1. Kerr, W. R., and Robertson, M., J. Comp. Path. Ther., 53, 280 (1943).
2. Caroli, H., and Bessis, M., C.R. Acad. Sci., Paris, 224, 969 (1947).
3. Coombs, R. R. A., Crowhurst, R. C., Day, F. T., Heard, D. H., Hinde, I. T., Hoogstraten, J., and Parry, H. B., J. Hyg., 46, 403 (1948).
4. Todd, C., and White, R. G., J. Hyg., 10, 185 (1910).
5. Ferguson, L. C., Stormont, C., and Irwin, M. R., J. Immunol., 44, 147 (1942).