Recent experiments (3) in this laboratory gave clear evidence that the plethoric dog with all its iron stores well filled did not absorb radio-iron, in contrast to the anemic dog which took up such iron promptly and in considerable amounts from the intestinal tract. The transfer of the radioiron to new red blood cells in anemia is very rapid.The experiments tabulated below deal with excretion of radioactive iron after its intravenous injection as ferrous gluconate. It is generally accepted that the urine is not a factor in iron escape from the body and the radioactive iron shows this to be true in these experiments, except for a short period of iron excretion following the intravenous dose of iron.The feces contain a remarkably uniform amount of radioactive iron under these conditions. Except for a short initial period of accelerated excretion following the intravenous iron we observe a steady and low output of 0.05 to 0.40 rag. per day, the larger dogs eliminating more iron, somewhat in proportion to their weight.The bile contains but small amounts of radio-iron in these experiments in bile fistula dogs. The induction of blood destruction greatly increases this excretion. Obviously the capacity of the dog to eliminate iron is strictly limited under these conditions, and this fact is of importance when we attempt to visualize the metabolism of iron in the body.Iron balance studies have always been difficult and the results uncertain to a degree because of the inability to distinguish between excreted iron and dietary iron which was unabsorbed in the gastro-intestinal tract. Iron balance studies called for the use of diets very low in iron content and very accurate iron analysis to obtain significant results. Varied results and con-* Aided by funds from Eli Lilly and Company.

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In this limited experience, tests of renal and hepatic function together with blood studies before and after the parenteral administration of streptomycin revealed no evidence of serious toxicity. Reactions, consisting of fever, arthralgias, and skin rashes as well as histamine-like effects, are believed to be due to impurities retained in the preparations of streptomycin employed in these studies.