It is probable, however, that susceptibility varies greatly in degree, and that race exerts an important influence.

Thus in Europe the French seem to be most susceptible, and the English and Scandinavians least so.

The impression that weak-minded persons are most available is quite mistaken.

On the contrary, patients in the insane asylums, idiots, etc., are the most refractory.

This is to be expected, from the fact that in these cases power of strong, steady attention is wanting.