1. G. A. Villee andA. B. Hastings, J. biol. Chem.179, 673 (1949).
2. A. Beloff-Chain, R. Catanzaro, E. B. Chain, I. Masi, F. Pocchiari, andC. Rossi, Proc. Roy. Soc. B143, 481 (1955).
3. M. Frank, Selected Papers from the Istituto Superiore di Sanità2, 75 (1959).
4. J. E. Kirk, P. G. Effersoe, andK. J. Iversen, Gerontol.9, 10 (1954).
5. V. Pantesco, J. Viaud, R. Fontaine, andP. Mandel, C. R. Soc. Biol.151, 1584 (1957).