1. Experiments are described in which were studied the effects of incomplete rations on the toxicity of elementary sulphur.
2. The incorporation of sulphur in the diet exerted toxic effects only when the basal ration itself could not support normal growth as the result of one or more deficiencies. The chief effect of sulphur under such conditions was to reduce food consumption per animal but not per unit body weight.
3. It •would seem that vitamins, proteins and minerals were all equally important in counteracting the deleterious effects of the sulphur.
4 . Although the rats lost considerably in weight when sulphur was added to the defective diets, the livers of the animals that were killed at the conclusion of the experiment did not show any constant pathological change whereas the same organs of those animals that died during the experiment exhibited haemorrhagic necrotic areas with slight or more advanced interstitial hepatitis.