One of the salient characteristics of emotions is their unifying power. It has aptly been said that in extreme emotional states one _is_ the emotion. The individual and his emotional state become one--a very different state of affairs from what is true in cognition. This element of unification is present to some extent in appreciation, although, because of its complex nature, to a lesser extent than in a simpler, more primitive feeling state. Still, in true appreciation one does become absorbed in the object of appreciation; he, for the time being, to some extent becomes identified with what he is appreciating. In, order to appreciate this submerging of one's self, this identification is necessary. Appreciation is bound up with four different types of situations which are of most importance to the teacher--(1) appreciation of the beautiful, (2) appreciation of human nature, (3) appreciation of the humorous, (4) appreciation of intellectual powers. The appreciation found in these four types of situations must vary somewhat because of the concomitants, but the characteristics which mark appreciation as such seem to be present in all four. True, in certain of the situations occurring under these types the emotional element may be stronger than in others--in some the intellectual element may seem to almost outweigh the affective, but still the predominant characteristics will be found to be those of an attitude which has the earmarks of appreciation. Appreciation of beauty has usually been discussed under the head of aesthetic emotions. As to what rightfully belongs under the head of aesthetics is in dispute--writers on the subject varying tremendously in their opinions. Most of the recent writers, however, agree that the stimulus for aesthetic appreciation must be a sense percept or an image of some sense object. Ideas, meanings, in and of themselves, are not then objects of aesthetic enjoyment. The two senses which furnish the stimuli for this sort of appreciation are the eye and the ear--the former combining sensations under space form and the latter under time form to produce aesthetic feelings. Our senses may cause feelings of pleasure, but the enjoyment is sensuous rather than aesthetic. Nature, in all its myriad forms, art, architecture, music, literature, and the dance are the chief sources of aesthetic appreciation. That there is a definite connection between physiological processes and the feeling of appreciation is without doubt true, but just what physiological conditions in connection with visual and auditory perception are fulfilled when some experience gives rise to aesthetic appreciation, and just what is violated when there is lack of such appreciation, is not known. It is known that both harmony and rhythm must be considered in music, and that the structure and muscular control of the eye plus the ease of mental apprehension play important parts in rousing aesthetic