Some investigations having been directed toward the measurement of carbonic anhydrase activity in the erythrocytes either of any normal subject, schizophrenic, or non-schizophrenic patient, together with a study as to the correlations that exsist between that and electric or insulinshock, or various toxines of vegetative nervous quality, (e.g., adrenalin, pilocarpine, atropine etc.) that should by administered to it; 1) In the case of schizophrenics, the activity of carbonic anhydrase has proved in general to be rather low than in normal subjects; exitatory type has proved the lowest. Then, in the course of transition from acute type to chronic, or improving, the activity has inclined to increase. 2) As for those non-schizophrenic patients, in the greater half it has proved to be lower than in normal subjects; with such diseases as hysteria, depression, or neurosis, which chiefly are consisted of psychiatric symptoms, it has proved distinctly to be lower than in those diseases in which physical symptoms are considered with importance such as hydrocephalus, brain haemorrage, and chronic toxicity. 3) When treated by electric or insulinshock, anhydrase activity both of schizophrenics or non-schizophrenic patients show a sure drop. If adrenalin may be injected, it would prove an increase invariably; in case atropine is applied, a drop in activity will occur in the schizophrenic group, while various attitude may take place among the non-schizophrenic groupes. Toward the injection of pilocarpine, both groups repsond with various attitudes. 4) I have tried certain investigations as to the significance those changes of anhydrase activity may suggest to us.