When we reflect that the sciences of astronomy, physics, and chemistry have only recently got rid of the metaphysical spirit, we cannot wonder much that physiology is not yet entirely emancipated from the pernicious thraldom. It was plainly impossible that physiology should be cultivated in the spirit of the positive method of investigation while the sciences upon the advance of which itsadvance is dependent were not sciences at all, but clouds of idle andshifting fancies. But there has been another and weighty reason why the science dealing with the structure and functions of the organism has remained so long in a metaphysical bondage: because psychology, the last stronghold and the forlorn hope of the meta physical method, is an important branch of it. Metaphysicians have for at least two thousand years been supremely self-satisfied to evolve, from the unfathomable depths of the inner consciousness, ingenious mazes of vague and ill-defined words which they have dignified with the name of mental philosophy; and the consequence has been that the physiologist, when he came in the course of his inquiries to the brain, contented himself with the anatomical de scription of it, and never dreamed of studying its functions as the mental organ. By a prescriptive right, sanctioned by the authority of generations, mind belonged to the metaphysician; and it naturally seemed sacrilegious to venture a scientific step in such holy ground. Not only so, but the mischievous influence of the metaphysical spirit spread beyond the department of psychology, and infected more or less strongly all physiological inquiries. However, this state of things could not last in face of the active progress of positive science; the or ans and functions of the body became objects of positive investigation, and even the brain no longer escaped scientific study. So it has come to pass that the germs of a mental science having a physiological basis have appeared, and now threaten to disturb the ancient ascendancy of metaphysical mental philosophy. The present position of matters is this: there are two systems of philosophy dealing with the same subject, but not having the slightest connection one with the other, and cultivated according to different methods by different men-metaphysical mental philosophy and positive mental science. A man might be deeply learned in all the wisdom of the former, and yet entirely ignorant of the very meaning of the simplest facts of the latter. It is hardly worth while considering seriously at the present day which of these rival systems is likely to prevail over the other; one of them is the latest issue of the advance of positive science, has its foundations deep rooted in the relations of natural laws, and exhibits a promising growth; while the other has moved in an everlasting circle, has no better foundations than the clouds and conceits of men's thoughts, and exhibits symptoms of active decay. Now and then it is skilfully galvanized into a spasmodic semblance of life, but each artificially excited convulsion is plainly the fore runner of an increase of the inevitable paralysis. Much remains to be done, however, before we can claim acceptance for a positive mental science. Not only is our knowledge of the structure and functions of the brain very defective, but there is nothing like exact information to be had regarding its pathology. It has been the fashion to give the name of some disease to a group of symptoms, without attempting to connect these with particular diseased states of the nervous centres. The pathology of all the diseases of the nervous system is, it must be confessed, in a most unsatisfactory condition.