"A gradual blunting of the emotions, indifference or silliness with serious defects of judgment and often hypochondriacal complaints, suspicions or ideas of reference.
"Development of peculiar trends, often fantastic ideas, with odd, impulsive or negativistic conduct not accounted for by any acute emotional disturbance or impairment of the sensorium.
"Appearance of autistic thinking and dream-like ideas, peculiar feelings of being forced, of interference with the mind, of physical or mystical influences, but with retention of clearness in other fields (orientation, memory, etc.).
"According to the prominence of certain symptoms in individual cases the following four clinical forms of dementia praecox may be specified, but it should be borne in mind that these are only relative distinctions and that transitions from one clinical form to another are common:
"(a) Paranoid type: Cases characterized by a prominence of delusions, particularly ideas of persecution or grandeur, often connectedly elaborated, and hallucinations in various fields.
"(b) Catatonic type: Cases in which there is a prominence of negativistic reactions or various peculiarities of conduct with phases of stupor or excitement, the latter characterized by impulsive, queer or stereotyped behavior and usually hallucinations.
"(c) Hebephrenic type: Cases showing prominently a tendency to silliness, smiling, laughter, grimacing, mannerisms in speech and action, and numerous peculiar ideas usually absurd, grotesque and changeable in form.
"(d) Simple type: Cases characterized by defects of interest, gradual development of an apathetic state, often with peculiar behavior, but without expression of delusions or hallucinations.
"(e) Other types."
A sufficient number of reports has been received from hospitals using this classification to warrant a preliminary survey of the information available at this time on the subject of dementia praecox. Perhaps it would be well to summarize first such information as is to be obtained from other sources. Diefendorf[309] states that dementia praecox constitutes from fourteen to thirty per cent of all admissions to institutions, fifty-eight per cent of the total number being of the hebephrenic, eighteen per cent, of the catatonic, and twenty-two per cent, of the paranoid variety. Kraepelin[310] (1913) found that dementia praecox constituted ten per cent of all admissions, classified as to types as follows:—Silly dementia, thirteen per cent; simple depressive dementia, ten per cent; delusional depressive dementia, thirteen per cent; circular dementia, nine per cent; agitated dementia, fourteen per cent; periodic dementia, two per cent; and katatonia, 19.5 per cent. He reported a history of hereditary taint in seventy per cent of his cases. Diefendorf found the onset of the disease in sixty per cent of all cases before the twenty-fifth year, Kraepelin, in fifty-seven per cent. Kraepelin[311] states that seizures occurred in twenty-one per cent of his cases of silly dementia and in the other types as follows:—simple depressive dementia, seventeen per cent; delusional depressive dementia, twenty-seven per cent; circular dementia, twenty per cent; agitated dementia, twenty per cent; katatonia, seventeen per cent; paranoid dementia gravis, three per cent and paranoid dementia mitis, five per cent. Unfortunately a survey of the other literature of the day throws little additional light on these subjects.