growth of certain sentiments and certain ideas. It now remains for us to study the factors capable of acting in a direct manner. We shall see in a forthcoming chapter how these factors should be put in force in order that they may produce their full effect.
In the first part of this work we studied the sentiments, ideas, and methods of reasoning of collective bodies, and from the knowledge thus acquired it would evidently be possible to deduce in a general way the means of making an impression on their mind.
We already know what strikes the imagination of crowds, and are acquainted with the power and contagiousness of suggestions, of those especially that are presented under the form of images.
However, as suggestions may proceed from very different sources, the factors capable of acting on the minds of crowds may differ considerably. It is necessary, then, to study them separately.
This is not a useless study. Crowds are somewhat like the sphinx of ancient fable: it is necessary to arrive at a solution of the problems offered by their psychology or to resign ourselves to being devoured by them.