1. Cayeux, P., and Panijel, J., Ann. Inst. Pasteur, 108, 623 (1965).
2. Tarasaki, P. I., Esail, H. I., Cannon, J. A., and Longmire, W. P., J. Immunol., 87, 383 (1961).
3. Murphy, G. E., Medicine, 42, 73 (1963).
4. Wahl, R., and Drach, G. (unpublished results).
5. Ehrenfeld, E. N., Gery, I., and Davies, A. M., Lancet, i, 1138 (1961).