A POPULAR STUDY. 339 



furnace, in the same manner as we can do in the 

 chemical experiment; but still we can " watch the 

 progress" as closely in the one case as in the other ; 

 and we have no more knowledge of the ultimate 

 principles of chemical union, than we have of 

 vegetable assimilation. 



From what we do observe, however, we can 

 accelerate, retard, and otherwise modify the ac- 

 tion of vegetables over a very considerable range. 

 It is upon our power of doing this that all cultiva- 

 tion, whether of the fields, the garden, or the 

 forest, is founded; and that cultivation may be 

 said to be the groundwork of all that we do and all 

 that we can possess. Our food is either directly 

 vegetable, or obtained by means of vegetables. The 

 corn, the pulse, the roots, the buds, the leaves, 

 and the fruits, which, in their immediate sub- 

 stance, prepared or unprepared by art, human 

 beings use for food, are very numerous ; so much 

 o that the list of those which are familiarly known 

 in the British markets, would fill a considerable 

 volume ; and when those that are used in other 

 countries are added, the number is almost incre- 

 dible. 



When a number of species, having those ap- 

 pearances, which lead botanists to consider them 

 as " allied," and form them into what they call a 

 "natural order," (there are no orders or classes 

 in nature, for all the productions of nature are 

 individuals ; and, though there be varieties in the 

 successions of individuals, sometimes produced by 

 circumstances which we can imitate and some- 

 times not, the succession is in the species that is, 

 the plant bears more resemblance to the immediate 

 parent plant than to a plant of any other kind) 

 G g 2 



