Qualities. Form, a liquid of the specific gravity 1·16, a fluid-ounce of which weighs about 527 grains, and according to Dr. Powell ought, when diluted, to dissolve 220 grains of limestone. Odour, strong and pungent; if exposed to the air it emits white fumes. Taste, intensely sour and caustic; it is however the weakest of the three mineral acids; and no remarkable elevation of temperature is produced by dilution. Chemical Composition. The liquid acid is a solution of muriatic acid gas in water; when of the specific gravity 1·16, according to Davy, it contains 32·32 per cent of the gas, which recent experiments have shewn to be a compound of Chlorine (Oxy-muriatic acid) and hydrogen in equal volumes. It has therefore received a name expressive of its composition, and is called Hydro-chloric^[348] acid. We accordingly find that the former element is disengaged from muriatic acid by adding any substance capable of uniting with its hydrogen. For the purpose of obtaining Chlorine, we may take three parts of common salt, one of black oxide of manganese, and rather less than three of strong sulphuric acid.^[349] Accounts have been received from Spain, that in the midst of the dreadful contagion which reigned in that country, the inhabitants always escaped in those houses where fumigations of chlorine had been used. In our own country, the Penitentiary has lately undergone fumigation by this gas, under the superintendance of Mr. Faraday.^[350] Muriatic acid gas has also been strongly recommended for the same purpose; it may be easily evolved by pouring sulphuric acid on common salt. If nitric and muriatic acids be mixed, a mutual decomposition takes place, of which water, chlorine, and nitrous acid are the results; this constitutes “nitro-muriatic acid,” the Aqua regia of the older chemists. A bath acidulated with an acid of this kind has been recommended by Dr. Scott, as a powerful remedy for diseases of the liver in particular, and as a substitute for mercury in general. On the possible influence of this bath, I would beg to make one observation,—that the extensive application of a dilute acid to the surface of the body, is, under certain circumstances, capable of affecting the bowels. I have witnessed such an effect from sponging with vinegar and water. In this way the acidulated bath may occasionally produce benefit, but it is extremely difficult to conceive how it can be indebted for its utility to any other mode of operation. (See Journal of Science and the Arts, No. 2.) Forms of Exhibition. Muriatic acid should be administered in some bland fluid, as barley water, gruel, &c. (Formula 145.) I have uniformly exhibited it with success in the most malignant cases of typhus and scarlatina, during several years extensive practice in the Westminster Hospital. See page 157. We should be careful not to apportion its dose in a leaden or pewter spoon. The antiseptic properties of this acid have been long known; Sir Wm. Fordyce relates that a “dry-salter” acquired a large fortune from possessing a secret that had enabled him to send out provisions to India in a better state of preservation than any others of the trade; his secret consisted in adding a small quantity of muriatic acid to the contents of each cask. After a copious evacuation of the bowels, it is in my experience the most efficacious remedy for preventing the generation of worms; for which purpose the infusion of quassia, stronger than that of the Pharmacopœia, is the best vehicle. Dose, ♏︎v-xx, frequently repeated. It may be here observed that where the permanent influence of an acid is required, a mineral one should be always preferred, as such bodies appear to be beyond the control of the digestive process,^[351] and are incapable of being decomposed by it; see Form. 158, whereas on the contrary it seems probable that the organs of assimilation have command over those of a vegetable nature, and generally decompose them. Dr. Marcet has very judiciously noticed this fact in his luminous work on the treatment of calculi, and I have ventured to offer some farther observations upon this subject, which may be of practical value, under the consideration of Lithonthryptics, page 123. Adulterations. Sulphuric acid is detected by diluting the acid with six parts of distilled water, and adding a few drops of the muriate of baryta, which occasions a white precipitate if any be present. Iron, by saturating a diluted portion with pure carbonate of soda, and adding prussiate of potass, which will indicate its presence by a blue precipitate; or by a solution of ammonia, which, when added slightly in excess, throws down the peroxide of iron of a reddish yellow colour. Copper, by the production of a blue colour when supersaturated with ammonia. The yellow tinge of the acid usually met with in commerce, may depend either upon the presence of iron, vegetable extractive, or a small portion of chlorine. This latter body may be recognised by the odour, or by its power of dissolving gold leaf.

