10 SYLVA AMERICANA. 



To describe each particular organ of a vegetable, is denomi- 

 nated the anatomy, and to enter upon the functions of those 

 organs with the results, the physiology of vegetables. To explain 

 their component or constituent parts, belongs to the province of 

 vegetable chemistry. And to treat on the sources by which their 

 growth is promoted, and their productions increased, comes 

 under the head of chemical agriculture, or agricultural chemistry. 



From the great similarity and strong analogy of the laws of 

 the vegetable and animal kingdoms, many modern philosophers 

 have considered the vegetable and animal kingdoms united by 

 one link, and forming a part of the same system ; or, in other 

 words, that a vegetable is only an inferior order of animal. 

 But admitting how nearly in many instances the laws of each 

 approximate, and how greatly a knowledge of the one facilitates 

 that of ihe other ; yet the more frequent presence of perceptive 

 powers, and more especially of a choice and capacity of motion 

 in the one kingdom, and a total abstinence of those qualities in 

 the other, present so broad and strong line of distinction, as 

 should make us pause before we admit a doctrine directly at 

 variance with our common observation, and so opposed to the 

 idea we have entertained of the intents and purposes of creation. 

 All that we ought to allow, is that resemblance only in the 

 physical properties and laws of the two kingdoms, by which the 

 vitality peculiar to each is preserved, the different parts are 

 nourished, growth promoted, secretions produced, reproductions 

 effected, and the common principles of decay and dissolution 

 are brought into action. But here their analogy ceases. 



Vegetables, we know, require a particular temperature, season, 

 soil and aspect, for their growth and maturity, and, in many 

 instances, even for their very existence. In cold climates, they 

 are, in consequence, proportionably limited in the number of 

 their species ; and, in the winter, even of temperate regions, 

 many of their functions are suspended ; they cease to grow, 

 they part with one of their most essential organs, their leaves, 

 and they require the return of a more congenial season, before 

 their variously animating powers are again roused into action. 

 Animals, on the contrary, so long as the vital principle be 



