protest against materialism readily admit that each acts continually upon the other. The sudden emotion that quickens the pulse, and blanches or flushes the cheek, and the effect of fear in predisposing to an epidemic, are familiar instances of the action of the mind upon the body, and the more powerful and permanent influence of the body upon the disposition is attested by countless observations. It is probable that this action extends to all parts of our moral constitution, that every passion or characteristic tendency has a physical predisposing cause, and that if we were acquainted with these, we might treat by medicine the many varieties of moral disease as systematically as we now treat physical disease. In addition to its incalculable practical importance, such knowledge would have a great philosophical value, throwing a new light upon the filiation of our moral qualities, enabling us to treat exhaustively the moral influence of climate, and withdrawing the great question of the influence of race from the impressions of isolated observers to place it on the firm basis of experiment. It would thus form the complement to the labours of the historian. Such discoveries are, however, perhaps far from attainment, and their discussion does not fall within the compass of this work. My present object is simply to trace the action of external circumstances upon morals, to examine what have been the moral types proposed as ideal in different ages, in what degree they have been realised in practice, and by what causes they have been modified, impaired, or destroyed. CHAPTER II. THE PAGAN EMPIRE. One of the first facts that must strike a student who examines the ethical teaching of the ancient civilisations is how imperfectly that teaching was represented, and how feebly it was influenced by the popular creed. The moral ideas had at no time been sought in the actions of the gods, and long before the triumph of Christianity, polytheism had ceased to have any great influence upon the more cultivated intellects of mankind.