1. See, for example, Errera, M. C. R., Bull. Soc. Chim. Biol., 33, 555 (1951). Bacq, Z. M., and Alexander, P., “Fundamentals of Radio-biology” (Butterworth, London, 1955).
2. Fricke, H., Cold Spring Harbor Symp. Quant. Biol., 6, 164 (1938); J. Phys. Chem., 56, 789 (1952); Nature, 169, 965 (1952).
3. Barron, E. S., and Finkelstein, P., Arch. Biochem. Biophys., 41, 212 (1952). Carrol, W. R., Mitchell, E. R., and Callanan, M. T., ibid., 39, 232 (1952).
4. Svedberg, T., and Brohult, G. S., Nature, 143, 938 (1938).
5. Brohult, S., and Rosen, D. (to be published).