Ten grains of Elaterium, obtained from a respectable chemist, and having all the sensible properties which indicated it to be genuine, were digested for twenty-four hours with distilled water, at a temperature far below that of boiling; four grains only were dissolved.

The solution was intensely bitter, of a brownish yellow colour, and was not in the least disturbed by alcohol, although a solution of Iodine produced a blue colour; the solution therefore contained no gum, and only slight traces of starch.

The solution, after standing twenty-four hours, yielded a pellicle of insoluble matter, which when burnt appeared to resemble Gluten.

The six grains which were insoluble in water, were treated for forty-eight hours with alcohol of the specific gravity ·817, at 66° of Fahrenheit; a green solution was obtained, but by slow evaporation only half a grain of solid green matter was procured. The insoluble residue obstinately adhered to, and coated the filtre like a varnish, and completely defended the mass from the action of the alcohol; it is probable that it consisted principally of Starch.

Ten grains of Elaterium, from the same sample, were treated with alcohol of the specific gravity ·817, at 66° Fahrenheit, for twenty-four hours; upon being filtered, and the residuum washed with successive portions of alcohol, the Elaterium was found to have lost 1·6 of a grain. The high specific gravity of the alcohol in this experiment was important; had it been lower, different results would have been produced.

The alcoholic solution obtained in the last experiment, was of a most brilliant and beautiful green colour, resembling that of the oil of cajeput, but brighter; upon slowly evaporating it, 1·2 grains of solid green matter were obtained.

The solid green matter of the last experiment was treated with boiling distilled water, when a minute portion was thus dissolved, and a solution of a most intensely bitter taste, and of a brownish yellow colour, resulted.

The residue, insoluble in water, was inflammable, burning with smoke and an aromatic odour, not in the least bitter; it was soluble in alkalies, and was again precipitated from them unchanged in colour; it formed, with pure alcohol, a beautiful tincture, which yielded an odour of a very nauseous kind, but of very little flavour, and which gave a precipitate with water; it was soft, and of considerable specific gravity, sinking rapidly in water; circumstances which distinguish it from common resin; in very minute quantities it purges. It appears to be the element in which the purgative powers of the Elaterium are concentrated, and which I have denominated Elatin.

The residuum, insoluble in alcohol, weighing 8·4 grs. (Expt. E) was boiled in double distilled water, when 5·9 grs. were dissolved.

The above solution was copiously precipitated blue by a solution of Iodine, and was scarcely disturbed by the Per-sulphate of Iron.

The part insoluble, both in alcohol and water, which was left after Experiment I, amounting to 2·5 grains; it burnt like wood, and was insoluble in alkalies.

It appears that the whole of the Elatin does not separate itself from its native juice by spontaneous subsidence, and that, on this account, the supernatant liquor possesses some powers as a cathartic. We cannot be surprised therefore that the Elaterium of commerce should be a very variable and uncertain medicine; for independent of the great temptation which its high price holds out for adulterating it, which is frequently done with starch, it necessarily follows that where the active principle of a compound bears so small a proportion to its bulk, it is liable to be affected by the slightest variation in the process for its preparation, and even by the temperature of the season; where pressure is used for obtaining the juices, a greater or less quantity of the inactive parts of the cucumber will be mixed with the Elatin, in proportion to the extent of such pressure, and the Elaterium will of course be proportionally weak.^[504] There is one curious result obtained in my experiments which deserves notice, viz. that there is a bitter principle in the Elaterium, very distinct from its extractive matter, and totally unconnected with its activity, for I diluted the solution obtained in experiment G. and swallowed it, but it produced upon me no effect, except that which I generally experience upon taking a powerful bitter,—an increased appetite; and yet notwithstanding this fact, when in combination with Elatin, it is far from being inert, since this latter body is considerably quickened by its presence. See page 152. The solution B was given to a person, but no effect whatever ensued. Dose of good Elaterium, as it occurs in commerce, is about one grain, or it is better to give it only to the extent of half a grain at a time, and to repeat that dose every hour until it begins to operate. It is probably, when thus managed, the best hydragogue cathartic which we possess; it differs however from the class of remedies to which it belongs, for it excites the pulse and whole animal system, so as to produce a considerable degree of febrile action. It was strongly recommended by Sydenham, Lister, and Hoffman, and all their cotemporaries and immediate successors, as a valuable remedy in dropsy; but in consequence of some fatal results from its improper application, it was driven from practice with a violence that marks prejudice rather than conviction; one author, in descanting upon its virulence, exclaims, “Elaterium esse in catalogo diaboli quo necat homines.” For its restoration to medicine, we are indebted to Dr. Ferriar of Manchester, who used it with great success in the cure of Hydrothorax.

