1. Intravenous commercial heparin produces a lymphocytosis in the calf. The effect is not due to the preservative commonly present in heparin. 2. The lymphocytosis is mediated to a great extent by an increased input of lymphocytes into the blood via the thoracic duct. 3. The necessity of considering, plus controlling the heparin effect on blood lymphocyte levels and on the output of thoracic duct lymphocytes in all studies on lymphocyte production, migration and behavior, is discussed and emphasized.

1. A method for extracorporeal irradiation of the circulating blood has been developed. 2. Extracorporeal irradiation of the blood will produce a lymphopenia promptly which persists for weeks. 3. Heparin in high doses in the calf produces a lymphocytosis and neutrophilic leukocytosis.

INCREASED RESISTANCE TO RADIATIONutilized for the synthesis of non-essential amino acids by the intact young rat, The possi'bility that urea can !be utilized in anabolic processes in the eviscerate rat should be considered.The possibility that urea can be metabolized in the eviscerate rat weakens one point of evidence that urea synthesis occurs only in the liver. The earlier studies( 1) on nlephrectomized-hepatectomized animals have shown that the blood and tissue urea did not change during the times that these observations were made. The assumption that urea could not be metabolized therefore required the conclusion that no extra-hepatic synthesis of urea could have occurred since the concentration in the body fluids remained uwhanged. However, if urea can be metabolized, it is hypothetically possible for extra-hepatic urea synthesis to coexist with an equal or higher rate of urea metabolism without increasing the concentration of urea in the body. -4s an analogy, it was first assumed that gluconeogenesis occurs only in the liver because the blood glucose falls following hepatectomy. I t has now been clearly established that glucose can >be formed in the kidney, but that this extra-hepatic gluconeogenesis is masked by a higher rate of glucose utilization (1 1). Evi-10. Rose? IT. C., Sniitli: L. C., Wormack, &I., and Shme, M., J. Eiol. Cliem., 1949, 7-181, 307.dence has been reported by Graham, Houchin and Turner(l2) Bhat the active mammary gland of thae goat can synthesize urea.Summary. Male rats of the Sprague-Dawley strain were eviscerated at a weight of 250 g and were given intravenous infusions of solutions of glucose, insulin and 0.9% sodium chloride for periods up to 48 hours. Comparisons were made of the total carcass plus urinary urea in 26 control rats taken immediately following evisceration, 24 rats which weree killed 24 hours following evisceration and, 16 rats which were killed 48 hours following evisceration. The average total carcass urea of the 24-hour rats was lower than that of the controls, and the average value for the 48-hour group was still lower. From the statistical standlpoint, it is hi.gihly probable that there was some extra-renal loss of urea following evisceration. These results are indirect evidence for the Occurrence of urea catabolism. The results are in agreement with observations on other species in showing that there is no rise in the urea concentration of thoe 'body in the absence of the liver.

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