far more effective in this way than the emotion itself is recognised by the practice of the _claqueurs_. When an audience has once been induced to give expression to a common emotion, its members are, as it were, set in tune with one another; each man is aware that he is in harmony with all the rest as regards his feelings and emotions, and, even in the periods during which all expressions are suppressed by the audience, this awareness serves to sustain the mood and to prepare for fresh outbursts. The mere silence of an audience, the absence of coughs, shufflings, and uneasy movements, suffices to make each member aware that all his fellows are attentive and are responding with the appropriate emotion; but it is not until the applause, the indignation, or the laughter, breaks out in free expression that the emotion reaches its highest pitch. And a skilful orator or entertainer, recognising these facts, takes care to afford frequent opportunities for the collective displays of emotion. We must recognise, then, that, even if telepathic communication be proved to be possible in certain cases, there is not sufficient evidence of its operation in the spread of emotion through crowds, and that the facts are sufficiently explained by another principle of general and indisputable validity, the principle of primitive sympathy. The second hypothesis to be considered in this connexion is that of the ‘collective consciousness.’ The conception of a collective consciousness has been reached by a large number of authors along several lines of observation and reasoning and is seriously defended at the present time, more especially by several French and German writers. They maintain that, in some sense and manner, the consciousnesses of individuals are not wholly shut off from one another, but may co-operate in the genesis of, or share in the being of, a more comprehensive consciousness that exists beside and in addition to them. The conception varies according to the route by which it is reached and the use that is made of it; but in all its varieties the conception remains extremely obscure; no one has succeeded in making clear how the relation of the individual consciousness to the collective consciousness is to be conceived. In the writings of many metaphysicians, of whom Hegel is the most prominent, ‘the Absolute’ seems to imply such a collective consciousness, an all-inclusive world-consciousness of which the individual consciousness of each man is somehow but a constituent element or fragmentary manifestation. But it would be unprofitable to attempt any discussion of the conception. We are concerned only with the empirical conception of a collective consciousness based on observation and induction.