If thus the memory idea is linked with the past experience entirely by the lasting physiological change in the brain, we have no reason to alter the principle, when we meet the memory processes of the hypnotized person or the hysteric. It is true their memory may bring to light earlier experiences which are entirely forgotten by the conscious personality, but that ought to mean, of course, only that nerve paths have become accessible in which the propagation of the excitement was blocked up before. That does not bring us nearer to the demand for a subconscious mental memory. The threshold of excitability changes under most various conditions. Cells which respond easily in certain states may need the strongest stimulation in others. The brain cells which are too easily excited perhaps in maniacal exultation would respond too slowly in a melancholic depression. Hypnotism, too, by closing the opposite channels and opening wide the channels for the suggested discharge, may stir up excitements for which the disposition may have lingered since the days of childhood and yet which would not have been excited by the normal play of the neurons. Quite secondary remains the question of how these reproduced images finally appear in consciousness, that is, whether they appear with reference to earlier happenings and are thus felt as remembrances, or whether they enter as independent imaginations, or whether they finally, under special conditions, take the character of real, new perceptions. The latter case is well-known in crystal-gazing, where long-forgotten memory ideas project themselves into the visual field like hallucinations. But for the theory of the subconscious, even these uncanny crystal visions do not mean more than the simplest awakening of the experience of a landscape image of yesterday. We turn to a second group of facts and again we have no fault to find with the observation of the facts, even of the most surprising and exceptional ones. Our objection refers to the interpretation of them. This second group contains the active results of such physiological nervous dispositions. In the first group, the dispositions come in question only as conditions for a new excitement which was accompanied by mental experience. In this second group, the dispositions are causes for other physiological processes which either lead to actions or to influences on other mental processes. The dispositions are here working like the setting of switches which turn the nervous process into special tracks. In the simple cases, of course no one doubts that a purely physiological basis is involved. The decapitated frog rubs its skin where it is touched with a drop of muriatic acid in a way which is ordinarily referred to the trained apparatus of his spinal cord, as no brain is left, and the usefulness of the action and its adjustment is very well understood as the result of the connecting paths in the nervous system.