After the abdominal sympathectomy of splenic branches in normal rabbits, the author studied the blood and bone marrow pictures and O(2)-consumption and glvcolysis of the femur bone marrow and obtained the following results: 1. In the peripheral blood picture a transient decrease in the erythrocyte count, hemoglobin content, leucocyte and platelet count can be recognized, presenting a picture what might be called 'splenic anemia'. 2. An increase in the percentage of the erythroblast series can be observed in bone marrow. 3. The respiration of bone marrow is transiently accelerated, and the aerobic glyeolysis tends to decrease slightly but changes in anaerobic glycolysis show no fixed tendency. 4. It seems that the anemia and an increase in the proportion of bone marrow erythroblasts as well as an increase in oxygen consumption of bone marrow tissue induced by the abdominal sympathectomy of splenic branches in rabbits are caused by the blood cell arrest in bone marrow. 5. The spleen has a close relationship to the hematopoietic function of bone marrow, especially of the erythrocyte series, and a part of its specific remote action is controlled by the central nervous system via the abdominal sympathetic nerves.