TEXT-BOOK OF PHYSIOLOGY. 



THE MECHANISM OF THE CIRCULATION OF 

 THE BLOOD. 



By LEONARD HiLL. 1 



CONTENTS: ACTION OF HEART. Form of Heart, p. 1 Valves and Papillary 

 Muscles, p. 8 Pressure in Cavities, p. 14 Heart Sounds, p. 28 Heart 

 Impulse, p. 33 Work of Heart, p. 40 Diastolic Filling of Heart, p. 45 

 Systolic Output, p. 48 Action of Nerves, p. 54 Cardiac Centres and Re- 

 flexes, p. 54 Depressor Nerve, p. 60 H^MODYNAMICS. Torricelli's Law, p. 

 63 Poiseuille's Law, p. 65 General Principles of Circulation, p. 69 Pres- 

 sure in Arteries, p. 78 Velocity of Flow, p. 83 Circulation Time, p. 89 

 Effect of Change of Posture on Circulation, p. 91 The Pulse, p. 97 THE 

 CAPILLARY CIRCULATION. Microscopical Examination, p. 113 Rate of Flow, 

 p. 1115 Capillary Pressure, p. 116 BLOOD-FLOW IN THE VEINS, p. 119 

 Pressure in Veins, p. 120 Effect of Muscular Movements, p. 121 Rate of Flow, 

 p. 122 INFLUENCE OF RESPIRATION ON CIRCULATION, p. 123 VASOMOTOR 

 MECHANISM. Historical, p. 131 Methods, p. 133 Action of Vaso-dilators, p. 

 136 Local Tone, p. 138 Traube-Hering Curves, p. 139 -Vasomotors of Veins, p. 

 141 CIRCULATION IN SPECIAL PARTS. Cerebral Circulation, p. 142 Pulmonary 

 Circulation, p. 149 Blood-Flow in Limbs, p. 156 Renal Circulation, p. 160 

 Mesenteric Circulation, p. 161 Hepatic Circulation, p. 162 Splenic Circula- 

 tion, p. 163 Pancreatic Circulation, p. 165 Coronary Circulation, p. 165 

 Vasomotor Reflexes, p. 166. 



ACTION OF THE HEAKT. 

 THE FORM OF THE HEART. 



THE changes in form of the heart during systole and diastole can be 

 studied in an animal, the heart of which has been exposed by opening 

 the thorax under an anaesthetic, artificial respiration being meanwhile 

 maintained. When the heart is watched beating in full vigour and 

 rapidity, it is an impossible task to unravel, by the eye alone, the 

 sequence of events which form the cardiac cycle. 



Harvey felt this difficulty, and writes: "When first I gave my 

 mind to vivisections, as a means of discovering the movements and uses 

 of the heart, and sought to discover these from actual inspection, and 



1 The writer of this article is greatly indebted to Tigerstedt's " Lehrbuch der Physiologic 

 des Kreislaufes," Leipzig, 1893. To this work the reader is referred for an exhaustive 

 analysis of the literature of the circulation. 

 VOL. II. I 