Extractum (Succus Spissatus. E.D.) Hyoscyami. L. This preparation is certainly powerfully narcotic, and tends to relax rather than astringe the bowels; where the constitution is rebellious to opium, it furnishes a more valuable resource to the practitioner than any other narcotic extract. Dose, gr. v to ℈j, in pills. See Form. 1, 3, 4, 19, 139.

Extractum Lactucæ. L. Succus Spissatus Lactucæ Sativæ. E. This preparation has found its way into the London Pharmacopœia, in consequence of the testimony of many highly respectable practitioners in favour of its sedative properties. In the memoirs of the Caledonian Horticultural Society, various suggestions are offered as to the best mode of obtaining an extract from the milky juice of the garden Lettuce, to which Dr. Duncan has bestowed the name of “Lactucarium;” it was first recommended to take the milk with cotton, afterwards with a sponge, and more recently with a painter’s brush; all these methods however are attended with considerable difficulty, and the juice cannot be collected in any quantity. Mr. Probart, a chemist in Great Portland Street, has lately cultivated large plantations of the lettuce, for the purpose of instituting experiments upon the subject, and I am happy in being enabled through his liberality, to introduce in this place, an account of the process which he pursues, and which he considers the only one by which the article can be brought into the market at any reasonable price.^[505]

In concluding the history of Inspissated juices, it deserves notice that the London College uniformly directs that the feculence should be preserved in the compound: there can be no doubt of the propriety of such advice, but the Colleges of Edinburgh and Dublin reject it. The French Codex gives directions for two extracts from each of these substances, one containing what they please to denominate the fecula, the other not; thus there is “Extractum Cicutæ absque Fecula” and “Extract: Cicut: cum Fecula.” There is one curious fact respecting these narcotic preparations, that most, if not all of them, contain nitre, common salt, and muriate of potass.

Manufacturing chemists, in order to give a smooth and glossy appearance to their Extracts, generally add to every ℔j, about ʒss of gum, fʒj of olive oil, and ♏︎xx of rectified spirit; there is no harm in the practice.

In a former Pharmacopœia of London, a sub-carbonate of iron was prepared, under the name of ferri-rubigo (rust of iron,) by exposing iron-filings to the action of air and water; and although the Colleges of Edinburgh and Dublin still retain this mode of preparation, yet they admit at the same time of another which, like the sub-carbonate of the present London Pharmacopœia, is produced by precipitation. Qualities. Form, a chocolate brown powder. Odour, none. Taste, slightly styptic. Chemical Composition. Mr. Phillips has shewn that this precipitate is liable to vary according to the temperature at which it is prepared, as well as from other differences of manipulation; it generally consists of mixtures of peroxide, and proto-carbonate of iron, in the proportion of four parts of the latter, and six of the former. By referring to the Medicinal Dynameter the practitioner may find the quantity of those ingredients in any given weight of the preparation, and compare its strength with the other chalybeate medicines. Solubility. It is insoluble in water, but acids dissolve it with effervescence. Forms of Exhibition. In powder or pills, combined with aromatics. Dose, gr. v to xxx. (Form. 38.) It has lately been brought into particular notice by the publication of Mr. Hutchinson of Southwell, who states that in doses of half a drachm to a drachm, two or three times a day, it has proved in his hands a most efficacious remedy in the cure of Tic doloureux. Mr. Hutchinson is well known to the profession as a judicious and inquiring practitioner, and we are well satisfied that he would not recommend any remedy to the attention of his brethren, without a well grounded assurance of its efficacy; at the same time it must be remembered that this disease is very frequently the consequence of an irritation in some nerve, by the mechanical operation of osseous spiculæ; in such cases we cannot expect the sub-carbonate of Iron to afford relief. A noble Marquis who lost his leg at Waterloo, suffered excruciating pains in his face, in consequence of exfoliation in the stump, which were relieved as soon as the local irritation subsided; and a late lamented physician appears to have owed his severe sufferings to the irritation produced on the brain by a bony excrescence. I have little doubt if cases of Tic doloureux were more carefully examined, they would be frequently found to derive their origin from a similar source. If it were necessary I could add several of such instances to those already enumerated.^[506]

