In the latter part of 1919 a patient who had hitherto proved inaccessible began to speak freely of his hallucinatory experiences. His observations were so interesting that it seemed to be an excellent opportunity to gain some insight into the obscure question of hallucinations, and I have therefore kept a complete record of everything which the patient has told me in the course of our conversations during the last year. The method of study has been purely conversational. The method of free association was not utilised for various reasons, and, in a sense, it was scarcely necessary since the patient really analysed himself naturally, and in his remarks made the origin of his experiences quite apparent. It is only proposed, in the present instance, to describe the hallucinations, and to discuss their origin and significance. There are many other features of interest in this case, such, for instance, as the reactions provoked by hallucinations, but these matters are much beyond the scope of a short paper. A brief history of the case will first be given.