From this point of view we can see clearly the general division of the whole field of possible psychotherapy. Psychotherapy influences psychophysical states in the interest of health. There are only two possibilities open: either the disturbance is in the psychophysical system itself or it is outside of it, that is in the other parts of the body which are somehow under the influence of the mind. In the first case when the disturbance occurs in the mind-brain system itself, we ought to separate two large groups, first those cases in which the system itself is normal and the disturbance comes from without, and second those in which the constitution of the system itself was abnormal and led to disturbances under conditions in which a normal system would not have suffered. We have to consider both groups somewhat more in detail, as each again allows a large variety of cases. Thus we have before us, first the normal mind-brain system into which a disturbance breaks, injuring more or less severely and for a longer or shorter time the equilibrium of the psychophysical functions. Here belong any bodily processes which produce pain or any bodily defects which produce blanks in the content of consciousness; the pain of sciatica or of rheumatism, or the defect of the blind or of the deaf, certainly interferes in a disturbing way with the perfect harmony of psychophysical activities. But here also belongs the suffering which results from conditions in the surroundings, the loss of a friend, a disappointment in life, any source of worry and grief. Social and bodily conditions alike may thus work to break up the equilibrium. The pain sensation interferes with the normal flow of mental life and the grief may undermine the mental interests. The psychotherapeutic effort may be directed toward removing the source of the disturbance, bringing the patient under other conditions, curing the diseased organ, and where that is not possible, may work directly on the psychophysical state, inhibiting the pain, suppressing the emotion, substituting pleasant ideas, distracting the whole mind, filling it with agreeable feelings, until the normal equilibrium is restored.