1. The removal of antibody from Bacillus typhosus is no more complete at pH 3 than at pH 7.
2. Approximately twelve agglutinating doses are firmly combined with the organisms. Immune body in excess of this amount is easily removable by distilled water.
3. A method of testing for the presence of immune body on the organism is described which depends on the difference in the acid agglutination of sensitized and unsensitized organisms.
4. Repeated washing in distilled water will serve to remove all the immune body from sensitized bacteria.