

Lea. II. ; of Plants. 259 
the fire, before it comes to have thick fumes, it boylsup with a very 
great foame or froath 5 and is the only Gum or Rofiz (of the Eleven ) 
that hath this property. So that I fufpeét, there is a great quantity of 
fome kind of volatile Spirit, which then flies away; and fo, in break- 
ing through the Oyly parts, huffsthem up to fo great a froath. 4 
Olibanum yields half a Drachm of Caput Mortuum. But it is to be 
noted, That the weight is encreafed by certain little Spar-Stones,which 
in the burning of feveral parcels, I always found mixed with this Guz. 
Thefe beg picked clean out, the Cap. Mort. weigheth not much more 
than that of Majfick. And is in like manner infipid, when the faid 
Stones are picked out. 
From hence it appears, how proper thefe Gums ate for the Cox- _ 
cotfion of Salt Rhewms 5, according to what I have formerly fuggefted Difcourfé 
from another Experiment. of Mixturé 
It may alfo be noted, that Rofiz and Maftick, feem to be more Cap. Ults 
purely Acidoleous Gums not only from their confiftence which is uni- 
forms; and their Swell, which is lef ftrong¢ and more pleafant: but 
alfo from the Acid Liquor they yield by Dy/fillatioz, and in that the 
young Leavs of Fir, and efpecially of Pize, are fowers and tis pro- 
bable that thofe of Maffick are fo likewife. Whereby thefe, and 
other like Gums are more efpecially fitted for the abovefaid purpofe. 
But Olibanum feems, befides its Acidity, to contetn fome Volatile Alkaly; 
and fo to be an Acid-AlkalineGum. For as it hatha ftronger Swell 
than the former, foa hotter Taftes both the ordinary effects of an 
Alkaline Sulphur, And being infufed in feveral Menféruums, appears 
to conttift of two Bodies, one of them more Refizowsthan the other: 
Of which, it is probable, that the one is made by the Acid parts as the 
other by the Alkaline, Whereby it is very well adapted in fome Ca/és, 
asina Pleurefie, for removing the Coagulations of the Blood, or its 
difpofition thereunto. 
Afa fetida yileds no lefs than half its weight or an Ounce of Caput 
Mort. that is 8 times asmuch as that of the other Guwms, and 48 times 
as much as that of fome of them. Yet doth it not contein one grain of 
Salt, fo far as can be judged by its Taz. Yet the Strength and Loath- 
fonnefs of the smell and Taft of the Gum do argue it to be highly im- 
pregnated with fome kind of Volatile .Alkaly proper to arreft thofe 
offenfive Vapours ( toufe the vulgar word ) which flying, either by 
the Blood or Nerves, from part to part, do often prove fo trouble- 
fome. 
Gum Arabick yields one Scruple of Cap. Mort. whereof, by the 
Tafte, about 34 part is Salt. ‘ 
Euphorbium yields one Drachwe of Caput Mort. of which, by the 
ftrength of the Ta/le, two Scruplesfeem to be Salt. Which confirms 
a former conjecture (2) of its being an Alkaline Gumus. (2) Of the 
iyrrh alfo yields a Drachm of Cap. Mort. and at leaft two Scruples Luation 
of Salt. Ofthe Eleven, thefe two Gums have the greateft quantity of Bodies, 
ofa fixed Alkaly. Ch. i. 
Opium yields half a Drachm of Cap. Mort. whereof the one half 
is Salt. 
Aloe yields a Drachm of Cap. Mort. conteining about one Scruple of 
Salt. 


Qq2 Scammony 



















































