Meduna and Rohny (1939) have recently commented on the rise of sugar and lactic acid in the blood of schizophrenic patients following therapeutic cardiazol fits. Insulin causes a lowering of the blood sugar, but later the resting level becomes higher than before treatment. Hence they suggest that the alteration of carbohydrate metabolism in the direction of diabetes may be the common mechanism underlying both forms of treatment, and this hypothesis is supported by Nyiro's observation (quoted by Meduna and Rohny) that diabetes is rare amongst patients with schizophrenia.