Summary: Evidence of the non-specific character of the scarlatinal toxinantitoxin flocculative reaction is presented. The formation of non-specific antibodies in the horse seems to parallel that of a specific scarlet-fever antitoxin during immunization with toxin containing specific and non-specific antigens. A possible explanation is given as to why the flocculative reaction can be used for evaluating antitoxic titers, whereas doubtful results may be obtained in the determination of toxin-flocculation values.