It is an undecided question, whether Peruvian bark was known as a medicine to the aborigines of S. America, before the discovery of the country by Europeans. Both sides of the question have the support of high authority; the affirmative being maintained by Ruiz and Joseph de Jussien, and the negative by Humboldt. Leaving aside some absurd stories in reference to the manner in which the remedy was discovered by the natives, and the mysterious secrecy said to have been observed by them in relation to it, the weight of probability appears to me to be in favour of its indigenous employment, long before the invasion of the Spaniards. The traditions in the country were to this effect; and it scarcely serins probable that a people, so civilized as the ancient Peruvians, should have overlooked a remedy so abundant, so easy of access, and so vitally important in the treatment of the fevers which must have prevailed among them. That among the ignorant and degenerate natives, at the time of the visit of Humboldt, violent prejudices should have existed against the bark, and an idea been entertained that it was poisonous instead of remedial, can hardly be admitted as an argument against this view of the subject; as a similar prejudice may be found among the vulgar, even in the most enlightened countries, where the remedy is much employed, and highly valued by the intelligent.

Peruvian bark, either of itself, or in some one of its preparations, is calculated to meet several distinct therapeutic indications; 1. as a simple tonic, 2 as an antiperiodic or anti-intermittent, 3. as a supersedent, and 4. in reference to its secondary sedative properties. Of these I shall treat severally, premising that not unfrequently two or more of these indications are presented conjointly in the same disease.

1. As a Simple Tonic

For this purpose, the medicine is employed in small doses, repeated several times a day. Difference of opinion exists as to the preferable form of administration. Some Suppose that the tonic property resides mainly, if not exclusively, in the alkaloids; others, that it belongs essentially to other principles in the bark, the alkaloids having little or none of it; while a third opinion, admitting its existence in quinia, cinchonia, etc., maintains that the colouring matters, tannic acid, etc., associated with them in the bark, so modify their influence as to render the conjoint operation of all considerably more effective than that of the alkaloids alone. My own conviction, derived from no little experience with the different forms of preparation of Peruvian bark, is, that its medicinal powers reside almost exclusively in the alkaloids, and, though the form of combination in which these naturally exist may somewhat modify their effects, by influencing their acceptability to the stomach, or the facility of their absorption or elimination, yet that the bark itself, wholly deprived of them, would be nearly if not quite medicinally inert and useless. The general experience too corresponds, I suspect, with my own; as quinia and its associated alkaloids have to a considerable extent superseded, even in reference to tonic effects, the use of bark, and of the various preparations most completely representing it.

The medicine may be used in simple debility of the digestive organs, or dyspepsia. Bark, in substance, is too apt to nauseate and oppress the stomach to be employed advantageously for this purpose; but recourse may be had to the extract, or one of the liquid preparations, especially the compound infusion of the U. S. Pharmacopoeia, which, in great debility of the stomach or system, may sometimes be usefully combined with the simple or compound tincture. Sulphate of quinia, however, is, upon the whole, the most convenient preparation. Still, it is in no respect superior, in this affection, to the simple bitters; while it is more apt to oppress the stomach, and is, therefore, comparatively little used.

In general debility, however, it stands at the very head of the tonics. It probably owes its superiority, in this condition, over the simple bitters, to the greater universality of its action. The latter medicines, though stimulant to the digestive, blood-making, and nutritive functions, have little influence over the nervous centres. Quinia acts energetically upon these centres, and extends, through them, independently of its direct influence upon the tissues, a powerful support to the weakened organic functions.

In the debility of convalescence it acts very favourably. In pure anaemia, when the morbid condition exists specially in the blood, without obvious deficiency in the digestive or nutritive powers, or in nervous excitability, as often happens in chlorosis, quinia does little good; the appropriate tonic in such cases being iron. But, in that debility of all the functions which is apt to follow the agitations of acute febrile and Inflammatory diseases, and from which it often happens that the unaided system rises slowly and with difficulty, no medicine is probably more efficient; and, if along with this condition there is a relative deficiency of the red corpuscles, it adds greatly to the effectiveness of the chalybeates.

When debility is associated with any organic mischief, as in the ulcerative condition left by inflammation and gangrene, the system is sometimes so prostrated as to be unable to carry on the reparative process, and ultimately sinks unless sustained. The tendencies are towards health, but the power to act duly is wanting. Under these circumstances, the preparations of Peruvian bark, in connection with a nutritious diet, are highly important.

When debility is produced or maintained by temporary exhausting influences, as by profuse suppuration, excessive secretion, or passive hemorrhage, it is often of the utmost importance to support the strength until the discharge has ceased; and a strong indication is offered, in such cases, for quinia or bark in some other shape, which may often be advantageously combined with opiates and alcoholic stimulants, especially the fermented liquors. Examples of this kind, dependent on profuse suppuration, we have in the advanced stages of extensive inflammation of the ordinary character, whether of the internal organs or external parts; in scrofulous abscesses; in erysipelas affecting the subcutaneous tissue; in metastatic abscess, purulent infection, pyogenic fever, or suppurative phlebitis; and in the last stage of confluent smallpox, in which large portions of the surface are bathed in pus, and subcutaneous purulent deposits sometimes form in enormous quantity.