The detection of immunological phenomena in pernicious anaemia (Schwartz, 1958; Taylor, 1959) introduced the concept of immunological assay of intrinsic factor. Several methods in which antibodies against intrinsic factor are used are now available (Jeffries and Sleisenger, 1965; Herbert, Gottlieb, Lau, and Wasserman, 1964; Abels, Bouma, Jansz, Woldring, Bakker, and Nieweg, 1963; Ardeman Chanar...