OF NATURAL HISTORY. 307 



lug In a different foil, or in a different climate, aflume fuch different 

 appearances, confidered and enumerated them as diflindt fpecies. 

 But the modern botanifts, to prevent the unneceflary multiplication 

 of feparate beings, have endeavoured to reduce all thofe varieties 

 arifing from fortuitous circumftances to their original fpecies. 



From thefe fads, and many others which might be mentioned, it 

 appears, that, in both the animal and vegetable kingdoms, forms are 

 perpetually changing. The mineral kingdom is not leis fubjefl to 

 metamorphofes ; but thefe belong not to our prefent fubjedt. Thougii 

 forms continually change, the quantity of matter is invariable. The 

 fame fubftances pafs fucceffively Into the three kingdoms, and con- 

 ftitute, in their turn, a mineral, a plant, an infe£l, a reptile, a fifh, a 

 bird, a quadruped, a man. In ihefe transformations, organized bo- 

 dies are the principal agents. They change or decompofe every 

 fubftance that either enters into them, or is expofed to the adtion of 

 their powers. Some tjiey affimulate, by the procefs of nutrition, 

 into their own fubftance; others they evacuate in different forms ; 

 and thefe evacuations make ingredients in the compofitions of other 

 bodies, as thofe of infeds, whofe multiplication is prodigious, and 

 affords a very great quantity of organized matter for the nourifli- 

 ment and fupport of almoft every animated being. Thus, from the 

 apparently vlleft and moft contemptible fpecies of matter, the richeft 

 produdions derive their origin. The moft beautiful flowers, the 

 moft exqnifite fruits, and the moft ufeful grain, all proceed from the 

 bofom of corruption. The earth is continually beftowing frelh 

 gifts upon us ; and her powers would foon be exhaufted, if what 

 fhe perpetually gives were not perpetually reftored to her. It is a 

 law of Nature, that all organized bodies fhould be decompofed, and 

 gradually transformed into earth. While undergoing this fpecies of 

 diffolution, their more volatile particles pafs into the air, and are 

 diffufed through the atmofphere. Thus animals, at leaft portions of 



Q^q 2 them, 



