Comparing these results with those reported formerly (Olitzki, 1934) it appears that the results obtained by the method of Bedson and Bland (1929) agree in most particulars with those obtained by cataphoresis. We have confirmed the fact, that in the case of Proteus bacilli and some strains of the Enteritidis group the H forms showed a higher migrative velocity than the corresponding O forms. It seems however, that this does not apply generally to all strains of the Salmonella group.

The specific effect of sera containing only H agglutinin on the charge of H forms formerly described for Proteus strains could be confirmed for all strains tested by this method.

Sensitization of Proteus bacteria with O agglutinins reduced only the migration of the O strains, if contact with the serum was 10 minutes or less. This result also agrees with that of previous experiments (1934), where the bacteria were subjected to cataphoresis immediately after coming in contact with the immune serum. The simplified method of Bedson and Bland made it possible to test the bacteria after different times of exposure to immune serum and showed that longer contact with O serum also affected the migration of H forms. The experiments with B. proteus further showed that the effect of O agglutinins was delayed by the presence of H antigen. In the Salmonella group no differences were found between the behaviour of H and O forms of the same strain.

The observation (Olitzki, 1934), that agglutination with H + O sera reduces the charge of all bacterial cells present in a culture-suspension could be confirmed only for Proteus bacteria and O agglutinable strains of the typhoid group. The inagglutinable virulent strains remained unaffected. On the other hand these strains were affected to a certain degree by Vi sera, and a maximal effect was obtained by sera containing O + Vi agglutinins. It seems to be a general rule that a complete alteration of surface-properties can be obtained only, if all partial antigens of the bacterial body are sensitized.

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