LETTER IX. 



87 



to form cellulose, starch, sugar, oil, gluten — nay, albu- 

 men and fibrine, and the several structures and juices 

 of which they consist. In forming these, they fulfil 

 the end of their being ; and having no object to serve 

 beyond this or not arising out of this,* and having 

 made provision concurrently with it in the form of 

 buds, or seeds, or both, for another race of the like 

 kind with themselves, they die. And accordingly, 

 they neither need nor do they exercise any such func- 

 tion as the molecular nutrition of animals. 



18. Let me take you one step farther. Dependent 

 as the whole animal creation thus is on the vegetable, 

 man is in an especial degree, and in an infinite variety 

 of ways, beholden to it. Gifted with reason, which 

 has been denied to the brute animals, his merely natu- 

 ral wants are far greater than theirs ; while the reason 

 which has been given him, and, as arising out of this, 

 the objects of his existence and the manifold relations 

 in which he is placed — all these multiply his wants 

 to a degree which it is scarcely possible for us to 

 conceive. 



* "Or not arising out of this." One exceedingly important object 

 of their existence is that of maintaining the atmosphere in a state of 

 purity for the respiration of animals. This they accomplish by the 

 power they possess of decomposing carbonic acid — retaining and 

 fixing the carbon within themselves, and setting free the oxygen. 

 But the carbonic acid existing in the atmosphere forms one main 

 source of their food, and the accomplishment of the object here 

 referred to may be said to spring from that mentioned in the text. 



