Caspari and Glässner[59] have reported observations made on two vegetarians, a man and his wife, aged 49 and 48 years respectively, who had lived for some years exclusively on a vegetable diet. The man had a body-weight of 68.8 kilos, while the woman weighed 58 kilos. During five days, the man consumed per day, on an average, 7.83 grams of nitrogen and 4559 calories. This corresponds to 0.114 gram of nitrogen per kilo of body-weight, and 66 calories per kilo. On this diet, the man gained slightly in weight and showed a plus nitrogen balance of 5.2 grams for the five days. In other words, even this low nitrogen or proteid intake was more than sufficient to meet the wants of his body. The wife, during the same period of time, consumed per day 5.33 grams of nitrogen and 2715 calories, corresponding to 0.092 gram of nitrogen per kilo of body-weight and 47 calories per kilo. On this diet, the woman gained 0.9 kilo in weight during the five days, and like the man, she showed a plus nitrogen balance of 2.45 grams for the entire period. The somewhat noted experiments of Sivén have been referred to in another connection, and it will suffice to recall the fact that he was able, with a body-weight of 60 kilos, to establish nitrogen equilibrium on 6.26 grams of nitrogen, and for a day or two on 4.5 grams of nitrogen, with a total fuel value of only 2444 calories in the day’s ration. [59] W. Caspari: Physiologische Studien über Vegetarianismus. Bonn. 1905. p. 13. These few illustrations will serve to indicate that, so far as the maintenance of nitrogen equilibrium is concerned during short periods of time, there is no necessity for the consumption of proteid food in such amounts as common usage dictates. The high proteid intake called for by the “standard dietaries,” and the ordinary practices of mankind, is not needed to establish a condition of nitrogen equilibrium. It would seem, however, as if results of this nature, presented from time to time by various investigators, have been considered more in the light of scientific curiosities than as data having an important bearing on physiological processes. So strong has been the hold upon the medical and physiological mind of the necessity of high proteid that such figures as the above have merely excited comment, without weakening in any measure the prevalent conviction that health, strength, and the power to work necessitate a high rate of proteid exchange.