IMPROVEMENTS IN THE PRESERVATION OF ANIMAL SUBSTANCES, SUCH IMPROVEMENTS BEING ESPECIALLY USEFUL WHEN THESE SUBSTANCES ARE INTENDED FOR USE AS FOOD
Year: 1865

page_text: LETTERS PATENT to Theophilus [Redwood, of No. 19, Montague Street,
Russell Square, in the County of Middlesex, for the Invention of
SHOW TRATT
Sealed the 1st May 1866, and dated the 23rd November 1865.
PROVISIONAL SPECIFICATION left by the said Theophilus 'Redwood
at the Office of the Commissioners of Patents, with his Petition, on
the 23rd November 1865.
I, THEOPHILUS REDWOOD, of No. 19, Montague Street, Russell Square,
in the County of Middlesex, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE PRESERVATION OF ANIMAL SUBSTANCES, SUCH
IMPROVEMENTS BEING ESPECIALLY USEFUL WHEN THESE SUBSTANCES ARE INTENDED
FOR USE AS FOOD," to be as follows:-
The object of my Invention is to provide for the prevention of putrefaction
decomposition and other changes which render animal substances unfit for use
as food. It is well known that these changes may be prevented by excluding
atmospheric air or gases containing uncombined oxygen from contact with
animal matter after it has been exposed to a temperature of about 212°
Fahr.

page_text: And my Invention consists in my improved method and means of accom-
plishing the object aforesaid. I effect the preservation of meat by immersing
it for some time in a substance kept liquid by heat, which substance exerts no
injurious effect on the meat, but affords the means of heating it to 212°
Fahr. or higher, and at the same time causes the expulsion or exclusion of
air from it; and as this liquid becomes a tenacious solid on cooling the meat
after having been heated in it to a sufficient extent on being taken out carries
a film of the liquid over its surface, which forms a solid coating that con-
tinues to exclude the air. This coating in which the meat is hermetically
sealed may be increased in thickness to any required extent by repeatedly
dipping the meat into the hot liquid, and allowing each successive layer of
liquid to be congealed by exposure to the air or otherwise. The substance
which I have found most successfully to fulfil this object is paraffin, but wax,
spermaceti, or stearic acid, used separately or added to paraffin, or a mixture
of any or either of these substances in the proportions of, say, five or ten
per cent. (but I do not confine myself to such proportions) may be employed,.
although not so advantageously as paraffin alone. When fresh meat is
operated upon the juices are concentrated during the immersion of the
meat in the hot paraffin by the evaporation of water, and this may be carried
to any required extent, so that the meat may be thus condensed, and, if
desired, it may be rendered hard and dry. In conducting this part of the
process I keep the paraffin at a temperature between 212° and 250° Fahr.,
by which means a more or less rapid evaporation and concentration of the
juices are effected. The meat is afterwards cooled by exposure to the air or
by transferring the meat to a part of the vessel in which the process is per-
formed where the temperature is sufficiently low to cool the meat, so that on
afterwards passing it through or putting it into the liquid paraffin some of the
latter will be congealed on its surface, or will congeal when brought into
contact with the air. The cooling of the meat for this purpose may be
advantageous effected by immersing it in a cold saline solution, consisting of
one pound of common salt and one ounce of nitre to a gallon of water, such
solution being contained in the lower part of the vessel containing the melted
paraffin, and forming a stratum beneath the latter. The coating of paraffin
first formed over the surface of the meat may be increased in thickness by
repeatedly dipping the coated meat into liquid paraffin at a temperature a
few degrees above its melting point, and allowing each successive layer to
harden by exposure to the air. The meat may also be further protected after
having been thus coated by putting it into a suitable vessel or receptacle,
and then pouring melted paraffin over it so as to envelope the meat.

