Essentials of Biology Presented in Problems: By George William HunterAmerican book Company, 1911 - 448 páginas |
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Página 15
... supply of water is given to our rivers , and thus freshets are prevented . Countries that have been deforested , such as China , Italy , and parts of France , are now sub- ject to floods , and are in many places barren . On the forests ...
... supply of water is given to our rivers , and thus freshets are prevented . Countries that have been deforested , such as China , Italy , and parts of France , are now sub- ject to floods , and are in many places barren . On the forests ...
Página 22
... supply of oxygen we allow to pass to the burning material . If we open the draft , allowing more oxygen to get to the fire , we increase the heat by more rapid oxidation ; if we shut off the oxygen supply , we decrease the amount of ...
... supply of oxygen we allow to pass to the burning material . If we open the draft , allowing more oxygen to get to the fire , we increase the heat by more rapid oxidation ; if we shut off the oxygen supply , we decrease the amount of ...
Página 24
... supply is cut off , or even greatly reduced , they will suffer and may die . From this , the definition which follows is evident . A food is a substance that forms the material for the growth or repair of the body of a plant or animal ...
... supply is cut off , or even greatly reduced , they will suffer and may die . From this , the definition which follows is evident . A food is a substance that forms the material for the growth or repair of the body of a plant or animal ...
Página 33
... supply of living things upon the earth is not de- creasing ; reproduction is constantly taking place . In a general way it is possible to say that plants and animals reproduce in a very similar manner . We shall study this more in ...
... supply of living things upon the earth is not de- creasing ; reproduction is constantly taking place . In a general way it is possible to say that plants and animals reproduce in a very similar manner . We shall study this more in ...
Página 52
... supply of air , light , and food . 1 At this point a field trip may well be taken with a view to finding out how the common fall weeds scatter their seeds . Fruits and seeds obtained upon this trip will make a basis for laboratory work ...
... supply of air , light , and food . 1 At this point a field trip may well be taken with a view to finding out how the common fall weeds scatter their seeds . Fruits and seeds obtained upon this trip will make a basis for laboratory work ...
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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.