To define the term catastrophe is scarcely necessary. The dictionary calls catastrophe "an event producing a subversion of the order or system of things," and such as "may or may not be a cause of misery to man."[2] It is desirable however to limit the use of the term, in primary investigations at least, to those disasters which affect communities rather than states or nations, for restricted areas are more amenable to study. National cataclysms, such as war, famine, and financial panic are too general in character, and function on too grand a scale for satisfactory treatment, at least until the ground is cleared. It is necessary also to limit this investigation to those social changes which follow upon catastrophies, rather than precede them. For there are social effects which result from living in anticipation of disaster, such as are observable among communities in volcanic areas. Interesting as a broad study might be, it would be likely to lead the investigator too far afield into the realm of speculation. Nevertheless a general point of view is necessary to give meaning to even a limited treatment of the theme. For this purpose there may be contrasted the catastrophic view of history, as illustrated by that of the Hebrew peoples, and the modern conception of progress through evolution. The former looks upon history as a series of vicissitudes mercifully ending one day in final cataclysm. The spirit of apocalyptic expectancy prevails. Social conditions rest hopelessly static. Faith is pinned to a spiritual kingdom which can grow and can endure. Against this has been set an optimistic evolution, pictured like an escalade with resident forces lifting the world to better days. Progress becomes a smooth continuous growth. On the other hand the newer philosophy sees in history not necessarily the operation of progressive evolution but also of retrogressive evolution and cataclysm.[3] There are great stretches of smooth and even current in the stream, but always along the course are seen the rapid and the water-fall, the eddy and reversing tide. The latter is the general subject of this dissertation, and its thesis is the place of the water-fall. Only a very small, and specialized treatment is attempted; the great Niagaras must be left to abler hands. [2] Catastrophies are those unforeseen events which the Wells-Fargo express receipts used to call quaintly "Acts of God, Indians and other public enemies of the government." [3] If nature abhors a vacuum, she also abhors stagnation. Is there not reason behind all this action and reaction, these cycles and short-time changes which her observers note? May it not well be that the ever-swinging pendulum has a stir-up function to perform and that the miniature daily catastrophies of life are the things which keep it wholesome and sweet?