Page:Mind (New Series) Volume 15.djvu/268

254 CRITICAL NOTICES 1 and listener. Of course, there is Wagner with Ms theories, which seem to count against this view. But it is shown that Wagner the artist was not a strict follower of Wagner the theorist. In Tannhduser, for instance, the intellectual framework is of the simplest ; the words, such as they are, form but the occasion for the music, and yet the emotional effect of the music is of the most subtle and powerful. In the next chapter, " Assoziationen der Vorstellungen und Em-- pfindungen," we are introduced to a careful study of " secondary sensations," coloured hearing, tactile hearing, olf active hearing, and other varieties. Naturally, " audition coloree " is discussed with most detail. This section forms an excellent summary of what is known on this topic. The author, however, omits all reference to Parish's Hallucinations and Illusions in discussing the relation of these to coloured hearing. There is, according to Dr. Wallaschek, no difference in the physiologico-anatomical basis of these three (p. 185). His explanation differs from those hither- to offered. Secondary sensations, he maintains, depend on the un- equal dilatability of the blood-vessels of the brain (p. 187). This view is supported by much ingenious argument. In a person whose brain-vessels are unequally dilatable, a tone-sensation might not only excite its appropriate centre, but also, through the more easily expanded vessels, affect the colour-centre even more readily than this could be stimulated by its own specific end-organs. This theory accounts certainly for some of the difficulties, but the evidence adduced to show that this vaso-motor inequality is a vein causa is scarcely adequate. The theory looks like proving too much. It does not explain the specific limitation of the secondary sensations, for instance, to vision, or to any other one sense.. There is a further ingenious suggestion that secondary sensations are the foundations of instincts (p. 191). The secondary sensa- tion is an anticipatory function. Dr. Wallaschek regards these sensations as a condition of life. They are variations that natural selection can use. But, as has more than once been indicated elsewhere, these sensations are extreme types. The line between the least marked of them and ordinary associations is difficult to- draw. Whether they are an incidental result of vascular inequal- ities, or in some degree the result of early, but partially obliterated, association, is a problem for further analysis by experiment and observ ition. The remaining chapters deal with Memory, Natural and Artificial Diseases of Re-presentation, Sleep, natural and hypnotic. These- chapters contain little that is essentially new, but the treatment is fresh and relevant. The author concludes on a high note, art is- essential to social and individual development ; it is not a luxury,, but a necessity of life. W. LESLIE MACKENZIE..