Since 1874, when Professor Kolbe, of Leipsic, first published his
results on the antiseptic action of salicylic acid, he has made many
efforts to apply this acid to the preservation of meat, but he has
invariably found that after the lapse of a few days an unpleasant flavor
has been developed, which is not that of putridity. If putrid changes be
noticed, it is a sign that salicylic acid is in insufficient quantity,
for where it has turned putrid the meat is found to be no longer acid,
but alkaline. This leads to the assumption that meat is protected from
change by acids, even by gases of that kind; and in fact it was noticed
that beef--from 2 to 5 kilos. being taken--when placed in an earthen
vessel and loosely covered with a wooden cover, was long preserved from
putridity if the bottom of the vessel contained some hydrochloric acid,
nitric acid, or aqueous sulphurous acid. The meat, however, no longer
had the taste of fresh meat, but of such as had long lain in ice.
Experiments were therefore made with carbonic acid, and these proved
highly successful. The meat was placed in a cylinder of metal plate, and
suspended from a rod which crossed the upper part and the lower part.
A small tube serves to admit a current of carbonic acid from a Kipp's
apparatus. The lid, which rested in a circular trough of glycerine,
was traversed by a similar tube in its center, and both tubes could be
closed with India-rubber tubing and screw taps as soon as sufficient
carbonic acid gas had traversed the apparatus. At the end of seven,
fourteen, and twenty-one days it was found that the meat was still quite
good, and the soup prepared from it was in every respect excellent. At
the end of the fourth or fifth week the meat thus preserved in the gas
was still quite free from all putridity; but the broth prepared from it
no longer tasted so well as fresh bouillon. The experiments were not
extended over a longer time. Carbonic acid is thus shown to be an
excellent means of preserving beef from putridity and of causing it to
retain its good taste for several weeks. Mutton does not preserve so
well. In eight days it had become putrid; and veal is by no means so
well preserved as beef. The comportment of beef in an atmosphere of
carbonic acid, to which carbonic oxide has been added, is curious. A
number of cylinders were filled in the usual way with such a mixture and
opened at the end of two or three weeks; in each case the flesh had the
smell and taste of good, pure meat, but it was not of the gray color
which meat preserved in carbonic acid gas gradually takes, but appeared
in the interior, as well as on the outside, of a bright flesh-red color,
and on the surface here and there, there were white round masses of
fungoid growth of the size of a 20-pfenning piece, which were removed
with the slightest rubbing. The flesh lying just below these was found
to have the same bright red color as that already described. Meat which
had been for three weeks in such a gas mixture gave a broth which,
in good taste and freshness, could hardly be distinguished from
freshly-made bouillon; and the boiled meats could not be distinguished
either in appearance or taste. The property of carbonic acid to preserve
meat suggests a use for the large supplies of this gas evolved from the
earth in many localities. And it is as interesting to determine in
how far the gas could be of service as an antiseptic during surgical
operations.
* * * * *