-24- Hibbard, P. L. and P. R. Stout. 1933. The estimation of potassium by titration of the cobaltinitrite with potas- Sium permanganate. J. Ass. Off. Agric. Chem. 16: 137-140. Joyner, T. and D. Chakravarti. 1960. The analysis of some trace elements in fish tissues. U. S. Atomic Energy Commission report No. UWFL-68. Laboratory of Radiation Biology, University of Washington. 14 pp. Kawabata, T. and E. E. Held. 1958. A method for the determination of strontium-90 in biological materials. Applied Fisheries Laboratory”, University of Washington. Unpublished. Kent, N. L. and R. A. McCance. 1941. The absorption and excretion of “minor" elements by man (2) Cobalt, Nickel, Tin and Manganese. Kraus, VI. Biochem. J. 35: 877-883. K. A. and G. E. Moore. 1953. Anion-exchange studies The divalent transition elements manganese to zinc in hydrochloric acid. J. Amer. Chem. Soc. 15: 1460-1462. Murai, Mary. 1954. Nutrition study in Micronesia. Atoll Research Bulletin No. 27. The Pacific Science Board, National Academy of Sciences, National Research Council, Washington, D. C. 239 pp. Nutritional Data. 1958. Third Edition. H. Pittsburg, Pennsylvania. Sandell, E. York. Tompsett, B. 1959. Heinz Company, Colorimetric Determination of Traces of Third Edition. Metals. J. Interscience Publishers, Inc., New 1032 pp. S. L. 1934. J. 28: 1544-1549. The copper content of blood. Biochem. Winton, A. L. and K. B. Winton. 1945. The Analysis of Foods. John Wiley and Sons, New York. 999 pp. *Now Laboratory of Radiation Biology