1. Measurements have been made of the potential and of the cohesive force at the surface of Bacillus typhosus and the bacillus of rabbit septicemia in solutions of various salts and acids.
2. Electrolytes in low concentration (0.01 N) affect primarily the potential, and in high concentration decrease the cohesive force.
3. As long as the cohesive force is not affected, agglutination occurs whenever the potential is reduced below about 15 millivolts.
4. When the cohesive force is decreased the critical potential is also decreased, and in concentrated salt solution no agglutination occurs even though there is no measurable potential.