PREFACE. The experimental evidence secured in connection with this research was made possible only through the active co-operation and personal interest of the gentlemen who acted as subjects. Our thanks are due to Mr. Kurt H. Arndt, Mr. J. J. Currie, and especially to Mr. H. L. Higgins and Mr. J. E. Fitzgerald, all of the laboratory staff. Mr. Fitzgerald furthermore assisted in practically all of the experiments on others than himself. We are indebted to Dr. W. G. Anderson, Director of the Yale University Gymnasium, not only for the physical measurements on some of our subjects, but likewise for his co-operation in certain of the tests. The extraordinary interest and fidelity to the routine exhibited on the part of the professional subject, Mr. Melvin A. Mode, should not pass without special comment. It would have been impossible to conduct a series of experiments of this type without the intelligent co-operation of the subject. The complicated tables in the report have received the careful preparation of Mr. W. H. Leslie, and the entire manuscript has had the editorial supervision of Miss A. N. Darling. To all of these co-workers we wish to express our thanks. NUTRITION LABORATORY, CARNEGIE INSTITUTION OF WASHINGTON, CONTENTS. Pioneer investigations on metabolism in its relation to muscular work and animal heat Gaseous exchange during muscular work Later investigations on metabolism in its relation to muscular work and animal heat. Methods and apparatus used in this research Determination of the basal metabolism Determination of the nitrogen excretion Determination of the alveolar air Observations on the influence of diet Experiments with untrained subjects The character of the katabolism as affected by muscular work Determination of the respiratory quotient Errors incidental to the determination of the carbon-dioxide production Errors incidental to the determination of the oxygen consumption The respiratory quotients of the bicycle ergometer experiments and their sig- Estimates of the amount of carbohydrates in the body Urine excretion in experiments with muscular work Mechanical efficiency of the human body Previous studies on the mechanical efficiency of the human body General comparison of the respiratory quotients Influence upon the respiratory quotient of increasing amounts of work Influence upon the respiratory quotient of variations in the amount of car- Subsidiary evidence with regard to the effect of muscular work on the char- Methods of computing the net efficiency Comparison of basal metabolism in bicycle ergometer experiments Increment in metabolism due to changing from a lying to a sitting position Increment in metabolism due to a change in position from lying on a couch to Increment in metabolism due to a change in position from lying on a couch to Efficiency in work experiments based on values obtained in experiments with the subject sitting on the bicycle ergometer Efficiency in work experiments based on values obtained in no-load experiments |