Voit’s[27] vegetarian is described by Voit himself as a man twenty-eight years old, weighing 57 kilos, well nourished, with well developed muscles, etc. He had lived on a purely vegetable diet for three years, and was found to be in nitrogenous equilibrium on 8.2 grams of nitrogen. No mention is made of any disagreeable effects connected with this low proteid ration, although persisted in for several years. Jaffa’s[28] experiments and observations on the fruitarians and nutarians of California “showed in every case (two women and three children) that though the diet had a low protein and energy value, the subjects were apparently in excellent health and had been so during the five to eight years they had been living in this manner.” In comparing the income and outgo of nitrogen on a diet composed mainly of nuts and fruits, it was observed in two subjects that 8 grams of nitrogen were sufficient to bring about nitrogen equilibrium, while with two other subjects on a like diet the nitrogen required daily for equilibrium was about 10 grams. The diet used in these experiments, however, was of necessity more or less restricted in variety, and was without doubt somewhat monotonous. Jaffa appears to agree with Caspari that the minimum amount of proteid required daily varies with the individual, and may even vary with the same individual at different times. Further, Jaffa, in harmony with Siven, believes that after the body has suffered a loss of nitrogen, there is at once an effort to attain nitrogenous equilibrium, and that any gain of nitrogenous body material is a comparatively slow process. If this is true, it is obvious that the living substance of the tissue protoplasm must be _slowly_ formed from the proteid of the diet. This, says Jaffa, should serve as a warning to anyone contemplating any appreciable decrease in the proteid of the daily diet.