18 THE VITAL FUNCTIONS. 



tive to other plants, which absorb them, and with more fa- 

 cility adapt them to the purposes of their own systems. 

 Here they receive a still higher degree of elaboration; and 

 thus the same materials may pass through several successive 

 series of modifications, till they become the food of animals, 

 and are then made to undergo still farther changes. New 

 elements, and in particular nitrogen, is added to the oxy- 

 gen, hydrogen and carbon, which are the chief constituents 

 of vegetable substances:* and new properties are acquired, 

 from the varied combinations i/ito which their elements are 

 made to enter by the more energetic powers of assimilation 

 appertaining to the animal system. The products which 

 result are still more removed from their original state of 

 inorganic matter: and in this condition they serve as the 

 appropriate food of carnivorous animals, which generally 

 hold a higher rank in the scale of organization, than those 

 that subsist only on vegetables. 



Thus has each created being been formed in reference, not 

 merely to its own welfare, but also to that of multitudes of 

 others which are dependent on it for their support, their pre- 

 servation, nay, even for their existence. In contemplating 

 this mutual relationship, this successive subordination of the 

 different races to one another, and this continual tendency 

 to increased refinement, we cannot shut our eyes to the mag- 

 nificent unfolding of the great scheme of nature for the pro- 

 gressive attainment of higher objects ; until, in the perfect sys- 

 tem, and exalted endowments of man, we behold the last re- 

 sult that has been manifested to us of creative power. 



* Nitrogen, however, frequently enters into the composition of vegeta- 

 bles: though, in general, in a much smaller proportion than into the sub- 

 stance of animals, of which last it always appears to be an essential constitu- 

 ent. 



