We may regard a nation from two points of view. First, we may look at the muscle and brain power of the individuals who comprise it; secondly, we may view it as a political organisation struggling against the effects of climate, geographical position and other rival organisations. These aspects are, of course, not mutually exclusive, for the success of a nation in its political struggle will depend in great measure upon its innate muscle and brain power; but, on the other hand, a nation possessing admirable innate or organic qualities may fail as a political organisation on account of insurmountable obstacles placed in its way. When therefore we read of the fall of the Roman Empire or the conquest of the Greek states, we may be dealing with a question of actual racial and organic deterioration comparable in some slight degree to senility; or, on the other hand, we may have before us a question entirely apart from this, that of the struggle of a people against obstacles which have at last become insuperable. It will be necessary to examine the facts of history in greater detail in order to find out whether a race undergoes of necessity any organic change comparable to growth, maturity and decay, exclusive of the changes which may occur in the political organisation of the race and its fortuitous position in respect to other organisations. _The Muscles and Brains of a Race are not bound to decay._ We are dealing in the following pages with race rather than nation; with muscle, blood and brain, rather than with political power and influence; let us turn then to history in order to find out whether or not organic deterioration must actually close the history of every race, for if this is the case, our studies of racial change, though of none the less intellectual interest, will have lost their promise of practical utility. But, fortunately for the hopefulness of our future work, we may anticipate by saying that history shows us that the innate and organic is that which is most permanent and lasting, and that change and catastrophe in a nation’s career have in most cases been due to circumstances which we may term surrounding or accidental. We shall see that races, unlike individuals, may remain through the whole of their historic period without any sign of organic decay, but that the organisations, on the part of individuals of the race for purposes of trade or protection, may be prone to dangers which sooner or later overtake them. _The Fall of Greek and Roman Political Organisation._