There can be little question that it was no accident that determined the direction of Huxley's career. He was a naturalist by inborn vocation. The contrast between a natural bent and an acquired habit of life was well seen in the case of Huxley and Macgillivray, his companion on the _Rattlesnake_. The former was appointed as a surgeon, and it was no part of his duties to busy himself with the creatures of the sea; and yet his observations on them made a series of real contributions to biological science and laid the sure foundation of a world-wide and enduring reputation. The latter was the son of a naturalist, a naturalist by profession, and appointed to the expedition as its official naturalist; and yet he made only a few observations and a limited collection of curiosities, and even his exiguous place in the annals of zoölogy is the accidental result of his companionship with Huxley. The special natural endowments which Huxley brought to the study of zoölogy were, in the first place, a faculty for the patient and assiduous observation of facts; in the second, a swift power of discriminating between the essential and the accessory among facts; in the third, the constructive ability to arrange these essentials in wide generalisations which we call laws or principles and which, within the limits necessarily set by inductive principles, are the starting-point for new deductions. These were the faculties which he brought to his science, but there were added to them two personal characteristics without which they would not have taken him far. They were impelled by a driving force which distinguishes the successful man from the muddler and without which the finest mental powers are as useless as a complicated machine disconnected from its driving-wheel. They were directed by a lofty and disinterested enthusiasm, without which the most talented man is a mere self-seeker, useless or dangerous to society. The faculties and qualities which made Huxley great as a zoölogist were practically those which he applied to the general questions of biological theory, to the problems of education and of society, and to philosophy and metaphysics. A comparison between his sane and forcible handling of questions that lay outside the special province to which the greater part of his life was devoted, with the dubious and involved treatment given such questions by the professional politicians to whom the English races tend to entrust their destinies, is a useful comment on that value of science as discipline to which Huxley so strenuously called attention. There can be no better way of ending this sketch of Huxley's life and work than by quoting his own account of the objects to which he had devoted himself consciously. These were: