Qualities. Form, a red crystalline cake, inodorous, insipid, and insoluble in water, alcohol, acids, and alkalies, although these bodies decompose it when melted with it; it is also decomposed by nitro-muriatic acid, which unites with the metal, and disengages the sulphur. Chemical Composition. It is a bi-sulphuret of Mercury, i. e. it consists of two proportionals of sulphur and one of mercury. Uses.[[533]] It is now only used for the purpose of mercurial fumigation, which is done by inhaling the fumes, produced by throwing ʒss of it on red hot iron; the effect which is generally produced is violent salivation; this however does not depend upon the action of the substance as a sulphuret, but upon its decomposition, and the volatilization of the metallic mercury with a portion of sulphate and sulphureous vapour. Mr. Pearson observes that it is useful in those cases of venereal ulcers in the mouth, throat, and nose, where it is an object to put a sudden stop to the progress of the disease, but that mercury must at the same time be introduced into the constitution, by inunction, just as much as if no fumigations had been made use of. Ulcers and excrescencies about the pudendum and anus in women are particularly benefitted by it; and in these cases it is conveniently applied by placing a red hot heater at the bottom of a night-stool pan, and after sprinkling on it a few grains of the sulphuret, placing the patient upon the stool. Adulterations. Red Lead[[534]] may be discovered by digesting it in acetic acid, and by adding sulphuret of ammonia, which will produce a black precipitate; or by burning a small portion of the suspected sample on a piece of bread in the candle, when metallic globules will announce its presence; for the oxide of mercury, although revived by this process, will at the same time be volatilized. The bread, by combustion, affords the carbon by which the metallic reduction is effected. Dragon’s Blood, by its giving a colour to alcohol when digested with it; Chalk, by its effervescence, on the addition of an acid. It is known in the arts under the name of Vermillion; and by the following simple expedient its presence may, in very minute quantities, be easily recognised; boil a portion with sulphuric acid in a platina spoon, and lay the sulphate thus produced, in a drop of muriatic acid, on a piece of gold, and bring a piece of metallic tin in contact with both, when the white mercurial stain will be produced.
HYDRARGYRI SULPHURETUM NIGRUM. L.E. Hydrargyrus cum Sulphure. P.L. 1787. Olim, Ethiop’s Mineral.
Qualities. Form, a very black, impalpable, insipid, and inodorous powder. Chemical Composition. It is a Sulphuret of Mercury, i. e. it consists of one proportional of sulphur, and one proportional of mercury; when heated in contact with the air it is converted into a bi-sulphuret. Solubility. It is entirely soluble in a solution of pure potass, from which the acids precipitate it unchanged; it is insoluble in nitric acid. Med. Uses. It is supposed to be alterative, and has been given for such a purpose, in doses from gr. v. to ʒss, but its medicinal virtues are very questionable. Adulterations. It is frequently imperfect, globules of mercury being still discoverable in it by a magnifying glass, or by its communicating a whiteness to a portion of gold upon which it is rubbed; ivory black may be discovered by the residue, after throwing a suspected sample on a red hot iron; it is also sometimes mixed with equal parts of crude antimony.
HYOSCYAMI FOLIA ET SEMINA. L.E.D.
(Hyoscyamus Niger.) Henbane.
Qualities. This plant, when recent, has a strong fetid, and narcotic odour; properties which are nearly lost by exsiccation. Chemical Composition. Resin, mucilage, extractive matter, gallic acid, and some salts; an alkaline element (Hyoscyama) is said to constitute its active principle. This principle differs from other vegetable alkalies, in being able to resist a low red heat, without undergoing decomposition. Solubility. Water freely extracts the narcotic powers of this plant, and decoction destroys them; diluted alcohol is the best menstruum. Incompatibles. Precipitates are produced by acetate of lead, nitrate of silver, and sulphate of iron; vegetable acids weaken its narcotic powers. The extract or inspissated juice is the best form in which it can be exhibited; see also the Tincture; its leaves form an anodyne cataplasm, and the smoke from its seeds, when applied by a funnel to a carious tooth, is recommended in severe fits of odontalgia. The root of this plant is poisonous.[[535]] In Dr. Molyneux’s appendix to Threlkeld’s “Synopsis Stirpium Hibernicarum” are related several cases of its effects on persons who had eaten them instead of Skirrets. Officinal Prep. Extract: Hyoscyam: Tinct: Hyoscyam: L.E.D.
ICHTHYOCOLLA.
(Acipenser Huso & Ruthenus. The great and small Sturgeon.)
Isinglass. Fish Glue.
The following kinds, imported from St. Petersburg, are found in the market. Short Staple; Long Staple; Book; and Leaf. Picking the Staple, as it is called, is a peculiar art practised by persons in this town, who gain a very good livelihood by it; they engage to return the same weight of isinglass in shreds, as they receive in Staple; this in itself secures very fair profit, for by damping the isinglass in order to pick it, it gains considerable weight; these persons moreover are in the habit of adulterating it with pieces of bladder, and the dried skin of soles; such frauds however are easily detected by their insolubility, for pure isinglass will dissolve entirely, and yield a clear and transparent jelly; a single grain will produce, with an ounce of water, a solution of considerable thickness; it is also soluble in acids and alkalies; and although insoluble in alcohol, yet it is not precipitated by it from its watery solutions, unless when added in a very considerable quantity; it is coagulated by the infusions and decoctions of vegetable astringents; carbonate of potass likewise throws down a precipitate. 100 parts of good isinglass consist of 98 of gelatine, and 2 of the phosphates of soda and lime. Its solutions soon putrefy. Uses. It is now rarely used except as a nutrient; its mechanical application in fining wines and turbid liquors is well known, and its mode of operation is equally obvious, for by forming a skin, or fine network, which gradually precipitates, it acts just like a filtre, with this difference, that in this case the filtre passes through the liquor, instead of the liquor through the filtre.