XVL PREFACE. 
number of them, which frequent the vicinity of 
human habitations, this arrangement of Provi- 
dence, by making ungrateful what is dangerous, 
has furnished almost the only safeguard from 
harm, to the inexperienced and unwary. 
These remarks have been offered on account 
of an impression which many persons entertain, 
that collateral evidences of the characters of plants 
are worthless and undeserving of attention. Even 
if the community were composed exclusively of 
physicians, such an opinion could not be wholly 
correct. Every one may be called on to form 
hasty decisions on subjects where his experience 
is deficient, and where an acquaintance with aux- 
iliary facts might lead him to a correct issue. It 
is not only curious and instructive to perceive the 
harmonies of nature, but to every inquirer among 
her works it must be practically useful. It can 
no where be more useful, or more deserving of 
study, than in a new country, where the face of 
nature presents an ungathered harvest, and where 
every clue to useful discovery derives importance 
from its influence and tendency. 
