Atherosclerosis has been produced in Cebus monkeys by dietary means. This disease has been produced by feeding diets high in cholesterol and low in sulfur amino acids over periods of 18 to 30 weeks. Within 2 to 8 weeks this regimen caused the concentration of cholesterol in the serum to rise to 300 to 800 mg. per cent. The hypercholesterolemia could be largely prevented by feeding 1 gm. per day of dl-methionine or l-cystine as supplements to the diet. After the serum concentration had become elevated, it could be restored to normal by feeding 1 gm. of dl-methionine but only partially restored by 0.5 gm. of l-cystine daily.
The vascular lesions were in the ascending aorta but extended from the valves of the left ventricle to the proximal portions of the carotid and femoral arteries. Minimal lesions have been observed in the coronary arteries. The aortic lesions were chiefly characterized by the presence of lipid-laden phagocytes and increase in collagen and elastic fibers. The lipids were in part cholesterol derivatives. Visceral cholesterolosis was not associated with this disease.