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WHY PLANTS UHUW. 



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plants have been makin^f, day by day, since God said, " Let the earth hring fi>rth 

 grasSj and the lirrh iji^'hlinij seed, and the fruit-tree (/ieldinfj fruit after his klndy 

 u'htme seed in 111 itnelf upon the earth, — and it was so 1 " The answer to these ques- 

 tions will show us plainly 



279. What Plants are made for. in the first place, in the very act of making 

 Ve^'etable matter, plants fulfil one <,'reat purpose of their existence, that is, 



280. 7'A''// I'ltrifij the air fur animals. That part of the air which r(>nders it fit 

 for breathing is called <u'i/(ien ; this makes up al)out one fifth part of the air wo 

 breathe. At every breath animals take in soine of this o.n/;/!/! and chan<je it 

 into rarhonic arid ; that is, they c»)ml)ine the o.\y<(en with carl)()n from their blood, 

 which makes carbonic acid, and breathe out this carbonic acid into the air, in 

 place of the oxygen they drew in. Now this carbonic; acid is unfit for the breath- 

 ing of animals, — so nuich so, that if it were to increase so as to nuike any con- 

 siderable part of the atmosphere, man and other animals could not live in it. 

 But plants prevent the carbonic acid from accumulating in the air. While 

 animals need the oxygen of the air, an<l in using it change it into carbonic acid, 

 huitful to them, plants need the cnrlxm of this cai-ljonicr acid ; indeed, it makes 

 a very large portion of their food, — as we plainly see it must, when we know that 

 about half of every part of a plant is carbon, that is, charcoal. And this caibonic 

 acid is the very part of the air that plants use ; they constantly take it from the 

 air, decompose it in their leaves dining sunsliine, keep the carbon, and give back 

 the oxygen pure, so keeping the air tit for the breathing of animals. The cai-- 

 bon which plants take from the air in tliis way, along with water, &c., they assimi- 

 late, that is, change into vegetable nuitter : aiul in doing this 



281. Ttieij make all the fond which a)iinials lire iijiou. Animals cannot live upon 

 air, water, or earth, nor are they able to change these into food which they may 

 live upon. 'V\\\a work is done for them by plants. Vegetable matter in almost 

 every form — especially as herbage, or more concentrated in the accunudations of 

 nourishment which plants .store up in roots, in bidbs and tid)ers, in many stalks, 

 in fruits and in seeds — is food for animals. *' And to erenj beast (f the earth, and 

 to every fowl of the air, and to ereri/fhing that creepifJi upon the earth," as well as 

 to men, is given " ereri/ ijn i herb for meat." Some animals take it by feeding 

 directly upon vegetables ; others, in feeding upon the flesh of herbivorous animals, 

 receive what they have taken from plants. Man and a few other animals take in 

 both ways what plants have prepared for them. But however received, and how- 



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