Iron seems to be a metal that proves active in its metallic state; its filings may be given in the form of powder, conjoined to some aromatic, or what is perhaps more eligible, in the form of an electuary. The Mahometan practitioners are in the habit of prescribing them, in conjunction with ginger, and cummin seeds, in cases requiring tonics. Dose, grs. v to ʒss. Impurities. Iron filings should be carefully purified by the application of the magnet, since those obtained from the work-shops are generally mixed with copper and other metals. For pharmaceutical purposes, iron wire should be preferred, as being the most pure, since the softest iron only can be drawn, and Mr. Phillips has shewn us, in his experiments upon the “Ferrum Tartarizatum” that soft iron is more easily acted upon by Tartar.

Qualities. Form, crystals, which are rhomboidal prisms, transparent, and of a fine green colour; when exposed to the air they effloresce, and at the same time become covered with a yellow powder, owing to the attraction of oxygen; when exposed to heat, they undergo watery fusion, and at a higher temperature, the acid is driven off and the peroxide of iron alone remains, which in commerce is known by the name of Colcothar. Chemical Composition. According to Dr. Thomson, it consists of 27·7 of sulphuric acid, 28·3 of protoxide of iron, and 45 of water; 8 parts, however, of this water, exist in combination with the oxide of iron. The Medicinal Dynameter will shew the proportion of protoxide in any given weight of this salt. Solubility. It is soluble in two parts of water at 60°, and three-fourths at 212°. The solution reddens vegetable blues. It is insoluble in alcohol; when however the iron is farther oxidized, it becomes soluble in that menstruum.^[507] Incompatible Substances. Every salt whose base forms an insoluble compound with sulphuric acid; the earths, the alkalies and their carbonates; borate of soda; nitrate of potass; muriate of ammonia; tartrate of potass and soda; acetate of ammonia; nitrate of silver; sub-acetate and acetate of lead; and Soaps. Whether the medicinal virtues of a salt of iron are injured by combination with astringent vegetable matter, seems to admit of doubt. Such substances have been usually ranked amongst the incompatibles, but I am disposed to think without sufficient grounds, for I have frequently witnessed the salutary effects of iron when exhibited in this questionable state of combination—may not the absorbents be more disposed to take up iron, when combined with vegetable matter, than when it is presented in a more purely mineral form?^[508] Medicinal Uses. Tonic, astringent, emmenagogue, and anthelmintic; in large doses, it occasions griping in the bowels. Dose, gr. j to v, combined with rhubarb, or some bitter extract. (form: 72, 87.) If given in solution, the water should be previously boiled, or the oxygen contained in the atmospherical air, which is diffused through it, will partially convert the salt into an oxy-sulphat, and render it insoluble. As an external astringent it is useful in the aphthæ of children.^[509] Officinal Prep. Mist: Ferri comp: L. (K) Pil: Ferri comp: L. (J).

Qualities. Form, crystalline grains, which deliquesce; Colour, orange yellow; Odour, resembling that of saffron; Taste, styptic. Chemical Composition. This is very variable; depending upon the degree of heat and length of time employed for its preparation. It seems to be a mixed mass, consisting of sub-muriate of ammonia and sub-muriate of iron, the metal being in the state of red oxide; and, Mr. Phillips states that in the London preparation a portion of sub-carbonate of ammonia is necessarily present. The same chemist has also shewn that the proportion of Peroxide of iron in 200 grains is not more than three grains. Its equivalents will be seen in the Medicinal Dynameter. Solubility, f℥j of water dissolves ʒiv of it; it is also very soluble in alcohol. Incompatible Substances. The Alkalies, and their Carbonates; Lime water, and Astringent vegetables. Medicinal Uses. It is tonic, emmenagogue, and aperient, but it is so uncertain in its composition and effects that it is rarely used. Officinal Prep: Tinct: Ferri Ammon: L. Form: 36, 43, 95. Impurities. These are indicated by the dull and pale yellow colour of the salt; it may be purified by resubliming it.

