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," 11. — 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 7 



Effects of varying proportions of CO2 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 CO2 percentage, 19. — Effects of varying 

 oxygen percentage of the alveolar CO2 percentage, 20. — Effects of varying CO2 

 percentage in the inspired air on the alveolar CO2 percentage, 21. — Extreme 

 sensitiveness of the respiratory center to variation in alveolar CO2 percentage, 

 22. — Apnoea after forced breathing is due simply to lowering of alveolar CO2 

 percentage, 24. — Constancy of mean alveolar CO2 pressure in spite of great 

 variations in rate and depth of breathing, 27. — Rise of alveolar CO2 percentage 

 during muscular exertion, 29. — Effects of varying barometric pressure on alve- 

 olar CO2 percentage, 30. — Constancy of alveolar CO2 pressure with varying 

 barometric pressure, 31. — Individual differences in alveolar CO2 pressure, 32. 

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

 Miller's ''pir-rsac" system, /3 5, — The "effective" or "virtual" dead space in 

 breathing/^^j^ — 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 



