In 1903 Hiss and Russell described their Bacillus Y which fermented mannite and maltose. From this time the confusion of the mannite-fermenting organisms dates, the custom being established of comparing the reactions on sugar-media of freshly isolated strains with those of strains which had been isolated years previously. It was not recognized that the powers of the recently isolated organism to attack sugars could difier from those exhibited by the organism after a prolonged saprophytic existence. The method had the apparent recommendation of simplicity, other sugars were added to the list and practically every investigator found it possible in this way to create new varieties of the dysentery bacillus. Investigators have consistently sought for the causative organisms of dysentery and allied conditions among the non-lactose fermenters. As regards the etiological significance of these organisms the evidence is by no means complete, but the results of numerous investigations make their connexion with the disease probable.