232 SELECTIONS FROM ADDRESSES. 



inexplicable by common rules, a thorough analysis ouglit to be 

 made by some really competent person. 



I have called attention to certain substances, as necessary to 

 a fertile soil, but have not particularly designated among them, 

 a name which is at the top of the first column of the table, " or- 

 ganic matter." This name does not refer to a single substance, 

 but to a class ; all of the other names in the column are inclu- 

 ded in another class, " inorganic matter." These names were 

 given as most fitly describing the grand distinction between two 

 great classes of bodies. 



Organic matter — is either living defined organs, or something 

 that may be considered a product of such organs. When ex- 

 posed to heat, the organic part burns and disappears, thus 

 showing that the solid substance burned had originally been 

 nothing but air. To form these organic bodies from the differ- 

 ent kinds of air or gas, requires the action of living organs. 

 Inorganic substances are also present in the plant, and in the 

 animal, but they were not formed in the plant, merely drawn 

 in by it from the soil. When the plant or the soil is heated, the 

 organic part is that which burns, being reconverted to its ele- 

 mentary form ; the inorganic part, being incombustible and not 

 volatile, remains in the form of ash. 



The organic matter of the soil is derived from the death 

 and decay of plants and animals. When in the form of vege- 

 table mould, its presence seems to exercise a remarkably bene- 

 ficial influence on all of our cultivated crops. It would occupy 

 too much of your time, were I to enter upon the contested theo- 

 ries as to the manner in which this organic matter acts so de- 

 cidedly. Leaving these aside, it is sufficient to say, that it is a 

 necessary portion of every fertile soil. In all ordinary cases, 

 the organic constituents of a soil decompose slowly ; a part goes 

 to the sustenance of plants, and part, being evaporated, disap- 

 pears entirely. These changes proceed most regularly, in the 

 presence of a sufiicient degree of moisture, air, and warmth. 

 If the quantity of water in the soil, however, be large, and re- 

 mains there permanently, its effect becomes quite injurious, 

 rather than beneficial. In the first place, air and warmth are, 

 in a great degree, excluded ; then the process of decomposition 



