The bark is generally injurious in fevers of the inflammatory kind and in topical inflammations; yet, in some cases of abscess, where the suppuration proceeds slowly, or the discharge is thin and glairy, it has been of use. In all cases of dyspnoea, whether from inflammation or any other cause, except in the kind formerly mentioned, it is hurtful. In infarctions of the viscera, in critical discharges, unless insufficient from weakness, it is generally injurious. In many cases of different kinds, or rather, perhaps, in many constitutions, it produces a stricture on the surface from the suppression of the perspiration. It sometimes purges; at others, lies like a cold weight at the stomach. In such cases some corrective should be employed. When it produces a stricture, which most frequently happens in fever, camphor, or the James' powder, will often obviate the inconvenience. The cathartic tendency is corrected by an opiate, and the cold heavy load by an aromatic. In every instance previous to the use of the bark, the stomach and bowels should be freely evacuated.

When the bark produces vomiting, the carbonic acid gas, or an opiate, will correct this tendency; and when it occasions costiveness, rhubarb may be added. Numerous other medicines are occasionally combined with bark, either to add to its virtues or to correct its supposed disadvantages. In fevers it has been usual to add emetic tartar or crude sal ammoniac; in stomach complaints, sulphuric acid, kali, lime water, or chalybeate preparations; in excessive discharges, sulphuric acid or alum. In each case some decomposition appears to take place, and we can place no confidence on the appropriate effects of the medicine. It is highly probable that some change occurs on the union of bark with emetic tartar, since the latter loses in a great degree its emetic power. The powder of Dr. James preserves in the combination its powers unimpaired.

In the Species Plantarum, published by Wildenow, there are nine species of cincona, two of which only occur in Linnaeus's own edition. These have been found in Peru, or in the American islands of St. Lucia, St. Domingo, etc. They agree in general, with the bark, in astringent and tonic powers; but possess qualities offensive to the stomach and bowels, which are lessened apparently, and would be, probably, ultimately lost by keeping. See Lambert on the genus cinchona; Vahl, Copenhagen Transactions, vol. i. ii. and iii.; Davidson, Philosophical Transactions, vol. lxxiv.

Various are the preparations of the bark; but when the stomach will bear it, the powder, if very fine, is the most agreeable and the most useful. If the powder cannot be taken, the infusion has been preferred; but where the active power of the bark is necessary, the infusion is a very weak inadequate preparation.

Infusion of the bark. To one ounce of bark in fine powder, add twelve ounces of soft water by a little at a time, continuing to triturate it for about ten minutes in a marble mortar; then let them stand together, without subjecting them to any heat, for twelve hours, and strain. If the water is poured on hot, the time necessary for the infusion may be less; and, indeed, with cold water, many pharmaceutists, after trituration, allow only of the infusion for an hour or two. The elegance and strength of the infusion are increased by the addition of a small quantity of French brandy during the triture. In this preparation, the component parts of the bark are not separated. It is a solution with little change In weak stomachs it is preferable, but its powers are inconsiderable.

In boiling, the bark is partly decomposed. The extractive matter, by the addition of oxygen, becomes a resin, dissolved while the water boils, but separating on cooling.

In decoction, the London college orders, for this reason, the bark to be boiled for a very short time in a covered vessel. An ounce is ordered to be boiled in a pint and quarter of pure water for ten minutes only.

Next to the infusion and decoction, an infusion in Rhenish wine may be preferred; and the tincture drawn with good French brandy follows. In scrofula, the shell lime water is said to be a good menstruum for the bark; and in cases where relaxation simply demands the use of the bark, the lime water made with stone lime should be preferred.

The addition of magnesia to the bark during the trituration, previous to the infusion, renders the colour much deeper, and is supposed to add to the strength of the preparation. A decomposition seems, in this instance, to take place; and it is, we think, still doubtful whether this infusion is really preferable as a medicine.

The unpleasant taste of the bark is covered by liquorice, orange peel, or a small quantity of winter's bark. In the following electuary, mucilage is thought useful in concealing the taste, and it is considered as an excellent medicine in scrofulous cases, equal to burnt sponge. Rx. sodae pp. 3 ij. pulveris cort. Peruv. i. mucilaginis gum. Arab. q. s. m. The dose 3 ij. two or three times a day.

The college of London directs the following extracts from the bark.

Extract of Peruvian bark. Take of Peruvian bark, coarsely powdered, one pound; distilled water, twelve pints; boil for an hour or two, and pour off* the liquor, which, while hot, will be red and pellucid, but as soon as it grows cold it becomes yellow and turbid; boil the bark again in the same quantity of water as before, repeating the operation till the liquor remains transparent when cold: then evaporate all the decoctions, strained and mixed together, to a proper consistence. Ph. Lond. 1788.

This extract is to be prepared under a double form; one of the consistence of a pill, the other hard enough to be reduced to powder.

It is not so active in its powers as is imagined, and it is difficult to prepare it without some degree of empyreuma; nor does the advantage of its form compensate for the expense and trouble. Ten grains of the hard extract are computed to be equal to half a drachm of the bark in powder, but it is scarcely superior to an equal weight of the powder.