The auditory experiences of dreams, to a greater extent perhaps than those involving the sense of touch, may be based on spontaneous disturbances within the sensory mechanism. This is notably also the case with visual experiences, and in many respects the conditions in the ear are analogous. Apart from increased resonance of the ear, or hyperaesthesia of the auditory nerve, producing special sensitiveness to sounds, an increased flow of blood through the ear, as well as muscular contractions and mucous plugs in the external ear, furnish the faint rudimentary noises which, in sleep, may constitute the nucleus around which hallucinations crystallise. Disease of the ear may obviously act in the same way, but, even apart from actual disease, various nervous disturbances favour the production of auditory hallucinations during sleep, and, in marked cases, even awake. We may dream of listening to music in the absence of all external sounds having any musical character. In such cases, no doubt, the actual conditions within the auditory mechanism are suggesting music to the brain, but the resulting music seems usually to be less definite, less rememberable, than when it forms around the nucleus of an external series of sounds. In many of these cases it is probable that we do not hear music in our dream; we are simply under conditions in which we imagine that we hear music. Thus, on going to bed soon after supper, but not perceptibly suffering from indigestion, I dreamed that I was present at a public meeting combined with an orchestral concert. A speech was to be made by a man who looked like an old sailor or soldier, and meanwhile the orchestra was playing. The speaker--unaccustomed, I gathered, to the etiquette of such a meeting--suddenly interrupted the orchestra by a remark, and the surprised conductor stopped the performance for a moment and then continued, subsequent remarks by the speaker failing to affect the music, which continued to the end, becoming more lively and vigorous in character. But what the music was, I knew not at the time, nor could I recall any fragment of it on awakening. It is even possible that such a dream is mainly visual, and that no hallucinatory music is heard, its occurrence being merely deduced from the nature of the vision.