large editions. But the great fence—the supposed immutability of species in the sphere of organic life—had still to be taken, and it is one of the singular so-called coincidences, of which there are many in the history of thought, that the road was being contemporaneously and independently explored in the first twenty years of the Victorian age by two Englishmen, Darwin and Wallace. Nothing can be finer or nobler than the relations which these two great men preserved to one another: it is one of the most honourable chapters in the annals of Science.
Darwin assumes three conditions without attempting to account for them—heredity, variation, overcrowding. He uses the phrase 'Natural Selection' to describe the process by which the fortunate possessors of a new and aggressively useful variation were able to oust their old-fashioned, unvaried, conservative competitors. The phrase which describes the conditions under which Natural Selection comes into play—the 'struggle for existence'—is, I believe, due to Wallace; and the phrase which describes the final result—the 'survival of the fittest'—to Herbert Spencer. The last turned out, perhaps, to be the unluckiest formula of the three (although all have given rise to misunderstanding), because as Huxley, after thirty years' experience, pointed out in his Romanes Lecture here in 1894, the term 'fittest' has, or is capable of having, a 'moral flavour'; while the only 'fitness' that is relevant to the argument is fitness having regard to the