4 



INTRODUCTION. 



Especially it ought to be most zealously inculcated, that 

 the applications of this science should only be taught or 

 learned after a previous study of its general principles. That 

 part of Botany which relates to forest trees, is as little capable, 

 as the medical department, of dispensing with the helps which 

 are afforded by the Nomenclature, the Classification, and the 

 physiology of Plants, 



