(156) 
reafon to diftrufl: their veracity and validity. In the pre- 
fent cafe, the perfuafion of the Ancients, and the Poficion, 
which I fhal I endeavor toil luftrate, though at the firft ap- 
pearance they feem diametrically oppofite, may be eafily 
reconciled, f formerly declared, that moft Vegetables 
burnc whilft green or moift , and with a fmothering fire, 
yield a kind of a Neutral Salt, which may be calFd tar- 
tareom ^ and fometimes not improperly Jiffe^^tial^ many 
of them rccainiiig the Vomitive, Purging, Sweating , Diu- 
retical. Opiate, or other general, and perhaps fbme fpe- 
cifical, properties, wherewith the Plants were enobled 
which produced them. Now , whether 'tis fome fmall 
quantity of the Ejfe^tial 0)1, which mixt with the Saline 
principle renders ic fo varioufly medicinal, the Eflential 
Oyles of Plants being manifeftly as 'twere a Compendium 
of the Plant , which they do equally exaftly refemble in 
fmell, taft, and other qualities: Or, whether thofe ver- 
tues are therefult of the crajis and mixture of the feveral 
principles ; certain I am, that, after the Oyl is evapou- 
red by an intenfe heat , or the crap difturbcd by avolati- 
on of fome parts, and new combinations of what remains , 
farewell all Specifical qualities, and confequently all 
ther differences, than what purety and impurity , and fe- 
veral degrees of heat may occafion ; fome being more 
white and fiery than others. Now, fome Salts are much 
more eafily deprived of their Acid and Oily parts than o- 
thers ; and in fome , on the contrary, the Oyl is of fo fixt 
a nature, or rather fo clofely combined with the other 
principles, that it muft be a very intenfe heatwhich can 
disjoyn them, and thereby reduce the Salt to the common 
ftandard or aggregate of qualities, wherein all Alcalies a- 
gree. 
The induftrious Tachenim does fomewhere pretend to 
demonftrate, that there is a real difference between the 
Alcalies of different Plants 5 which he would prove by 
the various EfFefls they have upon a Sublimate difolved 
In 
