of real acid, and will require at least one half part of water to reduce it to the strength of the best common distilled vinegar. It is found that acetic acid of 45 per cent. real acid, or of 95° of acetometer strength, dissolves Camphor and the Essential Oils very readily. The “ACIDUM ACETICUM FORTIUS,” which is now introduced into the Materia Medica of the London College, is directed to have a specific gravity of 1·046.[336] It is exactly six times the strength of Proof vinegar, or the strong Malt vinegar manufactured, but it requires to be diluted with nine times its weight of water to reduce it to the strength of the ordinary samples of distilled vinegar. Mr. Phillips states, that he has not met with acetic acid of greater specific gravity than 1·043,[337] being five times the strength of vinegar of specific gravity 1·009.[338] The strongest acid that can be procured is the _Glacial_ acid, which exists in a crystallized state under 50° _Fah._ It contains 79 per cent. of real acid, and is consequently of the strength of 167·5 of the Acetometer. If this acid be kept perfectly still, it may be reduced several degrees below its crystallizing point in a fluid state, when the slightest agitation of the vessel instantly occasions it to solidify. It will greatly facilitate our inquiries into the strength of different samples of acetic acid to know, that the representative numbers of acetic acid and pure white marble coincide on the scale of equivalents; it therefore follows that the weight of marble dissolved by a hundred grains of any acetic acid, will at once represent the percentage of real acid in such a sample. The Impure Pyroligneous acid, as it first comes over, contaminated with Tar, has, it is said, been very successfully employed as a lotion in Lepra, scrophulous ulcerations, chronic inflammation of the eyes, and edges of the eye-lids, and for promoting digestion of irritative ulcers, or those connected with carious bone. It has also been injected into sinuses to produce healthy discharge and adhesive inflammation.[339] M. Monge discovered that this acid has the property of preventing the decomposition of animal substances; it is sufficient to plunge meat for a few moments in this acid, even slightly empyreumatic, to preserve it as long as you please. “Putrefaction,” it is said, “not only stops but retrogrades.” To the empyreumatic oil a part of this effect has been ascribed, and hence has been explained the agency of wood smoke in the preservation of tongues, hams, herrings, &c. ACIDUM ACETOSUM FORTE, E. Acidum Aceticum. D. _Radical Vinegar._