In the case of human crowds the chief is often nothing more than a ringleader or agitator, but as such he plays a considerable part. His will is the nucleus around which the opinions of the crowd are grouped and attain to identity. He constitutes the first element towards the organisation of heterogeneous crowds,and paves the way for their organisation in sects; in the meantime he directs them. A crowd is a servilefiock that is incapable of ever doing without a master.The leader has most often started as one of the led.He has himself been hypnotised by the idea, whose apostle he has since become. It has taken possession of him to such a degree that everything outside it vanishes, and that every contrary opinion appears to him an error or a superstition. An example in point is Robespierre, hypnotised by the philosophical ideas of Rousseau, and employing the methods of the Inquisition to propagate them.