Powdered Bark. The powder might be the most efficacious form for administration, could it always be taken in sufficient quantities, and without irritation of the stomach. But its taste is so revolting to most patients, and it is so apt to occasion nausea, if not vomiting, that it is often almost impossible to employ it in quantities sufficiently large to produce the effects required. The taste may, it is true, to a considerable extent, be concealed or corrected by appropriate management; but still the medicine will often offend the stomach by its,directly nauseating properties, and, if in no other way, by its great bulk alone. So much do these disadvantages impair its efficiency, that formerly, when the bark in substance was mainly relied on in the treatment of periodical fevers. it was not unfrequently difficult to break them, and sometimes almost impossible; and, at all events, the treatment was much more prolonged than at present. Trousseau, indeed, considers the powder preferable to the sulphate of quinia, being, as he thinks, less apt to irritate the stomach, and, if properly administered, less offensive to the taste; but it seems to me that this eminent therapeutist must either never have taken the medicine himself, or be misled by personal idiosyncrasy; for certainly the general experience is very much opposed to him. Nevertheless, there may be instances in which, from constitutional peculiarity, sulphate of quinia may fail of its usual effect; or may be accidentally unattainable in due time; and, in either case, recourse may be had to the bark in substance The variety selected for internal use should be one of those richest in alkaloids; as it is important that as much strength should be concentrated in as small a bulk as possible. Hence, either the Calisaya bark, or the best red bark, or one of the finest varieties of the Carthagena barks, as the soft or hard Pitaya, should be preferred. (See U. S. Dispensatory, 12th ed.) Any bark containing two per cent. of alkaloids may be ranked among the efficient varieties.

The dose of powdered bark, as an antiperiodic, is about a drachm, repeated every hour or two, or at such intervals that from one to two ounces may be taken between the paroxysms. In reference merely to the tonic effect, from ten to thirty grains are sufficient to commence with.

The powder should be given diffused in water, or other liquid vehicle. It is not the best plan to mix each dose extemporaneously when administered; for the dry powder is not readily diffused in water, and the attempt often results in producing an offensive dose, sufficient, by its very appearance, to produce nausea in one who may have previously taken the medicine. A better method is to introduce a certain quantity of the bark and of the vehicle, say two ounces of the former and two pints of the latter, into a bottle, allow them to stand until the powder has become wet throughout, and then, when the dose is to be taken, to shake them well, and pour out a wineglassful of the turbid liquid. The addition of a fluidrachm of aromatic sulphuric acid, for each ounce of the bark, will correct in some degree the nauseous taste, and increase its efficiency by rendering soluble the compounds of the alkaloids with the colouring matter. Wine was formerly much employed as the vehicle; but it would be too stimulating for ordinary use. Trousseau strongly recommends hot sweetened coffee, which he says completely corrects the taste. When the bark purges, it should be conjoined with opium, when it constipates, with a little rhubarb.

Infusions. The U. S. Pharmacopoeia recognizes two infusions, one prepared from the yellow bark (Infusum Cinchonae Flavae), the other from the red (Infusum Cinchonae Rubrae). These are not simple infusions, like those of the preceding Pharmacopoeia; but are made in accordance with the old formula for compound infusion (Infusum Cinchonae Compositum, U.S. 1850), by the addition of a fluidrachm of aromatic sulphuric acid to a troyounce of the powdered bark. The acid is first mixed with a pint of water, and this mixture is then used in percolation, enough water being poured on, at the end of the process, to make the infusion measure a pint. These are elegant preparations, and afford one of the most efficient methods of administering cinchona. All the virtues of the bark are extracted, and probably in a condition of greater activity than in the powder itself; as, by means of the acid, the whole of the active matter is now dissolved, and therefore readily absorbable. These infusions may be used for all the purposes of the medicine. The dose is two fluidounces, to be repeated three or four times a day, as a tonic, in chronic debility; every two hours in low fevers; and in such a manner as to amount to one or two pints between the paroxysms, in periodical diseases. For use in the typhous state of fever, they may be prepared with wine as the menstruum instead of water.

The officinal infusions above described are expected to be made in the shop. For a simple extemporaneous infusion, the old method of macerating an ounce of the coarsely powdered or bruised bark in a pint of boiling water, may be resorted to, in accordance with the present British plan. The simple infusion may also be made by treating the coarsely powdered bark by percolation with cold water, which forms a more elegant, and probably stronger preparation. The hot infusion is somewhat turbid; that made with cold water, perfectly clear. In neither is the bark nearly exhausted; for water will not dissolve that portion of the alkaloids which is combined with the cinchonic red. Pale bark has sometimes been preferred, in consequence of its less disagreeable taste; but just in the same proportion is it less efficient. The preparation is at best feeble, and is used only as a tonic. The dose is two fluidounces, three or four times a day in chronic cases, more frequently in the acute.

Decoctions. The U. S. Pharmacopoeia directs separately the decoction of the yellow bark (Pecoctum ClNchonae Flavae). and of the red (De-coctum Cinchonae Rubrae). These are made by boiling an ounce of the bruised bark in a pint of water, for fifteen minutes, straining while hot, and adding enough water through the strainer to make the decoction measure a pint. At the end of the boiling, and before the liquid begins to cool, two drachms of orange-peel may be advantageously added. This mode of preparation was formerly much resorted to, when it was deemed desirable to obtain the virtues of the bark speedily in a liquid form. Its disadvantages are that it does not completely exhaust the bark, and that on cooling the decoction becomes turbid, and deposits a precipitate. The turbidness is owing, partly, to the formation of tannate of starch, which, though dissolved by the water when hot, is insoluble in cold water, and therefore subsides on cooling; and, partly, to the deposition of a compound of the alkaloids with the colouring matter, previously existing in the bark, and partially taken up by the water at the boiling temperature. Hence the necessity of straining while hot, so that a portion of the active matter extracted in the decoction may not be lost. Of course, the precipitated matter should be again mixed with the water by stirring, when the decoction is administered. It would be a great improvement in this preparation to add a little sulphuric, muriatic, or citric acid to the menstruum before boiling. The bark would then be exhausted, and the active matter retained in solution upon the cooling of the decoction. Wine may be advantageously substituted for water in the preparation, when there is an indication at once for alcoholic stimulation and the effects of the bark, as often happens in low fevers. Indeed, the decoction of bark in wine was formerly much used in the prostrate state of fevers of a typhoid character, and with great advantage. The dose of the decoction is two fluidounces, to be repeated in the same manner as the infusion.