Experimental and clinical investigations during the past few years have definitely established the value of studies of the cevitamic acid level in blood and urine in appraisal of the vitamin C balance. While determination of the cevitamic acid level in the plasma and the urine is not technically difficult, it seemed desirable to have a simple procedure that would enable the physician in his office to confirm a diagnosis of vitamin C deficiency before it became clinically manifest (subclinical scurvy). The values for cevitamic acid in the urine and the plasma have been shown to have a definite correlation with the degree of tissue saturation. Since the determination of cevitamic acid is dependent on the reduction of a blue dye, 2:6-dichlorphenolinclophenol, to its leuko form, the possibility of studying the reduction of the dye directly in the tissues suggested itself. While this was under consideration Rotter1of Budapest published