Several articles devoted to the etiology of dementia præcox have appeared within the last year in English and American journals; still, additions and contributions to knowledge on this point are much to be desired. It is with the hope of adding, even though slightly, to the knowledge of this condition that we present the following clinical findings: On examining the histories of 200 cases, in 65 per cent. we were able to find some mental or nervous defect in the family. The greater majority of these patients were apparently normal in body and mentally well endowed; in fact, a great many showed unusual ability to acquire school knowledge until the pubescent period was reached. At this time many complained of nervousness and loss of ambition; others were shy, seclusive and showed vasomotor irritability; again others developed exaggerated sexual feelings and practiced masturbation. These symptoms usually passed almost unnoticed by the