Endotoxins of gram-negative anaerobic bacteria

The author reviews the data available on endotoxins of Fusobacterium, Sphaerophorus, Leptotrichia, and Veillonella species, and reports his own findings with lipopolysaccharides extracted from Bacteroides fragilis strains by the trichloroacetic acid method. The latter extracts showed a very low toxicity for mice after i.v. injection of dosages of less than or equal to 500 micrograms and a slight leucopenic effect in mice after intraperitoneal injection of 50 micrograms.