Note 7 — Chapter IV

In this study Darwin came into communication, as early as 1839, with the Hon. and Rev. W. Herbert, afterwards Dean of Manchester, and received from him a personal account of his experiments on hybrids. It was Herbert who, as early as 1822, in the fourth volume of the “Horticultural Transactions,” and in his work on the Amaryllidaceæ, 1837, declared that horticultural experiments have established, beyond the possibility of refutation, that botanical species are only “a higher and more permanent class of varieties.” He extended the same view to animals, and believed that single species of each genus were originally created in a highly plastic condition, and that these have produced, chiefly by intercrossing, but also by variation, all our existing species.