1. Stanford, J. Soc. Chem. Ind., 4, 518 (1885).
2. Atsuki and Tomoda, Chem. Abstr., 21, 115 (1927). Ricard, Bull. Soc. Chim. Biol., 13, 417 (1931).
3. Kylin, Z. physiol. Chem., 94, 337 (1915).
4. Russell-Wells, Nature, 133, 651 (1934).
5. Dillon and O'Tuama, Sci. Proc. Roy. Dublin Soc., 21, 147 (1935).