Since there still exists considerable uncertainty concerning the relationship of certain constituents of the blood to the various personality disorders, another1report of the findings of this laboratory seems justifiable. Included in this report is a special study of the carbon dioxid combining power of the blood plasma, and of the urea nitrogen of the blood. METHODS OF PROCEDURE All specimens of blood were obtained within ten days after the patient had been admitted to the hospital. Blood for carbon dioxid determinations was taken by venipuncture before breakfast, twelve hours after eating, and while the patient was still in bed. Sodium oxalate was used to prevent clotting. The blood was allowed to flow directly into the tube containing the oxalate, with as little shaking as possible. The blood was centrifugalized, and the plasma was drawn off within from one-half to one hour after the blood had been collected, care