The prognosis for the general run of patients attacked by mental diseases has never been established. The popular impression is that such patients go from bad to worse, and that when they apparently recover they soon break down again. I hope that physicians who share this gloomy view will be encouraged by the facts set forth below. Beginning March 1, 1924, the careers of 1,054 consecutive patients admitted to the department for mental and nervous diseases of the Pennsylvania Hospital were studied for a period of from five to ten years. The patients had the more severe mental diseases, as may be judged from the diagnoses: senile and arteriosclerotic conditions, 13 per cent.; manic-depressive psychoses, 20 per cent.; dementia praecox, 16 per cent.; general paralysis, 5 per cent.; psychoses associated with somatic diseases, 11 per cent.; involution melancholia, 7 per cent.; psychoneuroses, 8 per cent.; unclassed psychoses, 10 per cent.;