INVESTIGATIONS IN HUMAN NUTRITION. 395 



and outgo of matter and energy were determined. The experiments 

 differ materially from earlier work reported in bulletins of the Office 

 of Experiment Stations in that the respiration calorimeter with which 

 they were made had been modified in important ways, so that the 

 direct measurement of the oxygen consumed by the subject was 

 possible. Preceding the account of the experiments is a description 

 of the respiration calorimeter in its modified form, which it seems fair 

 to say permits of a more complete determination of the balance of 

 income and outgo of matter and energy in the human body than has 

 hitherto been possible. 



The improved form of the respiration calorimeter with special 

 devices for the determination of oxygen was shortly thereafter 

 described by Atwater and Benedict " in a bulletin of the Carnegie 

 Institution of Washington. A later bulletin from the same source 

 described an extensive series of experiments made by Benedict ^ 

 with the apparatus on the metabolism of fasting men. The primary 

 object of this report is to present an accurate statement of the results 

 of an extended series of experiments with men on the effects of 

 inanition, and detailed statistics are given of eighteen general metab- 

 olism experiments of one to seven days' duration and of two nitrogen 

 metabolism experiments lasting, respectively, twenty-five and fourteen 

 days. The measurements in most cases contained complete data as 

 to the income and outgo of matter and energy measured with the 

 respiration calorimeter and accessor)^ appliances, together with obser- 

 vations of body weight, body temperature, pulse and respiration rate, 

 strength tests, and blood examinations. The respiratory exchange 

 and the heat output were subjects of special study. Experiments 

 during prolonged fasting were included to note fluctuations from da}' 

 to day and a series of two-day fasts with a number of men to elimi- 

 nate the influence of individuality. In the longer experiments the 

 subject was a young man who claimed some previous experience in 

 fasting and in the remainder the subjects were universit}^ students. 



The body excretions were the subject of special studv. In the case 

 of feces it was found practically impossible to isolate, with any degree 

 of accuracy, material which could be properly designated ''fasting 

 feces." The urine was excreted regularly. The volumes were in 

 general normal, though in many cases where the subject consumed 

 large volumes of water the amounts excreted were likewise great. 

 Considerable variation in the amount of total urinary nitrogen was 

 noted, but even in the longer experiments the daily output seldom 



" A Respiration Caloritneter with Appliances for the Direct Determination of 

 Oxygen: Carnegie Inytitution of \Va.shington, 1905. 



*» The Influence of Inanition on Mctaholi.^^ni: Carnegie Institution of Washington, 

 Pub. 77; for a summary see N. Y. Med. Jour, uml Phila. Med. Jour., 80 (1907), No. 

 12, p. 527. 



