Some Account of Lac, with the Method of Purifying It for Dying Scarlet, Painting, Making Sealing Wax, Varnishes, &c.

Some Account of LAC, with the Method of pu-
    rifying it for dying Scarlet, Painting, making
    sealing Wax, Varnishes, &c. 

[By Mr. Robert Saunders, Surgeon at Bogle-
                        poor in Bengal.]

LAC is the produce of, and a stape ar-
    ticle of commerce in Assam; and,
strictly speaking, is neither a gummy nor
resinous substance, though it has some pro-
perties in common to both. Gums are so-
luble in water, and resins in spirits; lac
admits of a very different union with ei-
ther, without the mediation of some other
agent.
    Lac is known in Europe by the differ-
ent appellations of stick lac, seed lac, and
shell lac. The first is the lac in pretty
considerable lumps, with much of the
woody parts of the branches on which it
is formed adhering to it. Seed lac is on-
ly the stick lac broke into small pieces,
garbled, and appearing in a granulated
form. Shell lac is the purified lac, by a
very simple process to be mentioned after-
ward.
    Many vague and unauthenticated re-
ports concerning lac have reached the pub-
lic; and though among the multiplicity
of accounts the true history of this sub-
stance has been nearly hit on, little credit
is given in Europe to any description of it
hitherto published. My observations, as
far as they go, are the result of what I have
seen, from the lac on the tree, the progress
of the insect now in my custody, and the
information of a gentleman residing at
Goalpara on the borders of Assam, who is
perfectly versant in the method of breed-
ing the insect, inviting it to the tree, col-
lecting the lac from the branches, and
forming it into shell lac, in which state
much of it is received from Assam, and ex-
ported to Europe for various great and
useful purposes. The tree on which this

fly most commonly generates is known in
Bengal by the name of the Biber tree, and
is a species of the Rhamnus. The fly is
nourished by the tree, and there deposits
its eggs, which nature has provided it with
the means of defending from external in-
jury by a collection of this lac, evidently
serving the two-fold purpose of a nidus
and covering to the ovum and insect in its
first stage, and food for the maggot in its
more advanced state. The lac is formed
into complete cells, finished with as much
regularity and art as a honey-comb, but
differently arranged. The flies are invited
to deposit their eggs on the branches of
the tree, by besmearing them with some of
the fresh lac steeped in water, which at-
tracts the fly, and gives a better and larger
crop.
    The lac is collected twice a year, in the
months of February and August.
    I have examined the egg of the fly with
a very good microscope; it is of a very 
pure red, perfectly transparent, except in
the centre, where there were evident marks
of the embryo forming, and opaque rami-
fications passing off from the body of it.
The egg is perfectly oval, and about the
size of an ant’s egg. The maggot is about
the one eighth of an inch long, formed of
many rings (ten or twelve) with a small
red head; when seen with a microscope,
the parts of the head were easily di-
stinguished, with small specks on the
breast, somewhat projecting, which seem-
ed to be the incipient formation of the feet.
This maggot is now in my custody, in the
form of a nymph or chrysalis, its annular
coat forming a strong covering, from which
it should issue forth a fly. I have never
seen the fly, and cannot therefore describe
it more fully, or determine its genus and
species. The gentleman to whom I owe
part of my information terms the lac the
excrement of the insect. On a more mi-
nute investigation, however, we may not
find it more so than the wax or honey of
the bee, or silk of the silk-worm. Nature
has provided most insects with the means
of secreting a substance which generally
answers the twofold purpose of defending
the embryo, and supplying nourishment to
the insect from the time of its animation
till able to wander abroad in quest of
food. The fresh lac contains within its 
cells a liquid, sweetish to the taste, and of
a fine red colour, miscible in water. The
natives of Assam use it as a dye, and
cotton dipped in this liquid makes after-
ward a very food red ink.
    The simple operation of purifying lac is
practiced as follows. It is broken into
small pieces, and picked from the branches
and sticks, when it is put into a sort of

canvas bag of about four feet long, and
not above six inches in circumference.
two of these bags are in constant use, and
each of them held by two men. The bag
is placed over a fire, and frequently turned
till the lac is liquid enough to pass through
its pores, when it is taken off the fire, and
squeezed by two men in different directi-
ons, dragging it along the convex part of
a plantain tree prepared for the pur-
pose; while this is doing, the other bag is
heating, to be treated in the same way. The
mucilaginous and smooth surface of the
plantain-tree seems peculiarly well adapt-
ed for preventing the adhesion of the heat-
ed lac, and giving it the form which en-
hances its value so much. The degree of
pressure on the plantain tree regulates the
thickness of the shell, and the quality of
the bag determines its fineness and trans-
parency. They have learned of late, that
the lac which is thicker in the shell than
it used to be, is most prized in Europe.
Assam furnishes us with the greatest quan-
tity of lac in use; and it may not be gene-
rally known, that the tree on which they
produce the best and largest quantity of
lac is not uncommon in Bengal, and might
be employed in propagating the fly, and
cultivating the lac, to great advantage.
The small quantity of lac collected in these
provinces afford a precarious and uncertain
crop, because not attended to. Some at-
tention at particular seasons is necessary to
invite the fly to the tree; and collecting
the whole of the lac with too great an avi-
dity, where the insect is not very general-
ly to be met with, may annihilate the
Breed.
    The best method of cultivating the tree,
and preserving the insect, being properly
understood in Bengal, would secure to the
Company’s possessions the benefit arising
from the sale of a lucrative article, in great
demand and of extensive use.