The excitement may last for months or even for a year or more and often stops suddenly, always with deterioration later. In the cases which have come to autopsy Alzheimer has reported severe and widespread cell alterations, fibre loss, glia reactions, and changes in the vessel walls, somewhat suggesting the pathological findings in general paresis. The cases in this group usually have been of the male sex between sixty and seventy years of age. Kraepelin speaks of the clinical picture as a mixture of the symptoms of general paresis, katatonia and manic-depressive psychoses and it is usually diagnosed as one or the other of these conditions. The paranoid presenile forms occur usually in women. Consciousness is clear, although there may be a mild anxiety or hypochondriasis. The persecutory ideas are variable and changeable. Delusions of jealousy are common although hallucinations are infrequent. Memory is often somewhat impaired and retrospective falsifications are occasionally observed. The mood is as a rule anxious and suspicious. Suicidal tendencies often appear. Restlessness, excitement, impulsive actions and outbursts of anger are noted at times. Rarely a more cheerful mood develops. The disease may become stationary and show no marked changes for years. Kraepelin himself seems to be very uncertain as to the significance and the delimitation of these various presenile forms. It must be confessed that some of the types described very strongly suggest the condition formerly looked upon by him as involutional melancholia. It will be noted that he considers as possible etiological factors the disturbance of metabolism which may result from regressive or involutional processes. The differentiation from manic-depressive forms, from arteriosclerotic disorders and from senile psychoses must also be looked upon as presenting some difficulties which cannot be entirely disregarded. Many possibilities suggest themselves. In the senile deteriorations Kraepelin notes particularly a loss in the capacity of apprehension and perception, with a sluggishness of the train of thought, a dulling of the emotions, a reduction of energy and the development of conduct disorders. Ranschburg in psychological tests noticed a lengthening of the reaction time, with a delay in the choice of action, the reading of words, the performance of addition, and the formation of judgment. The retardation was shown particularly in psychic processes and the association time. The reactions were, moreover, much more monotonous, irregular and unreliable than in the young. Memory tests also showed poor associations.