Experiments have been conducted to determine if protein, minerals and vitamin A are of equal importance for prolongation of life. One group of rats was fed on white corn alone. White corn is known to be deficient in protein, vitamin A and minerals. Rats on the above diet lived an average of 72 days. A second group of rats received a diet consisting of white corn 88 per cent together with casein 12 per cent. They lived an average of 75 days. A third group of rats received white corn 98 per cent, and 5 per cent of salt mixture. They lived an average of 87 days. The fourth group of rats received white corn 95 per cent and 5 per cent of butter fat. All are alive at the end of 160 days. None of the animals grew. Distilled water was furnished ad. lib. to all of the animals
