The Physiology of Aesthetics has also had its votaries in Great Britain, among whom may be mentioned J. Sully, A. Bain, and Allen. These at any rate show some knowledge of the concrete fact of art. Allen harks back to the old distinction between necessary and vital activities and superfluous activities, and gives a physiological definition, which may be read in his _Physiological Aesthetics_. More recent writers also look upon the physiological fact as the cause of the pleasure of art; but for them it does not alone depend upon the visual organ, and the muscular phenomena associated with it, but also on the participation of some of the most important bodily functions, such as respiration, circulation, equilibrium, intimate muscular accommodation. They believe that art owes its origin to the pleasure that some prehistoric man must have experienced in breathing regularly, without having to re-adapt his organs, when he traced for the first time on a bone or on clay regular lines separated by regular intervals. A similar order of physico-aesthetic researches has been made in Germany, under the auspices of Helmholtz, Brücke, and Stumpf. But these writers have succeeded better than the above-mentioned, by restricting themselves to the fields of optic and acoustic, and have supplied information as to the physical processes of artistic technique and as to the pleasure of visual and auditive impressions, without attempting to melt Aesthetic into Physic, or to deprive the former of its spiritual character. They have even occasionally indicated the difference between the two kinds of research. Even the degenerate Herbartians, converting the metaphysical forms of their master into physiological phenomena, made soft eyes at the new sensualists and aesthetico-physiologists. The Natural Sciences have become in our day a sort of superstition, allied to a certain, perhaps unconscious, hypocrisy. Not only have chemical, physical, and physiological laboratories become a sort of Sibylline grots, where resound the most extraordinary questions about everything that can interest the spirit of man, but even those who really do prosecute their researches with the old inevitable method of internal observation, have been unable to free themselves from the illusion that they are, on the contrary, employing _the method of the natural sciences_.