Of course, writers on the subject have given much attention to the British Association for Advancement of Science meeting in Oxford the following year with the notorious clash between Huxley and Bishop Wilberforce. But the arguments were rehearsed in different guises over many of the following years. Even today commentaries on the subject by Richard Dawkins and Steve Jones in this country and Steven J Gould in the United States still attract a great deal of understandable attention from both scientists and non-scientists. But perhaps it is not always fully realized and appreciated that at the time nothing was known of the genetic mechanisms by which species could evolve. Though Gregor Mendel's seminal papers on inheritance and the segregation of hereditary factors were presented in 1865 and published the following year his ideas, essential to any in-depth understanding of the origin of species and evolution, remained virtually unknown until 1900. Even then, those who realized their importance in the scheme of things, such as William Bateson, were sometimes misunderstood or disregarded.

    In his scholarly study, Forsdyke details the thinking among philosophers and scientists around the time of Darwin's publication who attempted to explain the most serious difficulties with Darwin's theory - namely, how could small initial variations lacking any apparent value to the individual (so-called 'non-adaptive') lead to the establishment of a new species without being swamped by intercrossing with its neighbours? Having outlined this and related problems, the author singles out for special mention George Romanes (1848-1894). Born in Kingston, Canada (where Forsdyke now lives), in early childhood Romanes accompanied his parents to England and later studied physiology at Cambridge and University College, London. He engaged in research on echinoderms and medusae, for example, and became a close friend of Darwin. Forsdyke here concentrates his attention on Romanes' theory of 'physiological selection' which he expounded in 1886, also at the Linnean Society. He proposed that physiological selection, by preventing intercrossing, enables natural selection to promote diversity and thereby evolution, and that sterility of the offspring of crosses between species (such as occurs in the mule, resulting from crossing a horse and donkey) was the natural result of 'some physiological change having exclusive, reference to the sexual system - - ' a concept which in Forsdyke's view anticipated modern developments in genetics.

    Incidentally the portraits of all three of the main characters in this story (Darwin, Huxley and Romanes) were painted by the Victorian artist John Collier (1850-1934) who married Huxley's two daughters in succession after the first had died. The portraits are reproduced here but not in colour unfortunately.

    This is a scholarly and very well referenced work. It will certainly appeal to all those with an interest in the thinking of Victorian philosophers and scientists as they struggled to understand how new species could arise and evolve.

Alan Emery, Exeter, UK