Improvements in Lyes or Liquors for Preparing Hides for Tanning.
Year: 1895

page_text: Date of Application, 15th Nov., 1805
Complete Specification Left, 13th Aug., 1896-Accepted, 10th Oct., 1896 -
Complete Specification Left, 13th Aug., 1896-Accepted, 10th Oct.,
1896
'
PROVISIONAL SPECIFICATION.
[Communicated from abroad by THE CHEMISCHTECHNISCHES UND HYGIE-
NISCHES INSTITUT, Dr. POPP & Dr. BECKER, of Frankfurt af Main, in
the Empire of Germany.]
Improvements in Lyes or Liquors for Preparing Hides for Tanning.
I, CHARLES DENTON ABEL, of No. 28 Southampton Buildings, Chancery
Lane, in the County of London, Consulting Engineer and Chartered Patent
Agent, do bereby declare the nature of this invention to be as follows:-
An important role in the process of manufacture of many kinds of leather is
played by the dung liquor or lye, which, in particular for calf skin, constitutes
one of the necessary preparatory operations for the subsequent actual tanning
process, and which has for its purpose, to bring the skins that have been previously.
Ewelled by the liming process into a condition which allows of the ready removal
therefrom of the lime and lime soap as also the remaining hairs, by the subsequent
mechanical treatments, and to obtain a uniform shrinking of the swelled hides.
The process consists in treating the hides for some time (sometimes 4 or 5 hours)
in a vat provided with a reel and containing a lye formed of solutions of dog or
pigeon or poultry dung,
Generally speaking, the dog dung acts best, and pigeon or poultry dung also in
certain cases, but no satisfactory and sound explanation has as yet been given as
to the kind of action obtained.
My correspondents have in the first place discovered that the action of these
lyes is the result of bacteriological processes, and certainly not, as has been very
generally assumed, of the action of phosphoric acid.
The examination of the dog, pigeon and poultry dung in bacteriological respect,
and of the industrial applicability of all the different results obtained, shows in
the first instance that even after removal of all other constituents which, according
to existing views, entered into reaction, the result of the treatment remains the
Báme. The continued research gave the second result that a great number of
micro-organisms play a role in the lye, partially advantageous, and partly
detrimental.
Generally speaking, the non-peptonising bacteria act advantageously, while the
peptonising ones generally have a detrimental effect. In connection herewith two
methods of utilising these discoveries have presented themselves.
One can either, according to the methods of bacteriology (plate process &c.)
remove all the detrimental or even the less useful bacteria, and effect the treatment
of the hides by means of a pure culture, or at least by a mixture of the most
effective bacteria; or, without employing such a refinement of the process, but with
utilisation of the said discoveries, the dog dung, and in particular the white
descriptions which are most effective, or for certain kinds of leather, the pigeon or
poultry dung, are subjected to a certain treatment, which by the use of a suitable
breeding bed, will develop the useful bacteria while on the other hand. by the
addition of materials for hindering development, the increase of the detrimental
bacteria can be prevented or retarded.
In every case, the employment of the process afford's greater rapidity of

page_text: '
execution, and more reliable and better results than the process heretofore
employed.
The leathers obtained are tough and yet softer, and in any case any discoloration
thereof, such as is often unavoidable with dog dung, is avoided.
An advantage not to be underrated with the use of germ cultures, is that liquore
having a definite percentage of really effective substance can be prepared,
whereas it was heretofore necessary to proceed by way of trials, the result being
subject to great uncertainty.
In addition, the dung liquors are subject to change overnight on the occurrence
of atmospheric changes (thunderstorms) in a most unaccountable manner, owing,
as has now been discovered by my correspondents to the detrimental bacteria
'which are mixed with the effective ones, and which gain the upper hand over the
former under the change of atmospheric conditions.
The features of the newly discovered useful bacteria are fully described in the
following, and experiments have shewn that in particular those kinds designated
with 3, 7, and 12 are the ones which are of the greatest importance for the purpose
in question; and in particular No. 12 is the most effective, and 3 the least effective
of these three descriptions.
All three are bacteria of dog dung, and bacteria No. 3 consist of very small rods
rounded at the ends which are exceedingly mobile, while bacteria No. 7 which are
similar to the hay bacillus are slowly moving rods, and bacteria No. 12 åre medium
sized rods having lively motion.
The prick-culture gives with bacteria No. 3 a very good growth in the depth;
from the inoculating prick extend laterally many arms into the gelatine. At the
ends of the arms are formed small knots. On the surface is formed a thin white
covering. The gelatine is not liquefied.
