Royal Society. 193 
touch they cleave to the fingers, and draw out into long threads 
like bird-lime. In like manner a liquid gum is obiervable 
on the ^JPinguicula ^ Nctey that the Imall drops and threads, or 
hairs in either of thefe two plants, are to be feen upon the 
uppermoft or inmoft fide of the leaf, and the outmoft and 
undermofl fides are fmooth or void of them; which is con- 
trary to what is obferved in other plants. About the middle 
oi yiugufl^ the chats of the alder feemed to be gummy 5 per- 
haps this gum did exfudate from the plant itfelf j as probably 
the honey-tall, or gummy dew on the leaves of the oak, ^c. 
are nothing other. 
The Jlmerican or Indian rhubarb, fown in our gardens, is 
the only plant Dr. Lifter ever obferved to yield a gum clear 
and hard, which it exfudates from all parts of the Italk and 
ribs on the under fide of the leaf itfelfj he gathered fome in 
form of pretty large drops, others as tho' the ftalk had been 
befmeared therewith, and others /hot into long and twifted 
wires or icicles 5 befides, he obferved, that the cankered ori- 
fices, or places, at which the gum had burft forth, could be 
traced with a knife into the fialk 5 and that thro' the fkin, in 
certain places, the juice within the plant was become gummy, 
and looked like clear water. It is the experiment of Mr. 
Fifier, that the clear and defecated juices of moft plants have 
more or lefs rcdnefs in them 5 again, that the dried root of 
^cetofa (a plant of the fame family with rhubarb, which 
may probably be called the Irulian forrel, or four dockcn) 
boiled, dies water of a fair red colour ^ and Dr. Lifter obferved, 
that the hufKs of the unripe feeds of rhubarb yield a very fair 
and deep purple 5 Note^ that rhubarb, forrel, ^^. do, when 
they decay, turn red. The juice extracted from the roots of 
our Englip rhubarb, by a tincture of fair water lleamed 
away, is nothing elfc but a lean uninflammable gum^ and tho* 
it differ in colour, as being of a deep liver colour, from the 
exludating gum, yet in other properties, as this of being unin- 
flammable, duftile in the flame of a candle, ^c. it agrees 
therewith ; this gum is fweet, or rather inlipid. To this pur- 
pofe. Dr. Lifer obferved, in fummer-time, even the juice of 
apples fpontaneoufly gellied in La/igucdoc, and the apples 
looked clear and hard like ice; whence they call that fort of 
apple, 'Pome gelJe, or the frozen apple ; tho', in realit)^, it be 
nothing elfe init the breaking or coagulating of the juice in 
fome fpors of it; for it is rare to fee one of them all over fo. 
We may here give a probable reafon, why a gentle infuficn or 
Vol. 111. B b mace- 
