The Gram-negative Bacteroides of the Intestine

illuminating in that they aided materially in the opening of a new field in intestinal bacteriology and broadened existing knowledge concerning non-sporulating anaerobes. Eggerth and Gagnon state that in 91 per cent of a series of 60 stools of adults the predominating organisms were obligate anaerobes of the genus Bacteroides. They isolated and made a taxonomic study of Gram-negative Bacteroides. Eggerth and Gagnon's observations naturally lead one to assume that these organisms must play a r6le of prime importance in the intestine, and that they constitute valuable material for further intensive investigation. No further stimulus was re-quired for the present writers to enter this new field. The following were points of outstanding interest: (1) the relative numbers of bacteroides in human feces; (2) the pro-portion of Gram-negative to Gram-positive non-sporulating anaerobes; (3) a comprehensive morphological, cultural and sero-logical study, and (4) the adoption of a definite system of classifi-cation of the isolated strains. Over 40 stools of human adults were cultured aerobically and anaerobically. A total of 87 anaerobic strains2 was isolated. To this number were added 22 strains received from Eggerth. These 109 organisms were studied systematically, together with