In nearly half of his cases Kraepelin found apoplectiform attacks appearing without any marked psychosis preceding them. In some instances no mental symptoms appeared for many years. The attacks were, however, immediately followed, usually, by periods of confusion and clouding, sometimes of excitement and violence. The acute disturbance as a rule subsides rather quickly and clears up partially or completely. Usually there remains a memory defect, an increased fatigability and a depressed or irritable mood. These he refers to as cases of apoplectic deterioration or mental enfeeblement. Recurrent apoplectiform seizures may result in excitement, depressions or deliria. Gradual progressive deterioration is the usual picture. As a general rule the cases with marked excitements, depressions and deliria are of short duration and have a bad prognosis. Kraepelin finds that the arteriosclerotic psychoses appear a decade earlier than the senile psychoses. Less than one per cent developed at the age of forty; 2.7 per cent at forty-five; 3.7 per cent at fifty; 7.4 per cent at fifty-five; twenty-two per cent at sixty; twenty-two per cent at sixty-five; 18.57 per cent at seventy; twelve per cent at seventy-five, etc. In the cases observed at a particularly early age he believes heredity to be a very important factor. Seventy-one and five-tenths per cent of his cases were men. Sixty-two per cent of the men and fifty-three per cent of the women were less than sixty-five years of age. The epileptic and demented forms appear earlier than the apoplectiform variety. Arteriosclerotic involvement of the smaller vessels occurs earlier than that of the larger arteries. Kraepelin found alcoholism more common in the history of his cases than syphilis. He is uncertain whether specific infections can produce a genuine arteriosclerosis or not. Erb has shown that by the experimental injection of adrenalin into the blood stream artificial arteriosclerosis can be produced, with an increase of blood pressure, splitting of the elastica, thickening of the vessel walls and aneurysm formation. Thoma considers alcohol, tobacco, coffee, tea, and infectious poisons important causes. Cramer found the disease more common in innkeepers, actors, directors, officers, bankers and parliamentarians. Alcohol, syphilis, overwork and high living are important etiological factors. Kraepelin assumes the existence of certain metabolic products in the blood, possibly the result of infections which affect blood pressure and the structure of the vessel walls during a period of lowered resistance.