The intrathecal injection of bone-marrow of cases of leukemia and pernicious anemia produces encephalitis-like symptoms in rabbits. The same symptoms were produced by intrathecal injection of normal human bone marrow. The bone-marrow of rabbits and guinea pigs had no effect. A characteristic finding is an enormous increase of glycogen in the liver. The symptoms produced with normal human bone-marrow closely resemble those observed by Gordon after the intracerebral injection of lymphadenoma gland tissue.