Qualities. Form, a powder of a brownish green colour; Odour, none; Taste, slightly styptic; it attracts humidity from the atmosphere, but does not deliquesce. Chemical Composition. Mr. Phillips has devoted much attention to this subject, and he states that as it is frequently prepared, it is a mere mixture of metallic iron with super-tartrate of potass, coloured by oxide of iron; when however it is made with more care, it appears to be a double salt, consisting of tartrate of potass and tartrate of iron; or may it not be one of those combinations which cream of tartar forms with metals, and of which I have spoken under the article Antimonium Tartarizatum? The quantity of peroxide of iron contained in any weight of this preparation may be seen by referring to the Medicinal Dynameter; five grains, for instance, will be found to contain gr. j of peroxide, which, it will be observed, are equivalent to ♏︎xiv of the Tinctura Ferri Muriatis, and to ♏︎xxv of the Liquor Ferri Alkalini, or to f℥j of the Vinum Ferri. Solubility. It is very soluble in water, and the solution remains for a great length of time without undergoing any change, except that of depositing tartrate of lime, which is an incidental impurity in the super-tartrate of potass. Incompatible Substances. All strong acids; lime water; hydro-sulphuret of potass; astringent vegetables? The fixed alkalies and their carbonates decompose the solution very slowly, unless heated; but ammonia and its sub-carbonate produce upon it no effect, whether it be hot or cold; this fact, observes Mr. Phillips, will enable us to exhibit iron in solution with an alkali, without the occurrence of an precipitate. Forms of Exhibition. The perfect preparation, from its tendency to deliquesce, cannot be well ordered in the form of powder; that of solution is probably the most judicious. Med. Uses. It is supposed to add to its chalybeate virtues those of a diuretic nature. Dose, grs. x to ʒss. See Form: 34, 53, 92. Dr. Bateman has recommended a watery solution of it, as a chalybeate peculiarly suited to children, from its tasteless quality.^[510]

Qualities. This root is nearly inodorous; its taste slightly bitter, sweetish, sub-astringent, and mucilaginous; as it contains no volatile ingredient, it may be given in decoction, but on account of its astringency, it must not be conjoined with a chalybeate. Chemical Composition. According to M. Morin, the Male Fern root owes its anthelmintic property to a fatty substance, capable of being saponified; of a nauseous odour quite like that of the root; of a very disagreeable taste, heavier than water, and distilling with water, and when burnt, giving a dense aromatic smoke. The root, moreover, contains gallic and acetic acids; uncrystallizable sugar; tannin; starch; a gelatinous matter insoluble in water and alcohol; lignine; and various salts. M. Morin considers the fatty matter as formed of a fixed and a volatile oil, but farther experiments are required to make the characteristic principle of this root better understood. (Ann. de Chim. xxvi. 219.) Dose, as an anthelmintic,^[511] ʒj to ʒiij, followed by a cathartic; its use however is superseded by more powerful and certain vermifuges. The root is sometimes boiled in ale to flavour it.