Qualities. A limpid liquid of the specific gravity 1·500, a fluid-ounce of which is equal to about 11 drachms, 1 scruple by weight, and ought to decompose of pure limestone an ounce; it emits white fumes of a suffocating odour. Taste, extremely acid; it is highly corrosive, and tinges the skin indelibly yellow; an effect which is considerably heightened by the subsequent application of an alkali, so that these agents afford the means of detecting minute portions of animal matter, and were ingeniously employed for such an object by Mr. Hatchett. Chemical Composition. When of the specific gravity 1·500, it contains 74·895 per cent. of dry acid; (whose ultimate elements are one portion of nitrogen and five of oxygen) the compliment 25·105 parts is water. It is decomposed with violent action by all combustibles, and when mixed with volatile oils, it causes their inflammation. It boils at 210°, and when its specific gravity is below 1·4, it is strengthened, when stronger than 1·45 it is weakened by ebullition. Uses. It is principally employed as a pharmaceutical agent; viz. for the preparation of Argenti Nitras; Liquor Ferri Alkalini; Hydrargyri Nitri-co-oxydum; Spiritus Etheris Nitrici; and Unguentum Hydrargyri Nitratis. As an escharotic it has been frequently employed for the destruction of tumours, and is certainly of value where an immediate destruction of diseased parts is required. The method of using the strong nitric acid in such cases is to smear all the sound parts in the immediate vicinity of the ulcer with Ung: Resin: Nig: and then to apply pledgets of lint firmly upon the ulcer for a few seconds, by which the whole surface will be deadened, and a deep slough remain, underneath which healthy suppuration and granulations will ensue.^[352] Adulterations. Sulphuric acid may be detected by a precipitate being produced on the addition of nitrate of baryta; in the application however of this test, Mr. Hume has shewn that unless this as well as the nitric acid be diluted, a precipitate will occur, although sulphuric acid should not be present; a circumstance which depends upon the barytic salt yielding its water of solution to the acid under examination, and becoming insoluble. Muriatic acid is discovered by nitrate of silver, affording a precipitate at first white, but becoming coloured by exposure to light; the nitric acid ought to be perfectly colourless, but to preserve it in such a state it must be closely stopped, and kept in a dark place, or it will soon be converted into nitrous acid.

It is much to be regretted that the proportion of water directed for the dilution of the acid, varies considerably in the different pharmacopœias; that prepared according to the Edinburgh and Dublin formulæ, being in strength to that of the present Pharmacopœia of London, as 4 to 1: specific gravity, 1·080; each fluid-drachm contains nearly 8½ grains of the concentrated acid, and saturates 18 grains of crystallized sub-carbonate of soda. Dose ♏︎x to xl. The acid is a very powerful anti-phlogistic remedy; it has been much extolled in diseases of the liver, and in syphilis. Mr. Pearson however observes that we ought not to rely upon it in any form of lues venerea, although it may be often serviceable in restraining the progress of the disease when an impaired constitution or other circumstances render the exhibition of mercury improper; when sufficiently dilute, it forms an excellent lotion for old indolent ulcers. It proves also expectorant, see Form. 139, 140; and it is occasionally used with success for the purpose of counteracting the consecutive effects of opium. See Form. 16.

Qualities. A liquid emitting fumes of a flame-red colour, and of a very pungent and remarkable odour. The acid is either blue, green, straw-coloured, clear orange yellow, according to the proportion of nitrous acid gas^[353] with which it is charged. Chemical Composition. This acid is improperly denominated Nitrous, for it is nitric acid, holding nitrous acid gas loosely combined; by dilution this last constituent is disengaged, and the acid, after passing through a succession of different colours, becomes pure nitric acid; the application of a gentle heat effects the same changes.

Qualities. Form, a thick liquid of an oily consistence, specific gravity 1·85; a fluid-ounce weighs a fraction of a grain more than fourteen drachms. Colour, none, but it acquires a brown tinge from the smallest portion of carbonaceous matter; mere exposure to the air is sufficient for this purpose, in consequence of the acid disorganizing and carbonating the vegetable and animal matter suspended in the atmosphere; it is therefore evident that bottles in which it is preserved ought not to have stoppers of cork, but those of glass. Chemical Composition. Like the other mineral acids, it has never been obtained in an insulated state without water; according to Davy, the composition of the strongest acid may be thus expressed: sulphur 30, oxygen 45, water 17. It has a very powerful affinity for water, and produces when mixed with it a very considerable heat; exposed to the atmosphere it imbibes at least seven times its own weight of water, and so rapidly as to double its weight in a month; when of the specific gravity 1·85, it rises in vapour at about 550°, and distils unaltered, whereas weaker acids lose water by being boiled, and are brought to that degree of concentration; when diluted with 12 or 13 per cent. of water, an acid results of the specific gravity 1·780, and in this state of dilution it boils at 435°, and freezes sooner than water; a knowledge of this curious fact suggests to the prudent chemist an important precaution; Mr. Parkes, in his Chemical Essays, vol. ii. relates the occurrence of a terrible accident which happened in consequence of this circumstance not having been attended to.—“Carboy after carboy burst by the expansion of the acid in the act of freezing, and had not the packed carboys that remained been immediately immersed in tepid water, not a single one would have escaped the general wreck.”

