1. Ewald, W., and Hübener, H. J., Naturwiss., 48, 720 (1961).
2. Troll, W. (unpublished observations).
3. Knox, W. E., and Pitt, B. M., J. Biol. Chem., 225, 675 (1957).
4. Pitt, B. M., Absts. 138th Meeting Amer. Chem. Soc., 7c (New York, Sept., 1960).
5. Pitt, B. M., Abst. Communications, Fifth Intern. Cong. Biochem., Moscow, 12 (1961).