Hewett Watson (1804-1881)
[S]ucceeding species may have been formed by mutation or metamorphoses of the preceding species. This hypothesis is plausible to say the least of it. If adopted as a true theory, it would account for much that is at present obscure or incomprehensible. (The Phytologist)
Just days before publication of On the Origin of Species, Hewett Watson, a British plant geographer and phrenologist, wrote Darwin to praise his work (Darwin had sent him a copy) and also to remind him of his own views on the subject of evolution: “[Y]ou will see that, a quarter of a century ago, I was also one of the few who then doubted the absolute distinctness of species & special creations of them. Yet I, like the rest, failed to detect the quo modo which was reserved for your penetration to discover, & by your discernment to apply.” (Letter)
Watson studied medicine and natural history at the University of Edinburgh and was well-known for developing a system to study the geographic distribution of British plant species.
Although born into a politically conservative family, Watson did not shy away from expressing his views of the transmutation of species in his publications, including his 1836 An Examination of Mr. Scott’s Attack upon Mr. Combe’s Constitution of Man, in which he defends the phrenologist George Combe’s natural progressivism and cites examples of domestic breeding as evidence for the mutability of species (in much the same way that Darwin would later do in On the Origin of Species). Watson’s 1845 four-part review of Robert Chamber’s Vestiges of the Natural History of Creation entitled On the Theory of “Progressive Development”, applied in explanation of the Origin and Transmutation of Species, endorsed Vestige’s general thesis of progressive development, while attempting to provide more accurate evidence in favor of what he called “a transition of species.”
Watson’s ideas on transmutation were greatly influenced by his botanical studies. Like many other early evolutionists, Watson found evidence for evolution in domestication history, the blurry line between varieties and species, and species turnover in the fossil record.
Unlike Darwin, Watson never proposed a coherent theory of descent with modification; rather, he made observations and reported them as potential evidence for a law of natural progress, or evolution. Watson’s espousal of evolutionary views and his expertise in plant species distribution did not go unnoticed, and in the years leading up to the publication of On the Origin of Species, Hewett Watson was an important correspondent with Charles Darwin.
Read a few passages from his writings:
“[S]ucceeding species may have been formed by mutation or metamorphoses of the preceding species. This hypothesis is plausible to say the least of it. If adopted as a true theory, it would account for much that is at present obscure or incomprehensible.” (page 110, The Phytologist, 1845)
“In the vegetable world, however, it is peculiarly man’s interest to bring hundreds or thousands of species (as they are called) into a domesticated state, to use his utmost skill in bringing about considerable changes in many of them, and to keep extending these changes…Accordingly, we find varieties produced, and regularly continued by descent, having greater differences between themselves, than are seen between other races generally supposed to be distinct species.” (page 26-7, An Examination of Mr. Scott’s Attack upon Mr. Combe’s Constitution of Man, 1836)
“[P]ast changes in the earth’s Flora were effected gradually…species after species disappeared, species after species appeared, singly and successively; no total change occurring at once, unless as a local event, which would not implicate the general Flora of the earth. It is extremely difficult to account for these changes, by natural means, unless on the hypothetical assumption that one species produced another, under changed conditions of climate or other circumstances.” (page 141, The Phytologist, 1845).
For a complete biography of Hewett Watson’s impressive career as a plant ecologist, botanist, and evolutionist, see Hewett Cottrell Watson: Victorian plant ecologist and evolutionist and History of the Ecological Sciences, Part 36: Hewett Watson, Plant Geographer and Evolutionist by Frank N. Egerton.