Agriculture . the veins to the heart(the right auricle). In Figure 80 we have a con-densed and modified illustrationshowing how the blood circulatesthrough the body. The arrowsshow the direction of flow. Theblack channels are the veins, andthe unshaded the arteries (ex-cept Nos. ID and 12). i isthe left side of heart; 2, the rightside; 3, the aorta from the leftventricle ; 4, artery to abdomen ;5, capillaries; 6, vein from ab-domen ; 7, artery to head ; 8, ca-pillaries ; 9, vein from head;10, artery from right ventricle tolungs; II, the lungs; 12, veinfrom lungs to left auricle; 13, ar-tery to
Agriculture . the veins to the heart(the right auricle). In Figure 80 we have a con-densed and modified illustrationshowing how the blood circulatesthrough the body. The arrowsshow the direction of flow. Theblack channels are the veins, andthe unshaded the arteries (ex-cept Nos. ID and 12). i isthe left side of heart; 2, the rightside; 3, the aorta from the leftventricle ; 4, artery to abdomen ;5, capillaries; 6, vein from ab-domen ; 7, artery to head ; 8, ca-pillaries ; 9, vein from head;10, artery from right ventricle tolungs; II, the lungs; 12, veinfrom lungs to left auricle; 13, ar-tery to intestines; 14, small in-testine; 15, capillaries and veinsfrom intestines carrying awaydigested food; 16, portal vein;17, artery to liver; 18, liver;19, vein from liver; 20, lacteals;21, duct leading to vein going tothe heart by which some ab-sorbed material is taken intocirculation; 22, artery to thekidneys; 23, the kidneys; 24, vein Fig. 80 -The circulation of the f^Q^-^ t^g kidneys, bloud in the body. •. DIGESTION AND USES OF FOOD. 167 Thus we have seen how the digested food gets into theblood, and how the blood is carried through all parts of thebody. The next question is as to what is done with thisblood. Uses of the Digested Food.—The animal must be keptwarm, and therefore some food is required as fuel. The oxy-gen of the air comes in through the lungs and unites with thematerial in the blood, or with material such as fat formed fromthe blood. To keep warm, therefore, food and fresh air arenecessary. Now you will understand why brisk walking,running, or working in fresh air, even in cold air, will causeyou to become warm, especially if you have been well fed. Itis like starting a fire with plenty of good dry fuel and openingthe draughts. Then there is bone to be built up in oneplace, muscle in another, wool or hair in another. If theanimal is growing, food is necessary; even if it is not growingfood is necessary, for the old parts are constantly wearing awayand new
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Keywords: ., bookcentury1800, bookdecade1890, bookidag, booksubjectagriculture
