1. Allegra, G., Niutta, R., and Giuff;ida, G. (1955). Brit. Abst. Med. Sci., 2, 333.
2. Chapman, G. H. (1943). J. Bact., 45, 405.
3. Coackley, W. (1951). J. med. Lab. Technol., 9, 227.
4. Johnston, J. A. (1956). Texas Rep. Biol. Med., 14, 74.
5. Bact;Kooistra, J. A. Jr.; Sellers, W,1957