Adulterations. The ordinary acid of the shops contains in general 3 or 4 per cent. of saline matter, which consists of about two-thirds of sulphate of potass, and one-third of sulphate of lead. Dr. Ure observes, that even more is occasionally found, in consequence of the employment of nitre to remove the brown colour given to the acid by carbonaceous matter; the amount of adulteration, he observes, may be readily determined by evaporating a definite weight of the acid in a small capsule of platinum; these impurities however in a medical point of view are immaterial, since they are at once separated by dilution, but in a commercial sense they deserve attention, as their presence considerably increases the specific gravity of the acid. Dr. Ure is of opinion that genuine commercial acid should never exceed 1·8485, and that any density beyond this is the effect of saline combination. Journal of Science and the Arts, No. 7.

By the dilution of this acid two objects are accomplished,—it is purified, and its dose is more easily apportioned; but it is a circumstance of regret that the strength of this preparation should so materially vary in the different Pharmacopœias.

After the acid is diluted, the sediment ought to be carefully removed, and the water employed for the purpose should be distilled, for although it be in its purest natural state, it will nevertheless contain impregnations capable of affecting the acid. Uses. In addition to the antiseptic and refrigerant virtues which it possesses in common with the other mineral acids, it has astringent properties that render it a most valuable medicine, especially in weakness and relaxation of the digestive organs, in colliquative sweats, in internal hæmorrhagy; in Epistaxis and Hemopthysis it was Sydenham’s favourite remedy; on the same account, when sufficiently dilute, it has been successfully used as a collyrium in the atonic stages of ophthalmia, and as an injection in protracted gonorrhæa. Dose, ♏︎x to xl, the quantity of strong sulphuric acid in any given quantity of the dilute may be found by the Dynameter. To prevent it from injuring the enamel of the teeth it may be sucked through a quill, and the mouth should be carefully washed after each dose. The Infusum Rosæ furnishes an elegant vehicle for its administration. See Form. 40. Officinal Preparations. Acidum Sulphuricum Aromaticum.^[354] E. Infusum Rosæ. L.

Qualities. Form, Crystals of considerable size, whose primary form is an oblique rhombic prism; they do not deliquesce when exposed to the air, but melt at a heat a little exceeding 212°. Taste, very acid and agreeable. Solubility. Water at 60° dissolves about one-fifth of its weight, and when boiling, a much greater proportion. The solution, which, if saturated, has the specific gravity 1·230, acquires, when diluted, like that of most vegetable acids, a mouldy pellicle by keeping. The saturating power of crystallized tartaric acid is almost exactly equal to that of crystallized citric acid, the atomic weight of the former being 76, and that of the latter 75. Chemical Composition. When uncombined with water, as it exists in tartrate of potass, it is composed of 5 atoms of oxygen, 3 atoms of hydrogen, and 4 atoms of carbon. The crystals consist of 1 atom of acid and 1 of water. Incompatible Substances. Alkalies, Earths, and their carbonates; the salts of lime and lead. The solutions of the salts of potass are converted by it into bi-tartrate, or super-tartrate. Medicinal Uses. It is introduced into the Pharmacopœia as a cheap and efficient substitute for the citric acid. It is also used in the preparation of Sodaic powders, Seidlitz powders, &c. Adulterations. When carelessly prepared it will contain sulphuric acid, to detect which, let a portion be dissolved in distilled water, and a solution of acetate of lead be added. A precipitate will appear which, if the acid be pure, will be entirely redissolved by a few drops of acetic acid, or pure nitric acid. If any portion remain undissolved, sulphuric acid is the cause. Muriate of Baryta also, when sulphuric acid is present, but not otherwise, gives a precipitate insoluble by an excess of muriatic acid.

