It should require considerable courage to add to the voluminous literature on the pathogenesis and chemistry of the so-called idiopathic pernicious anemia of Addison and Biermer. Our excuse is a threefold one:—first, to investigate with the aid of modern microchemical methods the metabolism of the blood lipoids as of probable diagnostic if not of etiological significance; second, to determine the nitrogen metabolism both in regard to its diagnostic as well as its prognostic value; and, third, to test the efficiency of Whipple's high iron diet when given to patients suffering from idiopathic anemia. We have had the opportunity to study eleven cases of pernicious anemia, several of which have been available for considerable periods of time or during subsequent admissions. As controls, and in order to obtain comparative data on the anemias, four additional cases have been employed, a case of aplastic anemia with von Recklinghausen's disease, a pregnancy anemia,