The significance of crisis in social change likewise requires attention, and it will be clarifying to our thought at this point to distinguish carefully between crisis and catastrophe, and to inquire what the nature of the former really is. The word "crisis" is of Greek origin, meaning a point of culmination and separation, an instant when change one way or another is impending. Crises are those critical moments which are, as we say, big with destiny. Battles have crisis-hours when the tide of victory turns. Diseases have them--the seventh day in pneumonia, or the fourteenth day in typhoid fever. Social institutions afford numerous illustrations, such as the eighth year of marriage.[6] There are critical years of stress and strain--the ages of fourteen and forty in life-histories, the latter being according to Sir Robertson Nicoll the most dangerous hour of existence. Other crises are "hours of insight" in the world of thought, and hours of opportunity in the world of action,--that "tide in the affairs of men, which taken at the flood leads on to fortune," hours of doubt in religion "when all the gods are dead." "Crisis," Professor Shailer Mathews observes, "is something more than a relative term. It describes a situation which is no ordinary member of a line of antecedents and consequents, but one that assures radical change in the immediate future." He distinguishes between a crisis and a revolution. "The difference between a revolution and a crisis is the difference between the fire and the moment when someone with a lighted match in hand pauses to decide whether a fire shall be lighted." The term covers the situation preceding change, whether this situation be the culmination of a process or the result of some particular stimulus. "It is not necessarily precipitated by great issues. Quite as often it is occasioned by events .... which are so related to a new situation as to set in motion an entire group of forces as a match kindles a huge bonfire when once the fuel is laid."[7] The failure to distinguish between that which occasions the crisis and the crisis itself has been the source of some confusion in thinking. "Defeat in battle, floods, drought, pestilence and famine," are not strictly crises, but they super-induce the crisis-situation, as does anything which brings about "a disturbance of habit," though it be simply "an incident, a stimulation or a suggestion." In short, crises are the result either of a slowly maturing process or of sudden strain or shock; and the nature of the reaction in the crisis-hour is nothing more than the effort towards the reestablishment of habits, new or old, when the former functioning has been disturbed. The situation, as has been pointed out, is closely correlated with attention. [6] Jeune, Sir Francis, a celebrated judge in divorce cases. [7] Mathews, Shailer, _The Church in the Changing Order_ (N. Y., 1907), ch. i, p. 1.