Qualities. Taste, moderately bitter, and acrid, leaving in the mouth a painful sensation of heat and roughness, followed by numbness in the gums and lips which continues for two or three hours. Odour, faint and narcotic; their peculiar properties are considerably deteriorated by drying. Chemical Composition. M. Brandes has ascertained that the narcotic principle of this plant is a peculiar alkali, to which he has given the name Aconita.^[356] Solubility, water and alcohol only imperfectly extract their virtues. Medicinal Uses. It is narcotic, and occasions, in over-doses, nausea, vomiting, vertigo, hyper-catharsis, cold sweats, convulsions, and death; effects which entirely depend upon its action on the brain. It was first administered in 1702, by Stöerk, of Vienna, in chronic rheumatism, gout, schirrus, and paralysis; more lately it has been employed in scrofula, cancer, and intermittents, and it is said with much effect. On account of the variable strength of the leaves they can hardly be given with safety and effect; the extract (which see,) presents the more eligible form of exhibition. The leaves are, however, sometimes given in the form of powder, generally combined with some mercurial alterative, or with antimonials, camphor, and other diaphoretics. Dose gr. i-x. Officinal Prep: Extractum Aconiti. L.E.

Qualities. Consistence, soft or nearly semifluid. Odour and Taste, none; at 97° it melts. Chemical Composition. It consists of two distinct bodies which appear to exist together in a state of mechanical mixture, viz. Stearin, (from στεαρ tallow) which is white, brittle, and in appearance somewhat resembling wax; and Elain (from ελαὶον, oil) very similar to vegetable oil in appearance, and is liquid at 59°. According to the experiments of Braconnot, the proportion of Elain is to that of Stearin, in hog’s lard, as 62:38. Solubility. It is insoluble in water and alcohol; with the alkalies it unites and forms soaps. Incompatible Substances. Extracts, Spirituous Preparations, Tinctures, and Infusions, are incapable of uniting perfectly with lard, without some intermedium; the following substances on the contrary are capable of contracting with it a most intimate union. 1. All dry powders, whether of a vegetable or mineral nature. 2. Fixed and Volatile Oils. 3. Balsams. 4. Camphor. 5. Soaps. It is principally employed in the formation of ointments, plasters, and liniments.

ÆRUGO. L. D. (Sub-acetas Cupri Impura.) Sub-acetis Cupri. E.

Verdigris.

Qualities. Form, a dry mass composed of minute crystals, not deliquescent; Colour, bluish green. Chemical Composition. Several constituents enter into its composition, viz. Acetate and sub-acetate of copper, carbonate of copper, and copper partly metallic and partly oxidized; it contains also the stalks of grapes and other extraneous substances. Solubility. Boiling water dissolves it in part, and produces in it a chemical change, by transforming one portion of the sub-acetate into the soluble acetate, and another into an oxyd of copper, which is precipitated; with cold water this substance demeans itself differently, the acetate is dissolved by it, whilst that portion which is in the state of sub-salt remains suspended in the form of a fine green powder. Vinegar converts all the Ærugo into a soluble acetate, this liquid therefore ought never to be employed for favouring vomiting in cases where an overdose has been swallowed, for the reasons stated in the first part of this work, p. 136. Sulphuric acid poured on powdered verdigris decomposes it with effervescence, and vapours of acetic acid are disengaged. It appears from the experiments and observations of Duval and Orfila, that sugar exercises a chemical action on it, by which its solubility is diminished, and that on this account it acts as a specific against its poisonous effects. Uses. It is so uncertain and violent in its operation that it is rarely employed, except externally,^[358] when it acts as a powerful detergent, and mild escharotic; and in the form of ointment, is a valuable application for many cutaneous affections, especially the aggravated kinds of Tetter. Officinal Preparations. Ærugo Præparata, D. Linimentum Æruginis. L. D. Adulterations. There is a spurious article sold under the name of English Verdigris, which consists of sulphate of copper, triturated with acetate of lead; and to make the fraud still more complete, the soft mass is mixed with the stalks of Raisins.

