In the 49,640 admissions to the New York state hospitals during a period of eight years the 2,318 cases diagnosed as psychoses with arteriosclerosis constituted 4.67 per cent of the total number. In twenty-one hospitals in other states there were 18,336 admissions, of which 492, or 2.68 per cent, were cases of arteriosclerosis. On the other hand, the Massachusetts hospitals show 9.63 per cent of their first admissions during 1919 as arteriosclerotic psychoses. There would appear to be no way to harmonize these dissimilar findings unless it is merely a question of differentiation between the senile psychoses and those due to arteriosclerosis. In a total of 70,987 admissions to all institutions, there were 3,100 cases of arteriosclerotic psychoses, a percentage of 4.36. It is worthy of note that in all of the various groups of institutions the percentage of senile and arteriosclerotic cases combined is practically the same. This would strongly suggest varying standards of diagnosis which will undoubtedly be reconciled in time. It is only recently that any great amount of attention has been given to the psychoses due to arteriosclerosis and it must be confessed that there has been entirely too great a tendency to dismiss without further interest as senile psychoses all mental disturbances occurring in persons of advanced years. On the other hand, the custom of basing a diagnosis of arteriosclerotic psychosis on the mere presence of an increased blood pressure without the existence of any of the other symptoms which characterize that condition indicates, if nothing else, the necessity of a greater uniformity in our methods of diagnostic procedure. CHAPTER IV GENERAL PARALYSIS