Qualities. It is a clear, colourless, and inodorous solution; Spec. grav. 1·446. Dose, ♏︎x to fʒj. See Potassæ Sub-carbonas, and Form: 39, 41. The proportion of the salt contained in any quantity of the solution may be learnt by referring to the Dynameter.

[This is a native tree of America, and one of the most magnificent to be found in our forests—distinguished no less by its great altitude than by its beautiful foliage. It grows in almost every part of the United States. The part used in medicine is the Bark. This has a rough, fibrous appearance and is of a whitish colour. Its taste is bitter, astringent, and somewhat acrid and aromatic. By analysis, it yields gum, resin, muriatic acid, iron, mucus, &c. In its action on the system, it is decidedly tonic, exhibiting at the same time, to a certain extent, stimulant properties. If given in considerable quantities it acts also on the skin and kidneys. It has been used with advantage and success in intermittent fever, chronic rheumatism, gout, hysteria, and in debilitated states of the stomach. It may be given in substance, which is the most efficacious form of using it, in doses of from ʒss to ʒij.]

[This is a plant very common in the United States. It has an acrid taste, very similar to that of green tobacco. By analysis it is found to contain an acrid principle, caoutchouc, and extractive. It is soluble both in water and alcohol. In its medicinal effects, the lobelia is analogous to common tobacco, and varies very much according to the dose in which it is given. It may thus be made to act either as an emetic, antispasmodic, expectorant, or diaphoretic. The diseases in which it has been found useful are asthma, croup, hooping cough, and catarrh. The tincture is the best preparation, and is prepared by digesting, for ten days, ℥ij of the plant in a pint of diluted alcohol. The dose is from ʒj to ʒiv—of the powder, the dose to prove emetic is from 10 to 20 grs.]

Qualities. Form, a white, very light, soft powder; Specific gravity, 2·3; it turns to green the more delicate vegetable blues. Solubility. Although it requires 2000 times its weight of water to hold it in solution, yet it has the property of considerably increasing the solubility of camphor, opium, and resins in the same fluid; it is soluble in solutions of the alkaline carbonates, but not in those of caustic alkalies. Chemical Composition. It is an oxide of a peculiar metal. Medicinal Uses. Antacid, and when acidity prevails, purgative; it is preferable to the carbonate whenever the bowels are distended with flatus, (Form: 150): in other respects, its virtues are the same. See Magnes. Carb. The Medicinal Dynameter will shew the equivalent doses of the pure earth and its carbonate; it will be seen for instance that 12 grains of the former will be as efficient, as an antacid, as 25 grains of the latter. Incidental Impurities. It ought not to effervesce with acids, and if magnesia and muriatic acid be placed at one time in separate cups, in a scale of a balance, no diminution of weight should take place on mixing them. Lime is detected by its solution in dilute sulphuric acid affording a precipitate with oxalate of ammonia; the sulphuret of lime betrays itself by yielding, when moistened, the smell of sulphuretted hydrogen.^[559]

This preparation was formerly considered by Mr. Phillips to be a mixture of carbonate and sub-carbonate of magnesia, an opinion which he has lately retracted; it is, says he, evidently a carbonate, i. e. magnesia combined with one proportion of carbonic acid, or forty-eight of carbonic acid to forty-three of magnesia. Dr. Thompson entertains a different opinion, he observes that it seems to be a mechanical mixture of carbonate of magnesia, caustic magnesia, and perhaps of hydrated magnesia; he found too great a diversity in its composition to permit the conclusion that it was a definite chemical compound; in a specimen purchased at Glasgow, he also found six per cent. of sulphate of lime. I take this opportunity of stating that in some specimens which I have examined, I have also detected portions of gypsum; and from the experiments of Dr. Percival, it appears that if hard water be employed for its preparation it will be less light, and will contain a portion of lime. Magnesia will be also liable to contain traces of silicious earth, derived from the alkali used in producing it. Incompatible Substances. Acids, and acidulous salts; alkalies and neutral salts; alum; cream of tartar; nitrate of silver; acetate of mercury; oxy-muriate of mercury; acetate of lead; sulphates of zinc, copper, and iron. Medicinal Uses. Antacid, and purgative. In cases of lithic calculi, carbonate of magnesia, in doses of ℈j to ʒj, has been proposed by Mr. Hatchett, as a valuable substitute for alkaline remedies. Its insolubility must render its absorption equivocal; its beneficial operation must therefore principally depend upon its neutralizing any excess of acid in the primæ viæ, and in this way there can be no doubt of its lithonthryptic agency; “but,” says Dr. Marcet, “such is the tendency which the public has to over-rate the utility of a new practice, or to take a mistaken view of its proper application, that there is every reason to believe that the use of magnesia has of late years become a frequent source of evil in calculous complaints.” See page 124. Officinal Prep. Hydrarg. cum Magnesia. D. Magnesia. L.E.D. Adulterations. Chalk may be detected by adding dilute sulphuric acid to a suspected portion, when, should any be present, the solution will be loaded with a white and insoluble precipitate; gypsum, by boiling a sample in distilled water, and assaying the solution by a barytic and oxalic test.^[560]