Qualities. A colourless liquid of specific gravity 739°. Odour, pungent and fragrant; it is highly volatile, and when perfectly free from alcohol it boils at 98°; it is extremely inflammable, a circumstance which should be remembered when it is poured from one vessel to another by candle light. Chemical Composition. When pure it consists of oxygen, hydrogen, and carbon; the rectified æther however still contains some water and alcohol, for Lovitz obtained an æther of 632. Solubility. One part requires for its solution ten of water; with alcohol and ammonia it unites in every proportion. Solvent Powers. It is one of the most powerful solvents known in vegetable chemistry, as it dissolves balsams, resins, gum-resins, wax, camphor, extractive, &c.; it takes up about a twentieth of its weight of sulphur, but it exerts no solvent power upon the fixed alkalies. Forms of Exhibition. In any liquid vehicle, if in decoctions or infusions, they should be previously cooled. See Formulæ 20, 22, 23. Medical Uses. It is highly valuable as a diffusible stimulant, narcotic, and antispasmodic. Dose, fʒss to fʒij, which, in order to produce the full effect of the remedy, must be repeated at short intervals. Æther, independent of such virtues, has another valuable property consequent upon its rapid evaporation, that of producing cold and dryness; it is therefore, when externally applied and allowed to evaporate, a most powerful refrigerant, and has proved valuable in scalds or burns, in facilitating the reduction of strangulated hernia, and in diminishing excessive circulation in the brain; if however it be so confined, that its rapid evaporation is prevented, a very opposite effect is produced, and it proves stimulant, rubefacient, and even vesicatory. With regard to the other property incidental to it, that of producing dryness, I am not aware that it has hitherto been applied to any pharmaceutical purpose; the fact may be satisfactorily shewn by a very simple experiment,—by rincing a phial with æther, to the interior of which drops of water obstinately adhere, when by exposing it to a current of air, it will be completely dry in a few minutes. It may be noticed in this place that a mixture of sulphuric and muriatic æthers evaporates instantaneously, and produces a degree of cold considerably below 0 of Fahrenheit. Officinal Preparations. Spiritus Æther: Sulph: L. Spir: Æth: Sulph: comp: L. Spir: Æth: Aromat: L. Adulterations and Impurities. Its specific gravity affords the best indication of its purity; Sulphuric Acid may be detected by a precipitation on the addition of a solution of baryta, and by its reddening the colour of litmus; Alcohol, by its forming with phosphorus a milky instead of a limpid solution. M. Gay Lussac has observed that when kept for a considerable time without disturbance, it undergoes spontaneous decomposition, and that acetic acid, perhaps some alcohol, and a particular oil, are produced from it.

Qualities. A transparent, and colourless liquid of the specific gravity ·815; it has not hitherto been rendered solid by any diminution of temperature; it boils at 176°, and if water be added, its boiling point is proportionably raised; hence, says Dr. Henry, the temperature at which it boils is not a bad test of its strength; it is combustible, and burns with a blue flame, leaving no residue. Chemical Composition. Alcohol, in a state of complete purity, consists of carbon, hydrogen, and oxygen, in proportions not hitherto determined with accuracy; this preparation however contains 7 per cent. of water; Lovitz and Saussure succeeded in obtaining it at a specific gravity of ·791, which may be considered as nearly pure. Alcohol unites chemically with water; and caloric is evolved during this union; the quantity of alcohol and water in mixtures of different specific gravities, may be learned from Mr. Gilpin’s tables, Philosophical Transactions, 1794, or Nicholson’s Journal, 4to. vol. 1. The Edinburgh Pharmacopœia has no process for the preparation of alcohol, but it most incorrectly assigns the title to that which is the “Rectified Spirit” of the other Colleges. Solvent Powers. Alcohol dissolves soap; vegetable extract; sugar; oxalic, camphoric, tartaric, gallic, and benzoic acids; volatile oils; resins, and balsams; it combines also with sulphur, and the pure fixed alkalies, but not with their carbonates: for its other habitudes, and applications, see Spiritus Rectificatus.

Qualities. This bulbous root has when recent a fœtid smell, and acrid taste, which are extracted by watery infusion; by decoction they are nearly lost; by expression, the root furnishes almost one-fourth of its weight of a limpid juice, and by distillation, an odorous, acrid, essential oil is procured, in which the existence of sulphur may be detected. Garlic has a considerable analogy to squill and onion, and like them, exerts a diuretic, diaphoretic, expectorant, and stimulant operation; (see p. 103). It is a very common domestic remedy for the expulsion of tænia, and it is undoubtedly of advantage in such cases; it is usually administered in the form of a decoction, with milk, on an empty stomach; it is however but rarely used in modern practice, as it possesses no superiority over remedies less nauseous and objectionable; the bruised root, externally applied, is highly stimulant, and rubefacient. Sydenham speaks highly of the application of garlic to the soles of the feet, as a powerful means of producing revulsion from the head. Officinal Preparation. Syrupus Allii. D.^[361]

There are three species met with in the shops, viz.

