Experiments have been performed on sternal marrow kept alive in vitro with serum as a nutritional medium.
Cross experiments with marrow and serum from two normal persons show roughly identical values for erythropoiesis. The same applies to marrows and sera from cases of mild simple anemia.
Marrow from a patient with pernicious anemia showed increased erythropoiesis in vitro if nourished on normal serum, whereas serum from the same case lowered the erythropoiesis of normal marrow. After treatment with liver extract, conditions tended to return to normal.
Marrow from 2 cases of lymphatic leukosis displayed corresponding phenomena, and showed a tendency to return to normal after treatment with urethane and folic acid.
Further investigations along these lines are in progress.