The people who surround us are the creatures of certain circumstances, but not of all circumstances. Our ego consists of the association of innumerable cellular egos, the residues of ancestral personalities. By their combination they form an equilibrium which is fairly permanent when the social environment does not vary. As soon as this environment is considerably modified, as in time of insurrection, this equilibrium is broken, and the dissociated elements constitute, by a fresh aggregation, a new personality, which is manifested by ideas, feelings, and actions very different from those formerly observed in the same individual. Thus it is that during the Terror we see honest bourgeois and peaceful magistrates who were noted for their kindness turned into bloodthirsty fanatics. Under the influence of environment the old personality may therefore give place to one entirely new. For this reason the actors in great religious and political crises often seem of a different essence to ourselves; yet they do not differ from us; the repetition of the same events would bring back the same men. Napoleon perfectly understood these possibilities of character when he said, in Saint Helena:-- ``It is because I know just how great a part chance plays in our political decisions, that I have always been without prejudices, and very indulgent as to the part men have taken during our disturbances. . . . In time of revolution one can only say what one has done; it would not be wise to say that one could not have done otherwise. . . . Men are difficult to understand if we want to be just. . . . Do they know themselves? Do they account for themselves very clearly? There are virtues and vices of circumstance.'' When the normal personality has been disaggregated under the influence of certain events, how does the new personality form itself? By several means, the most active of which is the acquisition of a strong belief. This orientates all the elements of the understanding, as the magnet collects into regular curves the filings of a magnetic metal. Thus were formed the personalities observed in times of great crises: the Crusades, the Reformation, the Revolution notably. At normal times the environment varies little, so that as a rule we see only a single personality in the individuals that surround us. Sometimes, however, it happens that we observe several, which in certain circumstances may replace one another. These personalities may be contradictory and even inimical. This phenomenon, exceptional under normal conditions, is considerably accentuated in certain pathological conditions. Morbid psychology has recorded several examples of multiple personality in a single subject, such as the cases cited by Morton Prince and Pierre Janet. In all these variations of personality it is not the intelligence which is modified, but the feelings, whose association forms the character. 2. Elements of Character Predominant in Time of Revolution.