METABOLISM OF MATTER AND ENERGY. 1019 



other investigators often suggests further lines of experimenting, and 

 by comparison of different investigations errors may be avoided. The 

 literature of metabolism experiments is extensive. Reports of experi- 

 ments have been published in various scientific journals in many lan- 

 guages. Many of these publications are not generally accessible. 

 More or less extended compilations of results have been made in the 

 past, but in no case so far as known have the individual experiments 

 been cited in detail. Therefore a compilation 1 has been prepared in this 

 Office of experiments with man and animals in which the balance of 

 income and outgo of matter and energy was determined. Some 2,300 

 experiments with man and about 1,400 experiments with animals have 

 been collected. In a large number the balance of nitrogen with or 

 without mineral matter was the factor determined. In a comparatively 

 huge number the balance of carbon, with or without hydrogen and oxy- 

 gen, was also determined. A still smaller number were calorimetric 

 experiments in which determinations of energy were made. The attempt 

 was not made to include the respiratory quotient experiments, as this 

 forms a subject by itself. In this compilation the food consumed, the 

 length of the experimental period, and the daily or average balance of 

 income and outgo have been quoted in detail. The material has been 

 arranged in convenient form for reference and the tabular matter is 

 supplemented by text in which the experiments are described, and the 

 objects sought, the experimental methods employed, and the conclusions 

 drawn are noted in more or less detail. 



1 IT. S. Dept. Agr., Office of Experiment Stations Bui. 15, '-A Digest of Metabolism 

 Experiments." 



