Pain is a frequent symptom of disease or injury and in most instances may be relieved by the removal of the underlying cause or by the use of anesthetic agents or analgesic drugs, or it may be tolerated with fortitude and varying degrees of resignation by those who possess such qualities of temperament. Every physician has patients in his practice who experience pain which is unrelieved by the usual measures and in whom great physical and mental suffering result. Not infrequently such patients are totally incapacitated, a burden to their families, addicted to drugs, at times mentally unbalanced, unpredictable and always self concerned. In the majority of instances, if not in all, there is originally a discernible anatomic or physiologic reason for the pain experienced. In certain instances, however, a fixed pain pattern is set up prior to the removal of the existing cause. This pain pattern may be interrupted