In the autumn of 1934 I received from Dr A. R. D. Adams, Superintendent of the Bacteriological Laboratory at Mauritius, 163 cultures of organisms. These had been isolated by him from the faeces of the inmates of the Beau Bassin Prison and Reformatory in a research on the intestinal flora and fauna of the general population in that island. In the course of the bacteriological examination the specimens of faeces had been cultured on plates of Endo's medium and incubated for 24 hours, at the end of which time non-lactose-fermenting organisms were picked off. A number of these strains were identified by Dr Adams as belonging to the typhoid, paratyphoid, or dysentery groups. One hundred and sixty-three strains which did not fall into these groups were sent to me for investigation.