_Observation._ When a large number of muscles are called into action after repose, as when we rise from a recumbent or sitting posture, the blood is impelled to the heart with a very strong impetus. If that organ should be diseased, it may arrive there in larger quantities than can be disposed of, and death may be the result. Hence the necessity of avoiding all sudden and violent movements, on the part of those who have either a functional or structural disease of the heart. -=-=-=-=-=-=-=-=-=-=-=-= Mention the illustration. 374. What is the effect when a number of muscles are called into energetic action? What effect has this accumulation of blood in the lungs? 375. How can such disagreeable sensations be avoided? Mention a practical observation. -=-=-=-=-=-=-=-=-=-=-=-= 376. _The mind exercises no inconsiderable influence upon the circulatory organs._ When an individual is stimulated by hope, or excited by anger, the heart beats more forcibly, and the arteries act more energetically, than when a person is influenced by fear, despair, or sorrow. Consequently, the system is more fully nourished, and capable of greater exertion, when the former condition obtains, than when the latter exists. 377. _The quality and quantity of the blood modify the action of the heart and blood-vessels._ If this fluid is abundant and pure, the circulatory vessels act with more energy than when it is deficient in quantity or defective in quality. _Illustrations._ 1st. In an athletic man, whose heart beats forcibly, and whose pulse is strong, if a considerable quantity of blood is drawn from a vein, as in bleeding, the heart will beat feebly, and the pulse will become weak. 2d. When the blood is made impure by inhaling vitiated air, the action of the heart and arteries is diminished, which produces an effect similar to that which takes place when blood is drawn from a vein. 378. _Hemorrhage from divided arteries should be immediately arrested._ When large blood-vessels are wounded or cut, the flow of blood must be immediately stopped, or the person soon faints, and the heart ceases its action. If it is a large artery that is wounded, the blood will be thrown out in jets, or jerks, every time the pulse beats. The flow of blood can be stopped until a surgeon arrives, either by compressing the vessel between the wound and the heart, or by compressing the end of the divided artery in the wound. -=-=-=-=-=-=-=-=-=-=-=-= 376. State some of the effects that the mind has on circulation. 377. What effect have the quantity and quality of blood upon the circulatory organs? Give illustration 1st. Illustration 2d. 378. What is necessary when large blood-vessels are wounded or cut? -=-=-=-=-=-=-=-=-=-=-=-= [Illustration: Fig. 76. The track of the large artery of the arm. 1, The collar-bone. 9, The axillary artery. 10, The brachial artery.]