Qualities. The above varieties of aloe differ in their purity, and likewise in their sensible qualities; the Socotrine is the purest, it is in small pieces of a reddish brown colour; the Barbadoes is in large masses, of a lighter colour, and having an odour much stronger and less pleasant; the Cabaline is still more impure and less powerful. All the kinds are characterized by an intensely bitter taste, which, in the Socotrine, is accompanied by an aromatic flavour. Chemical Composition. In this there appears to be some obscurity; M. Braconnot (Ann. Chim. tom. 68.) conceives it to be a substance, sui generis, which he terms “bitter resin,” while others regard it as composed of resin, gum, and extractive, the proportions of which are supposed to vary in the different species, but that their peculiar virtues reside in the extractive part. Solubility. It is to the slowness with which aloe undergoes solution in the primæ viæ, that it is indebted for the medicinal properties which distinguish this substance; by boiling water it is dissolved, but on cooling a precipitation ensues, and by long decoction it becomes quite inert; weak acids dissolve it more abundantly than water, but proof spirit is the most perfect solvent: its solubility is increased by the addition of alkaline salts and soaps, but by such a combination it undergoes a material change in its medicinal properties; the bitterness is diminished, its purgative effects impaired, and it ceases to operate specifically upon the large intestines, a fact so far valuable, as it enables us in certain cases to obviate its irritating action upon the rectum. Medicinal Use. Aloe is a bitter stimulating purgative, emptying the large intestines, without making the stools thin; it likewise warms the habit, quickens the circulation, and promotes the uterine and hemorrhoidal fluxes. Dose, gr. v.–xv. No greater effect is produced by a large dose than from one comparatively moderate; its tendency, however, to irritate the rectum renders it, in many cases, an objectionable remedy;^[363] and its sympathetic action on the uterus may occasionally produce mischief, in irritable habits, while in other states it may, for reasons equally obvious, prove beneficial. Forms of Exhibition. The form of pill should be preferred on account of its extreme bitterness, as well as being, for the reasons above mentioned, the one most likely to fulfil the intention of its exhibition; for in addition to what has been stated in a preceding part of this work, on the important influence of solubility, it may be here observed that since the aloe does not undergo solution in the stomach, it is admirably adapted for the basis of remedies intended to obviate constitutional costiveness, for in our endeavours to supply the deficiencies of nature by the resources of art, we should at least attempt to imitate the modes of her operation; the natural stimulus of the intestines, the bile, is poured into them below the stomach, and whenever it regurgitates into that organ it produces disease; so it happens with our cathartic medicines, and unless we so modify their solubility that their operation cannot commence until after their passage through the stomach, we shall find that we only increase the evil we are endeavouring to obviate, and that, in addition to the torpor of the intestinal canal, we shall induce the stomach to participate in the disease, or excite a morbid fretfulness of that organ which will be attended with the most distressing symptoms.^[364] See Formulæ 12, 13, 79, 80, 81. Aloes in combination with assafœtida furnishes an eligible purgative in the dyspepsia of old persons; it is also well calculated to obviate the costiveness so generally produced by Opium, (Form: 11, 12, 13.) See also p. 162. Officinal Preparations. Pulv: Aloes comp: L. Pil: Alöes cum Myrrha. L.E.D. Pil: Aloes comp: Pil: Alöes cum Assafœtida. E. Pil: Aloes cum Colocynthide. E. Pil: Cambogiæ comp: (B.M.) L. Pil: Rhei. comp: (F) E. Pil. Scammon, cum Aloe. D. Decoctum Aloes comp: L. Extractum Aloes purificatum. L.D. Extractum Colocynthidis comp: L.D. (F) Tinct: Alöes L.E.D. Tinct: Alöes comp: L.E.D. Tinct: Alöes Ætherea, E. Tinct: Benzoin: comp: (G) L.E.D. Tinct: Rhei et Aloes E. Vinum Alöes. L.E.D. Adulterations. It is frequently adulterated with common resin, but the fraud more generally committed is that of mixing with, or substituting the inferior species for the Socotrine, but the Barbadoes Aloes may, independent of its want of aromatic flavour, be distinguished from the Socotrine by a simple test, for the latter dissolves entirely in boiling water and alcohol, whereas the former, when treated in a similar manner, leaves a considerable residue; sometimes the Horse Aloes is made to appear so bright and pure, as not to be easily distinguished by the eye even from the Socotrine, but its rank odour, of which no art can divest it, will readily betray the fraud.

