that these three kinds of sensation can, unassisted, in and by themselves, produce a sensory pleasure. Certain colours, certain qualities of sound, certain chords, produce at once an agreeable impression. Then the representations evoked by memory excite, in their turn, a degree of pleasure quite distinct from the original sensations. Fechner, in his _Vorschule der Æsthetik_, distinguishes, in his analysis of the elements of the Beautiful, the direct factor, _i.e._ sensation, and the indirect or associative factor, that is to say, the associated ideas evoked. These two coexistent factors are only separable by psychological analysis, and the position established by Fechner for the intellectual elements has its equivalent for the emotional states.[37] Footnote 37: For further details on this point see Chapter VII. II. The generally accepted formula connecting pleasure with medium activities is supported by a commonly observed fact—viz., that pleasure carried to excess or continued too long often transforms itself into its opposite. The pleasures of eating may lead to nausea, tickling soon becomes a torture, as well as heat and cold, and one cannot endure even a favourite melody when played for two consecutive hours. In a word, a sensation or representation at first agreeable may, either gradually or suddenly, be found to have its opposite associated with it. While the sensory or intellectual element remains the same—at least in appearance—the affective state is changed. So familiar an occurrence, well known from the remotest antiquity, from which various consequences have been deduced by philosophers, would not in itself possess sufficient importance to arrest our attention, did it not, for all its insignificant appearance, afford us the opportunity of penetrating the depths of our subject. We may remark that the same transformation takes place inversely—a state in itself disagreeable may become agreeable. This transmutation is to be found at the root of nearly all the pleasures which we call _acquired_: a taste or smell at first repugnant may become delightful. The same thing happens with regard to certain physical exercises connected with touch and the muscular sense. The use of alcoholic drinks, of tobacco, of all sorts of narcotics, would furnish us with abundance of examples. Pleasure is found in certain forms of literature which were at first found revolting; the same thing may be said of painting; and the history of music is one long piece of evidence in favour of this transformation of tastes.