mucilages, which are commonly classed with the infusions, are instances of simple solution, and the chalk mixture is the mechanical suspension of an insoluble substance. When the menstruum used is water, the solution is termed simply an infusion; but when the menstruum is alcohol, and upon a colouring material, it is called a tincture; when wine or vinegar, a medicated wine or vinegar. Infu sions in water are extremely apt to spoil, and are generally extemporaneous preparations.

The following are those officially prescribed:

Infusum cinchonæ, Edin. infusion of Peruvian bark.

Infusum digitalis purpurex, Edin. infusion of fox-glove.

Infusum gentianæ compositum, Lond. infusum gentianæ luteæ comp. Edin. infusion of gentian, compound.

Infusum mimosa catechu, Edin. infusion of catechu.

Infusum rhei palmati, Edin. infusion of rhubard.

Infusum rosæ, Lond. infusum rose Gallicæ, Edin. infusion of roses.

Infusum sennæ, Lond. Dubl. infusion of senna.

Infusum sennæ tartarisatum, Lond. infusion of senna tartarised.

Infusum tamarindi Ind. cum cassia senna, Edin. infusion of tamarinds and senna.

CLASS XII. Mucilagines. MUCILAGES.

These, as officially prescribed, are as follow:

Mucilago amyli, Lond. Edin. mucilage of starch.

Mucilago tragacanthæ, Lond. mucilago astragali tragac. Edin. mucilago gummi tragac. Dubl. mucilage of tragacanth.

Musilago mimosa nilotica, Edin. mucilago gummi arabici, Lond. mucilage of gum arabic.

Mucilago sem. cydonii mali, Lond. mucilage of quince seed.

CLASS XII. Syrupi. SYRUPS.

In making these the following is the proportion, where no particulars are mentioned in respect to the weight of sugar.

Take of double-refined sugar twentynine ounces; any kind of liquor one pint (one pint and a half, Dubl.); dissolve the sugar in the liquor, in a water bath (mix and boil down to one pound, Dubl.); then set it aside for twenty-four hours; take VOL. IX.

off the scum, and pour off the syrup from the feces, if there be any.

Syrups are solutions of sugar in any wa tery fluid, whether simple or medicated. Simple syrup is nutricious and demulcent. When made of fine sugar, it is transparent and colourless. If necessary, it is easily clarified, by beating to a froth the white of an egg with three or four ounces of water, mixing it with the syrup, and boiling the mixture for a few seconds, until the albumen coagulates, and, enveloping all heterogeneous matters, it forms a scum, which may be easily taken off, or separated by filtration. When, instead of simple water, any other fluid is used for dissolving the sugar, the syrup is then medicated. Medicated syrups are prepared, either with express juices, infusions, decoctions, or saline fluids. The object of forming these into syrups is, either to render them agreeable to the palate, or to preserve them from fermentation. In the latter case, the quantity of sugar added becomes a matter of great importance; for if too much be employed, the sugar will separate by crystallization; and if too little, instead of preventing fermentation, it will accelerate it. About two parts of sugar to one of fluid are the proportions directed by the British Colleges with this view. But as, in some instances, a larger quantity of fluid is added, and afterwards reduced to the proper quantity by decoction, it will not be superfluous to point out some circumstances, which show the evaporation to have been carried far enough. These are, the tendency to form a pellicle on its surface, when a drop of it is allowed to cool; the receding of the last portion of each drop, when poured out drop by drop, after it is cold; and, what is most to be relied on, its specific gravity when boiling hot being about 1.385, or 1.3 when cold. The syrup which remains, after all the crystallizable sugar has been separated from it, has been much, and probably justly, recommended by some for the preparation of medicated syrups and electuaries, although its pharmaceutical superiority is actually owing to its impurity.

The following are the official preparations.

Syrupus simplex, Edin. simple syrup. Syrupus acidi acetosi, Edin. syrup of acetous acid.

Syrupus allii, Dubl. syrup of garlic. Syrupus altheæ, Lond. Edin. syrup of marshmallows.

E e

Syrupus zingiberis, Lond. syrupus amomni zing. Edin. syrup of ginger. Syrupus corticis aurantii, Lond. syrupus citri aurantii, Edin. syrup of orangepeel.

Syrupus limonis succi, Lond. Dubl. syrupus citri medici, Edin. syrup of lemons. Syrupus succi fructus mori, Dubl. syrupus succi fructus rub. idæi, Lond. syrup of mulberries.

Syrupus succi fructus ribis nigri, Lond. syrup of black currants.

