Exposure to unfavourable conditions resulted in an alteration of characteristics in certain strains of Salmonella:
(l) Different strains of Salmonella gallinarum yielded motile variants showing various H-antigens. In addition somatic antigenic components, not detectable in the parent strains, accompanied by altered morphological and biochemical characteristics as well as virulence were demonstrated.
(2) Strains of Salmonella dublin showed a change of 0- and H-antigens and acid and gas production in inositol.
It has not yet been established whether the new serotypes observed represent transitional variants of adaptive or mutant nature.