Qualities. Form, small needle-like crystals. Taste, bitter and nauseous; when pure, it effloresces. Chemical Composition. In its crystallized state, it may be considered as composed of 1 proportional of dry sulphate (Magnesia 18·5, and sulphuric acid 37·5) and 7 proportionals of water. Solubility. f℥j of water dissolves ℥j, and the solution measures fʒxj¼; it is insoluble in alcohol. Incompatible Substances. Muriates of ammonia, baryta, and lime; nitrate of silver; sub-acetate, and acetate of lead. The fixed alkalies and their carbonates, precipitate from it magnesia and its carbonate. Phosphate of soda occasions no immediate precipitate, unless ammonia be present, in which case the triple ammoniaco-magnesian phosphate will be produced. The addition of ammonia, which in the form of Spiritus ammoniæ aromat. is not unfrequently prescribed in conjunction with a solution of this sulphate, forms also a triple salt, and a portion of magnesia is precipitated: whenever therefore this ammoniacal stimulant is ordered with a purgative salt, the scientific physician will prefer a solution of the sulphate of soda. Forms of Exhibition. Dissolved in the Infusum Rosæ, or in a suitable quantity of beef tea, gruel, or any aqueous vehicle, its cathartic powers are increased by dilution, as well as by the addition of a little common salt; magnesia renders the taste of its solution less nauseous; and tartarized antimony quickens its operation. Dose, ℥ss to ℥ij, taken either at once, or in divided doses. Form. 37, 69, 72, 76. Officinal Prep. Enema Catharticum. Enema Fœtid. D. Adulterations. Sulphate of Soda is often substituted for this salt, which it may be made to resemble by stirring it briskly at the moment when it is about to crystallize; the fraud may be detected by a precipitation not ensuing on adding carbonate of potass; if only a part of the salt be sulphate of soda, the degree of sophistication can be learnt by the quantity of the precipitate formed; 100 parts of sulphate of magnesia, if pure, will yield between 30 and 40 of the dry carbonate. Epsom salt, as it commonly occurs, contains muriate of magnesia, which disposes it to deliquesce, but lately this salt has appeared in the market in a state of great purity and beauty; the mode of purification is founded upon the well known chemical law, that a saturated solution of one salt is still capable of dissolving another; in the present instance, therefore, the impure crystals are washed in a saturated solution of the same sulphate, which, although unable to act upon its kindred salt, can dissolve with facility the muriate, and any other saline contamination. I confess, however, that I am induced to regard this process as rather chemically ingenious than as medicinally useful, for the usual saline impurities of Epsom salt are not only harmless, but capable of increasing its purgative powers; the double refined sulphate is certainly less efficient as a cathartic. The presence of the muriate may be at once detected by dropping upon the suspected sample some sulphuric acid, by which the disengagement of muriatic acid vapour will be produced. Since the publication of the fourth edition of the present work, I have received samples of the sulphate of Magnesia, prepared by Mr. West of Lymington, and I can confidently recommend the article to the profession; he contrives to obtain them in large and beautiful crystals, which cannot be so easily mistaken for those of oxalic acid, a circumstance of no small importance to the drug vender; the form of these crystals is that of a square prism, having its edges replaced, and commonly terminated by a pyramid of four planes; the only cleavage is parallel to one of the diagonals of the prism. The numerous accidents which so frequently occur from mistaking Oxalic acid for Epsom Salts have given rise to many suggestions for obtaining an easy and popular test which may at once distinguish these bodies; it is evident that no test can be so simple as that afforded by the taste; but if such accidents are in future to be prevented, it must be done by imparting to the acid some external character by which it may be at once recognised; if a test were even discovered a hundred times more sensible than any which we possess, what would it avail?

