By the simple method of bone marrow tissue culture, the author studied on the effects on white blood cells of bone marrow by adding serum and spleen extracts of the rabbits with experimental splenic anemia, and obtained the following results. 1) In the group of rabbits with the abdominal sympathectomy of splenic branches, a little inhibition of tissue growth and a little decrease of the wandering velocity of pseudoeosinophils could be observed. 2) In the other group, both tissue growth and wandering velocity formed a contrast, and the specially efficient difference could not be observed. 3) From these observation, the author observed that the splenic toxic factor produced in the experimental anemic rabbits acted directly upon the bone marrow, and caused a increase in the leucocyte and the inhibition of the motor function.