Somatic and “X” agglutinins to theSalmonellagroup

An examination was made of 200 Wassermann sera, thirty-eight sera from typhoid, twenty-five from paratyphoid B and thirty-one from tuberculous cases, for somatic agglutinins to a range of Salmonellas representative of the O groups then available. In the Wassermann sera O agglutinins, except toBact. typhosumandBact. paratyphosumB, were rare, and the titres against these organisms were low, attaining a titre of 1: 80 againstBact. typhosumin one serum only. The sera of the enteric cases mostly possessed agglutinins to bothBact. typhosumO andBact. paratyphosumB O. Cross-relations withBact. paratyphosumA,Bact. londonand, to a less extent,Bact. paratyphosumC, were common in the typhoid sera. Otherwise there was no evidence of relation amongst the somatic groups tested. The response to T.A.B. inoculation of fifteen individuals suggested also the relation of some organism in the vaccine toBact. londonand its probable lack of relation to the other somatic groups. There was no evidence of increased frequency ofSalmonellaagglutinins in tuberculous cases. The cross-relations of the Salmonellas was found to be due to the possession of minor antigenic components and not to possession of X antigen, which was absent from the suspensions used. X agglutinins were not more frequent in the pathological than in the Wassermann sera. The relation of these findings to the diagnostic agglutination test is discussed, and the possibility of error consequent upon the use of suspensions containing X antigen is pointed out.