Qualities. Form, flakes of a granular texture; Colour, whitish, or pale yellow; Odour, slight but peculiar; Taste, nauseous sweet, with some degree of bitterness. Chemical Composition. This concrete vegetable juice, besides sugar, appears to contain mucilage and extractive, to which its taste and other peculiar properties are owing. Solubility. It is entirely soluble in water and alcohol. Med. Uses. It is now merely regarded as a laxative for children, or for weak persons. It generally requires some laxative adjunct, as castor oil, with which it may be combined by the medium of mucilage. Dose, for children, from ʒj to ʒiij, in warm milk. Officinal Prep. Confectio Cassiæ. L.E.D. Enema Cathart. D. Enema Fœtid. D. Syrup. Sennæ. D. Adulterations. There are several varieties in the market, the best of which is flake manna, manna canulata, in a stalactitic form. An article, entirely factitious, consisting of honey or sugar, mixed with scammony, is sometimes sold for genuine manna, but its colour, weight, transparency, and taste, must instantly lead to its detection.

The use of this resinous substance is to fill the cavities of carious teeth; a solution of it in oil of turpentine is sold as an odontalgic. The Turkish and Armenian women use it as a masticatory for cleaning the teeth, emulging the salivary glands, and imparting an agreeable odour to the breath. It forms a constituent of the Dinner Pills. See Aloes. Sonnini tells us that, in Egypt, the smoke of Mastich is supposed to kill any sick person that inhales it.

This well known substance appears to be merely collected from the flowers, and not elaborated by the internal economy of the insect; when properly diluted it undergoes vinous fermentation, the product of which is the beverage well known by the name of Mead. The English honey is more waxy than that from the south of Europe. Virgin honey is that wrought by young bees which have never swarmed, and permitted to run from the comb without heat or pressure. Chemical Composition. Sugar, mucilage, wax, an acid, and occasionally some essential oil. Clarified Honey, (Mel Despumatum. L.D.) has not the agreeable smell of crude honey; it does not however ferment so readily, nor is it so apt to gripe. Uses. It is principally employed for forming several officinal preparations, i. e. Mellita, viz. Mel Boracis. L. Mel Ros. L.D. Oxymel. L.D. Oxymel Colchici. E. Oxymel Scillæ. L.D.^[562] Sir John Pringle considered it as useful in nephritic disorders; it possesses also a laxative property, which renders it on many occasions preferable to Syrup. Adulterations. Flour may be detected by diffusing the honey in tepid water, by which it will be separated, and, by subsequent boiling, converted into a thick paste.

[This plant is a native of the East Indies, from whence it was introduced into Europe and North America. The part used in medicine is the bark of the root. It is a powerful anthelmintic, and affects the system in a way very similar to the Spigelia Marylandica, producing not unfrequently confusion of the head, stupor, trembling of the hands, &c. This is particularly the case if it be used in the months of March and April, when the sap rises in the tree. It is chiefly against the round worm that the Melia has been found successful, though in some cases it has proved effectual also against the Tænia. It is generally given in the form of decoction: to prepare this, ℥iij or ℥iv of the bark of the fresh root are put into a quart of water and boiled down to a pint, of which ℥ss to ℥j may be given every two or three hours till it operates. Administered in this way, it frequently causes both purging and vomiting.]

All the qualities of this plant depend upon an essential oil and camphor; it readily and strongly impregnates either water or spirit, by infusion; its infusion, and the water distilled from the plant, are carminative and antispasmodic; they also serve as vehicles for other medicines, to correct their operation, or to disguise their flavour. Officinal Preparations. Aq. Menth. Piperit. L.E.D. Spir. Menth. Pip. L.D. Ol. Menth. Pip. L.D. If this plant be cut in wet weather, it turns black, and is worthless.

Cold water extracts the more agreeable and active parts of mint in a few hours; a longer maceration extracts the grosser and less agreeable portions; hot water more quickly extracts its virtues, but if it be boiling it dissipates the aroma. Officinal Preparations. Aq. Menth. virid. L.D. Infus. Menth. comp. D. Ol. Menth. virid. L. D. Spir. Menth. virid. L.

