CONTENTS. 
Pakt I. 
PAGE 
Introduction _ . . . . 3 
Pioneer investigations on metabolism in its relation to muscular work and animal heat 5 
Gaseous exchange during muscular work 5 
Heat output of the animal body . . . > 8 
Later investigations on metabolism in its relation to muscular work and animal heat . 13 
Investigations by Zuntz and his associates 16 
Investigations in the French laboratories 17 
Investigations by the chamber method 18 
Methods and apparatus used in this research 21 
General plan of the research 21 
Determination of the basal metabolism 22 
Determination of the nitrogen excretion 24 
Pulse observations 24 
Determination of the alveolar air 24 
Observations on the influence of diet 24 
Experiments with untrained subjects 25 
Apparatus for muscular work 25 
Apparatus for determining the gaseous exchange 27 
Routine of experiments 31 
Computation of the energy output from the oxygen consumption 32 
Part II. 
Statistics of experiments 35 
Lying vs. sitting experiments 36 
No-load experiments 40 
Work experiments 43 
Part HI. 
Discussion of results 71 
The character of the katabolism as affected by muscular work 71 
Determination of the respiratory quotient 72 
Errors incidental to the determination of the carbon-dioxide production ... 73 
Errors incidental to the determination of the oxygen consumption 73 
Physiological sources of error in gas measurements 75 
— The basal metabolism 76 
The normal resting metabolism as determined in this research 77 
The character of the katabolism during muscular work as indicated by the re- 
spiratory quotient 80 
Theories of Chauveau and Zuntz as to the character of the katabolism during 
muscular work 80 
The respiratory quotients of the bicycle ergometer experiments and their sig- 
nificance . . . 83 
General comparison of the respiratory quotients 83 
Influence upon the respiratory quotient of increasing amounts of work . . 86 
— Influence upon the respiratory quotient of variations in the amount of car- 
bohydrates in the diet 88 
— Subsidiary evidence with regard to the effect of muscular work on the char- 
acter of the katabolism 89 
Influence upon the respiratory quotient of variations in the amount of work 
done 91 
— Conclusions regarding the influence of muscular work upon the character of 
the katabolism 94 
Estimates of the amount of carbohydrates in the body 96 
Urine excretion in experiments with muscular work 98 
Mechanical efficiency of the human body 101 
Previous studies on the mechanical efficiency of the human body 101 
