In the observations carried on the cell proliferation (growth area, cell density) and cell functions (wandering velocity of neutrophils and pseudoeosinophils, carbon-particle phagocytosis, vital staining) in the bone marrow tissue culture of the ribs of human and femur of rabbit, both stored at 8°C and conducted at various lengths of the postmortem time, and obtained the following results. 1. With the lengthening of time after death the growth area, wandering velocity and carbon-particled phagocytosis tend to decrease, and as for the vital staining the average stainability is increased, indicating the fall in the cell functions. However, the density of cell distribution of human neutrophils in the growth zone is higher at 12 hoursf ater death than that immediately after death, but the growth index is also lower than that immediately after death. 2. As for the bone-marrow tissue culture according to the lengths of postmortem time, 120 hours after death in femur and 7 days in rabbits are the maximum limit permissible to enable the culture of the bone-marrow. 3. Both in human and rabbits the diminution in the bone marrow functions becames striking the period between 48 to 72 hours after death as the demarcation line.