On gelatine plates, the deep seated colonies consist of pale yellow round discs,
which gradually penetrate to the surface and there form circular discs which
shew at the contre larger spots. On inclined' Agar-Agar there is formed a white
superstratum.
With bacteria No. 7 the gelatine is strongly liquefied in the prick-culture. On
the surface of the zone of liquefaction there is formed a white skin.
Along the liquefied prick are formed radiations into the solid gelatine. On
gelatine plates there are formed rapidly liquefying colonies forming at top a
white skin.
Agar-Agar gives a white unequal thin super stratum with branchings.
Bacteria No. 12, lastly, grow with prick-culture equally well along the prick,
the gelatine is not liquefied. On the surface there is formed a thin shining
covering.
On gelatine plates the deep lying colonies consist of pale yellow circular discs.
Many colonies bave tails similar to the surface colonies of the proteus. During
the growth of this bacterium on gelatine-plates a strong putrid smell is developed.
On Agar-Agar this bacterium forms a strong white shining superstratum.
We have furthermore discovered that a very suitable breeding-bed for these
"bacteria can be obtained by boiling down the flesh particles from the flesh sides
of the hides, which otherwise form a waste product of little or no value.
For this purpose a vessel provided with a cover is charged with equal parts of
waste flesh such as is obtained in the tannery, and water, and this is boiled for
about half an hour by the direct introduction of steam, after which concentrated
carbonate of soda solution is introduced until the reaction is slightly alkaline, after
which the decoction is cooled down. As soon as the temperature has sunk to
about 35° C. there is added the pure culture obtained by the gelatine plate process
(with dilution) described in the works on bacteriology of Koch, Fraenkel, Hüppe,
and others, and also by the further treatment corresponding to the characteristic
peculiarities of the bacteria, and the whole is allowed to stand covered up for
a period of from 12 to 24 hours, depending on the time of year and the
temperature.
1...
"
!

page_text: The hides are then dipped into the concentrated decoction for a short time,
according to the state of development of the bacteria; or the decoction can, be
diluted and the hides be then immersed therein for a greater length of time.
The farther treatment is then carried out in exactly the same way as though
the hides had been treated in dog dung lye, with. the exception that the duration
is shorter. Bran and similar materials also offer a good breeding bed; on account,
however, of the peculiar technical conditions, the described process with waste flesh
is preferable.
In case the pure culture of the bacteria is to be dispensed with, and it is only
desired to obtain an advantage over the existing methods in so far as to obtain,
on the one hand, an artificial increase of ooze-medium existing in the dog dung by
providing a suitable breeding bed, and on the other hand to be in a position to
limit oneself to the best initial material, the process can be carried on by starting
with a practically proved dog dung, therefore in particular the white kinds, and
the bacteria are caused to propagate in a decoction such as above described.
Afterwards it is advantageous to effect the killing of the detrimental bacteria
by a small addition of acid, such as 5 p.c. of dilute sulphuric acid
equivalent materials, as in this case the useful bacteria are also the most
enduring.
or
The more useful bacteria shew, in particular in the presence of alkalies, the
same behaviour.
.
For example, the more useful bacteria arrive at development equally with the
detrimental ones if to the described culture bed be added 0.5 p.c. of carbonate of
soda, while the useful bacteria preponderate to a considerable extent, and the
detrimental ones are practically unimportant, if the addition of carbonate of soda
be raised to about one per cent.
In order to obtain a product which shall both be durable and capable of being
delivered in definite doses, eterilised bran, flour, &c. can be inoculated with definite
quantities of the pure cultures, and the percentage of water be reduced, by drying,
pressing &c. to under a certain percentage (10 to 12 p.c.) which will not allow of
or will retard the evolution of germs.
Dated this 15th day of November 1895.
ABEL & IMKAI,
Agents for the Applicant.'
COMPLETE SPECIFICATION.
Improvements in Lyes or Liquors for Preparing Hides for Tanning.
1 CHARLES DENTON ABEL of No. 28 Southampton Buildings Chancery Lane
in the County of London Consulting Engineer and Chartered Patent Agent do
hereby declare the nature of this invention and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement:-
P
An important role in the process of manufacture of many kinds of leather is
played by the dung liquor or lye, which in particular for calf skins and skivers
constitutes one of the necessary preparatory operations for the subsequent actual
tanning process, and which has for its purpose, to bring the skins or hides, which
have been previously swelled by the liming process, into a condition which allows
the easy and thorough removal of the lime and lime soap as well as the remaining
hairs by the subsequent mechanical treatment and to obtain a uniform shrinking of
the swelled hides.
