CHAPTER VI. 



OEGANS OF CIKCULATIOX. 



Circulatory apparatus The heart, its shape and position. The pericar- 

 dium, its structure. Auricles and ventricles. Valves of the heart. 

 Bone of the ox's heart. Chordae tendineae. Endocardium Semilunar 

 valves. Eustachian valve. Foramen ovale. Muscular fibres of the*" 

 heart. Dr Pettigrew's researches. Arteries, capillaries, and veins. 

 Action of the heart. William Harvey. Sounds of the heart. Circula- 

 tion in the blood-vessels. The pulse. Capacity of the arteries in- 

 creased by subdivision. Forces inducing the blood's flow. Eapidity 

 of the circulation. Professor Bering's experiments. Vierordt's con- 

 clusions. Dr Dalton's diagram of the circulation. General disturbance 

 of the function. The pulse. Where felt, in the horse, ox, and smaller 

 animals. The pulse in disease. Its varieties. The pulse not sufficient 

 to indicate the propriety of blood-letting. A word of caution. Heart 

 disease. General symptoms. Palpitation, anaemic, dyspeptic, and 

 nervous. Eupture of the heart Of the vena azygos. Congenital mal- 

 formation of the heart. Ectopia cordis. Pervious foramen ovale or 

 cyanosis. Hypertrophy of the heart. Atrophy. Dilatation. Ossifica- 

 tion of the heart. Fatty degeneration. Tumors of the heart. 



THE principles which are dissolved in the process of digestion, 

 and fitted for the purposes of nutrition, circulate throughout 

 the system, modified or unmodified, in the blood. The blood- 

 vessels, through which the vital fluid is propelled by a mus- 

 cular organ, the heart, constitute the vascular or circulatory 

 apparatus. From the heart the blood passes into channels, 

 which, from being almost invariably empty immediately after 



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