The effects of metrazol on 10 curarized dogs were studied with the aid of the electroencephalograph. The electrical changes of the cortex, hypothalamus and medulla with metrazol, uncomplicated by asphyxia and muscular movements are described. The effects of a minimal convulsive dose could be prevented from developing by the injection of an appropriate amount of histamine. The mechanism for this inhibition is discussed. In the curarized (artificially respiring) animals, cerebral electrical changes appear with metrazol in the absence of any anoxemia. It is, therefore, suggested that a comparative study of the effects of metrazol in curarized and uncurarized patients could be used to determine the importance of anoxia in the therapeutic mechanism of metrazol treatment.Abstract Teaser