The authors reopen the old question, is catatonia psychogenic or is it organic? They believe that their 'rheoscopic studies' (movies) of catatonic movements will help to supply some answers. Catatonic stupors are improved by playing ball and by the administration of sodium amytal and carbon dioxide. But this improvement is only temporary. The authors call it 'pseudoreversible', and conclude that catatonic behavior is due to 'biological changes which transform the mode of being in the world beyond the reach of normal or abnormal purpose and motivation'.