Resistance of the parasites io arsenical drugs is of considerable practical importance in African trypanosomiasis since it interferes seriously with the chemotherapeutic control of the disease. The mechanism of arsenic resistance in trypaiiosomes has been studied from a primarily pharmacological o r biolmogical standpoint by Voegtlin, Dyer aiid Sliller ( '24), Murgatroyd aiid Yorke ( ' 3 7 ) , Yorlie, Nurgatroyd and Hawking ( '31), Fulton and Yorke ( '41), Eagle and Magnuson ('44)' and others ; Trypanosoma e q u i p e r d t m and T. rhodesiense were used chiefly. Biochemical studies m7cre done by Fulton and Christophers ('38) with T . rhodesiense, and Harvcy ('48, '49) with T. equiperduin and T . hippicum. So far, T. ga??zbieme, wliicli in Africa readily develops arsenic resistance, has not been studied biochemically.
The aim of our study is to give data on (1) the type of carbohydrate metabolism present in 1'. gainbiense, (2) the quantitative metabolic aspects of both a normals and an arsenicresistant strain, and (3) the response of both types of trypanosomes to a variety of metabolic inhibitors. These last studies were done in order to shed some light on the question of whether or not arsenic resistance is accompanied by definite iiietabolic chaiiges o r is due solely to chaiiges in permeability.
Laboratory of Tropical Diseases.