1. Sherrington, C., Proc. Roy. Soc., 55, 161 (1894).
2. St. Rusznyak, Löwinger, S., and Lajtha, L., Nature, 160, 757 (1947).
3. Jaques, L. B., Fidlar, E., Feldsted, E. T., and Macdonald, A. G., Canad. Med. Assoc. J., 55, 26 (1946).
4. Barikine, W., Z. Immunitätsforsch., 8, 72 (1910).