It was in the nineteenth century that pseudo-scientific speculation about music, described in this quotation, reached its high-water mark. It was then, as Sir Donald Tovey has remarked elsewhere, that “in England Rameau's doctrine raged unchecked by taste or common sense, and culminated in Dr. Day's famous application of homoeopathy to the art of music.” If with the advance of scientific knowledge, and a sounder sense of musical scholarship based on fuller acquaintance with the history of music, these speculations are generally ignored to-day, it is still possible to find traces of them in some modern writing. There has indeed been some recrudescence of them in attempts, by contributors to musical literature, to discover an explanation for some of the changes which composers are now bringing about. I am thinking particularly of “theoretical” discussion of the basis of the twelve-note semitonal technique. It will therefore be my purpose, this afternoon, to probe into this would-be theory, if” only because modern composition must stand or fall by its own musical merits, without the intrusion of “pseudo-scientific speculation.”