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 — Hemodynamics. — 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. 115 — 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, \x 163 — Pancreatic Circulation, p. 165 — Coronary Circulation, p. 165 — 

 Vasomotor Reflexes, p. 166. 



ACTION OF THE HEART. 



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 " Lelirbuch der Physiologie 

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

 analysis of the literature of the circulation. 

 VOL. II. — i 



