Note 133 — Chapter V · EVOLUTION OF THE PRINCIPAL CONCEPTS. (continued 2)

For the transformists, as is well known, variety, race, and species are not fixed concepts. “From variety to race, from race to species, there is a continuous insensible passage. Individual modifications, at first slight, give rise to a variety or to a race. Continuing to augment, and extending to a constantly increasing number of individuals, they may come to constitute specific characters. Pursuing its evolution, the species then finally reaches the rank of the genus, family, etc.”