Summary. A series of cases is recorded of enteritis and enterocolitis occurring in children and adults in Egypt from which the B. dysenteriaeSonne has been isolated. The organism recovered corresponds biochemically and serologically with the classical strains isolated by Sonne. It is not suggested that this organsim is more than one of the bacillary agents responsible for intestinal infections of this type, prevalent in Egypt during the warm season, but it is of importance to note that it was the only ætiological agent isolated in from 35 to 40 per cent. of a series subjected to careful investigation.