It may, of course, be urged that all this is covered and allowed for by heredity. This may be so, but I am arguing against those who while recognizing heredity fail to make adequate allowance for its operations. Or it may be said that "environment" covers all forces, including heredity. But in that case the distinction between organism and environment is useless--in fact, it disappears. If, however, the distinction between the two is retained, our theorizing must give full appreciation to both. And in that case we must not fail to allow for the transforming power of man over his surroundings. Nor must we overlook another and a very vital fact, that in a large measure the environment to which civilised mankind must adapt itself is largely a thing of human creation. Viewed as merely external circumstances, the physical environment of man remains constant. At any rate, such changes as do take place occur with such slowness that for generations we may safely deal with them as unchanged. The dissipation of the heat of the earth may be a fact, but no one takes this into account in dealing with the probabilities of human life during the next few generations. On the other hand, the organism represents the cumulative, and consequently, ever-changing power of human nature, and it is this that gives us the central fact of human civilization. Whether acquired characters be inherited or not may be still an open question, but in any case there is no denying that capacity is heritable, and natural selection will move along the line of favouring the survival of that capacity which is most serviceable. And how does increasing capacity express itself? It can do so only in the direction of giving man a greater ability to control and mould to his own uses the material environment in which he is placed. Looking at the course of social evolution, we see this increased and increasing capacity expressed in art, industries, inventions, etc., all of which mean in effect a transformation of the material surroundings and their subjugation to the needs of man. These inventions, etc., not only involve a transformation of the existing environment; they also mean the creating of a new environment for succeeding generations. Each mechanical invention, for example, is dependent upon the inventions and discoveries that have preceded it, and to that extent it is dependent upon the environment. But each invention places a new power in the hands of man, and so enables him to still further modify and control his surroundings. Human heredity is thus expressed in capacity as represented by a definite organic structure. This is one factor in the phenomenon of social evolution. The other factor is the environment in which the organism is placed and to which it responds. The two factors, organism and environment, remain constant throughout the animal world. It is when we come to deal with human society specifically, that we find