Quite fairly it may be urged that the writer of passages like these would, if writing in modern language, and with the aid of modern conceptions, have expressed himself much as Professor Huxley does when, declaring that the circulation of the blood and the regular movements of the respiratory, alimentary, and other internal organs are simply 'affairs of mechanism, resulting from the structure and arrangement' of the bodily organs concerned, from 'the contractility of those organs, and from the regulation of that contractility by an automatically acting nervous apparatus;' that muscular contractility and the automatic activity or irritability of the nerves are 'purely the results of molecular mechanism;' and that 'the modes of motion which constitute the physical bases of light, sound, and heat are transmuted by the sensory organs into affections of nervous matter,' which affections become 'a kind of physical ideas constituting a physical memory,' and may be combined in a manner answering to association and imagination, or may give rise to muscular contractions in those reflex actions which are the mechanical representatives of volition.' Quite fairly may a doctrine, capable of being thus translated, be described as leading 'straight to materialism.' Quite justly may its author be claimed by Huxley as joint professor of a materialistic creed. True, Descartes lodges within his human mechanism a _chose pensante_ or rational soul, whose principal seat is in the brain, and who is treated as corresponding to a hydraulic engineer stationed in the centre of waterworks for the purpose of increasing, slackening, or otherwise altering their movements. But this rational soul is a very needless appendage to either the Cartesian or the Huxleian system, wherein, if its post be not a literal sinecure, there is, at any rate, little or nothing for it to do which might not quite as well be done without it. The hydraulic engineer, sitting in his central office, has to wind up the whole machinery from time to time, and to turn now this tap, now that, when he wishes to set this or that particular machine in motion. But, as no one need be told, our _chose pensante_ has nothing to do with the winding up of our digestive, circulatory, or respiratory apparatus; and so far from internally arranging those other internal organs from the mere arrangement of whose parts, according to Descartes, the reception, conversion, and retention of sensations, and the movements, whether internal or external, thereupon consequent, naturally proceed, or from regulating the molecular mechanism, whence, according to Professor Huxley, results the automatic nervous activity which, in his opinion, governs the movements of the limbs not less absolutely than those of the intestines, it, nine times out of ten, neither knows nor suspects that any such organs or mechanism exist. If the functions above attributed to the human frame could be shown really to belong to it, pure, not to say crass,