=Evidence furnished by the method of hypnosis.=—It is almost common knowledge that when a person is hypnotized—whether lightly or deeply—he may be able to remember once well-known events of his conscious life which he has totally forgotten in the full waking state. It is not so generally known that he may also be able to recall conscious events of which he was never consciously aware, that is to say, experiences which were entirely subconscious. The same is true, of course, of forgotten experiences which originally had entered only the margin of the content of consciousness and of which he was dimly aware. Among the experiences thus recalled may be perceptions of minute details of the environment which escape the attentive notice of the individual, or they may be thoughts which were in the background of the mind and, therefore, never in the full light of attention. You must not fall into the common error of believing every hypnotized person can do this, or that any person can do it in any state of hypnosis. There are various “degrees” or states of hypnosis representing different conditions of dissociation and synthesis. One person may successively be put into several different states; many persons can be put into only one, but the degree of dissociation and capacity for synthesis in each state and in every person varies very much, and, indeed, according to the technical devices employed. Each state is apt to exhibit different systems of memories, that is, to synthesize (recall) past conserved experiences in a different degree. What cannot be recalled in one state may be in another. We may say as a general principle that _theoretically_ any experience that has been conserved can be recalled in some state, and, conversely, there is theoretically some state in which any conserved experience can be recalled. Practically, of course, we can never induce a state which synthesizes all conserved experiences, nor always one in which any given experience is synthesized. I shall later, in connection with particular types of conscious states, give examples of hypnotic memories showing conservation of such experiences as I have just mentioned. The point you will not lose sight of is that we are concerned with hypnotic phenomena only so far as they may be evidence of the conservation of forgotten experiences.