STUDIES ON THE ANTIGENIC COMPOSITION OF GROUP A HEMOLYTIC STREPTOCOCCI : IV. RELATED T BUT DISTINCT M ANTIGENS IN TYPES 15, 17, 19, 23, 30, AND IN TYPES 4, 24, 26, 28, 29, 46. IDENTIFICATION BY SLIDE AGGLUTINATION

1. The occurrence of closely related T antigens in the series composed of types 15, 17, 19, 23, and 30 accounts for most of the cross reactions observed among these types. Similarly T antigens, unrelated to the first series but mutually related, occur in a second series comprising types 4, 24, 26, 28, 29, and 46. 2. Matt variants of each of the eleven types studied possess type-specific M antigens demonstrable either by precipitin or agglutinin reactions. 3. In seven of these types, strains have been encountered which do not possess the T antigen usually associated with the type in question. 4. Procedures are outlined in the appendix for preparing specific antisera for the classification of these types by the slide agglutination technique.     

Complete heart-block of seven years' duration in a child resulting from injury

A case of complete auriculo-ventricular dissociation is presented, occurring in a healthy appearing and physically active boy 10 years of age. It is presumed that an injury, sustained seven years before produced this condition, for he was a healthy child at the time of the accident. The pulse rate was very slow afterward and has remained so.