Qualities. Form, variegated masses, of a yellowish brown colour; Odour, fetid; Taste, bitter and acrid. Chemical Composition. It is one of those vegetable products to which the name of gum-resin has been given, see Elemi. The latest analysis of galbanum by M. Meisner, affords the following results, Resin 65·8; Gum 22·6; Cerasin 1·8; Malic acid 0·2; Volatile oil 3·4; Vegetable Debris 2·8; loss 3·4. Solubility. Water, wine, and vinegar, by trituration, take up one-fourth of its weight, and form a milky mixture, which deposits its charge by rest; a permanent suspension, however, may be effected by the intermedium of egg or of gum arabic, for which purpose the galbanum will require half its weight of gum. Alcohol takes up one-fifth of its weight, and a golden yellow tincture results, which has the sensible qualities of the galbanum, and becomes milky on the addition of water, but no precipitate falls. A mixture of two parts of rectified spirit and one of water, will dissolve all but the impurities. By distillation, galbanum yields half its weight of volatile oil, which at first has a blue colour. Med. Uses. It is antispasmodic, expectorant, and deobstruent, and in a medical classification, might be placed between ammonia and assafœtida. Forms of Exhibition. No form is preferable to that of pill. Officinal. Prep. Pil. Galbani comp. L. Pil. Assafœtid. comp. E. (B) Pil. Myrrh. co. D. Tinct. Galb. D. Empl. Galb. D. Emplast. Galb. co. L. Emplast. Assafœtid. E. (B) Emplast. Gummos. E.

Qualities. Form, excrescences, nearly round and of different magnitudes, smooth on the surface, but studded with tuberosities; they are heavy, brittle, and break with a flinty fracture. Odour, none; Taste, bitter and very astringent. Solubility. The whole of their soluble matter is taken up by forty times their weight of boiling water. Alcohol, by digestion, dissolves .7, and æther .5 of their substance. The watery infusion possesses all the properties of the gall-nut, and reddens vegetable blues. Chemical Composition. Is at present involved in some obscurity; it contains tannin, gallic acid, a concrete volatile oil, and perhaps extractive and gum. M. Braconnot has also lately discovered in the gall-nut a new acid, which he calls Ellagic acid, from the word galle reversed, a nomenclature which it must be confessed is at least free from the objections urged against that which is founded upon chemical composition. (See Annales de Chimie, vol. ix. p. 187, new series; also Children’s Essay on Chemical Analysis, p. 276.) Incompatible Substances. The infusion and tincture of galls possess habitudes with which it is very important for the medical practitioner to be acquainted, not only for the purpose of directing their exhibition with success, but because the elements which impart to them their characteristic traits, viz. Gallic Acid and Tannin,^[512] are very widely diffused through the products of the vegetable kingdom, and will be found to be constantly active in their chemical, medicinal, and pharmaceutical relations. Metallic salts, especially those of iron, produce precipitates with infusion of galls, composed of tannin, gallic acid, and the metallic oxide; of these compounds the tanno-gallate of iron is the most striking, being of a black colour; those of sub-acetate and acetate of lead are greyish; tartarized antimony produces a yellowish; sulphate of copper a brown; sulphate of zinc reddish black; nitrate of silver, a deep olive; and nitrate of mercury, a bright yellow precipitate; the oxy-muriate of mercury produces only an opacity. Sulphuric acid throws down a yellowish curdy precipitate, muriatic, a flaky and white one, and nitric acid merely modifies the colour of the infusion, although it destroys its astringency; the solution of ammonia occasions no precipitate but renders the colour deeper, the carbonate however throws down a precipitate; the carbonates of the fixed alkalies produce a yellowish flaky, and lime water a copious green precipitate. The tannin in the infusion of galls is precipitated by a solution of isinglass or of any other animal jelly, by that of starch, and by many metallic oxides. Medicinal Uses. Galls are most powerfully astringent. The native practitioners of India not only administer them as astringents in dysentery, but as tonics in cases of intermittent fever. Forms of Exhibition. In that of powder; and in combination with other astringents (Form. 51,) or with aromatics and bitters. As a local remedy the gall-nut enters into gargles and injections; for blind piles, an ointment composed of 2½ parts of finely powdered galls, and a small portion of opium, with three parts of simple ointment as an excipient, offers a very valuable resource. (Form. 55.) In some cases of hemorrhoids, prolapsus ani, and fluor albus, the application may be made in the form of a fomentation, for which purpose two drachms of bruised galls should be macerated for an hour in a pint of boiling water, which, when cold, may be used in the usual manner. Dose, for internal exhibition, grs. x–℈ij, or more. Officinal Prep. Tinct. Gallarum. E.D. Observation. Those which are small, protuberant, bluish, and heavy, are the best, being such as have been collected before the larvæ within them had changed to the state of fly, and eaten their way out; a white, or a red hue indicates an inferior quality, and are those from which the insect has escaped. Aleppo galls are the most valuable, as being the most astringent.

