The adulteration of the blood and racial deterioration conditioned thereby are the only causes that account for the decline of ancient civilizations; for it is never by war that nations are ruined, but by the loss of their powers of resistance, which are exclusively a characteristic of pure racial blood. In this world everything that is not of sound racial stock is like chaff. Every historical event in the world is nothing more nor less than a manifestation of the instinct of racial self-preservation, whether for weal or woe.