1. Cysteic acid fed to albino rats as 12.5 to 15 per cent of the McCollum stock diet caused portal necrosis and cirrhosis of the liver within 2 weeks. Concentrations of cysteic acid of 6.25 per cent or less in the diet produced no liver lesions within 2 weeks.
2.dl-Methionine fed as 6.4 to 12.4 per cent of the McCollum stock diet or of a low protein, low fat diet, resulted in severe atrophy of the liver cells but no cirrhosis of the liver.
3. Taurine fed as 1 to 10 per cent of the McCollum stock diet produces no liver lesions.
4. For reasons discussed in the paper, it is concluded that the liver necrosis and cirrhosis produced by cystine and cysteic acid are not dependent upon the S-S linkage of the cystine, the oxidation of the sulfur, the formation and excretion of large amounts of urinary sulfate, or the presence of an amino group separated from a sulfur molecule by a 2 carbon chain.
