Cooley's Cyclopaedia of Practical Receipts Volume Ii Part 53

_Prop., &c._ A bright scarlet powder, insoluble in water, but soluble in alcohol and ether, and in the solutions of several of the iodides and chlorides. It is also soluble in cod-liver oil, and in several other fixed oils. Readily sublimed.--_Dose_, 1/16 to 1/4 gr., dissolved in alcohol or made into a pill; in the same cases as the subiodides, from which it differs chiefly in its greater energy and poisonous qualities.

=Mercuric Oleate.= See OINTMENT OF OLEATE OF MERCURY.

=Mercuric and Pota.s.sium Iodide.= HgI_{2}.KI. _Syn._ IODIDE OF MERCURY AND POTa.s.sIUM, IODO-HYDRARGYRATE OF POTa.s.sIUM; HYDRARGYRI ET POTa.s.sII IODIDUM, L. _Prep._ 1. (M. Boullay.) Mercuric iodide, pota.s.sium iodide, and water, equal parts; dissolve by heat, and crystallise by evaporation or refrigeration, or gently evaporate to dryness.

2. (Puche.) From mercuric iodide and pota.s.sium iodide, equal parts, triturated together.--_Dose_, 1/16 to 1/8 gr., dissolved in water; in the same cases as the biniodide, and in chronic bronchitis, hooping-cough, inflammatory sore throat, &c.

=Mercuric and Pota.s.sium Iodo-cy'anide.= _Syn._ HYDRARGYRI ET POTa.s.sII IODO-CYANIDUM, L. _Prep._ To a concentrated solution of mercuric cyanide add a rather strong solution of pota.s.sium iodide, and dry the precipitate by a gentle heat.

_Prop., &c._ Small, white, pearly, crystalline plates or scales. It is chiefly used as a test of the purity of hydrocyanic acid. When put into this liquid it is instantly turned red if any mineral acid is present.

=Mercuric Nitrate.= Hg(NO_{3})_{2}. _Syn._ PROTONITRATE OF MERCURY, PERNITRATE OF MERCURY. _Prep._ 1. (NEUTRAL.) This is obtained by solution of mercuric oxide, in excess of nitric acid. The solution, evaporated in a bell-jar over sulphuric acid, yields crystals which are neutral. The same compound is obtained as a crystalline powder when the syrupy liquid is dropped into strong nitric acid.

(Basic.) 1st. 2Hg(NO_{3})HO.H_{2}O. _Prep._ _a._ By saturating hot dilute nitric acid with mercuric oxide. The salt, which is bibasic, crystallises on cooling.

_b._ By dissolving mercury in excess of nitric acid, with heat, until the solution, when diluted with distilled water, ceases to give a precipitate with common salt. It is now a mixed solution of the neutral and bibasic pernitrates; but by evaporation crystals of the latter salt only are deposited. The acid solution (before evaporation) is used as a caustic in cancerous, syphilitic, and other ulcerations; but it frequently produces intense pain, and occasionally the usual const.i.tutional effects of mercury. It was formerly given in similar cases to those in which the bichloride is now employed.--_Dose_ (of the dry salt), 1/20 to 1/12 gr.

This is the preparation ordinarily referred to under the name 'pernitrate of mercury.'

2nd. 2Hg(NO_{3})HO.HgO. _c._ By saturating strong nitric acid with mercury, by heat, throwing the solution into cold water, and collecting and drying the precipitate. This salt, which is tribasic, is also formed when the preceding crystallised salts are put into hot water.

_Obs._ This last preparation is a heavy, yellow powder, but the shade varies according to its basicity, which increases with the temperature of the water employed to effect the precipitation, until, at the boiling temperature, the colour is a dull red. It is extensively employed for the extemporaneous preparation of the ointment of nitrate of mercury, according to the formula on the following label which accompanies each bottle:--"Hydrarg. subnitras." "Two scruples, mixed with one ounce of simple cerate, make the ung. hydrarg. nit. of the London Pharmacopia." We need scarcely add that this statement, so unblushingly uttered, is a dangerous falsehood. An ointment so made possesses neither the quant.i.ty of mercury nor of nitric acid employed in the Pharmacopia preparation, besides wanting many of its most sensible and valuable properties.

