Evening star. [volume] (Washington, D.C.) 1854-1972, 1907-07-13
THE MAKINGS OF GLUE.
Not Definite Organic Substance, But
Product of Transformations.


Glue Is not definite. positive. organic
substance, as most people suppose. Chem
lists tell us that glue does not pre-exst in
any animal organism except under abnor-
NAL condtions-as In disease-but is the
product of several transformations
The first transformation takes place in
drying the hide. If green hide Is boiled
after being prepared in exactly the same
manner by lining, etc. while it is yet
green. an entirely different product of less
consistency Is secured than by drying the
hide after lining and then boiling
The second transformation seems to take
place in boiling the material. probably from
action of the heat. The third TRANSFORMED
ton occurs in the drying of the jelly Sc
cured in the boiling operation.
Still another transformation occurs In
the drying of this jelly into actual glue,
and this series of changes does not end
here. for glue dissolved in water and again
boiled sufficiently long loses it's form once
more and will not gelatinize, but will re-
main in liquid form.
Glue-yielding substances are produced by
the animal economy from protene bodies
albumen. tbrine and caseine. The impossi-
bility of preserving for any length of time
the stock from which glue Is made renders
1t necessary to adopt some system in choos-
ing and preserving 1t until sufficient guam
titles are collected without fermentation or
neries consisting of the clippings of hides
and tail pieces of OK, calf and sheep
and from skins of other animals are pre-
ferred. because they can be dressed with
lime. which removes the hair and acts as
an antiSeptic.
The ordinary bone stock glue is made
from the larger bones of cattle and horn
piths. collected from different sources A
large quantity of waste bones is accumu-
lated in the preparation of timed provi-
sions.
If these have not been overheated and
are in good condition conSidera BILE amount
of glue be obtained from them. The
bones from the head, ribs and feet give
better yield than those of the thighs and
legs.
There is also the hoof glue, which is made
from the hoofs of different animals. Then
there is glue made from sinews and flesh
glue made from the skins Of hares and
rabbits. This glue makes a good water
test but should never be rsed to cement
belt. There Is large quantity of this
glue made in this country, and person not
very familiar with it could easily be de-
ceived.
The age of animals yielding glue stock
has an important influence on the product.
While from younger animals the produc-
ton. as a rule. IS OF lighter color more
abundant and more easily obtained it con-
talns more chondrin. that for solutions of
equal strength those from mature animals
will be found to be of the greater consist
ency and the glue more solid.
Then. again. there is what is known as
the pig stock glue. which Is made from the
feet of hogs. Next comes the fish glue or
isinglass. Its varieties are numerous and
a thorough knowledge of them can only be
obtained when one is personally acquainted
with the different factories and stock from
which they are made.
The best OF this material. however, is
made from the sounds air bladders of
the different species of fish. The air blad-
ders of the common sturgeon and other fish
caught in northerly climates make the best.