page_text: In preserving bacon and other meat that has been previously partially pre-
served by salting, spicing, or other similar means, it is not always necessary
to use the melted paraffin at so high a temperature as is required for fresh
meat. Thus I preserve bacon and hams by immersing them in melted
paraffin at a temperature of about 180° Fahr. for ten or fifteen minutes, and
then coating them with the paraffin by repeated dippings as already
described. In this way the meat is rendered fit for exportation to distant
countries or to be kept for lengthened periods. In the preservation of salted
tongues, however, I prefer before coating them to apply the full temperature
of 212° Fahr. and to keep them immersed in the hot paraffin until every part
has attained this temperature. Potted meats may be advantageously pre-
served by substituting paraffin for the fat hitherto used for excluding air, and
in this case I prefer to coat the inner surface of the pot or vessel containing
the meat with paraffin as well as to cover the surface of the meat with it.
This is easily effected by pouring melted paraffin into the cold and empty
pot, leaving it there for a few seconds or until a sufficiently thick coating has
been formed on the inner surface of the pot and then pouring out the
remainder of the paraffin. The prepared meat is then introduced into the pot
and melted paraffin poured over its surface. The meat is thus enclosed on
every side"
eby the paraffin, in which it is thus hermetically sealed. Butter
may be preserved in this way by substituting it for the prepared meat. I
effect the preservation of eggs by immersing them in melted paraffin at a
temperature of 150° Fahr. for about five minutes, and then immediately
allowing them to fall through a cold solution of common salt in water, the
density of such solution being nearly the same, but rather less than that of
the eggs.
In the first part of this operation air is expelled from the eggs and
escapes in small bubbles from the surface of the shells, and in the second part
of the operation the film of melted paraffin that adheres to the outer surface
of the eggs when they are removed from the melted paraffin, is quickly
congealed in the cold solution so as to form a smooth coating of uniform
thickness, and this prevents the absorption of air and consequent decomposi-
tion. I effect the preservation of cheese by immersing it in the melted
paraffin at about 180° Fahr., thus causing the formation of a coating of
paraffin that will exclude the air. Articles other than those specifically
referred to herein would be similarly treated according to their nature, the
object being to apply the preservative material in such manner as to effect the
exclusion of air from the substances to be preserved.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Theophilus Redwood in the Great Seal Patent Office on
the 23rd May 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THEOPHILUS
REDWOOD, of No. 19, Montague Street, Russell Square, in the County of
Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-third day of November, in the year of our
Lord One thousand eight hundred and sixty-five, in the twenty-ninth year
of Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Theophilus Redwood, Her special licence that I, the said
Theophilus Redwood, my executors, administrators, and assigns, or such others
as I, the said Theophilus Redwood, my executors, administrators, and
assigns, should at any time agree with, and no others, from time to time and
at all times thereafter during the term therein expressed, should and lawfully
might make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN THE PRESERVATION OF ANIMAL SUBSTANCES, SUCH IMPROVEMENTS
BEING ESPECIALLY USEFUL WHEN THESE SUBSTANCES ARE INTENDED FOR USE AS FOOD,"
upon the condition (amongst others) that I, the said Theophilus Redwood, my
executors or administrators, by an instrument in writing under my, or
their, or one of their hands and seals, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was to be
performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date of
the said Letters Patent.
NOW KNOW YE, that I, the said Theophilus Redwood, do hereby
declare the nature of the said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say :-
I have already in the Specification of a Patent granted to me on the 10th
of November 1865 (No. 2892), for improvements in the preservation of
meat and the concentration of its juices, described a method of preserving
meat by immersing it in melted paraffin or other substance so as to expel air
and to raise the temperature of the meat to 100° Centigrade or higher, and
by afterwards coating it with the same or a like substance, so as to exclude
air from contact with the meat; and my present Invention applies to certain
modifications of the methods therein specified for so preserving meat, and to

