All Huxley's work was marked by a quality which may be called conscientiousness or thoroughness. Looking through his memoirs, written many years ago, the subjects of which have since been handled and rehandled by other writers with new knowledge and with new methods at their disposal, one is struck that all the observations he made have stood their ground. With new facts new generalisations have often been reached, and some of the positions occupied by Huxley have been turned. But what he saw and described had not to be redescribed; the citations he made from the older authorities were always so chosen as to contain the exact gist of the writers. These qualities, admirable in scientific work, became at once admirable and terrible in his controversial writings. His own exactness made him ruthless in exposing any inexactness in his adversaries, and there were few disputants who left an argument with Huxley in an undamaged condition. The consciousness which he had of his own careful methods, added to a natural pugnacity, gave him an intellectual courage of a very high order. As he knew himself to have made sure of his premisses, he did not care whither his conclusions might lead him, against whatsoever established doctrine or accepted axiom. There was, however, a strong spice of natural combativeness in his nature, the direct result of his native and highly trained critical faculty. He tells us that in the pre-Darwinian days he was accustomed to defend the fixity of species in the company of evolutionists and in the presence of the orthodox to attack the same doctrine. Later in life, when evolution had become fashionable, and the principles of Darwinism were being elevated into a new dogmatism, he was as ready to criticise the loose adherents of his own views as he had been to expose the weakness of the conventional dogmatists.