1) The rabbits serum-iron markedly decreased by the subcutaneous repeated injection of patients serum or spleen extracts. And in case of reticuloendotherial system blocked rabbit with Indian ink, it was recognized that the sound and normal function of the R. E. S. is essential for the mobilization of depot-iron judging from going out of its function. 2) According to the fractional determination of depot-iron (in liver, spleen and bone marrow) of rabbits which were injected serum or spleen extracts, the slightly increase of depot-iron was niticed in spite of the marked decrease of serum iron. Therefore, the author would conclude that the splenogenous toxic factor acts inhibitory for the mobilization of depot-iron. 3) I studied 3 cases of atoxic splenomegaly (Tomoda) but I confirmed that these cases belong to so-called Banti's disease on the point of view of iron metabolism. 4) The etiology of anemia in so-called Banti's diseaseas stated in Part 1. is due to the fact that the splenogenous toxic factor acts inhibiting directly to bone marrow. But now I have oncluded that as suggested in Part 1. it must be mainly due to the disturbance of iron metabolism caused by splenogenous toxic factor.