IV 
PREFACE. 
new Light upon it , properly to promote its 
good , or prevent its bad E fell : When , or 
why j and how it produces one or the other , 
or its more general Ufe , requires a more JlriH 
and particular Confideration ; /o prevent its 
Abufe ; or to Jet the Ufers right when it has 
good or bad Qualities faljly afcribed to it 
by prejudiced Per/ons ; or its life becomes a 
conjiderable Branch both of the Revenue and 
Trade . 
Though there have been fever al European 
Trails written on this Indian Plant > yet their 
Authors have too often implicitly taken their 
Materials upon Truf , either from Travellers y 
who have only given its natural Hiftory, and 
Ufe among the Orientals ; or from the Im- 
porters and Venders or fuch as have given 
it random Virtues . And though fome have 
afcribed to it far greater medicinal Qualities 
than it ever pojfeffed , yet have they neither 
afforded us the leaft Light into its Principles , 
nor any rational Account how , or why , we are 
to expeli fuch wonderful Effells from it ; nor 
adapted its Ufe to different ConJlitutions y 
Ages, Climates, &c. Tet we find very few 
Things , 
