Essentials of Biology Presented in Problems: By George William HunterAmerican book Company, 1911 - 448 páginas |
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Página 36
... become seeds . An explanation of these con- ditions may be had if we examine , under the micro- scope , a very thin section of a pistil , on which pollen has begun to germinate . The central part of the style is found to be either ...
... become seeds . An explanation of these con- ditions may be had if we examine , under the micro- scope , a very thin section of a pistil , on which pollen has begun to germinate . The central part of the style is found to be either ...
Página 51
... become almost filled with a number of al- most ovoid bodies , at- tached along one edge of the inner wall . These we recognize as the young seeds . The pod of a bean , pea , or locust illustrates Fruit of the black locust ; a legume ...
... become almost filled with a number of al- most ovoid bodies , at- tached along one edge of the inner wall . These we recognize as the young seeds . The pod of a bean , pea , or locust illustrates Fruit of the black locust ; a legume ...
Página 63
... become an important business . Orchard and Other Fruits . In the United States over one hundred and seventy - five million bushels of apples are grown every year . Pears , plums , apricots , peaches , and nectarines also form large ...
... become an important business . Orchard and Other Fruits . In the United States over one hundred and seventy - five million bushels of apples are grown every year . Pears , plums , apricots , peaches , and nectarines also form large ...
Página 70
... previously prepared . Heat the mixture , which should now. A cornfield , showing staminate and pistillate flowers , the latter having become A hardwood forest showing representative di- cotyledonous trees . (. 70 SEEDS AND SEEDLINGS.
... previously prepared . Heat the mixture , which should now. A cornfield , showing staminate and pistillate flowers , the latter having become A hardwood forest showing representative di- cotyledonous trees . (. 70 SEEDS AND SEEDLINGS.
Página 78
... become smaller and smaller , until eventually their food contents having been absorbed into the young plant , they dry up and may fall off . The young plant is now able to care for itself and may be said to have passed through the ...
... become smaller and smaller , until eventually their food contents having been absorbed into the young plant , they dry up and may fall off . The young plant is now able to care for itself and may be said to have passed through the ...
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Términos y frases comunes
adapted alcohol algæ American Book Company amount archegonium arteries bacteria bean birds blood vessels body bones Botany breathing called calories carbon dioxide caused cavity cells cent chlorophyll color colorless corpuscles containing corn corpuscles cotyledons crayfish crustaceans developed digestive disease eggs ELEMENTARY Sharpe especially example fibers fish flower fluid food material food tube forest frog fruit germinate germs gills glands grain grow growth heat important insects intestine known Laboratory Manual large number larvæ layer leaf leaves legs living lungs Macmillan Company means membrane milk mollusks mouth muscles nerve nervous system nitrogen organs oxidation oxygen parasites pass Physiology pistil plants and animals poison pollen Prob proteid protoplasm Protozoa root hair seeds seen skeleton skin soil sponge spores stamens starch stem stomach stomata structure substances sugar supply surface temperature tiny tion tissues trees typhoid veins vertebrate walls wings worm young
Pasajes populares
Página 401 - Could the young but realize how soon they will become mere walking bundles of habits, they would give more heed to their conduct while in the plastic state. We are spinning our own fates, good or evil, and never to be undone.
Página 401 - As we become permanent drunkards by so many separate drinks, so we become saints in the moral, and authorities and experts in the practical and scientific spheres, by so many separate acts and hours of work.
Página 401 - I won't count this time." Well ! he may not count it, and a kind Heaven may not count it ; but it is being counted none the less. Down among his nerve cells and fibers the molecules are counting it, registering and storing it up to be used against him when the next temptation comes.
Página 376 - One of the most common and pernicious of the popular errors relating to alcohol is the supposition that it somehow strengthens the heart. The full, bounding pulse, usually produced by the administration of an ounce or two of brandy, gives the impression of an increased vigor of heart action; but it is only necessary to determine the blood pressure by means of a Riva-Rocci instrument or Gaertner's tonometer, to discover that the blood pressure is not raised and may be lowered.
Página 14 - It is within the power of man to cause all parasitic diseases to disappear from the world.
Página 343 - In small doses these substances are oxidized in the body and yield a corresponding amount of energy, but their value from this standpoint is altogether unimportant compared with their action as stimulants. Alcohol also, when not taken in too large quantities, may be oxidized in the body, and furnish a not inconsiderable amount of energy. It is, however, a matter of controversy at present whether alcohol in small doses can be considered a true foodstuff, capable of serving as a direct source of energy,...
Página 308 - ... lower animals. In this, too, they resemble man ; for he differs from the lower animals not only in the possession of a new sort of intelligence, but also in the tremendous extension of that sort which he has in common with them. A fish learns slowly a few simple habits. Man learns quickly an infinitude of habits that may be highly complex. Dogs and cats learn more than the fish, while monkeys learn more than they. In the number of things he learns, the complex habits he can form, the variety...
Página 410 - In like manner the influence of all drugs which affect the nervous system must be in the direction of disintegration. The healthy mind stands in clear and normal relations with Nature. It feels pain as pain. It feels action as pleasure. The drug which conceals pain or gives a false pleasure when pleasure does not exist forces a lie upon the nervous system.
Página 308 - In their method of learning, although monkeys do not reach the human stage of a rich life of ideas, yet they carry the animal method of learning, by the selection of impulses and association of them with different sense-impressions, to a point beyond that reached by any other of the lower animals. In this, too, they resemble man ; for he differs from the lower animals not only in the possession of a new sort of intelligence, but also in the tremendous extension of that sort which he has in common...
Página 426 - If we count the value of each life lost at only $1,700 and reckon the average earning lost by illness at $700 per year for grown men, we find that the economic gain from mitigation of preventable disease in the United States would exceed $1,500,000,000 a year.