Introduction. 7 



minations of the respiratory gases. Finally reference should be made to the 

 study of fasting metabolism by Sadovyen 28 in the Pashutin apparatus at St. 

 Petersburg, in which not only the nitrogen but the carbon dioxide elimination 

 was determined, the 1-day experiment of Likhachev 27 in the Pashutin appa- 

 ratus, which was so modified as to measure the heat elimination, and the obser- 

 vations of van Hoogenhuyze and Verploegh on the fasting girl Flora Tosca. 



PLAN AND PURPOSE OF THE EXPERIMENTS HERE REPORTED. 



The importance of the study of the fasting metabolism was early recognized 

 in the experiments on the nutrition of man that have been in progress in this 

 laboratory, and the results of three 24-hour experiments and one 48-hour 

 experiment were reported. 29 In these experiments the determinations included 

 those of nitrogen, carbon dioxide, water, and heat. In the computation of the 

 results of these experiments, the assumption was made, as is usual in metabolism 

 experiments in which the determination of the oxygen intake is not made, that 

 the amount of carbohydrate in the body remained unaltered. The error of this 

 assumption, especially in experiments on fasting, was only too obvious, but 

 not until provision was made for a direct determination of the oxygen consumed 

 was it possible to secure any definite knowledge regarding the changes in the 

 store of glycogen. 



The modified form of respiration calorimeter 30 makes it possible to deter- 

 mine not only the metabolism of nitrogenous material, but also the carbon 

 dioxide, water, and heat output and oxygen intake. With the new apparatus 

 and increase in number of determinable factors, a series of experiments to 

 study as completely as possible the metabolism in fasting men was planned. 

 This investigation was made possible by liberal grants of the Carnegie Insti- 

 tution of Washington. 



According to the plan of the experiments, the respiratory exchange and 

 heat output were made the special subjects of study. Experiments during 

 prolonged fasting were included to note the fluctuations in metabolism from 

 day to day, and since the number of subjects available for long fasts was limited, 

 a series of 2-day fasts with a number of men was included to eliminate the 

 influence of individuality. The rapidity and amount of gain of nitrogenous 

 material in the body consequent upon the ingestion of food after a prolonged 

 fast was studied as a closely related supplementary problem. 



^Trudi Russkavo obshtshestva okhraneniya Narodnavo Zdravia (1888), 12, 

 pp. 13-76, St. Petersburg. 



27 Dissertation, St. Petersburg (1893). 

 Zeit. f. physiol. Chemie (1905), 46, p. 440. 



28 Experiments on the metabolism of matter and energy in the human body, 1900- 

 1902. W. O. Atwater & F. G. Benedict. Bull. 136, Office of Experiment Stations, 

 U. S. Department of Agriculture (1903), Washington, D. C. 



30 Carnegie Institution of Washington Publication 42 (1905). 



