258 REPORTS ON INVESTIGATIONS AND PROJECTS. 



PHYSIOLOGY. 



Atwater, "W. O., and Benedict, Francis G., Wesleyan University, Mid- 

 dletown, Connecticut. Grant No. 258. Investigatio?is in nutri- 

 tion. (For previous reports see Year Book No. 2, p. xxxix 

 and Year Book No. 3, p. 130.) $7,5°°- 



Abstract of Report. — The experimental work has covered two gen- 

 eral lines : (1 ) The more important experiments, in which the com- 

 plete balance of income and outgo was determined and in which the 

 subject spent the time inside the chamber ; (2) nitrogen metabolism 

 and digestion experiments following fasting. 



The complete metabolism experiments were of two kinds : ( 1 ) 

 Those in which the subjects fasted ; (2) those in which the inges- 

 tion of food immediately followed a fast. 



The determinations included all those pertaining to transforma- 

 tions of both matter and energy. The experimental technique has 

 gradually developed to such an extent that during the later experi- 

 ments it was possible to determine many more factors than during 

 the earlier experiments. With regard to the measurements of heat, 

 there were determined during fasting experiments the heat elim- 

 inated from the body of the subject and measured by the respiration 

 calorimeter and the heat of oxidation of the solids in the urine. 



The determinations involved in the computation of the balance of 

 matter comprised (1) in the urine — weight, specific gravity, reaction, 

 total nitrogen, creatinine, total sulphates, phosphoric acid, total 

 sulphur, ash, chlorine, carbon, hydrogen (organic), and water : (2) in 

 the respiratory gases, the amounts of water and carbon dioxide 

 eliminated and the quantity of oxygen absorbed. 



No satisfactory separation of feces was obtained in the fasting 

 experiments. When food was ingested the determinations outlined 

 above were supplemented by complete analyses of food, drink, and 

 feces. These comprised determinations of water, nitrogen, fat, ash, 

 carbon, hydrogen (organic), sulphur, phosphorus, chlorine, and heat 

 of oxidation. 



Other observations on the subject were an accurate determina- 

 tion of the variations in body weight, a series of thorough medical 

 examinations by a medical practitioner, an anthropometric record, 

 continuous observations of body temperature, pulse rate, and blood 

 examinations, including a count of the red and white corpuscles, 

 determination of the haemoglobin and the microscopical examina- 

 tion of blood smears. In one instance a series of photographs of 

 the subject was taken before and after a four-day fast. 



