AN INVESTIGATION OF THE BACILLUS PASTEURI GROUP III. SYSTEMATIC RELATIONSHIPS OF THE GROUP

For many years the literature dealing with the active urea-decomposing bacteria of soils and manures (reviewed by Lohnis, 1910, and Waksman, 1931) has been overburdened with the names of imperfectly defined species. A considerable proportion of the organisms appear to belong to the Bacillus Pasteuri group, which has been described (Gibson, 1934) as a series of ureaclastic spore-forming bacilli which either require or exhibit a preference for alkaline media containing ammonia. An attempt has been made to collect the existing type cultures of organisms which, according to their original descriptions, might be expected to be related to B. Pasteuri, and several strains were secured. This paper contains a brief description of the type cultures, proposals con-cerning the classification of-the Pasteuri group, and an account of work pertaining to its differentiation from other bacteria. INVESTIGATIONS OF TYPE CULTURES The results of the study of type cultures and of their comparison with recently isolated strains are given in this section. In addi-tion, a short historical account of each type is presented, in order to evaluate its claim to recognition as a species and to clarify the confused nomenclature of the organsms. Bacillus Pasteuri (Miquel) Migula This organism, originally described as capable of decomposing 3 grams of urea in a liter of culture per hour, has been regarde