page_text: other applications of paraffin besides those described in the aforesaid Specifica-
tion. In preserving fresh meat after having immersed it in the melted paraffin
at a temperature above 100° Centigrade for a sufficient length of time, as
described in the previous Specification, I sometimes find it advantageous to
cool the meat to a temperature at which it can be coated with paraffin by
immersing it in a cold saline solution, made by dissolving one part of nitre
and sixteen parts of common salt in one hundred and sixty parts of water.
This solution before using it should be boiled beneath the surface of melted
paraffin so as to expel air and destroy the germs of animal or vegetable life,
and it should then be cooled without allowing air to come into contact with
it, which may be effected by means of a vessel with coils of pipe round its
inner surface through which steam or water may be made to pass. The saline
solution being contained in this vessel with a stratum of melted paraffin over
its surface, steam under pressure may be made to pass through coils of pipe
in contact with the solution so as to make it boil, and when the ebullition
has been maintained for about an hour, the steam is to be shut off and cold
water made to circulate through the pipes so as to cool the solution, while at
the same time the paraffin which floats on the surface of the solution is kept
fluid by steam or hot water circulating through pipes in contact with it. In
this way the lower part of the saline solution may be kept cold, while the
stratum of paraffin above it remains fluid and may be kept at a suitable
temperature (about 60° Centigrade) for coating the meat. In conducting the
process the meat is first immersed in hot paraffin contained in a suitable vessel
as described in my previous Specification, and after being heated there for a
sufficient length of time it is transferred to the vessel containing the saline
solution, and allowed to cool in contact with the cold solution. It is then
passed through the stratum of paraffin above, and coated by repeatedly dipping
it into the melted paraffin. I sometimes replace the coating of paraffin thus
formed after allowing it to remain on for a week or two, by immersing the coated
meat in melted paraffin at a temperature of about 60° or 70° Centigrade, leaving
it in the melted paraffin for about half an hour and then coating it again. By
this means a better and more adherent coating is obtained. If the meat is
intended for long keeping or for a hot climate, this re-coating may be preceded
by an immersion in melted paraffin at about 100° Centigrade for half an hour or
an hour. In preserving bacon and other meat that has been previously partially
preserved by salting, spicing, or other similar means it is not always necessary
to use the melted paraffin at so high a temperature as is required for fresh
meat. Thus I preserve bacon and hams by immersing them in melted
paraffin at a temperature of about 82° Centigrade for ten or fifteen minutes,

page_text: and then coating them with paraffin by dipping as previously described. In
this way the meat is rendered fit for exportation to distant countries or to be
kept for lengthened periods. Potted meats may be advantageously preserved
by substituting paraffin for the fat hitherto used for excluding air, and in this
case I prefer to coat the inner surface of the pot or vessel containing the meat
with paraffin as well as to cover the surface of the meat with it. This is
easily effected by pouring melted paraffin into the cold and empty pot, leaving
it therefore a few seconds or until a sufficiently thick coating has been formed
on the inner surface of the pot, and then pouring out the remainder of the
paraffin. The prepared meat is then introduced into the pot and melted
paraffin poured over its surface. The meat is in this way enclosed on every
side by the paraffin in which it is thus hermetically sealed. Butter may be
preserved in the same or a similar way by substituting it for the prepared meat.
I effect the preservation of eggs by immersing them in melted paraffin at a
temperature of 65° Centigrade for five or ten minutes, and then immediately
plunging them into cold water or a cold solution of common salt in water, the
density of such solution being nearly the same but rather less than that of
the eggs.
In the first part of this operation air is expelled from the eggs and escapes
in small bubbles from the surface of the shells, and in the second part of the
operation the film of melted paraffin that adheres to the outer surface of the
eggs when they are removed from the melted paraffin is quickly congealed so
as to form a smooth coating of uniform thickness, and this prevents the
absorption of air and consequent decomposition. I effect the preservation of
cheese by immersing it in the melted paraffin at about 80° Centigrade, thus
causing the formation of a coating of paraffin that will exclude the air.
Articles other than those specifically referred to herein would be similarly
treated according to their nature, the object being to apply the preservative
material in such manner as to effect the exclusion of air from the substances
to be preserved.
In witness whereof, I, the said Theophilus Redwood, have hereunto
set my hand and seal, this Nineteenth day of May, in the year of our
Lord One thousand eight hundred and sixty-six.
T. REDWOOD. (L.S.)