Antigens from disrupted cells of dysentery-provoking and of non-enteropathogenic Escherichieae were submitted to immunoelectrophoresis on cellulose acetate stripes at pH 8.0. Among 6 immune sera produced for this purpose by immunizing rabbits against desintegrated dysentery bacteria, only one contained a precipitine reacting with an antigen similar to the "generic antigen" of BELAYA. This - at pH 8.0 - cathode-bound group antigen (KGA) could not only be found in virulent but also in 5 attenuated cultures and in 5 from 6 avirulent strains of several dysentery types. Only the - apathogenic - type culture 1111/55 of dysentery-provoking E. coli O 136 showed no KGA-reaction. Some sources of methodical errors responsible for false outcomes of immunopherogrammes have been discussed.