People who are susceptible to hypnotism may remember absolutely nothing of what occurs to them in the hypnotic condition, though they will recall it without any difficulty if during hypnosis it is suggested to them that they should remember it. This represents the most prominent feature of secondary personality; the individuals who are affected by it do not recall in one state of personality what happens to them in the other. In the two states they are very different in character. These differences have been much emphasized with regard to a few cases that are especially abnormal and have not attracted much attention in cases where the differences are slight. Indeed, in a number of the cases where secondary personality asserted itself, the differences in the character of the individual in the two states were practically nil. The only difference was a lapse of memory for certain important events. Considerations such as these help in the understanding and psychotherapy of what are sometimes puzzling cases of apparent dualism of disposition. What we have to do with here are the suggestions of secondary personality which neurotic patients have been inclined to make to themselves as a consequence of the interest in the subject in recent years. The investigations of Head and of Gordon Holmes have undoubtedly shown, however, that there are true pathological conditions associated with certain definite and very marked manifestations of dualism of disposition consequent upon lesions in the optic thalamus. These cases so far as can be judged at the present time, at least, are quite rare and at most would account for duality and not for the plurality of personality that has come to be discussed by certain enthusiastic neurologists in recent years. The magnificent work done on this shows how much may yet be accomplished in the elucidation of nervous diseases by faithful study and investigation of selected cases. CHAPTER IX HYPNOTISM Hypnotism is popularly supposed to be a mysterious psychological process by which susceptible subjects are brought under the influence of a person possessing some marvelous power over others' minds and wills. According to this supposition, during the periods in which the subjects are under this influence, they either have some new source of energy transferred to them from the operator's strong personality, or else they share to some extent in the will power possessed by him. In the midst of the sub-consciousness which characterizes the hypnotic condition, then, they are in some way endowed with new strength, which enables them to overcome obstacles to physical or mental health, some of which seemed at least quite insurmountable under their normal condition. {152}