Granular “O” Agglutination in Paratyphoid B and Typhoid Fevers

The granular “O” agglutination of human serums from eighty cases of typhoid and paratyphoid B fevers has been titrated with carefully selected killed typhoid “O” and paratyphoid B “O” suspensions of high sensitiveness. In spite of a wide overlapping, due to common factors, a considerable specificity is shown, and this can be utilised in differential diagnosis, especially if due attention is paid to the different levels of “normal” agglutination for the two species.