As we have seen, the smaller subject for a period of many months showed a proteid katabolism equal to 0.1 gram of nitrogen, per kilo of body-weight, daily. The second and larger subject, on a totally different diet, for seven months and a half, metabolized daily, on an average, 6.53 grams of nitrogen. Taking the weight of the body at 70 kilos, it is readily seen that the nitrogen metabolized daily per kilo of body-weight was 0.093 gram, almost identical with the rate of nitrogen exchange found with the first subject. It is certainly very suggestive that these two individuals with their marked difference in body-weight, under different degrees of physical activity, and living on different forms of diet, with only the one point in common of voluntary restriction in the amount of proteid food, until a new habit had been acquired and a new level of proteid metabolism attained, should have quite independently reached exactly the same level of nitrogen exchange per kilo of body-weight. And when it is remembered that this was attained by the daily consumption of not more than one-third to one-half the minimal amount of proteid food called for by the dietetic customs of mankind, and with maintenance of all the characteristics of good health through this comparatively long period of time, there certainly seems to be justification for the opinion that the consumption of proteid food, as practised by the people of the present generation, is far in excess of the needs of the body. Referring for a moment to the calorific value of the food used by the second subject, in the last balance period, it is to be noted that the heat value per day averaged 2448 calories, as estimated on the basis of the chemical composition of the food. This would amount to 34 calories per kilo. Whether this figure is strictly correct is immaterial; it is certainly sufficiently so to warrant the statement that the needs of the body were fully met by an intake of food below the standards set by usage, and that maintenance of nitrogen equilibrium on a greatly diminished consumption of proteid food is possible without increasing the intake of non-nitrogenous matter.