The inner bark of this plant, when fresh, is corrosive and even vesicatory; the fruit is equally so, but neither have any smell; its virulence is counteracted by camphor. It contains, besides extractive matter, an acrid resinous substance, which, according to Plaff, bears a strong resemblance to the active principle of Cantharides. It is now seldom used except as an antivenereal remedy, or in cases of chronic cutaneous disease. Forms of Exhibition. In a decoction, made by boiling ℥ss of the bark, with an equal quantity of Liquorice root, in oiij of water down to oij; of which f℥ss may be given twice a day. From its pungency it is one of the substances used by fraudulent brewers to communicate a strong flavour to their beer. Where a discharge from issues cannot be kept up by the common means, it is said that the introduction of a little of this bark, instead of the pea, will in a few hours produce the desired effect. Officinal Preparations. Decoct. Sarsaparill. comp. L. Decoct. Daphnes. Mezerei. E. The Daphne Laureola is very generally sold for Mezereon.

The principles upon which this form of preparation is to be constructed, are fully detailed in the first part of this work, page 199.

Mistura Ammoniaci. L. This mixture is expectorant, and may be exhibited with tincture of squills, &c. (Form. 115, 136.) It is slightly curdled by vinegar, oxymel, æther, and oxy-muriate of mercury.

Mistura Amygdalarum. L. Emulsio Amygdali communis. E. Lac Amygdalæ. D. It is a useful demulcent and diluent, and forms an elegant vehicle for more active medicines. Incompatibles—Acids, Oxymel, Syrup of Squill, Spirit, and Tinctures, unless added in very small quantities, decompose this mixture; tartaric acid, super-tartrate of potass, and oxy-muriate of mercury, also disturb it. Form. 137.

Mistura Assafœtidæ. L. A nauseous preparation; and where its use is indicated, it will be more judicious to prescribe it as an extemporaneous mixture. See Assafœtida.

Mistura Camphoræ. L. This solution of camphor forms an elegant vehicle for more active stimulants. The camphor is separated from the water by a solution of pure potass, by sulphate of magnesia, and by several saline bodies. See Form. 7, 24, 25, 32, 47, 72, 116, 117, 123.

Mistura Cornu Usti. L. Decoctum Cornu Cervini. D. This is nothing more than a simple diffusion of phosphate of lime in a thin mucilage—Cui bono? It was retained in the Pharmacopœia in deference to the opinion of some experienced practitioners.

Mistura Cretæ. L.D. A common and useful remedy in diarrhœa, and may be combined with opium, catechu, or any other astringent. Form. 52. It is of course incompatible with acids, and acidulous salts.

Mistura Ferri Composita. L. This is nearly the same as the celebrated anti-hectic mixture of Dr. Griffith; to the result of the decompositions which take place from the mixture of its ingredients, it is wholly indebted for its medicinal energies; thus, a proto-carbonate of iron is formed, i. e. the iron combined with carbonic acid is at its minimum of oxidation, which renders it more active than the common carbonate, and probably less stimulant than the sulphate; this product, by means of the saponaceous compound formed by the union of the myrrh with the excess of alkali, is partly diffused and suspended in the mixture, and partly dissolved, whilst at the same time a sulphate of potass is formed, which serves to correct the astringent influence which iron is apt to exert upon the bowels. The iron in this preparation is disposed to combine with an additional proportion of oxygen, hence its ingredients should be quickly mixed together, and it ought to be considered as an extemporaneous preparation, and be preserved in a closely-stopt vessel. Its change of colour will generally indicate its loss of efficacy. This preparation must be regarded as permanently serviceable in Chlorosis, and the numerous sympathetic affections connected with it. In the painful swellings which infest the breasts of chlorotic young women, I have found it almost a specific. Dose, f℥j-f℥ij. The proportion of Proto-carbonate of iron, contained in any given quantity of this mixture, may be found by referring to the Medicinal Dynameter; for instance, bring the preparation to 12, and we shall perceive that this number of fluid-drachms contain 1 grain of Protoxide, or rather more than gr. iss of Proto-carbonate of iron; and we shall, at the same time, perceive that to give an equivalent quantity in the form of Pil. Ferri comp. we must prescribe ℈j. See Form. 96.

