When taken into the stomach it excites, -soon afterwards, a moderate sensation of warmth at the epigastrium; and if the dose be large, nausea and vomiting sometimes follow; and purging is not an uncommon result of its administration. Its influence upon the vascular system is soon also obvious by the pulse increasing both in frequency and in force; whilst, at the same time, the nervous system evinces that it is under its action by a sensation of tension and slight fulness in the head; sometimes with singing in the ears, and partial deafness. As an antiperiodic, its influence is displayed by its breaking the catenation of morbid symptoms which constitute the paroxysm of ague : but the manner in which this is effected is still involved in obscurity.

1 Among others, it was opposed by Chifletius in the work already noticed, owing to the time in which it was administered to his patron, the Archduke, preventing it from proving beneficial. This time was that ordered in the Schedion, "frigore febrili incipiente." It was opposed also in a tract, published in 1655, in defence of Chifletius, by Melippus Frolimus*, against one Honoratius Fabri, a French Jesuit, who called himself Antimus Conygius, and had ventured to extol the bark. It met with many opponents in England, also, from Alderman Underwood having died while using it, in 1658, and his death having been ascribed to the bark.

2 According to Condamine, this was the bark first introduced into Europe. He says it yields by incision a yellow odorous resin; and that the Jesuits of La Paz (whence the best bark of this species is still obtained) used to gather it with care, and send it to Rome, where it was specific in agues. But the Loxa bark coming to Europe soon after, the three kinds were confounded together.

3 Zea, Annates de Hist. Nat. 1. c. Rushworth discovered the efficacy of the red bark in gangrene.

* Protimus was a feigned name: it was Vopiscus Fortunatus Plempius.

In intermittent fever the remedial influence of Cinchona has long been undoubted. Some differences of opinion existed with regard to the best time of giving it, but these are now nearly settled. It was originally given in doses of 3 ij. immediately on the attack of the paroxysms. Boerhaave1 and others recommended that the fever should be allowed to run on for some time before it was administered; but a better practice is to give it as early as possible after the stomach and bowels are cleared by an emetic and cathartic. Sydenham first proposed to administer it in the intervals instead of during the paroxysms. Dr. Cullen recommended the exhibition of it in a large dose or doses immediately before the accessions 2 : but Morton's method of giving it directly after the hot stage of the paroxysm ceases, and repeating it in increased doses during the intermission, until the cold stage again returns, is generally adopted. It may be safely given, however, during the paroxysm, as practised by Dr. Clarke of Newcastle, 'but many stomachs are apt to nauseate it at that time.

It has also been found equally efficacious in other diseases; namely, intermittent hemicrania; dysentery, and diarrhoea, when they become intermittent; chorea, epilepsy, some coughs, and rheumatism : indeed I have long regarded it as a maxim, that wherever intermission clearly takes place, there cinchona or its preparations will prove useful: but it does not prevent the continuance of those paroxysms of ague which form one of the constitutional symptoms of stricture of the urethra, and some other local affections; and which can be cured only by removing the strictures and other sources of irritation. The yellow bark possesses the most powerful antiperiodic powers.

In remittent fevers, cinchona is also found beneficial; but the excitement, particularly in the remittents of warm climates, requires to be previously subdued by blood-letting, and the bowels to be kept open. It renders the remissions distinct, and by degrees checks altogether the febrile action.

In the low stage of continued fevers of the typhoid type, particularly when these are attended with symptoms of putridity, as in gaol-fever, cynanche maligna, scarlatina maligna, confluent small-pox, and in putrid measles, bark must be regarded as one of the most valuable remedies. The administration of it in pure typhus has been of late years judiciously delayed until the increased excitement is presumed to be subdued, and symptoms of great debility make their appearance; or until the morbid heat be carried off, and the skin opened. Several eminent modern physicians1, however, recommend it to be given early in the disease, and persevered in; but from my own experience I am inclined to consider the former the safer practice, and believe that the best effects will be produced from the cinchona, when its use, in pure typhus, is not begun until the system has been fairly brought under the influence of mercurials, till the skin becomes moist, the tongue is in part cleaned, and the urine deposits a critical sediment.

The best adjuncts in these cases are the diluted sulphuric, or the hydrochloric acids and aromatics, particularly the tincture of capsicum.

1 Aphorhmi, Sec. 767.

2 Mat, Med. ii. 97.

Cinchona was first conjectured to be useful in gout by Sydenham, and in some cases its efficacy is sufficiently evident. In rheumatism, also, Dr. Haygarth has lately strongly recommended it to be given, after the manner of Morton, Hulse, and Fothergill, from the commencement of the disease; the stomach and bowels being previously emptied by means of antimonial preparations. In my own practice, I have found it useful only after the liberal exhibition of calomel, tartarized antimony, colchicum, and opium, when the pain has partly abated, or assumed an intermittent character, and the pulse has become softer. Its efficacy in this disease is much increased by the addition of spirit of turpentine.

In phthisis, bark is found beneficial when the accompanying hectic puts on more of the intermittent form than usual; when the debility is considerable, and blood is mixed with the sputa; and in several cases of pneumonia, when, after repeated large bleedings and evacuations, the pulse continued hard and thrilling, and the blood buffy, although the expectoration was free and the skin open, I have seen bark produce the happiest effects.