BOOK III. 



OF THE PRIMARY PRINCIPLES OF 

 VEGETABLES. 



IF the principle of a laudable curiosity and grand Their in- 

 natural stimulus to the acquisition of human know- 

 ledge should fail to induce the phytologist to un- iable> 

 dertake the study of the primary and constituent 

 ' elements of which the plant is ultimately com- 

 posed, the necessity of the case will compel him* 

 For as plants are not merely organized beings, but 

 beings endowed with a species of life, absorbing 

 nourishment from the soil in which they grow, and 

 assimilating it to their own substance by means of 

 the functions and operations of their different or- 

 gans, it is plain that no great progress can be made 

 tin the explication of the phenomena of vegetable life, 

 and no distinct conception formed, of the rationale 

 of vegetation, without some specific knowledge of 

 the principles in question, and of their mutual ac- 

 tion upon one another. The latter requisite pre- 



