The world which man has conquered, and is still conquering, is no longer the purely physical. He is working now toward the discovery and control of the powers of the air, and has already harnessed some of them to do his bidding. The succession of great events and discoveries will mark this century as an epoch in the world's history, and is responsible for economic changes which create social disturbance, and to which both men and women must adjust themselves, often without knowing the why or wherefore of that which is so different from what has been. It is one of the paradoxes in human nature that women, while being made responsible for human conditions, have been condemned to individual isolation. It has been largely the result of general physical differentiation and the dependence that grew out of it, and, secondarily, the long ages required to produce settled social conditions and a reversal of that great unwritten law of kings and men--that might made right. It is true that there was a time, some traditions of which are still preserved among the Indian tribes of North America, when the woman possessed controlling influence and power. This matriarchal or mother age passed with the primitive period in which the energies of men were absorbed in hunting and fighting. It was a tribal effort through tribal women to formulate and give importance to family life, and it must have been accepted and more or less sanctioned by the men. This tribal leadership, at first domestic and social, disappeared with the development of military leaders, the acquisition of military powers, and the centralization of property in lands, houses, and personal belongings, that required constant and effective methods of protection and defence. Instances are not wanting of heroic women of those early days who were capable of holding and defending person and property against aggression and warfare. But the logic of events was strong then, as now, and the destiny of the woman was not that of military supremacy. The first step in associated life taken by women was a simple protest against the use and abuse of power on the part of men, wrought up by fear or loathing to the point of desperation. Women, usually of rank, fled to the desert with one or two companions, and encountered unheard-of hardships rather than submit to the fate to which they had been condemned by father, brother, or some other man who could exercise authority over them. The first Church-sisterhood grew out of such beginnings, and gradually obtained the sanction of the Church. A recent remarkable work, "Women in Monasticism," shows how wide and powerful the system of religious sisterhoods had become as early as the fifth century, and traces its growing strength and enlargement until its decline, which was coeval with the Reformation.