I had the will, though I did not know the way to do what you wanted.
"I have said nothing on the infinitely many passages and views, which I admired and which were new to me. My notes are badly expressed, but I thought that you would excuse my taking any pains with my style. I wish my confounded handwriting was better. I had a note the other day from Hooker, and I can see that he is much pleased with the dedication."
With this came seven foolscap pages of notes, many giving facts from his extensive reading which I had not seen. There were also a good many doubts and suggestions on the very difficult questions in the discussion of the causes of the glacial epochs. Chapter xxiii., discussing the Arctic element in south temperate floras, was the part he most objected to, saying, "This is rather too speculative for my old noddle. I must think that you overrate the importance of new surfaces on mountains and dispersal from mountain to mountain. I still believe in Alpine plants having lived on the lowlands and in the southern tropical regions having been cooled during glacial periods, and thus only can I understand character of floras on the isolated African mountains. It appears to me that you are not justified in arguing from dispersal to oceanic islands to mountains. Not only in latter cases currents of sea are absent, but what is there to make birds fly direct from one Alpine summit to another? There is left only storms of wind, and if it is probable or possible that seeds may thus be carried for great distances, I do not believe that there is at present any evidence of their being thus carried more than a few miles."
This is the most connected piece of criticism in the notes, and I therefore give it verbatim. My general reply is printed in "More Letters," vol. iii. p. 22. Of course I carefully considered all Darwin's suggestions and facts in later editions of my book, and made use of several of them. The last, as above quoted, I shall refer to again when considering the few important matters as to which I arrived at different conclusions from Darwin. But I will first give another letter, two months later, in which he recurs to the same subject.
The fourth folio contains a particularly interesting and previously unpublished mention of Darwin's feelings about the Galapagos Islands:
'Galapagos. — I regret that you have not discussed plants. Perhaps I overvalue these Islds for how they did interest me & how they have influenced my life,
asas one main element of my attending to origin of species.'
As in his other descriptions of the Galapagos, however, Darwin here too refers to them not as the sole influence, but one of a number of the most important influences that first convinced him that species must evolve.
See also an abstract of Island life in CUL-DAR205.2.207.
John van Wyhe
Darwin, C. R. [Notes on Wallace's Island life]. [11.1880] Text & image NHM-WP6.4.1