The demonstration by Minot and Murphy1 that the feeding of liver brings about complete remission in pernicious anemia led to the development of liver extracts of various types, of which that of Cohn and his associates2 is most generally used. A search for the effective substance in liver led to partial purification of the material, but these more or less purified substances developed by Cohn and his associates3 and by West and his associates4 have proved too expensive to be practical in the treatment of pernicious anemia.
To Gänsslen5 belongs the credit of having first prepared at moderate expense an extract of liver suitable for injection intramuscularly. He injected daily into the gluteal muscles 2 cc., equal in effect to from 200 to 400 Gm. of liver.
Castle and Taylor6 obtained a maximal response in reticulocytes from a single intravenous injection of the extract