It was not until 1899 that these conditions were clearly differentiated by Kraepelin[277] and the purely emotional and recoverable forms separated clinically from the deteriorative processes which he has associated with dementia praecox. The former he described as manic-depressive psychoses, which included mania, melancholia and a majority of the circular and alternating types previously described. This delimitation had a prognostic as well as an important symptomatic significance. The emotional excitements were characterized by an increased psychomotor activity, with a flight of ideas and distractibility, usually associated with a clear sensorium. Graver forms were, however, recognized, with a clouding of consciousness, and disorientation, occasionally terminating in stupor. Hallucinations and delusions when present were not prominent symptoms. The depressions were characterized by an emotional disturbance in the form of sadness with difficulty in thinking, associated with marked retardation in speech and a motor inhibition. More advanced stages showed clouding, disorientation, stuporous phases and hallucinations. He also recognized alternating or circular as well as mixed types. The prognostic importance of this clinical grouping was the tendency towards a complete recovery from the individual attack, with, however, an extreme probability later of a recurrence, the subsequent attacks assuming either form of the disease. As a rule Kraepelin found that the unfavorable types formerly included in the manias and melancholiac, together with the hebephrenia and katatonia of his fifth edition, presented the definite characteristics of the disease which he described as dementia praecox. His views have been modified from time to time. For instance, he at one time excluded the involutional and anxiety psychoses from his manic-depressive group. Later these were included. In his last edition he has described depressed and agitated forms of dementia praecox, which would strongly suggest that his lines of demarcation were not so clear as he believed them to be in 1899. Of the manic-depressive psychoses he says, "Manic depressive insanity as described in this chapter includes on the one hand the entire domain of the so-called periodic and circular insanities, on the other, simple mania, the larger part of the disease process described as melancholia and also a not inconsiderable number of cases of Amentia. Finally we include certain mild morbid emotional states, some periodical, some continuous, which heretofore have been looked upon either as introductory to more severe disturbances or as belonging, without being sharply circumscribed, to the domain of individual makeup. As years go by I have become more and more convinced that these all represent manifestations of one disease process." The following classification of manic-depressive psychoses was shown in Kraepelin's last edition (1913):—