We see now how widely different starting points can lead to sleep and can understand from it how widely different disturbances can prevent sleep. Sleep must result when fatigue is coming, but sleep must also result when the elements of the rest feeling are produced, and as we saw that the components of the rest feeling were the sensations of decreased sensitiveness and decreased activity, sleep must result when either the sensations and associations are absent and actions are suppressed, or when monotonous sensations and automatic actions raise the threshold. Sleep must arise further if our will associates the mere idea of such rest, and finally physical or chemical means may produce a sleep bringing effect either on the lower center or on the blood-vessels and cells of the cortex. Correspondingly sleep may be prevented by disturbances in any one of these spheres. There may be no normal fatigue, there may be no fatigue sensation, there may be no rest feeling on account of perceptions, or on account of associations, or on account of impulses to action; there may be no normal response in the subcortical center, there may be no physical effect in the cortex on account of an existing hyperaemia or on account of an abnormal condition of the cells. The psychotherapeutic treatment must carefully analyze which element would be fit to supply the last link in the circular chain. Sometimes we need the suggestion of fatigue, sometimes the inhibition of ideas, sometimes the suppression of impulses, sometimes the suggestion of rest, and so on. A mere general suggestion of sleep is on the whole effective only in the cases of those persons in whom this idea in itself awakens those various components. Very often it is entirely ineffective in this general form. Sometimes it is possible to carry the hypnotic state itself directly over into sleep, but it seems more in the interest of the patient to separate those two states distinctly. We are still confined to processes in the brain itself if we turn to headache. If it were only a question of inhibiting the pain by mental suggestion, the case would not be different from inhibiting the pain of a peripheral organ without attempting to cure the diseased organ itself. But in the case of headaches, it seems justified to claim that in certain varieties of this multifold symptom, not only the pain is suppressed but the disturbance itself is removed. Especially where the headache seems to result from hyperaemia, the trouble seems to be accessible to psychotherapeutics. On the other hand I have never seen any lasting effect on the so-called sick headache or migraine. While continuous headaches or headaches which occur daily yielded to my influence, sometimes completely, I was unable to prevent even by preparatory hypnotization any migraine which appears periodically, for instance, simultaneously with menstruation.