Syrupus colchici autumnalis, Edin. syrup of colchicum.

Syrupus caryophylli rubri, Lond. syrupus dianthi caryophylli, Edin. syrup of clove July flowers.

Syrupus croci, Lond. syrup of saffron. Syrupus mannæ, Dubl. syrup of manna. Syrupus papaveris somniferi, Edin. syrupus papaveris albi, Lond. syrup of white poppies.

Syrupus papaveris erratici, Lond. syrup of red poppies.

Syrupus opii, Dubl. syrup of opium. Syrupus rhamni cathartici, Edin. syrupus spinæ cervi, Lond. syrup of buckthorn.

Syrupus rosa, Lond. syrupus rosæ centifolia, Edin. syrup of damask roses. Syrupus rose Gallicæ, Edin. syrup of

roses.

Syrupus scillæ maritimæ, Edin. syrup of squills.

Syrupus tolutanus, Lond. syrupus toluiferæ balsami, Edin. syrup of balsam of tolu.

Syrupus viola, Lond. syrupus viola odoratæ, Edin. syrup of violets.

CLASS XIII. Mellita. MEDICATED
HONEYS.

Honey itself is first to be despumated or clarified by dissolving it in a water-bath, and removing the scum as it arises. The following preparations are then made of it. Mel. acetatum, Lond. honey acetated, simple oxymel.

Oxymel colchici, Lond. oxymel of meadow saffron.

Mel. rosa, Lond. Dubl. honey of roses. Mel. scillæ, Lond. honey of squills. Oxymel scillæ, Lond. oxymel of squills. Oxymel æruginis, Lond. oxymel of verdigris.

insoluble in water, are mixed with, and suspended in, watery fluids, by means of such viscid substances as mucilages and syrups.

Emulsio amygdala communis, Edin. lac amygdala, Lond. almond emulsion. Emulsio arabica, Edin. Dubl. gum arabic emulsion.

Emulsio camphorata, Edin. mistura camphorata, Lond. camphorated emulsion or mixture.

Lac ammoniaci, Lond. Dubl. emulsion of gum ammoniac.

Lac asæ fœtidæ, Lond. emulsion of asafœtida.

Mistura moschata, Lond. musk mixture.

Mistura cretacea, Lond. chalk mixture. Decoctum cornu cervi, Lond. decoction of hartshorn.

CLASS XV. Aceta. MEDICATED VINEGARS.

Infusions of vegetable substances in acetic acid are commonly called medicated vinegars. The action of the acid in this case may be considered as twofold.

1. It acts simply as water, in consequence of the great quantity of water which enters into its composition, and generally extracts every thing which water is incapable of extracting.

2. It exerts its own peculiar action as an acid. In consequence of this, it sometimes increases the solvent power of its watery portion, or dissolves substances which water alone is incapable of dissolv. ing, and in a few instances it impedes the solution of substances which water alone would dissolve.

As acetic acid, in itself sufficiently perishable, has its tendency to decomposition commonly increased by the solution of any vegetable matter in it, it should never be used as a menstruum, unless where it promotes the solution of the solvend, as in extracting the acrid principle of squills, colchicum, &c. and in dissolving the volatile, and especially the empyreumatic oils, or where it coincides with the virtues of the solvend.

Acetum aromaticum, Edin. aromatic vinegar, thieves vinegar.

Acetum colchici, Dubl. vinegar of mea

This double class comprehends preparations in which oils and other substances,

Acetum scilliticum, Lond. acetum scilla maritimæ, Edin. vinegar of squills.

Acidum acetosum camphoratum, Edin. camphorated acetous acid.

CLASS XVI. Tincture. TINCTURES.

The term tincture has often been employed in a very vague sense. It is now commonly applied to coloured solutions, made by digestion in alcohol, or diluted alcohol. But it is also, though perhaps incorrectly, extended to solutions in ether, etherial spirits, and spirit of ammonia.

Alcohol is capable of dissolving resins, gum resins, extractive, tannin, sugar, volatile oils, soaps, camphor, adipocere, colouring matters, acids, alkalies, and some compound salts. Many of these, as the gum resins, soaps, extractive, tannin, sugar, and saline substances, are also soluble in water, while water is capable of dissolving substances, such as gum, gelatine, and most of the compound salts, which are insoluble in alcohol. But the insolu

bility of these substances in the different menstrua is not absolute, but merely relative; for a certain proportion of alcohol may be added to a solution of gum in water without decomposing it; and a solution of resin in alcohol will bear a certain admixture of water without becoming turbid. Therefore, diluted alcohol, which is a mixture of these two menstrua, sometimes extracts the virtues of heterogeneous compounds more completely than either of them separately.

