THE PRESENT investigation was undertaken to determine the glucose utilization of the retina under a variety of physiological and pathological conditions. Because of its unique respiratory activity, the retina occupies a special place among the various tissues of the body. Warburg1 showed that the retina had the highest rate of respiration and the highest anaerobic metabolism of any tissue studied. Dickens and Simer2 stated that the aerobic glycolysis in vitro was very high, even greater than that of most tumors. The latter authors concluded that the respiratory quotient was 1, thus implying that the metabolism consisted strictly in oxidation of carbohydrates. As carbohydrates seem to be the main source of energy for the retina, it was thought that an analysis of the glucose utilization of the retina under various experimental conditions offered the possibility of gaining additional information on the metabolism of the retina. The first essential was