Essentials of Biology Presented in Problems: By George William HunterAmerican book Company, 1911 - 448 páginas |
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Página 20
... energy released by the burning of coal may be transformed into any kind of work power . Energy is the ability to perform work . We shall later find that the oxidation of certain materials in the bodies of plants or animals releases The ...
... energy released by the burning of coal may be transformed into any kind of work power . Energy is the ability to perform work . We shall later find that the oxidation of certain materials in the bodies of plants or animals releases The ...
Página 24
... energy for it . Nutrients . - Organic food substances may be classed into a number of groups , each of which may be detected by means of its chemical composition . Such groups of food substances are known as nutrients . Let us now ...
... energy for it . Nutrients . - Organic food substances may be classed into a number of groups , each of which may be detected by means of its chemical composition . Such groups of food substances are known as nutrients . Let us now ...
Página 33
... energy for movement and the other activi- ties of plants and animals . ( 6 ) Protoplasm has the power to rid itself of waste materials , especially those which might be harmful to it . A tree sheds its leaves , and as a result gets rid ...
... energy for movement and the other activi- ties of plants and animals . ( 6 ) Protoplasm has the power to rid itself of waste materials , especially those which might be harmful to it . A tree sheds its leaves , and as a result gets rid ...
Página 77
... energy contained in a piece of coal we must burn or oxidize it . To do this we must have a constant supply of fresh air containing oxygen . The seed , in order to re- lease the energy locked up in its food supply , must have oxygen , so ...
... energy contained in a piece of coal we must burn or oxidize it . To do this we must have a constant supply of fresh air containing oxygen . The seed , in order to re- lease the energy locked up in its food supply , must have oxygen , so ...
Página 102
... energy needed for growth . We shall see later that the leaves are the chief breathing organs of the plant . But all the year round oxygen is taken in and carbon dioxide given off through the lenticels , as the breathing holes in the ...
... energy needed for growth . We shall see later that the leaves are the chief breathing organs of the plant . But all the year round oxygen is taken in and carbon dioxide given off through the lenticels , as the breathing holes in the ...
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adapted alcohol algæ American Book Company amount archegonium arteries bacteria bean Biology birds blood vessels body bones Botany breathing called calories carbon dioxide caused cavity cells cent chlorophyll color containing corn corpuscles cotyledons crayfish crustaceans developed digestive disease eggs 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 peas Physiology pistil plants and animals poison pollen Prob Problem 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 xerophytes young
Pasajes populares
Página 405 - 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 405 - 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. Nothing we ever do is, in strict scientific literalness, wiped out. Of course, this has its good side as well as its bad one. As we become permanent drunkards by so many separate drinks, so we become saints in the moral, and authorities and experts...
Página 405 - The hell to be endured hereafter, of which theology tells, is no worse than the hell we make for ourselves in this world by habitually fashioning our characters in the wrong way.
Página 405 - Let no youth have any anxiety about the upshot of his education, whatever the line of it may be. If he keep faithfully busy each hour of the working day, he may safely leave the final result to itself. He can with perfect certainty count on waking up some fine morning to find himself one of the competent ones of his generation, in whatever pursuit he may have singled out..
Página 405 - 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. Every smallest stroke of virtue or of vice leaves its never so little scar. The drunken Rip Van Winkle, in Jefferson's play, excuses himself for every fresh dereliction by saying, 'I won't count this time!
Página 347 - 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 427 - A healthy mental attitude implies many elements, but they are all roughly summed up in the word "serenity." Probably no other one hygienic requirement is of greater importance than this. Moreover, the attitude of "healthymindedness" should be striven for not only in order to produce health, but as an end in itself, for which, in fact, even health itself is properly sought. In short the health of the body and the health of the mind act and react on each other.
Página 14 - It is within the power of man to cause all parasitic diseases to disappear from the world.
Página 414 - 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.