Mistura Moschi. This is an eligible form for the administration of Musk. Dose, f℥j-f℥ij, to which may be added extemporaneously, ammonia, æther, and other diffusible stimulants.

The Dose of the above mixtures is f℥j-to f℥ij twice or thrice a day.

Qualities. Form, grains concreted together, dry, yet slightly unctuous. Colour, deep brown with a shade of red; Odour, aromatic, peculiar, diffusive, and durable; and it has the curious property, when added in a minute quantity, to augment the odour of other perfumes without imparting its own; this renders it a valuable article in perfumery, on which account it is a usual ingredient in lavender water. Taste, bitterish and heavy. Chemical Composition. Resin combined with volatile oil, and a mucilaginous extractive matter, with small portions of albumen, gelatine, muriate of ammonia, and phosphate of soda. Solubility. Boiling water dissolves it perfectly; rectified spirit takes up most of its active parts, although the odour is only discovered upon dilution; sulphuric æther is its most complete menstruum. Incompatible Substances. The solutions are decomposed by Oxy-muriate of Mercury; Sulphate of Iron; Nitrate of Silver; and the Infusion of Yellow Bark. Med. Uses. Stimulant and antispasmodic. As early as the time of Meade it was employed in typhus fever; Pringle administered it in gout of the stomach, a practice which received the concurrence of Cullen; conjoined with ammonia it has been celebrated for its powers in arresting the progress of gangrene, and of imparting fresh excitement to the nervous system. It has been also administered with success in epilepsy, hooping cough, and other spasmodic affections. Forms of Exhibition. The best form is that of bolus, combined with ammonia or camphor, or some other similar remedy, (Form. 21); it may be also administered in a mixture, for which purpose it requires five times its weight of mucilage, consequently the London College has not directed a sufficient quantity to retain the musk in suspension: by previously triturating it with sugar, its minute division is much facilitated. Dose, grs. x to xxx. See Form. 22, 30. Officinal Prep. Mist. Mosch. L. Tinct. Mosch. D. Adulterations. The bag containing the musk should have no appearance of having been opened: the presence of dried blood may be suspected, by its emitting, as it inflames, a fetid smoke; Asphaltum is discovered by its melting and running before it inflames: the artificial bags are known from the deficiency of the membrane which lines the real musk bags. To increase the weight of the musk, fine particles of lead are frequently added; this is easily detected, for by rubbing it with water the metallic particles will subside.

Moschus Factitius. Artificial Musk, strongly resembling the real, may be formed by digesting f℥ss of Nitric Acid, for ten days, upon ℥j of fetid animal oil, obtained by distillation; to this is to be next gradually added oj of rectified spirit, and the whole is then to be left to digest for one month: or—

2. Drop fʒiiiss of nitric acid upon fʒj of rectified oil of amber; after standing twenty-four hours, a black, resinous pellicle, exhaling the odour of musk, will be formed.

This preparation consists of one part of gum and two of water; in preparing it, the dispenser is particularly recommended to pulverize the gum, and never to employ that which is purchased in the state of powder, as it is always impure and incapable of forming a pellucid and elegant solution.^[564] Incompatible Substances. Neither the strong acids nor alcohol, when considerably diluted, occasion any disturbance in it; but sulphuric æther and its compound spirit, the tincture of muriated iron, and sub-acetate of lead, produce very dense precipitates: the acetate of lead only occasions decomposition, when an alkaline salt is present in the formula; the volatile alkali curdles the mucilage, and hard calcareous waters render the mixture difficult and often impracticable. In the pharmaceutical application of this mucilage, it should be remembered that it contains in its composition an astringent principle, which is perhaps of but trifling consequence except in the exhibition of some very few active metallic salts, which are certainly decomposed by it (e. g. grs. x of nitrate of mercury are decomposed by ʒij of gum arabic.^[565]) It contains also lime in combination with some vegetable acid. Uses. Diluted with four times its bulk of water, this mucilage forms a demulcent mixture of appropriate tenacity, which affords a convenient vehicle for several efficient remedies; the pharmaceutical use of this mucilage depends upon the fact of its rendering expressed and essential oils, balsams, resins, gum-resins, resinous tinctures, and fatty bodies, miscible with water, but if a syrup be added, the union will be more perfect; the proportions necessary for this purpose vary according to the nature of the substances; thus, oils will require about three-fourths their weight, Balsams and Spermaceti an equal part, Resins a double quantity, and Musk five times its weight; the following Formulæ illustrate this property, 9, 19, 22, 135.

