It has been demonstrated by Riddle and Sturgis1 that a single massive dose of liver extract (30 vials) produces a therapeutic effect on pernicious anemia which is approximately that obtained by administering three vials daily for ten days. The large dose, however, produces more active stimulation of the bone marrow. They report the results found in the blood of three patients with pernicious anemia following a single massive dose. In all, large numbers of nucleated red cells appeared in the circulating blood ("blood crisis," "blast crisis") during the first two or three days after the liver extract was given. In previous communications we2 have reported the results obtained in pernicious anemia by the intramuscular injection of concentrated gastric juice from man, swine and dogs and have shown that the response is due to the presence in the normal gastric secretions of a powerful hematopoietic substance. Further, we have