Qualities. Form, wrinkled pieces of various length and thickness; Odour, not particular; Taste, intensely bitter, but not nauseous. Chemical Composition, resin, a small portion of oil, bitter extractive, and a proportion of tannin; it contains also mucilage, in consequence of which the infusion frequently becomes ropy. Since the last edition of this work, the continental chemists have announced the existence of an alkaline principle, which they call Gentia or Gentiania, and which is said to concentrate within itself all the virtues of the Gentian root; it does not appear to be in the least poisonous; M. Majendie has injected it into the veins without any obvious effects, and has himself swallowed two grains without experiencing any sensation but that of extreme bitterness, followed by gentle warmth in the region of the stomach.^[513] The root, moreover, contains saccharine matter, for when fermented with water, it yields a spirit which is extensively used by the Swiss. Solubility. The virtues of this root are extracted by water and alcohol; proof spirit is perhaps its most perfect menstruum. See Infus. Gentian. comp. Med. Uses. It is tonic and stomachic, and its use for such purposes is of ancient date;^[514] in dyspepsia, hysteria, and in all cases where a vegetable bitter is indicated, it will be found a serviceable remedy. Dose, in substance, from grs. x to ʒj. Officinal Preparations. Extract: Gentian. L.E.D. Infusum Gentianæ comp. L.E.D. Tinct. Gentian. comp. L.E.D.^[515] Vinum Gentianæ compositum. E.

[This plant is very common in the United States, and is usually found in the vicinity of moist, woody situations. From the analysis of Bigelow, it appears to contain a very large proportion of tannin. It is accordingly powerfully astringent, and has been used with advantage in diarrhœa, chronic, dysentery and cholera infantum. In powder the dose of the Geranium is from 20 to 30 grs.—in extract, 10 grs.—in tincture from ʒj to ʒij—and in decoction from ℥j to ℥ij.]

Qualities. Taste, sweet and mucilaginous. Chemical Composition. Gum, with a peculiar modication of saccharine matter (Glycion), or sugar in its purest form, for it is not fermentable; on which account it is added to beer for the purpose of imparting a sweet taste, and at the same time enabling it to keep better. Solubility. Water extracts both its principles, but by long coction it becomes bitter; alcohol extracts only its saccharine matter. Med. Uses. It is principally employed as a demulcent in combination with other mucilaginous vegetables; the root will yield nearly half its weight of extract. Liquorice covers the taste of some unpalatable medicines more effectually than any other substance, and it has long enjoyed the reputation of assuaging thirst, whence the Greeks distinguished this root by the term Adipson; and, perhaps, the English word Liquorice may be derived from the same belief. Officinal Prep. Decoct: Sarsaparill: comp. L.D. (O) Infus: Lini, L. (B) Extract: Glycyrrhizæ. L.E.D. Confectio Sennæ^[516] L.E. (O) Adulterations. The powdered root is generally sophisticated with flour, and sometimes with powdered guaiacum; the fraud may be detected by its colour being a fine pale, instead of a brownish yellow, and by its reduced or foreign flavour.

What has been said respecting the Gall-nut, applies with equal truth to this substance. The efficacy of the bark of the root of the pomegranate, says Dr. Ainslie (Mat. Med. of Hindostan), as a remedy for the tape worm is now well established in India; it is given in decoction, prepared with two ounces of the fresh bark, boiled in a pint and a half of water until only three quarters of a pint remain.

Qualities. This wood is heavier than water, and emits when heated an aromatic odour; Taste, bitterish and sub-acrid; to extract its virtues long decoction is required. It has enjoyed great reputation as a specific in the venereal disease; it was imported into Europe in 1517, and gained immediate celebrity from curing the celebrated Van Hutten: long before this period, however, it was used by the natives of St. Domingo. Boerhaave, so late as the eighteenth century, maintained its specific powers. It seems probable that the discipline which always accompanied its exhibition, such as sweating, abstinence, and purgation, might be the means, in the warmer climates, of effecting cures which were attributed to the guaiacum. Officinal Preparations. Decoct: Guaiaci comp: E. Decoct: Sarsaparill: comp: L.D.

