CONTENTS Xlll 



PART III 

 CIRCULATION OF THE BLOOD 



CHAPTER XV PAGE 



BLOOD PRESSURE 124 



The Mean Arterial Blood Pressure, 125; Mercury Manometer Tracings, 125; 

 Spring Manometer Tracings, 128; Clinical Measurements, 129. 



CHAPTEE XVI 



THE FACTORS CONCERNED IN MAINTAINING THE BLOOD PRESSURE 135 



Pumping Action of the Heart, 135 ; Peripheral Resistance, 135 ; Amount of 

 Blood in the Body, 138; Effects of Hemorrhage and Transfusion, 140; Vis- 

 cosity of the Blood, 141; Elasticity of Vessel Walls, 143. 



CHAPTER XVII 



THE ACTION OP THE HEART . . 145 



The Pumping Action of the Heart, 145; Intracardiac Pressure Curves, 146; 

 Comparison of the Curves, 148. 



CHAPTER XVIII 



THE PUMPING ACTION OF THE HEART (CONT'D) '. 151 



Contour of the Intracardiac Curves, 151; Ventricular Curve, 151; Auricular 

 Curve, 153; The Mechanism of Opening and Closing of the Valves, 154; The 

 Heart Sounds, 156; Causes of Sounds. 157; Record of Heart Sounds (Elec- 

 trophonograms), 158. 



CHAPTER XIX 



THE NUTRITION OF THE HEART 161 



Blood Supply, 161; Ferfusion of the Heart Outside the. Body, 161; Heart- 

 Lung Preparation, 163; Resuscitation of the Heart in Situ, 165; Relationship 

 of the Chemical Composition of the perfusion Fluid in Cold-blooded and 

 Warm-blooded Hearts, 166. 



CHAPTER XX 



PHYSIOLOGY OF THE HEARTBEAT 170 



Origin and Propagation of the Beat, 170; Physiological Characteristics of 

 Cardiac Muscle, 170; Myogenic Hypothesis, 171; Neurogenie Hypothesis, 

 172; The Pacemaker of the Heart and Heart-block, 174; Physiological Char- 

 acteristics of Cardiac Muscle, 176. 



CHAPTER XXI 



PHYSIOLOGY OF THE HEARTBEAT (CONT'D) 182 



Origin and Propagation of the Beat in the Mammalian Heart, 182; Conduct- 

 ing Tissue in Mammalian Heart, 182; Site of Origin of Beat, 187. . 



CHAPTER XXII 



PHYSIOLOGY OF THE HEARTBEAT (CONT'D) 191 



Mode of Propagation in the Auricles and from the Auricles to the Ventricles, 

 191 ; Spread of Beat in the Ventricle, 193 ; Fibrillation of the Ventricles and 

 Auricles, 195. 



