ONE of the essential problems in psychopathology is that of differentiation between primary and secondary determinants of abnormal mental states. Reduction of various clinical symptoms to a point where one group of characteristics finally emerges as the supposedly specific pathologic nucleus of a clinical entity led to the development of the concept of the "fundamental disturbance." Bleuler,1 representing the Swiss school; Berze,2 Birnbaum,3 Küppers4 and Kronfeld,5 the German school, and Minkowski6 and Claude,7 the French school, are the main investigators of this subject. It was Claude who, in 1924, reported a new method which he believed to be experimental and objective. He selected negativistic schizophrenic patients, anesthetized them with ether and observed the changes in attitude which some of the patients displayed as they passed from consciousness into a state of narcosis. He concluded that patients who showed no changes at all suffered