The effect of the “Origin” was completely to convince Huxley on the first ground: from that time he never doubted the truth of evolution, however it may have been brought about. With regard to the second ground, it is quite clear that Huxley had a very high opinion of natural selection: he thought it incomparably the best suggestion upon the subject that had ever been made, and he firmly believed that it accounted for something--that it may even have taken a dominant part in bringing about evolution. On the other hand, he never felt quite confident about the entire sufficiency of the evidence in its favour. It is probable that he was far more interested in the establishment of evolution as a fact than in natural selection as an explanation of it. He saw the vast amount of research in all kinds of new or almost neglected lines, which would be directly inspired by evolution. And his own investigations in some of these lines soon afforded some of the most weighty evidence in favour of the doctrine. Natural selection had not the same personal interest for him; no one has expounded it better or defended it more vigorously and successfully, but Huxley’s own researches never lay in directions which would have made them available as a test of the theory. Of natural selection he might have used the words of Mercutio--it may not be “so deep as a well, nor so wide as a church door,” to contain the whole explanation of evolution, “but ’tis enough ’twill serve”; it will, at any rate, prevent him from feeling the second ground on which he had maintained an agnostic position. I believe that he maintained these views with inflexible consistency throughout his life, the only indications of change being in the last year, when the contrast between his certainty of evolution and his uncertainty of natural selection, as expressed in the two speeches quoted on pp. 140, 141, was, perhaps, more sharply marked than at any other period. It is now proposed to support this conclusion by many extracts from Huxley’s writings, as well as from his speeches, which have been alluded to above. The deep interest of the subject, and the wide differences of opinion with regard to it, justify, and indeed demand, copious quotations selected from works and speeches, written and spoken at many different times during the years between 1858 and 1894. It may not be out of place to emphasise the fact that the sole responsibility for the conclusions here drawn rests with the author of this volume, and that the evidence on which the conclusions rest is supplied in full.