A method for chemically fractionating lymphatic organs has been described. The method has been shown to be applicable to bovine palatine tonsils, sheep palatine tonsils, and bovine thymus. Approximately 50 per cent of the dry weight of tonsils and about 30 per cent of thymus has been found to be soluble in the 0.15 M NaCl extract. Four components have been isolated which together account for 65 per cent by weight of the material in the extracts. Four other components have been identified and partially defined by means of electrophoretic mobility, solubility, or some other chemical or physical property.