THE subject of secondary and multiple personalities includes many phenomena that were once regarded as mystifying and uncanny. Today the veil of occultism has been snatched away and we know the secondary personality for what it is, simply the symptom of a disordered mental mechanism, the personification of dissociation run wild.

The word "personality" has a variety of meanings. Commonly it denotes those individual characteristics by which one person is distinguished from another. Every personality in this sense is made up of changing materials. Socially, each one of us has almost as many different personalities as he has groups of acquaintances whose good opinion he values. To every such person he shows a different aspect of his nature.

The "social climber" does not appear among her "swagger" friends as she may show herself to the intimates of her household. The father is not the same man with his children as he may appear to be among the "good fellows" of his club. The merchant may be one man to his employees and another to his customers. The judge as an individual may feel profound compassion for the prisoner in the dock, yet as the minister of justice he must mete out the penalty that the law provides. Many a man would dread exposure to his business acquaintances of the character of his so-called "private life."

This disposition is not altogether a chameleon-like reflection of the characters of those about us. It is due in some degree at least to the love of approbation, the desire to so pattern our behavior as to simulate that picture of ourselves which we want those with whom we are in contact to carry in their minds.

In the phrases "primary personality," "secondary personality," and "multiple personality," as we shall use them, the term "personality" has no such significance as that we have been describing. In this connection it means, rather, a group of mental states bound together by a common element of memory.

In normal life, all thoughts, all mental pictures, that come to us out of the past, are recognized by consciousness as part of our past. They do not come to us as new or strange. We know them for what they are, a part of ourselves.

All our conscious mental states, past and present, are therefore normally linked together by a mental sense of recognition not only as to their individual elements but as to each other. They merge into a flowing stream of consciousness.

Memory's recognition of the past as past thus unifies all conscious experience and enables us to think of ourselves as one individual or being.

The man we were yesterday was but another manifestation of the man that we are today. And, in normal life, each person has normally but one "personality." There are, however, abnormal conditions in which one or more groups of mental states become split off from the others with no power of recognition or recall on the part of memory to bridge the gap.

A characteristic type of abnormal dissociation is that mental ailment known as functional amnesia, or forget-fulness, by which, as we have seen, a long period of time or an epoch in a man's life is blotted from his memory, is so dissociated from the stream of consciousness that he is neither able to recall it nor to recognize it as belonging to his past. Another is the paralysis of anesthesia shown in cases of hysteria.

In the former type, the dissociation might be said to be a dissociation of conscious experiences, since it amounted to a setting off to one side of a vast number of experiences of which the individual was conscious at the time that they occurred but which by this dissociative process have become detached from his normal personality. In the latter type, the type of anesthesia, dissociation takes place simultaneously with the experience itself, so that the individual never at any time becomes conscious of it.

It is important to bear in mind that dissociation is a normal function of the mind, and, as a selective agency complementary to attention, enables the individual to adapt himself to the incessant changes of environment. It is only when the activity of this dissociating mechanism becomes enormously exaggerated or deranged that it is properly termed abnormal. That such disturbances are purely functional and indicate no brain defect is demonstrated by the cases cited in our last chapter evidencing the fact that these dissociations can be produced and removed by hypnotic suggestion. Obviously, a suggested idea could not be accepted and acted upon, if there was not a normal bodily mechanism.

In the examples of abnormal dissociation we have thus far considered, the process has never gone beyond the failure to perceive or the inability to recall certain necessary sensory experiences. Such abnormal dissociations may, however, become so complete that the un-perceived or lost experiences assume a systematic or organized form. We then have the phenomenon of abnormal life known as "secondary personality." By this is meant a separate group of mental states contemporaneous with the primary personality, but not connected with it by any power of conscious recollection, "Secondary Personalities" have all the reality of another person with distinct traits and peculiarities inhabiting the body contemporaneously with the true owner. Each group of mental states, each form of consciousness, has its own individuality and its own memory, but knows nothing of the existence of the other except through information gathered from outside sources. Illustrations will make this clear.

One of the most famous cases of this sort is that of Madame B, of which Professor Janet's study and account has become historic. In this case the dissociation of mental states developed three distinct personalities, which are best described in Professor Janet's own words, as recorded by Mr. F. W. H. Myers:

"In these researches Mme. B., in her everyday condition is known by the name of Leonie. In the hypnotic trance she has chosen for herself the name of Leontine, which thus represents her secondary personality. Behind these two, this triple personality is completed by a mysterious Leonore, who may for the present be taken as nonexistent. A post-hypnotic suggestion was given to Leontine, that is to say, Leonie was hypnotized and straightway became Leontine, and Leontine was told by Prof. Janet that after the trance was over, and Leonie had resumed her ordinary life, she, Leontine, was to take off her apron - the joint apron of Leonie and Leontine - and then to tie it on again. The trance was stopped, Leonie was awakened, and conducted Prof. Janet to the door, talking with her usual respectful gravity on ordinary topics. Meantime, her hands - the joint hands of Leonie and Leontine - untied her apron, the joint apron, and took it off. Prof. Janet called Leonie's attention to the loosened apron. Why, my apron is coming off!' Leonie exclaimed, and, with full consciousness and intention, she tied it on again. She then continued to talk, and for her - Leonie - the incident was over. The apron, she supposed, had somehow come untied, and she had retied it. This, however, was not enough for Leontine. At Leon-tine's prompting, the joint hands again began their work, and the apron was taken off again and again replaced, this time without Leonie's attention having been directed to the matter at all.