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disease, as would appear from the experiments or 

 Bonnet. This ingenious physiologist sowed three 

 seeds of the pea in the same kind of soil: one he suf- 

 fered to remain exposed to the free air; the other he 

 inclosed in a tube of glass; and the third in a tube of 

 wood. The pea in the tube of glass sprouted, and 

 grew in a manner scarcely at all different from that 

 under usual circumstances; but the plant in the tubjf 

 of wood deprived of light, became white, and slender, 

 and grew to a much greater height. 



The plants growing in a soil incapable of supply- 

 ing them with sufficient manure or dead organ- 

 ized matter, are generally very low; having brown 

 or dark green leaves, and their woody fibre abounds 

 in earth. Those vegetating in peaty soils, or in lands 

 too copiously supplied with animal or vegetable matter, 

 rapidly expand, produce large bright green leaves^ 

 abound in sap, and generally blossom prematurely. 



Where a land is too rich for corn it is not an 

 uncommon practice to cut down the first stalks, as by 

 these means its exuberance is corrected, and it is less 

 likely to fall before the grain is ripe; excess of poverty 

 or of richness is almost equally fatal to the hopes of 

 the farmer; and the true constitution of the soil for the 

 beskcrop is that in which the earthy materials, the 

 moisture and manure, are properly associated; and in 

 which the decomposable vegetable or animal matter 

 does not exceed one-fourth of the weight of the earthy 

 constituents. 



The canker, or erosion of the bark and wood, is 

 a disease produced often in trees by a poverty of soil; 



