In the first report the author presented the normal ripening course of reticulocytes of guinea pig in vitro and in the second report demonstrated that there are two periods of anemia in the course of tuberculosis in guinea pig and in this paper the author reports the developing mechanisms of these tuberculous anemia. 1. The observation on the ripening course of reticulocyte and the life span of erythrocyte from the guinea pig in the primary anemia proved that this anemia observable 30-40 days after infection is due mainly to the accelerated destruction of erythrocyte overwhelmingly the marked proliferation of erythroid cells in bone marrow whith can generally be recognezed in this period. The marked recovery tendency observed in this anemia can be reasonably explained with the elevated bone marrow function and the increased RC Index. 2. In the secondary anemia it has been found that the life span of erythrocyte is rather prolonged as is calf cul ated from the prolonged maturing period of reticulocyte and the extremely lowered RC Index. But the erythropoietic function of the bone marrow is markedly depressed as is supposed from the cytological findings on the bone marrow. 3. Histological observation of the bone marrow revealed the accelerated erythropoiesis in the period of primary anemia and the fibrotic changes in the period of secondary anemia. The changes of viscera are intimately connected with stages and types of anemia as has been described in the second report.