The process hitherto employed consists in treating the hides or skins for, some
time (such as for 4 or 5 hours) in a vat provided with a reel and containing miye
or brine formed of solutions of dog or pigeon or poultry dung.

page_text: Generally speaking, the dog dung acts best, in some cases and pigeon or poultry
dung in other cases, but no satisfactory and sound explanation has as yet been
given as to the nature of the action.
My correspondents have in the first place ascertained that the action of these
lyes or brines is the result of bacteriological processes, especially of the products
created by the action of certain bacteria, and is certainly not, as it has hitherto
been generally assumed, the result of the action of phosphoric acid or other acids.
The examination of the dog, pigeon and poultry dung in bacteriological respect
and of the industrial applicability of all the different results obtained, shows in the
first instance that, even after removal of all other ingredients which, according to
the hitherto ruling views, enter into reaction, the result of the treatment remains
the same, as it had been before the removal. The continued research led to the
second result that a great number of micro-organisms play a role in the lye
partially an advantageous, and partially a detrimental onc.
$
Generally speaking, the non-peptonising bacteria act advantageously, while the
peptonising ones generally have a detrimental effect. In connection herewith two
methods of utilizing these discoveries have been found.
One can either, according to the methods of bacteriology (plate process), remove
all the detrimental or even the less useful bacteria, and effect the treatment of the
hide or skins by applying a pure culture of one or at least a mixture of the
different most effective bacteria; or one can without employing such a refined
process, but still utilizing the said discoveries, apply the dog dung, and in
particular the white descriptions which are most effective, or for certain kinds of
leather, the pigeon or poultry dung, subjecting the said dungs to a certain
treatment, which by the use of a suitable cultivating bed, will develop the useful
bacteria, while on the other hand the increase of detrimental bacteria, may be
prevented or retarded by the addition of materials hindering the development of
the latter.
In every case, the employment of the process secures greater rapidity of
execution, and more reliable and better results than the process beretofore applied.
The leathers obtained are tough and yet softer, and in any case any discoloring,
such as is often unavoidable with dog dung, islavoided.
An advantage not to be underrated with the use of germ cultures, is that liquors
or cakes having a definite percentage of really effective substance can be prepared,
whereas it was heretofore necessary to proceed by way of trials, the result being
subject to great uncertainty.
In addition, the dung liquors are subject to changes overnight under the
influence of atmospheric changes (thunderstorms) in a most unaccountable manner,
owing, as has now been discovered by my correspondents to the growth of
⚫ detrimental bacteria which are mixed with the effective ones, and which gain the
upper hand over the latter under the change of atmospheric conditions.
The features of the newly discovered useful bacteria are fully described in the
following, and experiments have shown that the particular kinds designed with 3, 7
and 12 in the table of bacteria set forth in the Specification to German Patent
No. 86335 and hereinafter fully described are those which are of value for the
purpose in question, in particular No. 12 is the most effective, and 3 the least
effective of these three descriptions.
All three are bacteria to be found in the dog dung and bacteria No. 3 consists
of very small rods rounded at the ends and are exceedingly mobile while bacteria
No. 7 which are similar to the hay bacillus are slowly moving rods, and bacteria
No. 12 are medium sized rods having rapid motion.
'
The prick-culture gives with bacteria No. 3 a very good growth in the depth;
from the inoculating prick extend laterally many arms into the gelatine., At the
ends of the arms are formed small knots. On the surface is formed a thin white
covering. The gelatine is not liquefied.
་་
Ou gelatine plates, the deep seated colonies consist of pale yellow round discs,
which gradually penetrate to the surface and there they form circular discs which

page_text: snow at the centre larger spots: Un inclined Agar-Agar there is formed & white
superstratum.
With bacteria No. 7 the gelatiue is strongly liquefied in the prick-culture. On
the surface of the zone of liquefaction there is formed'a white skin.
Along the liquefied prick are formed radiations into the solid gelatine. On
gelatine plates there are formed rapidly liquefying colonies forming at top a white
skin. Agar-Agar gives a white unequal thin super stratum with branchings.
Bacteria No. 12 grow with prick culture equally well along the prick, the
gelatine is not liquefied. On the surface there is formed a thin shining covering.
On gelatine plates the deep lying colonies consist of pale yellow circular discs.
Many colonies have tails similar to the surface colonies of the proteus. During
the growth of this bacterium on gelatine-plates a strong putrid smell is developed.
On Agar-Agar this bacterium forms a strong white shining superstratum.
