A new bacterial variant: the non-motile H form

From the faeces of a carrier a strain ofSalm. paratyphiB was grown repeatedly which—even under conditions most favourable for bacterial motility—was completely non-motile despite its being richly flagellated and optimally Hagglutinable. The strain has in all subcultures, so far, for more than 1 year retained its peculiarity, viz. absence of the motor function of the flagella which morphologically and serologically appears to be normally developed. This new bacterial variant, the non-motile H form, is considered to be the result of a loss variation which—possibly related to a somatic degradation of the bacilli—affects the genetic factor responsible for the function or the development of the centre for the motility of the flagella.