=Mercuric Oxide.= HgO. _Syn._ PROTOXIDE OF MERCURY, RED OXIDE OF MERCURY, OXIDE OF M., BINOXIDE OF M., DEUTOXIDE OF M., PEROXIDE OF M.; HYDRARGYRI OXYDUM, H. O. RUBRUM, B. & L. There are several methods by which this substance may be prepared. The following are those which have been ordered at different times in the Pharmacopias:--

1. By precipitation (HYDRARGYRI BINOXYDUM--Ph. L. 1836.). Mercuric chloride (corrosive sublimate), 4 oz.; distilled water, 6 pints; dissolve and add of liquor of pota.s.s, 28 fl. oz.; drain the precipitate, wash it in distilled water, and dry it by a gentle heat.

_Obs._ A bright orange-red powder. It usually contains a little combined water; hence its readier solubility in acids than the oxide prepared by heat. When heated sufficiently it yields oxygen, and the mercury either runs into globules or is totally dissipated. It is entirely soluble in hydrochloric acid. (Ph. L. 1836.) The preparation of the shops has frequently a brick-red colour, and contains a little oxychloride, arising from too little alkali being used.

2. By calcination of the nitrate (RED PRECIPITATE; HYDRARGYRI NITRICI OXYDUM Ph. L. HYDRARGYRI OXIDUM RUBRUM, B. P., Ph. L., Ph. D.) _Prep._ B.

P. Mercury, by weight, 8; nitric acid, 4-1/2; water, 2. Dissolve half the mercury in the water and acid, evaporate to dryness, and triturate with the rest of the mercury until well blended. Heat in a porcelain capsule, repeatedly stirring, until acid vapours cease to be evolved.

Mercury, 3 lbs.; nitric acid, 18 fl. oz. (1-1/2 lb., Ph. L. 1836); water, 2 quarts; dissolve by a gentle heat, evaporate to dryness, powder, and calcine this in a shallow vessel, with a gradually increased heat, until red vapours cease to arise. The process of the Ph. E. and D. are similar, except that the Dublin College directs the evaporation and calcination to be performed in the same vessel, without powdering or stirring the ma.s.s.

_Obs._ Bright red crystalline scales, which usually contain a little undecomposed pernitrate of mercury; in other respects it resembles the last two preparations. It is more generally used as an escharotic and in ointments than the precipitated oxide. It is volatilised by heat without the evolution of nitrous vapours.

According to Mr Brande it contains about 2-1/2 per cent. of nitric acid.

According to Mr Barker the process of the Ph. D. yields the finest coloured product; but Mr Brande states that "the nitrate requires to be constantly stirred during the process, which is usually performed in a cast-iron pot." On the large scale, the evaporation is generally conducted in a shallow earthen dish, and as soon as the ma.s.s becomes dry a second dish is inverted over it, and the calcination is continued, without disturbance, until the process is concluded. The heat of a sand bath is employed. 120 lbs. of mercury, and 48 lbs. of nitric acid (sp. gr. 148) yields 112 lbs. of red precipitate. (Brande.)

_Uses, &c._ Red oxide of mercury, whether obtained by calcination or precipitation, possesses the same general properties. It is very slightly soluble in water, but sufficiently so to give that fluid an alkaline reaction, and a metallic taste. It was formerly employed in medicine to induce salivation; but is now chiefly used as an escharotic, either in the form of powder or made into an ointment.--_Dose_, 1/8 to 1 gr., combined with opium. It is very poisonous.

=Mercuric Sulphide.= HgSO_{4}. _Syn._ PROTOSULPHATE OF MERCURY; HYDRARGYRI SULPHAS (Ph. B.), H. PERSULPHAS, H. BIPERSULPHAS, L. _Prep._ 1.

(Neutral.)--_a._ By boiling together sulphuric acid and metallic mercury until the latter is wholly converted into a heavy, white, crystalline powder; the excess of acid is removed by evaporation. Equal weights of acid and metal may conveniently be employed.

_b._ (Ph. D. 1826.) Dissolve mercury, 6 parts, in a mixture of sulphuric acid, 6 parts, and nitric acid, 1 part, by boiling them in a gla.s.s vessel, and continue the heat until the ma.s.s becomes perfectly dry and white. Used to make calomel.

