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adult amount aphid back swimmer bacteria beetle blood body breathing breeding buds called calories carbon dioxide carried cells cent Chapter chief CLASS DISCUSSION color common Conrad Slide corn crops digestion Directions disease germs domesticated animals earthworm eating effect eggs enemies evolution feed fishes flies flowers forests forms fruits fuel value fungi game birds grasshopper grow habits harm inches injurious insects killed kinds LABORATORY PROJECT larva leaf leaves legumes live Macmillan malaria means meat method milk mosquito moth mouth mushrooms nest OUTLINE SUMMARY oyster parasites pests plants and animals pollen potato pounds proteins pupa QUESTIONS FOR CLASS rats reproduction roots season skin snowy tree cricket soil species spider spores stamens stem temperature toad TOPICS FOR REPORTS trees twigs typhoid fever varieties vegetables ventilation weed seeds wild wings winter yeast yellow fever
Page 247 - The plough is one of the most ancient and most valuable of man's inventions; but long before he existed the land was in fact regularly ploughed, and still continues to be ploughed, by earthworms. It may be doubted whether there are many other animals which have played so important a part in the history of the world, as have these lowly organized creatures.
Page 452 - The large calorie, or the amount of heat required to raise 1 kilogram of water 1° C.
Page 378 - Britannica, states that this disease ' has been estimated to produce one-half of the entire mortality of the human race ; and inasmuch as it is the most frequent cause of sickness and death in those parts of the globe that are most densely populated, the estimate may be taken as at least rhetorically correct.
Page 463 - Department of Agriculture Office of Experiment Stations AC True: Director Prepared by CF LANGWORTHY Expert in Charge of Nutrition Investigations COMPOSITION OF FOOD MATERIALS.
Page 553 - ... from the anther of one flower to the stigma of another flower of the same plant is called self pollination.
Page 109 - Ownership," and were submitted to the Senate on June 1. It was found that over two-thirds of the original forests of the United States have been culled, cut over, or burnt, and three-fifths of their merchantable timber is gone. The country is taking about 26,000,000,000 cubic feet of wood annually from its forests and is growing but 6,000,000,000 feet.
Page 230 - Tt is probable that with adequate protection in the breeding season, from ten to twelve million pelts can be taken annually in North America without depleting the supply. The prices paid for muskrat pelts vary considerably from year to year.
Page 443 - Two secretions are mixed with the food in the duodenum, the bile from the liver and the pancreatic juice from the pancreas.
Page 580 - Skeletons of the gibbon, orang, chimpanzee, gorilla, man. Photographically reduced from diagrams of the natural size (except that of the gibbon, which was twice as large as nature) drawn by Mr Waterhouse Hawkins from specimens in the Museum of the Royal College of Surgeons.