It is extraordinary how close is the analogy when we come to work it out. The impressions stored up by the Conscious Personality and entrusted to the care of the Unconscious are often, much to our disgust, not forthcoming when wanted. It is as if we had given a memorandum to our wife and we could not discover where she had put it. But night comes; our Conscious Self sleeps, our Unconscious Housewife wakes, and turning over her stores produces the missing impression; and when our other self wakes it finds the mislaid memorandum, so to speak, ready to its hand. Sometimes, as in the case of somnambulism, the Sub-conscious Personality stealthily endeavours to use the body and limbs, from all direct control over which it is shut out as absolutely as the inmate of a Hindu zenana is forbidden to mount the charger of her warrior spouse. But it is only when the Conscious Personality is thrown into a state of hypnotic trance that the Unconscious Personality is emancipated from the marital despotism of her partner. Then for the first time she is allowed to help herself to the faculties and senses usually monopolised by the Conscious Self. But like the timid and submissive inmate of the zenana suddenly delivered from the thraldom of her life-long partner, she immediately falls under the control of another. The Conscious Personality of another person exercises over her the same supreme authority that her own Conscious Personality did formerly.
There is nothing of sex in the ordinary material sense about the two personalities. But their union is so close as to suggest that the intrusion of the hypnotist is equivalent to an intrigue with a married woman. The Sub-conscious Personality is no longer faithful exclusively to its natural partner; it is under the control of the Conscious Personality of another; and in the latter case the dictator seems to be irresistibly over-riding for a time all the efforts of the Conscious Personality to recover its authority in its own domain.
What proof, it will be asked impatiently, is there for the splitting of our personality? The question is a just one, and I proceed to answer it.
There are often to be found in the records of lunatic asylums strange instances of a dual personality, in which there appear to be two minds in one body, as there are sometimes two yolks in one egg.