vitalism 345 physics and chemistry. We must not refuse to admit that it is possible to treat living― things as if they were simply physico-chemical mechanisms and that for the practical ends of medical science this may even be the most useful course to take. But physiological chemistry can take no account of the historical aspect of the organism; it must take the organism as given, and it can deal only with the present of the organism, the past is out its reach. It can describe and explain the mechanism of the organism s responses to stimulation, but it cannot explain why this mechanism exists, for this is a problem of origins. Its field is in the present, but the organism is the product of the past, which refuses itself to chemical investigation. In contrast therefore to the sciences of inorganic nature, whose objects are not capable of historical explanation, biology is a science of origins. Not of absolute origins certainly, for biology must start out from the fundamental properties of living things. But biology may trace the historical development which is rendered possible to the organism by the possession of these properties, and so be a science of relative origins. Its object must therefore be to discover those properties of living matter which have rendered evolution possible. It must seek these properties not by studying the physics and chemistry of protoplasm, for by so doing it can arrive at only a vague and abstract description of vital activities in terms of a lower order. It must work down from the concrete facts of biology to the general vital properties underlying them. For indeed it is not the discovery of the laws or their mere abstract statement which is the important thing, but the interpretation of the facts, the illumination of experience which they provide. A law is an empty ami uninteresting formula unless we have knowledge of the concrete facts which it explains. Biology must therefore work down from the facts to the laws, but reascend from the abstract laws to a vision of the facts as they appear lighted up by the laws. London. Vj. S. Russell