When first I undertook the study of the theory of Art, many years ago, I was impressed by the emphasis of pleasure attainment in all descriptions of art works, and by the emphatic pleasurableness of my own mental state during the contemplation of artistic productions. My thought being thus turned to the consideration of the relation of aesthetics to hedonics, I was led to make a careful study of the psychology of pleasure and of its correlate pain: the results of this study I here lay before those who may be interested.