In the bone-marrow tirsue culture of eight different benes from the same rabbit the author observed summarily the cell proliferation (growth area, cell density) and cell functiones (the wandering velocity, carbon-particle phagocytosis, and vital staining of pseudoeosinophils) inorder to determine the bone-marrow functions; and arrived at the following conclusios. 1. Summarizing, the bone marrow functions of each one of short bones are higher, while those of long bone are lower with some exception. 2. Of the short bone group, the functions of the bone marrow in scapula and innominate bones are most active in an equal degree, followed by those of vertebra. 3. Of the long bone group, the bone marrow functions of femur are good, followed by those of humerus and tibia, but in radius and rips the bone marrow functions are markedly low. 4. On the whole, the bone marrow functions in scapula and innominate bones are decidedln active, followed by femur and vertebra, and in the descending order of hnmerus, tibia, ribs and radius.