The ninth volume of Charles Darwin’s correspondence comprises all the surviving letters both from and to Darwin from the year 1861.
On the Origin of Species had been published in late 1859, and, at this stage, Darwin was supposed to be working on his long-planned ‘big book’ on species, of which he had described Origin as an ‘abstract’. But, as Darwin admits several times in this volume, he much preferred experimenting to writing, so was easily distracted. In the event, Darwin spent much of 1861 investigating the complex pollination mechanism of orchids, which he would eventually describe in his snappily entitled 1862 book, On the Various Contrivances by which British and Foreign Orchids are Fertilised by Insects, and on the Good Effects of Intercrossing.
As with his previous eight-year study of barnacles, the pollination of orchids might sound like an inexplicably esoteric diversion for Darwin, who must surely have had far bigger fish to fry; but, as always, Darwin’s latest ‘hobby-horse’ bore considerable relevance to his theory of evolution by means of natural selection. Darwin was convinced that in-breeding in general, and self-fertilisation in particular, were detrimental to sexually reproducing species, so adaptations that help cross-fertilisation should be favoured by natural selection. With his orchids study, Darwin showed how the wonderfully complex designs of many species of orchid are adaptations to ensure pollen is carried to other flowers by insects, rather than fertilising the flower in which it develops. In parallel with his orchid studies, Darwin had another side-project to investigate the dimorphism (different forms) of flowers in the same species, especially primulas. Once again, Darwin was really studying how these plants avoid self-pollination.
But 1861 wasn’t just about poking around in flowers’ private parts. During the year, Darwin also put out a revised, third edition of On the Origin of Species. His correspondence also shows him, among many other things:
- writing to his American friend Asa Gray about the American Civil War;
- egging on his combative friend Thomas Henry Huxley in his ongoing feud with anatomist Richard Owen about the similarity or otherwise of human and ape brains;
- repeatedly defending natural selection as a scientific theory by comparing it to the wave-theory of light: another suggested mechanism that explained a great deal without having been directly observed;
- being thrilled at new(ish) friend Henry Walter Bates’s demonstration of mimicry in South American butterflies;
- giving Bates writing tips;
- encouraging other scientists in their evolution-adjacent studies;
- joking about the impossibility of a theory of his being wrong;
- writing a posthumous tribute to his favourite old college professor and close friend John Stevens Henslow;
- receiving news that the philosopher John Stuart Mill endorsed the philosophical he had adopted in Origin;
- finally conceding that he had previously committed ‘one long gigantic blunder’ in attributing the Scottish geological features known as the Parallel Roads of Glen Roy to the action of the sea, rather than glaciers;
- arranging a job for his oldest son as a partner in a bank.
As with all the volumes in this series, this book is really aimed at people with a serious interest in Charles Darwin. As with all the other volumes, every letter is annotated with meticulously researched footnotes explaining its context and references. The series as a whole is a masterpiece of scholarship.