The Lancefield Groups of Hemolytic Streptococci Found in Children *

In a recent paper Boisvert,' reports that of 509 strains of Streptococcus hemolyticus isolated from 262 cases of streptococcal disease and grouped by means of the precipitin test, all fell into Lancefield's Group A; all of these cases were infants and children. Our own work has been along similar lines and was planned as a further test of the striking relationship between Group A streptococci and disease in children. At the same time we took the opportunity to test Fuller's method2 of preparing extracts to be used in the precipitin test. This method depends on the solvent properties of formamide. We have grouped all strains recovered from the routine cultures made on all children, except the healthy newborn infants, admitted to the Pediatric Service of the New Haven Hospital. The period of study was from October 28, 1938, to March 18, 1939.t All strains were identified by Mrs. Mildred Fousek, Bacteriologist in this department, using as criteria for identification: (a) Colony on blood agar plates, (b) usual morphology, (c) ability of blood culture to hemolyse S per cent rabbit erythrocytes suspended in saline, and (d) resistance of the culture to bile.