A superficial glance at the page of history would tempt us to answer in the negative, for the apparent causes of the downfall of the great empires of antiquity were very different in each case. Yet, if we pierce below the surface, we find in this very necessity of decay, which weighs so imperiously upon all societies without exception, the evidence of the existence of some general, though concealed, cause, producing a natural death, even where no external causes anticipate it by violent destruction. We also discover that all civilizations, after a short duration, exhibit, to the acute observer, certain intimate disturbances, difficult to define, but whose existence is undeniable; and that these present in all cases an analogous character. Finally, if we distinguish the ruin of civilizations from that of States (for we sometimes see the same culture subsist in a country under foreign domination, and survive the destruction of the political body which gave it birth; while, again, comparatively slight misfortunes cause it to be transformed, or to disappear altogether), we become more and more confirmed in the idea that this principle of death in all societies is not only a necessary condition of their life, independent, in a great measure, of external causes, but is also uniform in all. To fix and determine this principle, and to trace its effects in the lives of those nations, of whom history has left us records, has been my object and endeavor in the studies, the results of which I now lay before the reader.