_c._ (Ph. B.) Place 20 oz. of quicksilver in a porcelain capsule with 12 fl. oz. of sulphuric acid, and apply heat until nothing remains but a white, dry, crystalline salt. Used to make perchloride and chloride of mercury.

2. (Basic.) HgSO_{4,2}HgO. _Syn._ TRIBASIC SULPHATE OF MERCURY, TURPETH MINERAL, TURBITH M., QUEEN'S YELLOW, SUBSULPHATE OF MERCURY, TRIBASIC PERSULPHATE OF M.; HYDRARGYRI SUBSULPHAS, H. S. FLAVUS, TERPETHUM MINERALE, L.--_a._ Dissolve mercury in an equal weight of sulphuric acid by boiling them to dryness, fling the ma.s.s into hot water, and wash and dry the resulting yellow powder.

_b._ (Ph. D. 1826.) Mercuric sulphate, 1 part; warm water, 20 parts; triturate together in an earthen mortar, wash well with distilled water, drain, and dry it.

_Prop., &c._ A heavy, lemon-yellow powder, soluble in 2000 parts of cold, and about 600 parts of boiling water. By long-continued washing with very hot water it loses all its remaining acid, and is at length converted into red oxide of mercury.--_Dose._ As an alterative, 1/8 to 1/2 gr.; as an emetic, 3 to 5 gr.; as an errhine, 1 gr.; mixed up with a pinch of liquorice powder or fine snuff. It is a powerful poison, and one of the least useful of the mercurial preparations.

_Obs._ The temperature of the water employed to decompose the neutral sulphate influences the shade of colour of the resulting salt in a similar manner to that pointed out under the nitrate. It is now superseded as a pigment by chrome yellow and orpiment, which are not only more beautiful, but cheaper preparations.

=Mercuric Sulphide.= HgS. _Syn._ PROTOSULPHIDE OF MERCURY, RED SULPHURET OF MERCURY, FACt.i.tIOUS CINNABAR, VERMILION, SULPHURET OF MERCURY, SULPHIDE OF M., BISULPHURET OF M.; HYDRARGYRI BISULPHURETUM (Ph. B. & Ph. L.), CINNABARIS (Ph. E.), H. SULPHURETUM RUBRUM. L. _Prep._ (Ph. L.) Quicksilver, 24 oz.; sulphur, 5 oz.; melt together, and continue the heat till the mixture swells up, then cover the vessel, remove it from the heat, and when cold, powder and sublime it. (Ph. B.) Quicksilver, 2 lbs.; sulphur, 5 oz.

_Prop., &c._ Mercuric sulphide has a dark-red semi-crystalline appearance in the ma.s.s, but acquires a brilliant scarlet colour by powdering. It is tasteless, odourless, and insoluble. It is chiefly used as a pigment; but it is occasionally employed in medicine as a diaph.o.r.etic and vermifuge, and in some cutaneous diseases and gout.--_Dose_, 10 to 30 gr.; as a fumigation, about 1/2 dr. is thrown on a plate of iron heated to dull redness. For the last purpose it is inferior to mercurous oxide, owing to the more irritating nature of its vapour.

_Tests._ MERCUROUS SALTS. Sulphuretted hydrogen and ammonium sulphide give black precipitates, insoluble in dilute acids, ammonium sulphide, pota.s.sium cyanide, and hot nitric acid, but slightly soluble in sodium sulphide, and decomposed by nitro-hydrochloric acid.

Pota.s.sium hydrate and ammonia give black grey or black precipitates, which are insoluble in excess of the precipitant.

Hydrochloric acid and the soluble metallic chlorides occasion a precipitate, which a.s.sumes the form of a very fine powder of dazzling whiteness, insoluble in excess, but soluble in aqua regia and liquid chlorine. Pota.s.sium hydrate and ammonia turn it dark grey or black.

Pota.s.sium iodide gives a greenish-yellow precipitate, soluble in ether, and subliming in red crystals when heated.

