uttered in my hearing, may make me think of that language in general or of a voice which once pronounced it in a certain way. These two associations by similarity are not due to the accidental arrival of two different representations, which chance brought by turns within the attracting influence of the actual perception. They answer to two different mental dispositions, to two distinct degrees of tension of the memory; in the latter case nearer to the pure image, in the former more disposed towards immediate response, that is to say, to action. To classify these systems, to discover the law which binds them respectively to the different 'tones' of our mental life, to show how each of these tones is itself determined by the needs of the moment and also by the varying degree of our personal effort, would be a difficult task: the whole of this psychology is yet to do, and for the moment we do not even wish to attempt it. But every one is clearly aware of the existence of these laws, and of stable relations of this kind. We know, for instance, when we read a psychological novel, that certain associations of ideas there depicted for us are true, that they may have been lived; others offend us, or fail to give us an impression of reality, because we feel in them the effect of a connexion, mechanically and artificially brought about, between different mental levels, as though the author had not taken care to maintain himself on that plane of the mental life which he
