VI PEEFACE. 



species, and of the influence exercised by climate upon 

 their development ; and, lastly, from botany as now 

 understood, in its most extensive signification, is insepa- 

 rable the knowledge of the various ways in which the 

 laws of vegetable life are applicable to the augmentation 

 of the luxuries and comforts, or to the diminution of the 

 wants and miseries of mankind, It is by no means, as 

 some suppose, a science for the idle philosopher in his 

 closet ; nor is it merely an amusing accomplishment, 

 as others appear to think ; on the contrary, its field is 

 in the midst of meadows, and gardens, and forests, on 

 the sides of mountains, and in the depths of mines, 

 wherever vegetation still flourishes, or wherever it attests 

 by its remains the existence of a former world. It is 

 the science which converts the useless or noxious weed 

 into the nutritious vegetable ; which changes a bare 

 volcanic rock into a green and fertile island ; and which 

 enables the man of science, by the power it gives him of 

 judging how far the productions of one climate are sus- 

 ceptible of cultivation in another, to guide the colonist 

 in his enterprises, and to save him from those errors 

 and losses into which all such persons unacquainted with 

 Botany are liable to fall. This science, finally, it is 

 which teaches the physician how to discover in every 

 region the medicines that are best adapted for the 

 maladies prevalent in it ; and which, by furnishing him 

 with a certain clue to the knowledge of the tribes in 

 which particular properties are, or are not, to be found, 

 renders him as much at ease, alone and seemingly with- 

 out resources, in a land of unknown herbs, as if he were 

 in the midst of a magazine of drugs in some civilised 

 country. 



