CHAPTER XXI. 



OF MANURE. 



To manure a plant is to feed it artificially. 



We see that plants and animals exist in a wild state without 

 the aid of any other food than what is presented to them 

 spontaneously. There is everywhere around us a hountiful 

 provision for sustaining life. Providence has created animals 

 and plants to be fed on by man, animals prey on animals and 

 plants, plants subsist upon the decay of animals and plants ; 

 and these mutual relations are so nicely adjusted, that we have 

 no reason to suppose that any one species has disappeared 

 since the creation from want of food. When species have 

 perished they have been exterminated by man. 



But although plants are surrounded on all sides by the 

 materials necessary to sustain life, yet when man invades their 

 haunts and turns them to his peculiar purposes, natural 

 circumstances no longer suffice. Water and air and what 

 belongs to them remain indeed as before, but the food provided 

 in the soil becomes exhausted ; when the races of plants are 

 altered by domestication they require more abundant nutri- 

 ment; and to obtain from the earth a greater produce than it 

 can yield spontaneously becomes a matter of the first neces- 

 sity ; hence arises the application of manure, which is to the 

 vegetable kingdom what artificial feeding is io animals. 



The object of manuring is either to increase the fertility of 

 land, or, if fertile by nature, to keep it in that state by con- 

 tinually returning to it the substances which crops may have 

 removed. If a tree advances in the course of time from a mere 



