mankind. Henceforth the conditions for the maintenance of physical life became different from what they had been throughout the past history of the animal world. It was no longer necessary for men to quarrel for their food like dogs over a bone; for they could now obtain it far more effectively by applying their intelligence to the task of utilizing the forces of inanimate nature; and the due execution of such a task was in no wise assisted by wrath and contention, but from the outset was rather hindered by such things. Such were the beginnings of industrial civilization. Out of its exigencies, continually increasing in complexity, have proceeded, directly or indirectly, the arts and sciences which have given to modern life so much of its interest and value. But more important still has been the work of industrial civilization in the ethical field. By furnishing a wider basis for political union than mere blood-relationship, it greatly extended the area within which moral obligations were recognized as binding. At first confined to the clan, the idea of duty came at length to extend throughout a state in which many clans were combined and fused, and as it thus increased in generality and abstractness, the idea became immeasurably strengthened and ennobled. At last, with the rise of empires, in which many states were brought together in pacific industrial relations, the recognized sphere of moral obligation became enlarged until it comprehended all mankind. XIII. Methods of Political Development, and Elimination of Warfare.