CONTENTS 

 PREFACE vii 



CHAPTER I. HISTORICAL INTRODUCTION i 



Early theories of respiration, i. Boyle and Mayow, i. Black and Priestley, 

 2. Lavoisier's interpretation of respiration and the source of animal heat, 2. 

 Mayer and the source of vital energy, 3. Discoveries as to the composition of 

 animal food and excreta, 3. Discoveries as to the blood gases and the part they 

 play, 4. Theories and discoveries as to physiological regulation of vital oxida- 

 tion, 4. Work of Liebig, Voit, Rubner, Pfliiger, and others, 5. Discoveries 

 as to physiological regulation of body temperature, 6.-^-The "energy require- 

 ments" of the living body, 6. The problem of regulation of breathing, 8. 

 The respiratory center. Work of Legallois and others, 8. The vagus nerves and 

 breathing. Work of Hering and others, 9. Chemical excitation of breathing. 

 Work of Rosenthal and others, 10. Theories of "vagus apnoea" and "chemical 

 apnoea," n. Conclusions as to various chemical and other excitants of breath- 

 ing, 13. Criticism of these conclusions and starting point of the investigations 

 described in succeeding chapters, 14. 



CHAPTER II. CARBON DIOXIDE AND REGULATION 

 OF BREATHING . . . . . . .15 



Effects of varying proportions of CO 2 and oxygen on breathing in man, 15. 

 Importance of the alveolar air, 16. Method of sampling the alveolar air, 17. 

 relative constancy of the alveolar CO 2 percentage, 19. Effects of varying 

 oxygen percentage of the alveolar CO 2 percentage, 20. Effects of varying COa 

 percentage in the inspired air on the alveolar CO 2 percentage, 21. Extreme 

 sensitiveness of the respiratory center to variation in alveolar CO 2 percentage, 

 22. Apnoea after forced breathing is due simply to lowering of alveolar CO 2 

 percentage, 24. Constancy of mean alveolar CO 2 pressure in spite of great 

 variations in rate and depth of breathing, 27. Rise of alveolar CO 2 percentage 

 during muscular exertion, 2g. Effects of varying barometric pressure on alve- 

 olar CO 2 percentage, 30. Constancy of alveolar CO 2 pressure with varying 

 barometric pressure, 31. Individual differences in alveolar CO 2 pressure, 32. 

 The anatomy of bronchioles and alveoli, 33. "Alveolar air" is air of 

 Miller's "air-sac" system, 35. The "effective" or "virtual" dead space in 

 breathing, 35. Great variations in effective dead space with varying depth of 

 breathing, 37. "Alveolar" and true respiratory quotients, 38. Errors due to 

 ignorance of the variations in the effective dead space, 39. Gas pressures of 

 alveolar air and arterial blood, 41. Question as to varying composition of 

 air in different alveoli, 42. General conclusion from Chapter I, 42. 



CHAPTER III. THE NERVOUS CONTROL OF BREATH- 

 ING . 43 



Voluntary and reflex disturbances of breathing, 43. Experiments on man 



