Bleuler,1 in 1908, substituted the name "schizophrenia" for the term dementia praecox. Kraepelin,2 in 1896, had collected under the latter name a large group of cases which he designated in the fifth edition of his textbook deteriorating psychoses (Verblödungspsychosen) and had opposed them to a group of cases that tended to recovery; the latter he designated periodic psychoses, and later3 manic-depressive insanity. This proposal of Kraepelin represented the most important step in scientific psychiatry after the beginning of the nineteenth century. The only really important step that had been taken before that time was the clear delimiting of the organic cases from the so-called functional insanities. Paresis had been recognized as due to a definite disease of the brain as early as 17984 by Haslam, and particularly by Bayle, in 1822;5 at the same time it became clear that definite alterations of the brain accounted