The Cairo bulletin. (Cairo, Ill.) 1???-1928, 1907-11-15
THE MAKI.Is OF GLUE.
Not Definite Organic Substance, but
the Product OF Several.

|
Glue is not definite positive or
ganlc substance as most people sup
posc. Chemists tell us that glue
does not pre-exist In any animal or
ranism except under abnormal con-
ditions rs In dseasebut Is the
| product Of several transformations.
The first transformation takes
place IN drying the hide. Ii green
Eide Is boiled after being prepared In
Exactly the same manner by lining,
| eto while II Is vet green, an entirely
different product Of less consistency
Il secured than by drying tho hide
after lining and then boiling.
she second transformation seems
to take place in boiling the material.
probably from action OF the heat.
i The third Transformation occurs in
the drying Of the Jelly secured In the
| boiling operation.
| sim another transformation occurs
I 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
viii not gclatinize, but Will remain
In LIQUID form.
Glue Welding substances are pro-
duced by the animal economy from
proteine bodies, albumen, fibrine and
caeeine, The impossibity OF pre-
serving for any length of time the
stock from which glue Is made rend-
ers IT necessary to adopt some sys-
tenn IN choosing and preserving 1t
until sufilcient'quantities are collected
without fermentation or decomposi-
lion, Hence the refuse from tanner
les consisting of the clippings Of
hides. ear and tail pieces of OK, calf
and sheep. and from skins Of other
animals are preferred, because they
can be dressed with lime, which re-
moves the hair and acts as an anti
septic
The ordlntry bone stock glue Is
made from the larger homes of cat
tie and horn piths, collected from
different sources. A large quantity
Of waste bones is accumulated In
the preparation Of timed provisions
II these have not been overheated
and are in good condition a consider
able amount Of glue can 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 mado
from sinews and fleshings, and also
a grade known as rabbit glue made
from the skins OF hares and rabhia
This glue makes a good water test.
but should never be used to cement
a belt. There is a large quantity Of
this glue made in this country. and
a person not very familiar with it
could easily be deceived.
The age Of animals yielding glue
stock has an important influence on
the product While from younger
animals the production. as rule,
Is of lighter color, more abundant.
end more easily obtained 1t contains
more chondrin. so that for solutions
Of equal strength those from mature
will be found to be of tho
greater consistency 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 It's
varieties are numerous, and a thor
ough knowledge of them can only he
obtained when one is personally ae--
quainted with the different factories
and stock from which they are ma Re.
The best of this material however.
Is made from the sounds or air bad
ders of the different species Of rsh.
The air bladders of the common
and other fish caught in
climates make the best.