RECENTLY there has been a revival of interest in clinical applications of hypnosis. At the same time, renewed use of anesthesia induced by hypnotic suggestion has been seen, particularly in the fields of obstetrics and dentistry. Hypnotic anesthesia is especially interesting because of the conflicting and challenging nature of reports in the literature. While there has been considerable progress in psychotherapeutic employment of hypnosis,1 little has been added to our understanding of its physiological aspects. The literature on the physiology of hypnosis has been recently reviewed by Gorton,2 whose article serves to emphasize the necessity for considerable controlled experimentation if many disputed points are to be clarified.In 1845 Esdaile3 performed many minor and major operations, including amputations, using hypnotic anesthesia. He claimed that his patients offered no complaint of pain, lay quietly during the surgical procedures, and failed to show changes in pulse or respiration rate or in pupillary dilation, usually considered objective physiological signs of pain. For a time hypnotic anesthesia was rather widely employed by surgeons, and Bramwell's review of the topic covers it in a These studies were aided by a contract between the Office