Alcohol is used as a menstruum:

1. When the solvend is not soluble, or sparingly soluble, in water.

2. When a watery solution of the solvend is extremely perishable.

3. When the use of alcohol is indicated as well as that of the solvend.

In making alcoholic tinctures, we must observe, that the virtues of recent vegetable matters are very imperfectly extracted by spirituous menstrua. They must, therefore, be previously carefully dried, and as we cannot assist the solution by means of heat, we must facilitate it by reducing the solvend to a state of as minute mechanical division as possible. To prevent loss, the solution is commonly made in a close vessel, and the heat applied must be very gentle, lest it be broken by the expansion of vapour.

The action of tinctures on the living system is always compounded of the action of the menstruum, and of the matters dissolved in it. Now, these actions may either coincide with, or oppose, each other; and as alcohol is at all times a powerful agent, it is evident that no substance should be exhibited in the form of a tincture, whose action is different from that of alcohol, unless it be capable of

operating in so small a dose, that the quantity of alcohol taken along with it is inconsiderable.

Tinctures are not liable to spoil, as it is called, but they must nevertheless be kept in well closed phials, especially when they contain active ingredients, to prevent the evaporation of the menstruum.

They generally operate in doses so small that they are rarely exhibited by themselves, but commonly combined with some vehicle. In choosing the latter, we must select some substance which does not decompose the tincture, or at least separates nothing from it in a palpable form.

The London college direct all tinctures, except that of muriate of iron, to be prepared in closed phials.

The Dublin college explain, that, when they order substances to be digested, they mean it to be done with a low degree of heat; and when they are to be macerated, it is to be done with a degree of heat between 60° and 90°.

Tinctura aloes, Lond. tinctura succotorinæ, Edin. tincture of aloes.

Tinctura aloes composita, Lond. tinctura aloes cum myrrha, Edin. tincture of aloes with myrrh.

Tinctura cardemomi, Lond. tinctura amomi repeutis, Edin, tincture of carda

moms.

Tinctura serpentariæ, Lond. tinctura aristolochiæ serpentariæ, Edin. tincture of snake-root.

Tinctura asæ fœtidæ, Lond. Dubl. tincture of asafoetida.

Tinctura aurantii corticis, Lond. Dubl, tincture of orange-peel.

Tinctura balsami peruviani, Lond. tincture of balsam of Peru.

Tinctura benzoes composita, Lond. Edin. tincture of benjamin, compound.

Tinctura camphora, Edin. spiritus camphoratus, Lond. Dub. tincture of camphor, camphorated spirit.

In this the Edinburgh title is grossly inaccurate; the preparation being quite colourless instead of tinctured.

Tinctura cascarilla, Lond. Dubl. tincture of cascarilla.

Tinctura sennæ, Lond. Dubl. tincture of

senna.

Tinctura cassiæ sennæ composita, Edin. tincture of senna compound; elixir of health.

Tinctura castorei, Lond. Dub. tincture of castor.

Tinctura cinchona, Lond. Edin. tincture of Peruvian bark.

Tinctura cinchona, composita, Lond.

Dubl. tincture of Peruvian bark, compound.

Tinctura columbæ, Lond. Edin. Dubl. tincture of Columbo.

Tinctura jalapæ, Lond. Dubl. tinctura convolvuli jalape, Edin. tincture of jalap. Tintura croci, Edin. tincture of saffron. Tinctura digitalis purpureæ, Edin. tincture of foxglove.

Tinctura galbani, Lond. tincture of galbanum.

Tinctura gentianæ composita, Lond. Edin. tincture of gentian, compound.

Tinctura guaiaci, Edin. tincture of guaiacum.

Tinctura hellebori nigri, Lond. Dubl. tincture of black hellebore.

Tinctura hyoscyami nigri, Edin. tincture of henbane.

Tinctura kino, Edin. Dubl. tincture of kino.

Tinctura cinnamomi, Lond. Dubl. tinctura lauri cinnamomi. Edin. tincture of cinnamon.

Tinctura lauri cinnamomi composita, Edin. Lond. tincture of cinnamon, compound.

Tinctura lavendula comp. Dubl. spiritus lavendulæ comp. Lond. spiritus lavendulæ spicæ comp. Edin. tincture of lavender, and spirit of lavender.

Here the Dublin title is wrong; the tincture is not derived from the lavender, but from the red saunders.

