Observations on the Etiologic Relationship of Achylia Gastrica to Pernicious Anemia

IT HAS been shown that various foods — for example, beef skeletal muscle,1 milk2 and eggs3 —contain a heat-stable, unidentified substance,4 the so-called extrinsic factor. When such a source of extrinsic factor as beef muscle is ingested by a patient with pernicious anemia, untreated or in relapse, it produces little or no hematopoietic effect unless normal human gastric juice is also administered, either simultaneously or at least within six hours.5 The very small amount of the gastric secretion of the patient with pernicious anemia thus apparently supplies little or none of the heat-labile substance, possibly an enzyme,6 7 8 that is responsible . . .