As mentioned in the proceedings of the last meeting of this Society, the hemolytic action of the immune sera prepared by injection of alcoholic blood extracts is inhibited by the addition of these same extracts. In analogy to the Forssman heterogenetic antibodies (Sordelli and Pico, Sachs and Guth) these sera were found to give a very distinct flocculation reaction with an emulsion of the extract. The technique is similar to the one used by the authors named with the exception of the omission of cholesterin. The washed sediment of one part blood was extracted with 2 1/2 volumes and again with one volume of alcohol overnight at room temperature, and the mixed alcoholic extracts evaporated to one-half of the original blood volume. To 1 cc. of this fluid 5 cc. of saline were added drop by drop with constant shaking, a homogenous stable emulsion being formed. Mixture of equal parts of the emulsion and diluted (1/2 to 1/16) immune serum were allowed to stand in the incubator for 20 hours.Similar reactions thou...