At first sight it seems a simple matter to describe the effect of the “Origin” upon Huxley, considering that he, more than any other man, expounded it, and defended it from the most weighty of the attacks made upon it. Hence, it is only natural to believe, as many have done, that he was in entire agreement with the conclusions of the book as regards natural selection as well as evolution. On the other hand, the opinion has often been expressed that Huxley, although agreeing with the “Origin” for some years after its first appearance, changed his mind in later years, and no longer supported Darwin’s views. I shall give reasons for rejecting both these opinions about Huxley, although the first is far nearer the truth than the second. The latter is clearly untenable, and was probably merely an inference from the fact that after a time Huxley ceased to enter into Darwinian controversies. But this was because he had done his work with entire success, and therefore turned his attention in other directions. Whenever he was called on to write or speak about Darwinism, as he was on two occasions within a few months of his death, his writings and speeches left no doubt about his thoughts on the subject. Furthermore, in the Preface to “Darwiniana,” written in 1893, he expressly denied that he had recanted or changed his opinions about Darwin’s views. In order to appreciate the influence of Darwin upon Huxley, we must find out the beliefs of the latter upon the “species question” before the appearance of the “Origin.” In his chapter “On the Reception of the ‘Origin of Species’” (“Life and Letters,” Vol. II.) Huxley says that, before 1858, he took up an agnostic position as regards evolution “... upon two grounds: firstly, that up to that time, the evidence in favour of transmutation was wholly insufficient; and, secondly, that no suggestion respecting the causes of the transmutation assumed, which had been made, was in any way adequate to explain the phenomena.” It is obvious that these two grounds are entirely distinct, and that the logical foundation of the first is far more secure than that of the second.