Tinctura cantharidis, Lond. Dubl. tinctura meloes vesicatorii, Edin. tincture of cantharides.

Tinctura misose catechu, Edin. tincture of catechu.

Tinctura moschi, Dubl. tincture of

musk.

Tinctura myrrhæ, Lond. Edin. Dubl. tincture of myrrh.

Tinctura opii, Lond. Edin. Dubl. tincture of opium.

Tinctura opii camphorata, Lond. Dubl. tincture of opium camphorated.

Tinctura rhabarbari, Lond. Dubl. tinctura rhei palmati, Edin. tincture of rhubarb.

Tinctura rhabarbari composita, Lond. tincture of rhubarb, compound.

Tinctura rhei cum aloe, Edin. tincture of rhubarb with aloes.

Tinctura rhei cum gentiana, Edin. tincture of rhubarb with gentian.

Tinctura sabinæ composita, Lond. tincture of savin, compound.

Tinctura saponis, Edin. linimentum saponis compositum, Lond. linimentum saponaceum, tincture of opodeldoc.

taining the elements of bad vinegar. As a solvend, diluted alcohol perfectly supersedes the use of wine; and if we wish to use wine to cover the taste, or to assist the operation of any medicine, M. Parmentier proposes, that a tincture of the substance should be extemporaneously mixed with wine as a vehicle.

Notwithstanding this argument appears to us to have great weight, we shall allow to the medicated wines, retained in the pharmacopoeias, the characters they still generally possess.

Vinum aloes, Lond. vinum aloes succotorinæ, Edin. wine of aloes.

Vinum gentianæ compositum, Edin. wine of gentian compound.

Vinum ipecacuanha, Lond. Dubl. wine of ipecacuanha.

Vinum nicotiana tabaci, Edin. wine of tobacco.

Water is the menstruum most economically employed in making extracts, as it is capable of dissolving all the active principles except resin, and can have its solvent powers assisted by a considerable degree of heat.

Watery extracts are prepared by boiling the subject in water, and evaporating the strained decoction to a thick consist

ence.

It is indifferent, with regard to the medicine, whether the subject be used fresh or dry; since nothing that can be preserved in this process will be lost by dry. ing. With regard to the facility of extraction, there is a very considerable difference; vegetables in general giving out their virtues more readily when moderately dried than when fresh.

The metalic wines have been noticed already.

CLASS XIX. Extracta. EXTRACTS.

Extract, in pharmacy, has been long used, in the true and general sense of the term, to express a substance extracted from bodies of all kinds, by the action of whatever menstruum, and reduced to spissitude by the evaporation of that menstruum. Of late, however, it has been employed in a different and more limited sense, as the name for a peculiar principle, which is often, indeed, contained in extracts, and which before had no proper appellation. It is in the former sense that we employ it here, and in which we wish it to be only used, while a new word should be invented as the name of the new substance. Till a better be proposed, we shall call it extractive.

Extracts are of various kinds, according to the nature of the substances from which they are obtained, and the menstruum employed; but they commonly consist of gum, sugar, extractive, tannin, gallic acid, or resin, or several of them mixed in various proportions. The menstrua most commonly employed are water and alcohol. The former is capable of extracting all the substances enumerated, except the resin, and the latter all except the gum. Wine is also sometimes employed, but very improperly; for as a solvend it can only act as a mixture of alcohol and water, and the principles which it leaves behind, on evaporation, are rather injurious than of advantage to the extract.

struum.

The quantity of water ought to be no greater than is necessary for extracting the virtues of the subject. This point, however, is not very easily ascertained; for although some of the common principles of extracts be soluble, in a very small proportion of water, there are others, such as the tannin, of which water can dissolve only a certain proportion, and cannot be made to take up more by any length of boiling, and we have no very good method of knowing when we have used a sufficient quantity of water; for vegetable substances will continue to colour deeply successive portions of water boiled with them, long after they are yielding nothing to it but colouring matter. Perhaps one of the best methods is, to boil the subject in successive quantities of water, as long as the decoction forms a considerable precipitate with the test which is proper for detecting the substance we are extracting, such as, a solution of gelatine for tannin, of alum for extractive, &c.

"The decoctions are to be depurated by colature; and afterwards suffered to stand for a day or two, when a considerable quantity of sediment is usually found at the botton. If the liquor, poured off clear, be boiled down a little, and afterwards suffered to cool again, it will deposit a fresh sediment, from which it may be decanted before you proceed to finish the evaporation. The decoctions of very resinous substances do not require this treatment, and are rather injured by it, the resin subsiding along with the inactive dregs."