We have a series of psychical symptoms visibly connected with each other, from which we may conclude to certain central changes. The most that can be done, however, in this relation is to fashion an hypothesis concerning the physical processes running parallel to the psychical processes. On the other hand, certain psychological interpretations attempt to base the whole of psychology on the one fact of suggestion, thus deriving the known from the unknown. The phenomena are explained by 'sympathy' or 'double consciousness,' theories which are closely allied to certain occultistic conceptions. Schmidkunz, Taine, Pierre Janet, Dessoir, and Moll have offered such pseudo-explanations. We must seek for an explanation of all these facts in the laws of consciousness. W. regards it as established that 'suggestion,' the awakening of ideas by words or acts, is the chief if not the only cause of hypnotic states. Suggestion is association plus a simultaneous contraction of consciousness to the ideas aroused by the association. Given such a contracted consciousness, the rise of ideas follows the usual laws of association. The chief problem is this, How does this concentration of consciousness arise, which gives to these ideas their overpowering force? An examination of states analogous to the hypnotic condition throws light on the subject. The dreamer as well as the hypnotized subject shows a diminished sensibility to all impressions lying outside of a certain circle of ideas which, for the time being, have sway over consciousness. The absence of other psychical forces which would oppose these one-sided associations is the peculiar trait. On the other hand, the stimuli which do act produce an intensified reaction. Considering the matter physiologically, we may say that the diminution of the general sensibility is compensated by an increase in special sensibility. If a large portion of the central organ is in a state of functional latency, the excitability of the functioning part is more intense. The excitability of a central element depends not only on its condition at the moment of excitation, but also on the condition of the other elements connected with it. An excitation occurring in adjacent parts lowers its own excitability, while a state of latency there favors an explosion of energy in the affected part. Ganglionic cells accumulate latent energy, and may, when excited, liberate and transmit energy. In sleep an immense amount of energy is accumulated. Its discharge at a certain point causes an increased transmission from all neighboring points that are in a state of tension. This explains the heightened excitability in sleep. This principle of neuro-dynamic compensation is strengthened by the principle of vaso-motor compensation. The same principles act in hypnotism. Here, however, the central organ not being in a state of exhaustion, the neuro-dynamic compensation is more energetic. Hence the ease with which func-