This is a strong, insipid, inodorous mucilage, which is principally employed as a vehicle for exhibiting Opium in the form of Enema, see Amylum.

Tragacanth is, strictly speaking, not soluble in water, but imbibes a large portion of it and swells into a considerable bulk, forming a soft but not a liquid mucilage; on the farther addition of water, a fluid solution may be obtained by agitation, and the liquor is turbid; but on standing, the mucilage subsides, the limpid water on the surface retaining a little of the gum;^[566] it differs from all gums in giving a thick consistence to a larger quantity of water, its power in this respect being to that of gum arabic as twenty to one; one part converts twenty of hot water into a stiff mucilage. Tragacanth is not increased, but actually diminished in solubility by the addition of any other gum, it accordingly separates from water with much greater facility when gum arabic is present. This preparation, according to the Edinburgh college, consists of one part of gum and eight of water; the resulting mucilage is stiff, and is principally employed for making troches. The Dublin preparation contains four times that quantity of water.

All the properties of this well-known substance depend upon an essential oil, filling the dark coloured veins which run through its substance, the other components are starch, gum, wax, and a fixed oil. The oil obtained by expression is improperly called oil of mace, for it would appear to be a triple compound of fixed oil, volatile oil, and wax, and which, although limpid when first drawn, soon acquires on cooling the consistence of spermaceti. Mace is the involucrum of the nut. Med. Uses. Stimulant, and in large doses, as from ʒij to ʒiij, narcotic, frequently producing delirium. See Cullen Mat. Med. ii. 201. Officinal Prep: Spir: Myristicæ. L.E.D. Frauds. Nutmegs are frequently despoiled of their essential oil, by being punctured and submitted to the operation of decoction, the orifices being subsequently closed by powdered Sassafras; the imposition is detected by the comparative lightness of the nutmeg, and by its extreme fragility; the holes may also be discovered by carefully examining the surface of the nut, after having steeped it in hot water.

Qualities. Form, irregularly shaped pieces, translucent, of a reddish yellow colour; Odour, peculiar and fragrant; Taste, bitter and aromatic. Chemical Composition. Resin, gum, essential oil, and some extractive. Solubility. When triturated with soft, or distilled water, nearly the whole appears to be dissolved, forming an opaque, yellowish solution, but by rest the greater part is deposited, and not more than one-third is actually dissolved; its solubility, however, in water may be increased by trituration with camphor or an alkali; rectified spirit dissolves it, and the resulting tincture, when diluted, becomes turbid, although no precipitate occurs. Med. Uses. Stimulant, as in Form. 103. Expectorant, 132, 133, 138. Emmenagogue, 95, 98, 99. It is also tonic, and agrees with some constitutions better than any of the bitters. Forms of Exhibition. No form is so eligible as that of substance. Dose, grs. x to ʒj. The alkalies, in their crystalline state, when triturated with myrrh, reduce it to the form of a tenacious fluid. Officinal Preparations. Tinct. Myrrh. L.E.D. Tinct. Aloes et Myrrh. E. Tinct. Aloës Ætherea. E. Mist. Ferri comp. L. (G L) Pil. Aloes cum Myrrha. L.E.D. Pil. Ferri cum Myrrha. L. Pil. Galb. comp. L.D. (B) Pil. Assafœtid. comp. E. (B) Pil. Rhei, comp. E. (G) Adulterations. It is subject to a variety of frauds, being frequently mixed with adventitious gums, which are to be detected by their foreign odour, their white or dark colour, and by their opacity.

