Observations have been made as to the changes produced in blood sugar and lactic acid of normal rabbits during continuous intravenous injection of epinephrine at rates ranging from 0.00005 to 0.001 mgm. per kgm. per min. The minimal effective rate of injection of 0.00005-0.0001 mgm. per kgm. per min. produces an increase not only in blood sugar but also in blood lactic acid. This rate of injection is 30 times less than the maximal rate of discharge of epinephrine from the adrenals as recorded by Cannon and Rapport and 8 times less than the rate of intravenous injection which causes a rise in blood pressure of unanesthetized rabbits. In view of these facts the increase in blood lactic acid after epinephrine injections is regarded as physiologically significant. As soon as the injection is discontinued, both blood sugar and lactic acid begin to fall, showing that epinephrine is destroyed rapidly and that the after effect is of short duration. These points are also illustrated in experiments in which 0.03 mgm. of epinephrine per kgm. was injected at once into the blood stream. After such an injection the peak value of blood sugar and lactic acid is reached in 15 min. or sooner and there is a return to normal in 1 hr. This is in contrast to the sustained and to the much larger increase in blood sugar and lactic acid to be observed when the same amount of epinephrine is injected in the course of 1 hr. The similarity between the sugar and lactic acid curves in blood observed after subcutaneous and after continuous intravenous injection of epinephrine is emphasized. The smallest rate of injection of epinephrine which causes a perceptible rise in the blood pressure of unnarcotized rabbits is close to 0.0008 mgm. per kgm. per min.