We can hardly imagine any concourse of human beings, however fortuitous it may be, utterly devoid of the rudiments of organisation of one or other of these three kinds; nevertheless, in many a fortuitous concourse the influence of such rudimentary organisation is so slight as to be negligible. Such a group is an unorganised crowd or mob. The unorganised crowd presents many of the fundamental phenomena of collective psychology in relative simplicity; whereas the higher the degree of organisation of a group, the more complicated is its psychology. We shall, therefore, study first the mental peculiarities of the unorganised crowd, and shall then go on to consider the modifications resulting from a simple and definite type of organisation. Not every mass of human beings gathered together in one place within sight and sound of one another constitutes a crowd in the psychological sense of the word. There is a dense gathering of several hundred individuals at the Mansion House Crossing at noon of every week-day; but ordinarily each of them is bent upon his own task, pursues his own ends, paying little or no regard to those about him. But let a fire-engine come galloping through the throng of traffic, or the Lord Mayor’s state coach arrive, and instantly the concourse assumes in some degree the character of a psychological crowd. All eyes are turned upon the fire-engine or coach; the attention of all is directed to the same object; all experience in some degree the same emotion, and the state of mind of each person is in some degree affected by the mental processes of all those about him. Those are the fundamental conditions of collective mental life. In its more developed forms, an awareness of the crowd or group as such in the mind of each member plays an important part; but this is not an essential condition of its simpler manifestations. The essential conditions of collective mental action are, then, a common object of mental activity, a common mode of feeling in regard to it, and some degree of reciprocal influence between the members of the group. It follows that not every aggregation of individuals is capable of becoming a psychological crowd and of enjoying a collective life. For the individuals must be capable of being interested in the same objects and of being affected in a similar way by them; there must be a certain degree of similarity of mental constitution among the individuals, a certain mental homogeneity of the group. Let a man stand on a tub in the midst of a gathering of a hundred Englishmen and proceed to denounce and abuse England; those individuals at once become a crowd. Whereas, if the hundred men were of as many races and nations, their attention would hardly be attracted by the orator; for they would have no common interest in the topic of his discourse. Or let the man on the tub denounce the establishment of the Church of England, and the hundred Englishmen do not become a crowd;