the agriculturists ; the land is poor and pretty well 

 exhausted, and, until manures are introduced and 

 the agriculturists are taught and induced to use 

 them, the land will not yield much more than it 

 does now. 1 ' 



The only reliable foundation of our knowledge 

 of the laws of nature is based upon observation : 

 by observing the works of nature, we can form 

 correct conclusions as to the laws which govern 

 them ; and this remark applies also to vegetable 

 life. We must observe plants in their natural 

 state, that is, when undisturbed and untended by the 

 hand of man, to arrive at a correct knowledge of the 

 general laws which govern their growth, existence, 

 and decadence, and by which laws we should be 

 guided in their cultivation, or, more correctly 

 speaking, in the artificial rearing of once wild plants. 



A plant in its natural state, if perennial, returns 

 constantly a portion of what it had withdrawn 

 from the soil and air, by shedding its leaves, which 

 become decomposed into their constituent parts, 

 and serve again as food, perhaps to the same plant 

 which had shed them. Eventually it dies oh the 

 spot where it had grown, and all the inorganic 

 substances withdrawn from the soil are returned, 

 together with all those substances which it had 

 derived from water and atmospheric air. For imme- 

 diately upon the sustaining power of life becoming 

 extinct, in vegetable as in animal life, the general 



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