This seed has not at present a place in the British pharmacopœiæ; it presents however several points of interest to the physiologist, the physician, and the chemist. Its virulent action upon animals has been long known; and it has been administered in combination with gentian in intermittents.^[567] (Ludovic. Phar. p. 113,) and as a narcotic in mania; it also constituted an ingredient in the famous Electuarium de ovo, (Ph. Angl. p. 263.) Nux vomica has been said to produce benefit in the plague; the German writers have strongly commended it in mania, epilepsy, and hydrophobia; as well as in chronic rheumatism, gout, scrophula, lues venera, and cutaneous eruptions; in Sweden it is stated to have displayed very beneficial effects in Dysentery. Dr. Fourquier has lately introduced its use in the Hopital de la Charité, in cases of partial paralysis, and it is said, with very great success.^[568] The value of the practice has been since confirmed by the experiments of Dumeril, Majendie, Hebreard, Husson, and Asselin. The dose is four or five grains of the powder in pills, during the day. The French codex contains two alcoholic extracts of this substance; the one prepared with a strong spirit (22, 32, Beaumé, i. e. from sp. gr. ·915 to ·856,) is much more active and powerful than that made with a weak spirit. (12, 22, Beaumé, i. e. from sp. gr. ·985 to ·915.)

M. M. Pelletier and Caventou have discovered in this substance, a peculiar proximate principle, to which its virulence is owing; it was named Vauqueline, in honour of the celebrated French philosopher, but in deference to the opinion of the French Academy of Sciences, the discoverers have substituted the name Strychnia, because “a name dearly loved, ought not to be applied to a noxious principle!”^[569] (Annales de Chimie, vol. 8 to 10.) Strychnia is highly alkaline, and crystallizes in very small four-sided prisms, terminated by four-sided pyramids; its taste is insupportably bitter, leaving a slight metallic flavour, and is so powerful as even to be perceptible when a grain is dissolved in eighty pounds of water;^[570] it has no smell; is not changed by exposure to the air, nor is it either fusible or volatile, for when submitted to the action of heat, it only fuses at the moment of its decomposition which takes place at a temperature inferior to that which destroys most vegetable substances; it is so extremely active and violent, that in doses of half a grain it occasions serious effects, and in larger ones convulsions and death; it is perhaps the most powerful,^[571] and next to hydro-cyanic acid, the most rapid of poisons; notwithstanding its strong taste, it is very sparingly soluble in water, requiring 6667 parts of that fluid for its solution at 50, and 2500 at 212°. It is very soluble in alcohol, but unlike most of the other vegetable alkalies, is nearly insoluble in æther; with acids it forms neutral and crystallizable salts; these salts as well as their base, have the singular property of becoming bloodred by the action of concentrated nitric acid. The alcoholic solution of Strychnia has the property of precipitating the greater number of metallic oxides from their acid solutions. It is precipitated by alkalies and alkaline earths. Strychnia exists in native combination in the Strychnus with an acid which has some analogy with the malic, and which Pelletier and Caventou propose to call the Igasuric acid, from the Malay name for the bean of St. Ignatius,^[572] (Strychnus Ignatius,) in which its properties were first examined. In conformity with such views, the active principle of the tribe of Strychni is an Igasurate of Strychnia;—a fact which suggests the existence of a most singular and striking analogy between the chemical constitution of these narcotico-acrid bodies^[573] and that of opium. The recent experiments of Pelletier have shewn, moreover, that besides Strychnia, the Nux Vomica contains Brucia, an alkaline body which had been previously discovered in spurious Angustura. Its properties are similar to those of Strychnia, but it is less active. Being much more soluble in alcohol than Strychnia, if care be taken to crystallize the latter several times in alcohol, it will be separated, the Brucia remaining in the mother waters. Strychnia has been given in doses of one-twelfth of a grain, but it is a most dangerous remedy, and is liable to occasion tetanic convulsions.^[574] It has been said, however, to prove serviceable in cases of Epilepsy that had resisted every other method of cure. Dr. Fleming informs us that the Hindoos of upper India are in the habit of adding Nux Vomica in the process of distilling Arrack, for the purpose of rendering the spirit more intoxicating. The London Porter brewers have been accused of the same pernicious practice.