Qualities. Form, octohedral crystals, whose sides are equilateral triangles; they are slightly efflorescent. Taste, sweet, rough, and acidulous. Chemical Composition. It is a triple, or sometimes a quadruple salt, with excess of acid, consisting of sulphuric acid and alumina, with potass, or ammonia, or frequently both of them; the nature of the alkali however does not in the least appear to affect the properties of alum, although it produces a crystallographic modification; for where potass is present the summit of the crystal will exhibit a truncation. Dr. Ure has lately produced alum with soda, and the combination differs from common alum only in its greater degree of solubility, a property which at once recommends it to the attention of the pharmaceutist and physician. Solubility. A fluid-ounce of cold water dissolves 30 grains, but if boiling four drachms; it is insoluble in alcohol. Incompatible Substances. Alkalies and alkaline salts, after neutralizing the excess of acid, precipitate the alumine. It is also decomposed by carbonate and muriate of ammonia, carbonate of magnesia, and tartrate of potass, by lime-water, acetate of lead, and the salts of mercury, as well as by many vegetable and animal substances, especially galls and kino. It is on this account very injudicious to combine alum with any vegetable astringent with a view to encrease its virtues; thus the “Pulvis Sulphatis Aluminæ compositus” of the Edinburgh college, is less powerful than any of the ingredients of which it is composed; and the addition of alum to the decoction of bark, undoubtedly diminishes its efficacy as an astringent injection. Medicinal Uses. Alum is internally a powerful astringent, in hæmorrhages and inordinate fluxes, and is externally useful for repellent and astringent lotions, gargles, and collyria. Dioscorides and Hippocrates praised its effects as a lotion in various kinds of ulcers, and particularly in sores of the mouth, and in spongy, swelled gums. Van-Helmont was the first person who employed alum in uterine hemorrhage, and the success of the practice very considerably enhanced his reputation. Boerhaave’s astringent powder for the ague consisted of Alum and Nutmeg with the addition of Armenian bole. Dose, gr. x. In large doses it is liable to excite nausea, and to act upon the bowels. Nutmeg or some aromatic should therefore be joined with it. Forms of Exhibition. In solution, or in substance made into pills with extract; (Form: 53, 56,) it is sometimes given with advantage in the form of whey (Alum-whey—Serum Aluminosum) made by boiling ʒij with a pint of milk, and then straining, the dose of which is a wine glass full; (Form; 54.) By briskly agitating a drachm of alum with the white of an egg, a coagulum is formed, (Alum curd of Riverius; Albumen. Aluminosum) which is serviceable in some species of ophthalmia, when applied between two pieces of thin linen rag.^[365] As alum is not decomposed by sulphate of lime, hard water may be safely used for its solution. It has the effect of retarding, and in some instances of preventing, the acetous fermentation in vegetables; thus when added to common paste it prevents its becoming sour; animal substances, as glue, are preserved by it in a similar manner. It has also the property of clearing turbid water, wine, and spirituous liquors, for which purpose it is extensively employed. Officinal Preparations. Liquor Alum: co. L. Pulv: Alum: co. E.

Alumen Exsiccatum, L. Ustum. D. Dried Alum. By the action of heat alum undergoes watery fusion, yields its water of crystallization, and loses more than one third of its weight; if the heat be too intense, or long continued, it is deprived of a great part of its acid. It has been recommended in doses of a scruple, in cholic, when it has been said to operate gently upon the bowels, and to relieve the pain: I have myself experienced this good effect when the cholic has been produced by the action of lead: Dr. Grashuis, a Dutch Physician, first recommended its use in Cholica Pictonum. The preparation however is principally used as an external application, having a degree of escharotic power, which renders it serviceable in venereal chancres, as well as in other ulcers having weak and spongy granulations; it is also very frequently employed to destroy fungous excrescencies, but it should be remembered that, as it owes such power to an excess of acid, unless it be carefully prepared, it must be inefficient. It ought to redden syrup of violets.

Alumen Rupeum. Roche or Rock Alum. This variety was originally brought from Roccha, formerly called Edessa, in Syria, in fragments of about the size of an almond, covered with an efflorescence of a pale rose colour; that however which is now sold under this name is common English alum, artificially coloured. It is unimportant.

Alumen Romanum. Roman Alum is in irregular octohedral masses, powdery on the surface; it is the purest kind, and contains no ammonia in its composition.

Qualities. Form, masses composed of fragments, of tears, yellow on the surface, and white within; Taste, a nauseous sweet, followed by a bitter flavour; Odour, faint but not unpleasant. Specific gravity, 1·200. Chemical Composition. Gum-resin, gluten, and some volatile matter. Solubility. It is partly soluble in water, vinegar, alcohol, æther, and in the solutions of the alkalies; when triturated with water a milky liquor is formed, which is a solution of gum holding the resin in suspension, and if the yolk of an egg be employed the mixture is more permanent; water appears to be its proper solvent. Uses. Stimulant, antispasmodic, and expectorant: in large doses gently purgative and sometimes diuretic; after the exhibition of smart purgatives, in combination with rhubarb, it proves valuable in mesenteric affections by correcting the viscid secretion of the intestines; dissolved in nitric acid, it is said to prove an excellent expectorant in cases where large accumulations of purulent or viscid matter exist with feeble and difficult expectoration. See Form: 140. Forms of Exhibition. In solution, see Mist: Ammoniac: it may also be given when dissolved in the Liquor ammoniæ acetatis; ʒij of the former may be dissolved in ℥iij of the latter; or it may be exhibited in pills with bitter extracts, myrrh, and other gum-resins; if rubbed with camphor a mass is at once produced very suitable for pills; vinegar renders it soft, and adapts it for plasters. Dose, grs. x to xxx. Officinal Preparations. Mist: Ammoniac: L.D. Pil: Scillæ co: L.E. (B) Emplast: Ammoniac: L. Emplast: Gummos: E. Emplast: Ammoniac: cum Hydrargyro. L. Adulterations. Two varieties are met with in the market, that in tears, guttæ ammoniaci, ought to be white, clear, and dry; and that in lumps, lapis ammoniaci, which sells for one-third the price of the former, being very impure, is generally adulterated with common resin, for which it may be purified by softening the mass in a bladder which is immersed in boiling water, and straining it while fluid.