These bacteria grow easily in any decoction of meat, and the flesh particles from
the flesh sides of the hides, which otherwise form a waste product of little or no
value may be advantageously employed for this purpose; bran and other materials
known to offer good culture-beds may be employed instead.
For this purpose a vessel provided with a cover is charged with equal parts of
waste flesh such as is obtained in the tannery, and water, and this is boiled for
about half an hour by the direct introduction of steam, after which concentrated
carbonate of soda solution is introduced until the reaction is slightly alkaline, after
which the decoction is cooled down. As soon as the temperature has sunk to
about 35° C. there is added the pure culture obtained by the gelatine plate process
(with dilution) described in the works on bacteriology of Koch, Fraenkel, Happe
and others, and also by the further treatment corresponding to the characteristic
peculiarities of the bacteria, and the whole is allowed to stand covered up for a
period of from 12 hours to five days, depending on the time of year and the
temperature.
The hides or skins are then dipped into the concentrated decoction for a short
time, according to the state of development of the pacteria; or the decoction can
be diluted and the hides be then immersed therein for a greater length of time.
The farther treatment is then carried out in exactly the same way as though the
hides or skins had been treated in dog dung lye, with the exception that the
duration is shorter.
[
In caso the pure culture of the bacteria is to be dispensed with, and it is only
desired to obtain an advantage over the existing methods in so far as to obtain, on
the one hand, an artificial increase of the ooze medium vie. the number of useful
bacteria and their products existing in the dog dung by providing a suitable
culture bed, and on the other hand to be a position to limit oneself to the best
initial material, the process can be carried out by starting with a practically
proved dog dung, therefore in particular the while kinds, and the bacteria, are
caused to propagate in a decoction such as above described. Afterwards it is
advantageous to effect the killing of the detrimental bacteria by a small addition
of acid such as 0,5 p.c. of dilute sulphuric acid or equivalent materials, as in this
case the useful bacteria are also the most enduring.
The more useful bacteria shew, in particular in the presence of alkalies, the
same behaviour.
For example, the more useful bacterin arrive at development equally with the
detrimental ones if to the described culture bed be added 0,5 p.c. of carbonate of
Boda, while the useful bacteria preponderate to a considerable extent, and the
detrimental ones are practically unimportant, if the additions of carbonate of soda
be raised to about one per cent.
The pure cultures of the bacteria may be preserved in a suitable liquid or solid
material and brought on the market in a suitable packing.
Ju order to obtain a product which shall both be durable and capable, of being
delivered in definite doses, sterilised bran, flour etc., cau be inoculated with definite
quantities of the pure cultures, and the percentage of water be reduced, by drying,

page_text: pressing etc. to under a certain percentage (10 to 12 p.c.) which will not allow of
or will retard the evolution of germs.
The bacteria may also, after having been properly developed, especially after
having created a sufficient quantity of their products, be killed, for instance by
heating, and the resulting stuff be brought on the market in liquid or solid form as
an effectual lye or brine, it having been found that the liquids containing the said
bacteria do not lose their effect if they are sterilised and the bacteria thereby.
killed provided that a sufficient number of bacteria has been produced.
F
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The process for the production of a lye for treating hides or skins preparatory
to tanning, consisting in tlie propagation of the bacteria of dung in particular dog
and bird dung, by means of suitable culture beds substantially as described.
2. As a new article of manufacture a lye containing a pure culture of one or
more of the described bacteria.
3. In the process of producing a lye referred to in the first claim the elimination
of the detrimental agents substantially as described.
4. In the process referred to in the first claim the addition of acids or alkalies
for the purpose set forth and substantially as described.
5. The process for the production of a lye for treating hides consisting in the
separation from; the dung of the bacteria herein designated as 3, 7, and 12 pro-
ducing pure cultures thereof, and introducing the same into a decoction preferably
freed by boiling from other bacteria and containing a suitable culture bed
substantially as:described.
6. A process for the production of cakes for the treatment of hides consisting
in the inoculation of sterilised bran, flour etc., with cultures having a definite
percentage of bacteria, and the removal of the proportion of water that is
necessary for the development of the bacteria substantially as described.
7. As a new article of manufacture sterilised cakes containing a certain quantity
of the described bacteria substantially as described.
8. As a new article of manufacture the solid or liquid material containing the
products of the decomposition as generated by the pure cultures of the said bacteria
whether such material does or does not also contain the said bacteria either in 'the
active condition or killed by sterilisation substantially as described.'
Dated this 13th day of August 1896.
ABEL & IMRAY,
Agents for the Applicant..