Variations in the Electrophoretic Mobilities of Escherichia, Aerobacter and “Intermediate” Strains

Since, by cultural methods, it is often difficult to obtain any well defined differentiation between the Escherichia, Aerobacter and "intermediate" organism it was thought that a determination of the zeta potential of the various strains comprising these groups might be of assistance in their identification. Chapman (1929) has shown the zeta potential of various strains of Escherichia coli to be constant. Numerous experiments conducted by us show that this is true, not only for Escherichia coli strains, but for Aerobacter aerogenes as well. One hundred and twenty-seven strains of Escherichia, Aerobacter and "intermediates" were isolated from oysters and oyster water,' water, urine, feces, and necropsies, or obtained from the Tittsler collection. They were distributed according to Bergey's Determinative Bacteriology (1934) and Tittsler and Sandholzer's (1935) review groups as shown in table 2.