From the Journal of Science.
ANTISEPTIC POWER OF THE PYROLIGNEOUS ACID.
Results of some experiments made by Mr. W. Ramsay.—
A number of herrings were cleaned on the 10th of July, 1819; and without being salted, were immersed for three hours in distilled pyroligneous acid, specified gravity 1012. When withdrawn they were softened and not so firm as fish taken out of common pickle. They were hung up in the shade; July and August were hot months, but the herrings had no signs of putrefaction about them, but had a very wholesome smell, combined with that of the acid. One being broiled the empyreumatic smell was very strong. The rest, after six months, were in complete preservation.
It was afterwards found that the period of immersion had been too long. If the fish are simply dipped in acid of specific gravity 1012, and dried in the shade, it is sufficient for their preservation; and such herrings, when boiled, are very agreeable and have not the disagreeable empyreuma of the former.
A number of haddocks were cleaned, split, and slightly sprinkled with salt for six hours; then being drained, dipped for about three seconds in pyroligneous acid, and hung in the shade for eight days. On being broiled, they were of an uncommonly fine flavour, delicately white, and equal to the highly esteemed Finnan Haddock.
Herrings were cured in the same way as the haddocks. After being dried in the shade for two months, they were equal in quality and flavour to the best red herrings. The fish retained the shining and fresh appearance they had when taken from the sea.
A piece of fresh beef was dipped for one minute in pyroligneous acid of specific gravity 1012, in July 1819. On March 4, 1820, it was as free from taint as when first immersed. No salt was used in this experiment. A piece of beef was dipped in at the same time in pure vinegar, of specific gravity 1009. It was perfectly free from taint on the 18th of November. This experiment indicates antiseptic powers in pure vinegar; some haddocks were cured with it, which remained free from taint, but when cooked had an insipid taste.
When beef is partially salted, and then steeped for a short time in the pyroligneous acid, after being drained and cooked, it has the same flavor as Hamburg beef.
Mr. Ramsay has no doubt, that with proper modifications, the use of the acid may be extended to the preservation of every species of animal food.