In investigation of various factors acting on the bone marrow tissue growth in tissue culture (Carrel's flask method) of normal rabbits to which sera of various patients were added, and in observations of effect of such sera on the carbohydrate metabolism of the rabbit bone marrow, the following results were obtained:
1) From these studies it has been found that in sera of hypoplastic anemia, Banti's disease, chronic myelogenous leukemia, monocytic leukemia and lymphocytic leukemia are contained some factors which act directly upon bone marrow as to inhibit the carbohydrate metabolism. As for inhibitory action of these factors, that in hypoplastic anemia proves to be highest, followed by those in monocytic leukemia, Banti's desease, chronic myelogenous leukemia, and in lymphocytic leukomia, in the order mentioned.
2) No factor acting directly upon bone marrow as to inhibit the carbohydrate metabolism has been found in ser^a of such diseases as idiopathic hypochromic anemia, hookworm anemia, Werlhof's disease, liver cirrhosis, chronic hepatities, chronic nephritis, pulmonary tuberculosis and diabetes mellitus.