GUM 
with the notes of Manfredi ; and the whole 
of liis works were printed in a collective 
form at Geneva, in 1719, in two volumes 
quarto. 
GUIAC. See Resin. 
GUIDE, in music, the name given to 
that note in a fugue which leads off and an- 
nounces the subject. 
GUILANDINA, in botany, bonduc or 
nicker-tree, a genus of the Decandria Mono- 
gynia class and order. Natural order of 
Lomentaceae. Leguminosse, Jussieu. Es- 
sential character : calyx one-leafed j salver- 
shaped ; petals inserted into the neck of 
the calyx, nearly equal ; seed vessel a le- 
gume. There are six species. 
GUILD, or Gild, a fraternity or com- 
pany. As to the original of these guilds or 
companies, it was a law among the Saxons 
that every freeman of fourteen years of age 
should find sureties to keep the peace, or 
be committed ; upon which the neighbours 
entered into an association, and became 
bound for each other, either to produce 
him who committed any offence, or to make 
satisfaction to the injured party ; in order 
to which they raised a sum among them- 
selves, which they put into a common stock ; 
out of which they, upon occasion, made a 
pecuniary compensation according to the 
quality of the offence committed. These 
guilds are now companies, joined together 
with laws and orders made by themselves, 
by the licence of the prince. 
GUITAR. See Musical instruments. 
GULES, in heraldry, signifies the colour 
red, which is expressed in engraving by 
perpendicular lines falling from the top of 
the escutcheon to the bottom. 
GUM, a thick transparent tasteless fluid, 
which exudes occasionally from certain spe- 
cies of trees. It is adhesive, and gradually 
hardens without losing its transparency. 
Gum is chiefly obtained from different spe- 
cies of the mimosa, particularly from M. 
nilotica, a native of Egypt and Arabia, 
which is known by the name of gum arabic. 
The specific gravity of gum is about 1.4. 
It is not changed by exposure to the air, 
but is deprived of its colour by the action 
of the sun. By heat it becomes soft, and 
is speedily reduced to the state of charcoal, 
which enters largely into its composition. 
The constituent parts of gum are carbon, 
hydrogen, and oxygen, with smaller propor- 
tions of nitrogen and lime. The oxygen is 
much less in quantity than the saccharine 
matter. See Sugar. The existence of 
lime and nitrogen in gum renders it essen- 
GUM 
tially different from fecula and sugar, to 
which, in other respects, it bears a near 
relation ; they, however, are able to under- 
go the vinous fermentation, which is not the 
case with gum. Gum readily dissolves in 
water, and the solution, which is thick and 
adhesive, is known by the name of muci- 
lage. It is soluble also in the vegetable 
acids. Sulphuric acid decomposes it, and 
converts it into water, acetic acid, and 
charcoal. With the assistance of heat, mu- 
riatic acid, and nitric acid, produce a simi- 
lar effect. It is insoluble in alcohol and 
ether Such are the chief properties of 
gum arabic. There are, besides this, other 
gums, of which the principal is denomi- 
nated tragacanth, from the astragalus tra- 
gacantha, a native of the island of Crete, 
which is in the form of vermicular masses ; 
it is less transparent, and more adhesive 
than gum arabic, but by distillation it yields 
similar products. In our garden and or- 
chards we find, in good quantities, gum 
exuding from the cherry and plumb trees, 
which differs chiefly from gum arabic in be- 
ing softer and more soluble. Gum, in a 
state of mucilage, exists in a number of 
plants, especially in the roots and leaves. 
It is most abundant in bulbous roots, and 
of these the hyacinth seems to contain the 
largest quantity. A pound of the bulbs of 
this root, when dried, yields four ounces of 
a powder, which, when macerated in water, 
give a mucilage that acts, well as a mor- 
dant for fixing the colours in calico-printing. 
Gum is used in medicine, and is considered 
as a specific against the stranguary occa- 
sioned by blisters ; it constitutes, under par- 
ticular forms, a nutritious food, and it is 
well known as an important article in the 
manufacture of our ink. 
Gum resins, are certain substances that 
have long been used in medicine. They 
are all solid, generally brittle and opaque, 
have a strong smell, and a pungent and bit- 
ter taste. They consist chiefly of gum and 
resin, the proportions varying with the par- 
ticular substance. They are never ob- 
tained by means of spontaneous exudation, 
but are procured by wounding the plants 
which contain them. The principal of the 
gum-resins are, 1 . Ammoniac, which see. 
2. Assafoetida, obtained from the ferula 
assafoetida, a plant found in Persia The 
gum resin is extracted from the roots by 
cutting off the extremities ; a milky juice, 
flows out, which is dried in the sun. It is 
brought to Europe in masses ; its smell is 
very fetid, and its taste acrid. It ia pai> 
D d 2 
