Abstract
The genetic determinants of O antigen 5 of Salmonella group B may be situated near his and not far from met locus, and can express its action only in an organism in which O antigen 4 is also manifested. On the other hand, the genetic determinants of O antigen 4 of Salmonella group B and 9 of Salmonella group D are found to be situated on the O locus near his and to be probably allelic. The genetic determinant of O antigen 5 is at least outside the range of cotransduction by use of P22 (iota) phage with his+ and O-4.
