As a matter of course, in the overwhelming mass of cases the frankness and the good will of the patient himself will support the physician and accordingly his examination is not obliged to trap the patient but simply to guide him to important points. But then begins the most essential study of diagnostical differentiation. With all the means not only of psychology but of neurology and internal medicine, he has to separate the particular case from similar ones and to examine whether he deals with, for instance, a hysteric or with a paranoiac, with a neurasthenic or with a case of dementia praecox; and he will not forget that there exist almost no symptoms of serious diseases which the nervous system of the hysteric may not imitate for a time. Not ours is the task of analyzing special methods of neurological and mental differential diagnosis such as are used in the psychiatric clinic and in the office of the nerve specialist. There the family history with reference to nervous and other diseases, the history of the patient himself, the infectious diseases which he has passed through, his habits and anomalies, his use of alcohol and of drugs, his experiences in social life, the demands of his profession, his recent troubles and their first origin are to be recorded carefully. Then begins the physical examination, the study of his sense organs and his nerves, of the motor inabilities, the pains, the local anaesthesias and paraesthesias, the disturbances of the reflexes, of the spasms, tremors, convulsions, and incooerdinations, of the vasomotor and trophic disorders, and so on. In a similar way the psychical examination tests the hallucinations and illusions, the variations and defects of memory and attention, of judgment and reasoning, of orientation and self-consciousness, of emotions and volitions, of intellectual capacities and organized actions. But we do not have to enter here into a discussion of such diagnostic means; our chief interest belongs to the therapy.