Qualities. Form: white, semi-transparent masses, of a striated or crystalline aspect, which, on exposure to air effloresce; Odour, pungent and peculiar; Taste, acrid but cooling. Chemical Composition. It will be found to vary materially in its composition according to the temperature employed for its preparation; the quantity of alkali varying from 20 to 50 per cent. Mr. Phillips considers the Sub-carbonate of ammonia to be a Sesque-carbonate, composed of 3 atoms of carbonic acid, 2 atoms of ammonia, and 2 of water; or that it is a definite compound of Carbonate and Bi-carbonate, one atom of each, with two atoms of water; one hundred parts, by experiment, consist, of 54·2 carb: acid, 29·3 Ammonia, and 16·5 water; if we consider it as a Sesque-carbonate, its constitution, according to Dr. Wollaston’s scale, will be 55·72 Carbonic Acid, 29 Ammonia, 15·28 water. Solubility. According to Duncan it is soluble in twice its weight of cold water; Mr. Phillips states four times; the mean of these will be found nearly correct. Its solubility however is increased by increase of temperature, but when dissolved in boiling water it effervesces, and undergoes a partial decomposition; it is quite insoluble in alcohol, and hence on the addition of spirit to a strong solution, a dense coagulum is produced. Incompatible Substances. It is decomposed by acids, fixed alkalies, and their sub-carbonates, lime, solution of muriate of lime, magnesia, alum, super-tartrate of potass, and all the acidulous salts, sulphate of magnesia, acetate, sub-muriate, and oxy-muriate of mercury, acetate, and sub-acetate of lead, and the sulphates of iron and zinc. If it be added to decoctions and infusions they must be previously cooled. Forms of Exhibition. Since by exposure to air its virtues are impaired, it ought not to be kept in powdered mixtures; in the form of pill it is preserved much longer, especially if it be combined with some vegetable extract. Uses. It is stimulant, antispasmodic, diaphoretic, powerfully antacid, exceeding in this respect the fixed alkalies, and in large doses it is emetic. It is highly useful as a stimulant in those gastric affections which supervene habits of irregularity and debauchery; combined with opium it affords a powerful resource in protracted diarrhœa attended with debility of the alimentary canal: and in cases of muscular atony so frequently witnessed, as the sequela of chronic rheumatism, ammonia, in large doses, offers the best remedy; I have moreover witnessed the beneficial effects of this remedy in hoarseness depending upon relaxed states of the throat. In typhus fever it has been particularly recommended by Huxham, Pringle, and many other physicians, and some have considered it superior to any other stimulant upon such occasions. It is also useful in syncope and hysteria, in the form of smelling salts;^[366] with respect to its application for making saline draughts, see Acid: Citricum: Dose, grs v to ℈j: to produce emesis ʒss. See Form. 48, 49, 83, 152. Officinal Preparations. Liquor Ammoniæ sub-carbonatis, L. Liquor Ammoniæ acetatis (I) L.E.D. Liniment: Ammoniæ Sub-carbonatis. L. Cuprum Ammoniatum, (I) L.E.D. Adulterations. This salt ought to be entirely volatilized by heat; if any thing remain it may be considered impure; it ought also to be free from all fetor; should this not be the case it may be corrected by subliming it in conjunction with powdered charcoal; there is at present a large quantity of this impure article in the market, which has been manufactured from the residue sold by the gas light companies.^[367] When long exposed to the air, it becomes opaque and friable, and the excess of ammonia, upon which its odour depends, escapes, carbonic acid is absorbed, and an inodorous bi-carbonate remains, consisting of carbonic acid 55·70, Ammonia 21·52, and water 22·76, or 2 atoms of carbonic acid, 1 atom of ammonia, and 2 atoms of water.