Qualities. Form; it has the aspect of a gum resin; Colour, greenish brown; it is easily pulverized, and the powder, which is at first grey, becomes green on exposure to air and light, which appears to depend upon the absorption of oxygen: when heated, it loses its colour; it melts by heat; and has a sp. grav: of 1·2289. Solubility. Water dissolves out of it about 9 per cent. of extractive matter; alcohol 95, and æther 40 parts in a hundred. The alkaline solutions and their carbonates dissolve it readily; Sulphuric acid dissolves it with scarcely any effervescence, and affords a solution of a rich claret colour; Nitric acid dissolves it with a copious extrication of nitrous fumes; Muriatic acid dissolves a small portion only; but in all these cases the guaiacum is decomposed; the acids are therefore incompatible with it. Chemical Composition. The experiments of Mr. Hatchett demonstrate that it is a substance sui generis, and not a resin, or gum-resin. Med. Uses. Stimulant, diaphoretic,^[517] and in large doses, purgative. Forms of Exhibition. In that of bolus; or diffused in water, by means of one half of its own weight of gum arabic. Dose, gr. x. to ʒss. Officinal Prep: Mist: Guaiac: L. Tinct. Guaiac. L.E.D. Tinct. Guaiac. Ammoniat. L.E.D. Pulv. Aloes com. L.D. (O.M.) Adulterations. Common resin may be detected by the turpentine emitted when the guaiac is thrown upon hot coals; Manchinal gum, by adding to the tincture a few drops of sweet spirit of nitre, and diluting with water; the guaiac is thus precipitated, but the adulteration floats in white striæ.

Qualities. The wood is hard, compact, and heavy. Odour, none; Taste, sweet, and astringent; Colour, deep red. Chemical Composition. The colouring matter of this wood has been very recently submitted to a rigid examination; and the name of Hematin has been given to it; it affords small brilliant crystals of a reddish white colour, and slightly astringent, bitter, and acrid flavour; sulphuretted hydrogen passed through its solution in water, gives it a yellow colour, which disappears in a few days. Gelatine throws it down in reddish flakes. The habitudes of Logwood are curious with respect to mutability of colour. The recent infusion, made with distilled water, is yellow, but that with common water has a reddish purple colour, which is deepened by the alkalies, and changed to yellow by the acids; various salts precipitate it; acetate of lead; alum; the sulphates of copper and iron; tartarized antimony; and sulphuric, muriatic, nitric, and acetic acids, are on this account incompatible with it. Med. Uses. It is supposed to be astringent, and is therefore given in protracted diarrhœas, and in the latter stage of dysentery. Officinal Prep. Extract. Hæmatoxyli. L.

As this plant is merely retained in the list of materia medica on account of its anthelmintic properties, it might be well dispensed with, since we possess many others which are much more safe, as well as more efficacious.