The British pharmacopœiæ direct them to be obtained by distillation only; the French codex orders several of them to be prepared by expression. Qualities. Form, liquid, sometimes viscid; specific grav. various; oil of turpentine, which is the lightest, being only 0·792, whilst the oil of cloves, cinnamon, and allspice, exceed 1·030, and that of sassafras, which is the heaviest, amounts to 1·094; these latter oils hold resin in solution, and of course sink in water. Odour, penetrating and fragrant; Taste, acrid; they are volatilized at a temperature somewhat below that of boiling water; they are very inflammable. Solubility. Very soluble in alcohol, forming what are termed in perfumery Essences; in water they are very sparingly soluble; the solutions are known in pharmacy under the title of distilled waters; they are also dissolved by æther, and the fixed oils; when digested with ammonia, some of the less odorous acquire a considerable degree of fragrance, whilst on the contrary, fixed alkalies universally impair their odour; they are rapidly decomposed by nitric and sulphuric acids, and their action is sometimes attended with instant inflammation. Volatile oils, from continued exposure to the air, absorb oxygen, and become resinous, by which they lose their volatility, fragrance, and pungency, hence they should be preserved in small opaque phials, completely full and well stopped. Med. Uses. They act as powerful stimulants and aromatics; they remove nausea and flatulence, correct the griping of certain purgatives, and cover the offensive taste of various remedies. See Aquæ destillatæ. They, moreover, have the property of defending certain animal and vegetable preparations from mouldiness. This curious fact has been already noticed, see page 177. The following is a list of the species admitted into our British pharmacopœiæ; those designated in italics are principally for internal use. Olea Anisi, Anthemidis, Carui, Juniperi. Lavandulæ, Menthæ Piperitæ, Menthæ viridis, Origani, Pimentæ, Pulegii, Rosmarini, L. Olea Volatilia, Juniperi communis, Juniperi Sabinæ, Lavandulæ Spicæ, Lauri Sassafras, Menthæ Piperitæ, Myrtæ Pimentæ, Pimpinellæ Anisi, Rorismarini Officinalis. E. Olea Juniperi, Pimento, Corticis et Ligni Sassafras, e Seminibus Anisi, Carui, Fœniculi dulcis, Florum Lavendulæ, Foliorum Sabinæ, Herbæ florescentis Menthæ Sativæ, Origani, Pulegii, Rorismarini, Rutæ, D. Adulterations. Fixed Oils may be detected by moistening writing paper with the suspected article and holding it before the fire: if the oil be entirely essential, no stain of grease will remain; as castor oil is more soluble in spirit than the others, it is the one generally selected for this fraudulent purpose, and the addition of alcohol restores the sophisticated oil to its proper degree of consistency. Alcohol is discovered by adding water, which, if it be present, occasions a milkiness, and at the same time, an increase of temperature; a decrease of bulk also takes place, which may easily be ascertained by measuring the oil and water separately, and then transferring them, in a state of mixture, into a tube of small diameter. Cheaper oils, as that of turpentine, are recognised by their peculiar odour, which may be developed by rubbing a drop upon the hand and holding it to the fire, or, by the dense black smoke with which they burn. The oil of aniseed, as it crystallizes at 50°, is frequently sophisticated with wax, spermaceti, or camphor; the fraud is detected by warming the oil, when the crystals, if genuine, will dissolve.^[575] In some cases the refractive power of the oil affords a test of its purity. See my work on Chemistry in its relations to Medicine, § 318.

These are obtained from animal matter by fusion, and from vegetable by expression, or decoction with water. Qualities. Odour, none; Taste, mild; they boil at 600°, but undergo decomposition, becoming acrid and empyreumatic; the oil, in this state, was formerly used in medicine under the name of philosopher’s oil.^[576] By exposure to air they absorb oxygen and become rancid; they congeal at a temperature of 32°, and some even above that. When the oil is expressed by heating the plates of the press, or by previously roasting the seeds, it is more disposed to become rancid; cold drawn oils are on this account to be preferred for the purposes of pharmacy. Solubility. They are insoluble in water, and, except castor oil, nearly so in alcohol and æther; with caustic alkalies they combine and form soaps; when aided by heat they readily unite with oxide of lead, forming the solid compound well known by the term plaister. They unite also very readily with each other, and with volatile oils. Solvent Powers. They dissolve sulphur, and form a kind of balsam with it; they also possess the power of extracting and dissolving the narcotic and acrid principles of several vegetable and animal substances, in consequence of which, the French pharmacopœia directs a series of preparations under the term “Olea Medicata;” thus there are olea Cicutæ, Hyoscyami, Solani, Stramonii, Nicotianæ;^[577] which are made by digesting with a gentle heat, one part of the subject in two parts of olive oil.^[578]