Precipitation and Complement Fixation Reactions With Residue Antigens in the Non-Hemolytic Streptococcus Group

The applicability to the non-hemolytic streptococci of the technique used for the extraction of a soluble precipitating substance from the hemolytic streptococci is demonstrated. With this substance as antigen, it is demonstrated by means of precipitation and complement fixation that the non-hemolytic streptococci form an antigenically distinct, but entirely heterogeneous group. Such cross-reactions as do occur within this group are not useful in the systematic classification of these organisms.