Abstract
Attempts to confirm certain statements that ether-soluble specific substances can be obtained from B. typhosus have lead to negative results. Two serologically active protein substances and another that was non-protein have been separated from B. typhosus. The first two are not resistant to tryptic digestion or to treatment with alkaline hypochlorite solution whereas the third resists both. One of the proteins could be extracted with 75 per cent alcohol. Specific precipitable substances reacting like the non-protein substance of B. typhosus and containing large amounts of carbohydrates have been prepared from B. paratyphosus B, B. enteritidis, and Proteus HX19 and OX19. Observations on the serological behaviour of these preparations are described.