The suggestibility of crowds is a peculiar form of that limitation of choice by the environment already discussed. We have here a very transient environment which owes its power over choice to the vague but potent emotion so easily generated in dense aggregates. The thick humanity is in itself exciting, and the will is further stupefied by the sense of insignificance, by the strangeness of the situation, and by the absence, as a rule, of any separate purpose to maintain an independent momentum. A man is like a ship in that he cannot guide his course unless he has way on. If he drifts he will shift about with any light air; and the man in the crowd is usually drifting, is not pursuing any settled line of action in which he is sustained by knowledge and habit. This state of mind, added to intense emotion directed by some series of special suggestions, is the source of the wild and often destructive behavior of crowds and mobs, as well as of a great deal of heroic enthusiasm. An orator, for instance, first unifying and heightening the emotional state of his audience by some humorous or pathetic incident, will be able, if tolerably skilful, to do pretty much as he pleases with them, so long as he does not go against their settled habits of thought. Anger, always a ready passion, is easily aroused, appeals to resentment being the staples of much popular oratory, and under certain conditions readily expresses itself in stoning, burning, and lynching. And so with fear: General Grant in describing the battle of Shiloh gives a picture of several thousand men on a hill-side in the rear, incapable of moving, though threatened to be shot for cowardice where they lay. Yet these very men, calmed and restored to their places, were among those who heroically fought and won the next day’s battle. They had been restored to the domination of another class of suggestions, namely those implied in military discipline.[10] Suggestibility from exhaustion or strain is a rather common condition with many of us. Probably all eager brain workers find themselves now and then in a state where they are “too tired to stop.” The overwrought mind loses the healthy power of casting off its burden, and seems capable of nothing but going on and on in the same painful and futile course. One may know that he is accomplishing nothing, that work done in such a state of mind is always bad work, and that “that way madness lies,” but yet be too weak to resist, chained to the wheel of his thought so that he must wait till it runs down. And such a state, however induced, is the opportunity for all sorts of undisciplined impulses, perhaps some gross passion, like anger, dread, the need of drink, or the like.