Qualities. The fibres of the root are the parts employed; they are about the thickness of a straw, corrugated, externally of a deep dark colour, hence the epithet black; internally white, or of a yellowish hue. Odour, unpleasant; Taste, bitter and acrid. Chemical Composition. An analysis of this root has lately been effected by M. M. Feneulle and Capron, from which it appears that its active principle, unlike that of the White Hellebore (Veratrum) is not an alkali; the following substances enter into its composition, viz. 1. A Volatile Oil.—2. A Fatty matter.—3. A Resin.—4. Wax.—5. A Volatile Acid.—6. A bitter principle.—7. Mucus.—8. Alumina.—9. Gallate of Potass.—10. Acidulous Gallate of Lime.—11. A Salt, with an Ammoniacal base. Solubility. Both water and alcohol extract its virtues, but the spirituous solution is the most active; long coction diminishes its powers, hence the watery extract acts more mildly than the root. Medicinal Uses. This is one of the most ancient articles of the materia medica. Ctesias, who lived in the time of Plato, and anterior to Hippocrates, speaks of it as a medicine of important virtues. By the Greek and Roman physicians it was highly esteemed as a remedy in Mania (see p. 8.) The extraordinary cures performed at the island of Anticyrus, famous for its Hellebore, are celebrated by the poets and historians of antiquity. It is a drastic cathartic, and may prove therefore emmenagogue, and hydragogue, but in this country, its reputation has been destroyed by the decided manner in which Dr. Cullen reprobated its use. Forms of Exhibition. It is seldom given in substance, but in the form of tincture or extract; or in that of decoction, made with two drachms of the root to a pint of water. Dose of the powdered root, grs. x to ℈j; of the decoction, f℥j. Officinal Preparations. Tinct. Hellebori Nigri. L.E.D. Extractum Hellebori Nigri. E.D. Adulterations. The roots of the poisonous aconites are often fraudulently substituted; this is easily discovered, for the aconite is lighter coloured than the palest specimens of black hellebore; it is safe therefore to choose the darkest.

Barley is formed into Pearl Barley, by the removal of its husk or cuticle,^[519] and afterwards by being rounded and polished in a mill. These well known granules consist chiefly of fecula, with portions of mucilage, gluten, and sugar, which water extracts by decoction, but the solution soon passes into the acetous fermentation; the bran of barley contains an acrid resin, and it is to get rid of such an ingredient that it is deprived of its cuticle. Officinal Preparations. Decoct. Hordei. L.E.D. Decoct. Hordei. comp. L.D.

Qualities. Odour, fragrant, and sub-narcotic. Taste, bitter, astringent, and aromatic. Chemical Composition. Tannin, 5 grs.; Extractive, 10 grs.; Bitter principle, 11 grs.; Wax, 12 grs.; Resin, 36 grs.; Lignin, 46 grs. The fact, with respect to the residence of the properties of the hop in the yellow grains scattered over its scales, has been since confirmed by the observations of M. Payen and A. Chevalier, who have moreover detected a volatile oil in the Lupulin, amounting to 2 per cent.; its proportion, however, appears to vary in the Hop of different countries; the French hop, for instance, has been found to contain more than the Belgic, but less than the English; Hops, moreover, soon after having been picked, yield, cæteris paribus, more oil and less resin than the old; a circumstance which induced M. M. Payen and Chevalier to suspect that the oil is capable of being resinified. (Journal de Pharmacie, Juin 1822.) This oil is similar in odour to the hop, but much more penetrating, narcotic, and very acrid in the throat.

Solubility. Boiling water, alcohol, and æther, extract their virtues; but their aromatic flavour is destroyed by decoction; like most vegetable bitters, the cold is more grateful than the warm infusion; its colour is deepened by alkalies, and rendered turbid by the mineral acids; metallic salts also produce decomposition. Medicinal Uses. Hops have been said to be tonic, narcotic, and diuretic; they have been recommended in the cure of rheumatism; and, like many articles in the materia medica which have received the sanction of respectable practitioners, they have been extolled far beyond their merit. They undoubtedly possess the advantages of a pleasant bitter combined with a feeble narcotic; the late Mr. Freake was very sanguine as to their powers, and at his request I made a series of experiments at the Westminster Hospital, but I confess that their results have not established my confidence in their efficacy. Officinal Preparations. Extract. Humili. L. Tinct. Humili. L. Their use as a preservative of beer is well known, and the philosophy of their agency is fully described in the first part of this work, (page 168); it is equally notorious, that various vegetable substances are daily substituted for them, such as Quassia^[520] and Wormwood, both of which are inferior to the Menyanthes Trifoliata, or Marsh Trefoil. The people of Jersey are said to use the wood-sage, Teucrium Scorodonia; it imparts however a very high colour to the beer. During the first four years that the Cape of Good Hope was in the possession of the British, more than 300,000 pounds of Aloes were imported into England; how could such a quantity be consumed? except, as Mr. Barrow states, by the London Porter brewers; it must however be allowed that a considerable quantity of this article is used by the Varnish makers.