ILLUSTRATIONS. 



PAGE. 



FRONTISPIECE. Subject and apparatus in readiness for experiment. 



Fia. 1. Treadmill, with spirometer and various recording devices 19 



2. Double spirometer. 22 



3. Respiration counter 24 



4. Electrical counter for recording number of respirations 24 



5. Detail of valve-operating device and period counter 28 



6. Framework used in determining the angle of ascent 29 



7. Step-lift recorder 30 



8. Typical records of pulse-rate as obtained with oscillograph and string gal- 



vanometer 34 



9. Metabolism of E. D. B. in standing experiments without food 98 



10. Increments in total heat-output over standing requirement for subjects 



walking on a level at different rates in meters per minute, with per- 

 centage increase for E. D. B 146 



11. Average energy cost per horizontal kilogrammeter of walking on a level at 



various distances per minute 148 



12. Typical pulse-rate curves for E. D. B. and W. K. during standing and hori- 



zontal-walking experiments 166 



13. Total heat-output, oxygen consumption, pulmonary ventilation, respira- 



tion-rate, and pulse-rate of E. D. B. and W. K., referred to hori- 

 zontal kilogrammeters for experiments with subjects walking on a 

 level at different speeds 170 



14. Typical body-temperature curves for E. D. B. during periods of standing 



and periods of walking on a level at various speeds 173 



15. Reproduction of kymograph records in mouthpiece experiments, with 



intermittent renewal of oxygen 183 



16. Total carbon-dioxide production of T. H. H., H. R. R., and W. K., re- 



ferred to kilogrammeters of work performed in walking on different 

 grades 225 



17. Total carbon-dioxide production of E. D. B. referred to kilogrammeters of 



work performed in walking on different grades 226 



18. Total oxygen consumption of T. H. H., H. R. R., and W. K. referred to kilo- 



grammeters of work performed in walking on different grades 227 



19. Total oxygen consumption of E. D. B. referred to kilogrammeters of work 



performed in walking on different grades 227 



20. Respiratory quotients of W. K. and E. D. B. referred to kilogrammeters 



of work performed in grade walking 230 



21. Total heat-output of W. K. referred to kilogrammeters of work performed 



in walking on different grades 234 



22. Total heat-output of E. D. B. referred to kilogrammeters of work performed 



in walking on different grades 234 



23. Total oxygen consumption and heat-production of W. K. referred to kilo- 



grammeters of work performed in grade walking 236 



24. Total oxygen consumption and heat-production of E. D. B. referred to 



kilogrammeters of work performed in grade walking 237 



25. Daily increments in heat-production over standing requirement and hori- 



zontal component referred to kilogrammeters of work done in walking 

 experiments on different grades with W. K 239 



26. Daily increments in heat-production over standing requirement and hori- 



zontal component referred to kilogrammeters of work done in walking 

 experiments on different grades with E. D. B 239 



27. Average increments in heat-production due to grade-lift in walking experi- 



ments with E. D. B 240 



vii 



