Cognate in some of its essential characteristics to the phenomenon of obsession is that of dual personality; and although it has nothing to do with the question of spiritism, it may as well be noted here as elsewhere. By this term is not meant the duality of mentaL organization which pertains to every human being, but it refers to a specific phenomenon which has received that name .from recent scientific observers. It is characterized by a complete loss of knowledge of personal identity. The patient assumes a new name, a new personality, and a new character, the last being often in marked contrast to the normal one in every essential particular. The old personality is sometimes completely forgotten, and sometimes it is remembered only as a person whom the patient has once known. In some instances the two personalities alternate at somewhat irregular intervals. In others, the phenomenon occurs only once in a lifetime. In others, several different personalities will be assumed at different times. In all these cases certain characteristics constantly reappear, the most notable appearing in the fact that the new personality is always consistent with itself; that is, it is always the same, whenever it reappears.

Its moral characteristics are sometimes in marked contrast to the lifelong character developed in the normal state, but it never varies from one time to another. If a dozen different personalities should be assumed at different times, each would always be consistent with itself. The incidents occurring during the continuance of one interval of the abnormal personality will always be remembered whenever the same personality reappears, so that the existence of the new personality, when it reappears with frequency, is practically continuous; that is, the intervals of normal consciousness do not seem to be remembered. The normal personality, however, never remembers aught of what occurred during the abnormal interval. As before remarked, the abnormal personality sometimes remembers the existence of the normal one, but always as that of a third person, upon whom it often looks, and of whom it sometimes speaks, with pitying contempt. It generally happens, in case two or more abnormal personalities are assumed, that each remembers all the other abnormal characters, but regards them as third persons having no connection whatever with itself.

One of the most remarkable cases which have been reported in the United States was that of one Ansel Bourne, a Baptist clergyman, who suddenly disappeared from his home in Rhode Island a few years ago. Every effort was made to find him, but without avail. At the end of two months he returned to his home, after an experience of the strangest character. It appears, from an investigation conducted in the most careful and painstaking manner, in behalf of the London Society for Psychical Research, that Mr. Bourne lost normal consciousness soon after leaving home, and wandered around in several different towns and cities, finally reaching Norristown, Pa., where he rented a store, stocked it with small wares, and carried it on successfully for a period of six weeks, under the name of A. J. Brown. He appeared to the citizens of Norristown as a normal person, conducting his business properly, contracting no unnecessary debts, and always paying promptly. At the end of six weeks of a mercantile career he suddenly regained his normal consciousness, and remembered nothing whatever of his abnormal experience.

The article in the Proceedings of the Society for Psychical Research, written by Richard Hodgson, LL.D., exhibits exhaustive research in the investigation of this case, and its entire verity cannot be doubted. It appears that Mr. Bourne had once, in early life, had a remarkable experience, which shows a tendency to abnormal psychic conditions; but nothing was developed which throws any light upon any specific cause for the particular phase of his later experience. He had never before engaged in trade, nor had he had any taste for such a life, and nothing could be remembered which could explain why it was that he assumed the name of A. J. Brown. It is stated, however, that he had once been hypnotized, when young, and made to perform many amusing antics on the stage; but no recollection was had that the name of A. J. Brown had been suggested to him at the time. It is extremely probable, however, that that name was suggested to him at that time, and that his subjective mind retained the memory of the name, and that the impression lasted all those years, only to reappear when he again went into a hypnotic trance.

This is only a conjecture, however; but it has been shown in a previous chapter how the subjective mind of a young lady retained the impression of its identity with a certain fictitious character, which she had once assumed in a play, and with which it again identified itself in obedience to her suggestion, made when she was in the normal condition.

Again, it is a common stage experiment in hypnotism to suggest some name to the subject, and some character in which he is made to act, that of a merchant being not uncommon. When we remember how lasting are such impressions upon the subjective mind, and how prone they are to reappear at any subsequent time when the same conditions exist, we are prepared to believe that such a suggestion, made in early life, would be an ample explanation of the subsequent event. The fact that the suggestion, whatever it was and by whomsoever it was made, was made while the subject was in the hypnotic condition, and could not, therefore, be remembered objectively, explains why it is that in few, if any, of such cases can any clew be obtained as to the origin of the suggestion, or any reason assigned for the assumption of any particular personality.

The dual character of the persons thus afflicted constitutes the most indubitable evidence of the duality of man's mental organism, and it is beginning to be so recognized by European scientific observers. Some of them say, however, "If this is evidence of duality of mind, what shall we say of those who exhibit a triple personality? Is that an evidence of a trinity of mind?" The question is pertinent, and is easily answered. It is obvious that the persons exhibiting the phenomenon are in a hypnotic trance, and are, therefore, governed by the laws pertaining to hypnotism. They have an objective mind, which is the controlling power in the normal condition. In the hypnotic state the normal, or objective, faculties are in abeyance, and the person is amenable to control by the power of suggestion. Whatever name or character is then suggested is at once assumed by the subject. The suggestion may be oral, and proceed from another; or it may be an auto-suggestion, arising from something suggested in a previous hyp-notization, or from some forgotten circumstance. Be that as it may, the suggested character is assumed and carried out with all the deductive logical exactitude characteristic of subjective reasoning. This is a well-known result of a common hypnotic experiment.

It is also well known that the subject can be made to assume any number of characters by the same process. It is a common stage experiment to cause a versatile subject, who is easily controlled, to assume a dozen different characters in the course of an evening's performance. It is obvious, therefore, that persons who are afflicted with a second personality, which occasionally takes possession of them, are also liable to assume a third, or, indeed, any number of names and characters, if anything happens to suggest them. In fact, the power of suggestion over the subjective mind, in the line of multiplication of characters, is practically unlimited. It is not a multiplication of personalities, however, nor an evidence of a triple or a quadruple personality, but merely an exhibition of the power of the second, or subjective, personality of man to assume, in obedience to the law of suggestion, any number of real or imaginary characters. The same power is exhibited by the subjective personality of a spirit medium when it assumes the names and characters of any number of spirits of the dead, whose names are suggested.

The specific character of the mental operations of persons in whom the second personality is abnormally developed has not been recorded, so far as we are aware. It will be found, however, when observations are made in that direction, that they have practically no capacity for reasoning by the inductive process when under the control of the second personality. This will certainly be the case if the hypnosis is perfect. Otherwise it might be modified by the synchronous action of the objective mind. It is hoped that future observers will direct their attention to this question, to the end that a series of facts may be collated which shall assist in determining the direction and extent, as well as the exact limitations, of subjective mental power. When that is accomplished, the first great step will have been taken in bringing psychology within the domain of the exact sciences.