During the absorption of the digestion products of fat, lymph in the lacteals and thoracic duct contains a hemolytic agent which is not neutral fat, bile salts, enzymes, or glycerol, or changes in osmotic pressure, pH, or temp. Free fatty acid and soap in quantities sufficient to account for the hemolysis observed (3.3 to 6.3 mg. per cc.) occur in chyle. Apparently some of the fat digestion products fail to be recombined into neutral fat, and are absorbed into the lymphatics as hemolytic free fatty acid or soap. It is possible that absorption of these substances into the lacteals instead of directly into the blood, is a protective device.