1. The effect of 9 different diets on the liver lesions resulting from excess dietary cystine has been studied in 130 rats.
2. The incidence and severity of each of the following liver lesions were varied by changes in the composition of diets containing 5 or 10 per cent cystine:
(a) Hemorrhage was least severe with low fat diets.
(b) Necrosis was most severe with synthetic diets.
(c) Cirrhosis was delayed by a diet high in lard, 20 per cent, and cod liver oil, 5 per cent, but not by a diet high in butter, 25 per cent.
(d) Fatty infiltration was found consistently only with low protein, high fat diets.
In other words, the pathogenesis of the liver lesion due to excess dietary cystine can be modified by diet.
3. In the presence of cystine as 5 per cent of a low protein, high fat diet, 1 per cent choline inhibited fatty infiltration but did not protect the liver against damage by cystine.
4. In these experiments there was no apparent correlation between fatty infiltration of the liver and the incidence or degree of cirrhosis.