1. MacMunn, C. A., J. Physiol., 6, 22 (1885).
2. Keilin, D., Proc. Roy. Soc., B, 98, 312 (1925).
3. Warburg, O., for a summary, see “Schwermetalle…”, chapter 14 (Freiburg, 1949).
4. Warburg, O., and Negelein, E., Biochem. Z., 214, 64 (1929).
5. Keilin, D., and Hartree, E. F., Proc. Roy. Soc., B, 127, 167 (1939).