Vitamin B(1) and B(2) did not show the direct influences on the bone marrow. Vitamin B(12) acted directly on the bone marrow, and there became the extreme increase of erythrocytes. Contrally, though there are many reports that folic acid causes the increase of erythrocytes, the author did not find its direct influence on the bone marrow. It means that only after activated folic acid can show its accelerating-power on the bone marrow. Hemoglobinsynthesis was not found by addition of any vitamins.