The use of HL (hemolytic) antigen adsorbed onto erythrocytes, and L. biflexa repeatedly extracted with 50% ethanol, permits the preparation of antisera containing only type-specific (agglutinating) or genus-specific (HL) antibodies. HL antigen, as extracted from L. biflexa with 50% ethanol, contained small quantities of type-specific antigen, which was capable of adsorbing onto rabbit and sheep erythrocytes along with the HL reactive antigen. However, the type-specific antigen was apparently not operative in the hemolytic reaction. HL antibodies would not precipitate HL reactive antigen, agglutinate leptospiral cells, nor fix complement in the presence of HL reactive antigen or L. biflexa cells. Preliminary studies indicate that the HL antigen contains polysaccharide which is probably complexed with some low molecular weight nitrogenous material.