1. All experience has its origin in sensory data, but such data are elaborated and integrated through various levels of the central nervous system. According to Foerster(22), pain should be classified as feeling and emotion rather than as sensation and perception, but no biological or psychological phenomenon can be comprehended in terms of single cause and effect, and almost invariably pain must be considered both an emotional and sensory experience. Its source may be a stimulus in the periphery, or it may be central and cortical and projected to the periphery, as in the case of phantom limb pain or physical pain substituted for anxiety and guilt by the patient with, for instance, conversion hysteria. Treatment can therefore be designed:(a) to interrupt the passage of the sensory impulse: neuronectomy; cordotomy; sympathectomy; procaine nerve block; or even cervical, bulbar, and mesencephalic tractotomy, including bulbar trigeminal tractotomy;(b) to diminish or abolish the perception of the sensory impulse, even despite the fact that the end-organs continue functioning: chemical narcosis, hypæsthesia, and anæsthesia hypnotically induced; or(c) to attack the problem centrally in some other way: thalamotomy, bilateral frontal lobotomy, partial postcentral gyrectomy; psychological lobotomy by hypnosis, induction of deep sleep under hypnosis; psychotherapy of various types with both hypnotized and nonhypnotized patients.2. Various techniques can be utilized for the hypnotic and hypnotherapeutic control of pain: (a) Deep "sleep" may be suggested (patient No. 2 with terminal carcinoma). (b) Direct suggestion can be given to the effect that the patient feels nothing. This is a relatively simple procedure, but can be dangerous for the patient if the pain result from deep-seated emotional needs. This symptom, like other conversion symptoms, may mask an underlying depression that can come to the fore, even in suicidal proportions, if the pain be suggested away without giving the patient something positive in its stead (patient No. 6). On the other hand, suggestion hypnosis has been used in dentistry, surgery, and obstetrics as an analgesic, sedative, narcotic, and anæsthetic—and the resultant anæsthesia is as profound as that produced by chemical anæsthetics. The advantages here are obvious. (c) Hostility may be abreacted—and the pain disappear (patients Nos. 4 and 5.) (d) The psychological equivalent of a lobotomy may be suggested. The patient is told that no stimulus, no matter how intense, can possibly disturb him. He then feels the same "pain" sensation, which nevertheless does not disturb, annoy, hurt, or "pain" him (patient No. 1, a primigravida who was delivered by this technique). This analogy with a lobotomy is, of course, superficial and holds only with respect to clinically observable reactions of patients toward painful stimuli. (e) The fantasies back of the pain may be acted out (patient No. 3 with the diagnosis of a ruptured disc for which she had already bad operative intervention).3. Illustrative patients may be seen in almost every section of the hospital. If the emotional component is pronounced, their pain for the most part is poorly controlled by the more usual medical and surgical procedures. Of those patients whose protocols were utilized specifically for the preparation of this article, 5 were neurosurgical, 3 were orthopedic, 2 were surgical, and 1 was urological; 2 were obstetrical and 5 were medical.4. During the discussion of that part of the clinical material that was utilized for illustrative purposes: (a) the technique of the psychological lobotomy was described; (b) specific dangers of treatment under hypnosis were emphasized; and (c) stress was placed upon the fact that pain, like other psychogenically based symptoms, is frequently utilized as justification and rationalization for drug habituation or addiction, or for the operative intervention for which some patients have so great a need in order to justify the continuance of their neurotic patterns of behavior (patient No. 7).5. Although we believe that symptom disappearance by direct hypnotic suggestion constitutes an exceedingly superficial form of therapy and is not infrequently contra-indicated, selected patients can be treated to advantage under hypnosis by most of the more usual psychotherapeutic techniques and by some made possible only because of the hypnotic relationship itself. The superstition, however, is rampant, that work with hypnosis requires less background, less training, and less knowledge on the part of the therapist. For this reason, we have stressed the dangers involved.6. Psychotherapy of any type can of course be exceedingly dangerous to the patient if its practitioner be incompetent. As Raginsky (23) states in his discussion of mental suggestion as an aid in anæsthesia, "One should be as careful with the psychologic scalpel as with the surgeon's scalpel and no less trained in the use of the psychologic microscope than in that of the bacteriologist or pathologist."