2 PRINCIPLES OF BOTANY. 



is always advantageous to take a general survey of the 

 limits within which it is restricted, and to obtain some 

 notions of the objects of which it professes to treat. 

 We shall, therefore, offer a few remarks upon the 

 position which Botany holds with respect to other 

 kindred branches of Natural History ; and point out 

 the separate and subordinate departments into which it 

 may be advantageously divided. 



(2.) Botany. In the most extended sense of the 

 term, Botany may be considered as embracing every 

 inquiry which can be made into the various phenomena 

 connected with one of the three great departments into 

 which the study of nature is divided, and which is 

 familiarly styled the Vegetable Kingdom. And this 

 inquiry should extend as well to the investigation of 

 the outward forms and conditions in which plants, 

 whether recent or fossil, are met with, as to the exa- 

 mination of the various functions which they perform 

 whilst in the living state, and to the laws by which 

 their distribution on the earth's surface is regulated. 

 We may conveniently arrange these several phenomena 

 under two heads. The one may be called the 

 " Descriptive" department of the science, being de- 

 voted to the examination,- description, and classification 

 of all the circumstances connected with the external 

 configuration and internal structure of plants, which 

 we here consider in much the same light as so many 

 pieces of machinery, more or less complicated in their 

 structure; but of whose several parts we must first 

 obtain some general knowledge, before we can expect 

 to understand their mode of operation, or to appreciate 

 the ends which each was intended to effect. In the 

 " Physiological," which is the other department, we 

 consider these machines as it were in action ; and we 

 are here to investigate the phenomena which result 

 from the presence of the living principle, operating in 

 conjunction with the two forces of attraction and 

 affinity, to which all natural bodies are subject. 



(3.) Subordinate departments. Each of the two 



