Knowledge of natural history, revfrom Reason why: natural history, giving reasons for hundreds of interesting facts in connection with zoology; and throwing light upon the peculiar habits and instincts of the various orders of the animal kingdom . ves room; and the contraction of the chest again occasionsthe expulsion. Thus the lungs are set going by atmospheric pressureand elasticity; and the action is kept up and regulated by this andmuscular force conjointly. KNOWLEDGE OF NATURAL HISTORY. 33 Lifes cares are comforts; such by Heaven designed;He that has none must make them or be wretched.—Yo
Knowledge of natural history, revfrom Reason why: natural history, giving reasons for hundreds of interesting facts in connection with zoology; and throwing light upon the peculiar habits and instincts of the various orders of the animal kingdom . ves room; and the contraction of the chest again occasionsthe expulsion. Thus the lungs are set going by atmospheric pressureand elasticity; and the action is kept up and regulated by this andmuscular force conjointly. KNOWLEDGE OF NATURAL HISTORY. 33 Lifes cares are comforts; such by Heaven designed;He that has none must make them or be wretched.—Young. 86. Why does the chestheave when we breathe? Because when we in-spire the air, the ribs aredrawn upward and out-ward, and the diaphragmat the same time is forceddown. When we expirethe air, the ribs return totheir natural place, whilstthe diaphragm is againdrawn up. 87. In the accompanying il-lustration, the front half of theribs being cut away, the in-terior of the chest is C is the cavity of the chest,empty. D D D D the diaphragm,rising high in the center anddescending very low at the sides and behind. The white space is itstendonous portion. The lower part is muscle that contracts to drawit downward. A A is the 88. What is the liver, and how are its functions per-formed? The liver lies horizontally on the right side of the bodyimmediately below the diaphragm, and is protected by theinterior ends of the lower ribs. Its function is to secretethe greenish-yellow fluid, the gall or bile, which is conveyedfrom the liver by a canal called the hepatic duct. On thelower surface of the liver is situated a small pear-shapedbag, the gall bladder, which is also furnished with a duct,callecLthe crystic duct, which unites with the duct fromthe liver, and forms the common biliary duct. 89. What is the composition of the brain?The brain is composed of two substances, namely, ofa gray-colored pulp, and of a white fibrous texture. The 34 n KNOWLEDGE OF NATURAL HISTO
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1916
