The "ionizable" iron content, by means of dipyridyl, of a large number of British foodstuffs, expressed as % of their total Fe content, is as follows: green-leaf vegetables, 50-80%; roots and tubers, and stem and flower vegetables, 95-100%; apricot and peach, 100%; other fruits, 60-95%; legumes and cereals, 80-100%; in white-fleshed fish, practically all the Fe is in ionizable form; in the herring family, 40-70%; roast beef and mutton, 10-25%; pork (bacon, ham, chops), 15-47%; glandular organs, 60-100%. Although the "total" Fe content of various samples of a particular foodstuff may be widely different, the "ionizable" Fe, expressed as a % of the "total" Fe, is relatively constant.