The author did the measurement of the quantity of serum iron and the fractionation of depot iron (liver, spleen, kidney, duodenum and bone marrow) together with the examination of reticuloendothelial system in various experimental anemic rabbits. Next he investigated the iron metabolism in case of venesection or the administration of phenilhydracine which brings out the accelerating function of the bone marrow, and in case of collargol, benzol, X-ray or saponin which bring out the disturbing function of the bone marrow. And he clarified movements of each fractionation that is P(1), P(11), P(111) or S(111) of non-hemin iron in the intermediate process of iron metabolism. At the time of being disturbed of the hematopoietic function. There is a delicate and important relation between the function of R. E. S. and the iron metabolism. At least, the author can say that P(111) and S(111) iron fraction was metabolized more rapidly and sharply than P(1) and P(11) done, and increased when the hematopoietic function was declined.