Indeed, the process of digestion and the influence it exerts on the sources of mental and moral power, have received little attention in any scheme for fitting men and women for the practical duties of life. No doubt the truth has long been accepted, at all events by intelligent persons, that a man's temper, and consequently the character of his actions, often depend on the contingency that what he eats is properly converted, or not, into healthy material, suitable for the ceaseless work of building up both muscle and brain. But the truth of that fact has never been generally admitted to an extent at all comparable with its exceeding importance. It produces no practical result on the habits of men in the least degree commensurate with the claim it has to be believed and acted upon. For it is certain that an adequate practical recognition of the value of proper food to the individual in maintaining a high standard of health, in prolonging healthy life (the prolongation of unhealthy life being small gain either to the individual or to the community), and thus largely promoting cheerful temper, prevalent good nature, and improved moral tone, would achieve almost a revolution in the habits of a large part of the community.