=Mercurous Acetate.= Hg(C_{2}H_{3}O_{2}). _Syn._ ACETATE OF MERCURY, SUBACETATE. _Prep._ (P. Cod.) Dissolve mercurous nitrate, 1 part, in water (slightly acidulated with nitric acid), 4 parts, and precipitate the liquid with a solution of sodium acetate, gradually added, until in slight excess; carefully wash the precipitate with cold water, and dry it in the shade.

_Prop., &c._ Small, white, micaceous, flexible scales; insoluble in alcohol; soluble in about 300 parts of water; blackened by light; and carbonised by a strong heat. It has been said to be one of the mildest of the mercurials; but this cannot be the case, as it occasionally acts with great violence on both the stomach and bowels, producing much pain and prostration.--_Dose_, 1/6 to 1 gr., night and morning, gradually increased.

=Mercurous Bromide.= HgBr. _Syn._ SUBBROMIDE OF MERCURY; HYDRARGYRUM BROMIDUM, L. _Prep._ (Magendie.) By precipitating a solution of mercurous nitrate by another of pota.s.sium bromide. It closely resembles calomel in both its appearance and properties.--_Dose_, 1 to 5 gr.

=Mercurous Chloride.= HgCl or Hg_{2}Cl_{2}. _Syn._ CALOMEL, SUBCHLORIDE OF MERCURY, MERCURY CHLORIDE; HYDRARGYRI SUBCHLORIDUM (B. P.), HYDRARGYRI CHLORIDUM (Ph. L.), H. C. MITE (Ph. U. S.), CALOMELAS (Ph. E. & D.), L.

This substance is one of the best known, and probably the most valuable, of all the mercurials.

_Prep._ 1. (Ph. L.) Mercury, 2 lbs.; sulphuric acid, 21-1/2 fl. oz.; mix, boil to dryness (in a cast-iron vessel), and when the resulting ma.s.s has cooled, add of mercury, 2 lbs., and triturate the ingredients in an earthenware mortar until they are well mixed; then add of sodium chloride, 1-1/2 lb., and again triturate until the globules are no longer visible; next sublime the mixture, reduce the sublimate to the finest possible powder, diligently wash it with boiling distilled water, and dry it.--_Prod._ 117 or 118% of the weight of mercury employed.

2. (Ph. F.) Mercury, 4 oz., is dissolved in a mixture of sulphuric acid, 2 fl. oz. 3 fl. dr., and nitric acid, 1/2 fl. oz., by the aid of heat; when cold, mercury, 4 oz., is added, and the remainder of the process is conducted as before.

3. (CALOMELAS SUBLIMATUM.--Ph. D.) Sulphate of mercury, 10 parts; mercury, 7 parts; dry sodium chloride, 5 parts; triturate, &c., as before, and afterwards resublime it into a large chamber or receiver.

4. (Ph. B.) Same as Dublin.

5. (Apothecaries' Hall.) Quicksilver, 50 lbs., and sulphuric acid, 70 lbs., are boiled to dryness in a cast-iron vessel; of the dry salt, 62 lbs. are triturated with quicksilver, 40-1/2 lbs., until the globules are extinguished, when sodium chloride, 34 lbs., is added, and after thorough admixture the whole is sublimed, &c., as before.--_Prod._ 96 to 100 lbs.

6. (Jewel's Patent.) The receiver, which is capacious, is filled with steam, so that the calomel vapour is condensed in it in a state of extremely minute division. The engr. represents the apparatus now usually employed when this plan is adopted. The product is extremely white, and of the finest quality. It is sometimes called 'hydrosublimed calomel' and 'hydrosublimate of mercury.' The 'flowers of calomel,' of old pharmacy, were prepared in a nearly similar manner.

[Ill.u.s.tration: _a._ Furnace.

_b._ An earthenware retort, having a short and wide neck, containing the ingredients for making calomel.

_c._ An earthen receiver, having three tubulatures.

_d._ A vessel containing water.

_e._ A steam-boiler.]

7. (Soubeiran.) The crude calomel mixture is heated in an earthen tube in a furnace, and a current of air is directed uninterruptedly into the tube by means of a small ventilator. This sweeps away, as it were, the vapours of calomel, and in a straight tube will carry them a distance of 60 feet, to avoid which the end of the recipient is immersed in water, by which means the calomel is moistened and falls down. This plan, slightly modified, is now extensively adopted in this country.