EN
By the SDS treatment of subcellular fractions from the bovine spleen, the subfractions showing antimitotic activity in relation to the spleen were separated from those showing activity against lymph nodes and the thymus of mice. The farmer is contained in sediments II from rough microsomes (B1S) supernatants, and the latter mainly in the sediment and supernatant II from the smooth microsomes (A1S) supernatants and in supernatant II from B1S. The protein analysis seems to indicate, that chalone active in relation to the spleen is a protein, showing gamma globulins mobility. The chalone active in relation to the lymph nodes seems to be a protein with mobility of α-globulins and of prealbuminus. Separations on Sephadex seems to give satisfactory purification of chalone.