The sensible qualities of the bark show it to be a warm tonic and astringent; excelled in its warmth by many aromatics, and in its astringency by the oak bark and the tormentil: as a stimulant, its effects are very inconsiderable. On dead animal matter it appears to be an antiseptic; yet in this quality it is exceeded by the myrrh and some other substances. Authors have consequently found considerable difficulties in explaining the sources of the benefit derived from its use. We may combine aromatics, tonics, and antiseptics, in every variety of proportion, without obtaining the advantages of the union which this natural combination offers; yet approaching so near to it, that, paradoxical as it may seem, we could, perhaps, better give up this medicine than many other articles of the materia medica. As, however, its excellence is generally allowed, it has been 3 S 2 styled a specific; and, indeed, from its indiscriminate use, physicians seem to have adopted this opinion.

The peculiar advantages of the hark are certainly derived from its tonic power. How far this is connected with its astringency has not been shown; yet we have laid the foundation for the enquiry under the article Astringentia, q. v.; and may now add, that we consider this tonic power as connected with its astringency, joined with a peculiar proportion of aroma, which affords a slight, and seldom, if ever, an injurious stimulus. Whatever are the real effects of bark may be explained from this view; for botanical analogy does not at all assist us in the enquiry, since in its natural order we find simple astringents only of no peculiar virtues. If the bark be given to a healthy person, it produces no striking change in the pulse, or any of the other natural functions. If continued, it is said to make the pulse fuller and slower, to increase the appetite, and often to produce costiveness. We have, therefore, little assistance from this source; and our best assistance is derived from its effects in diseases.

The variety of disorders in which the bark can be used to advantage, formerly entitled it almost to the character of an universal medicine: in many diseases it is supposed to be a sovereign remedy; but every practitioner, in proportion as his knowledge of its qualities increases,•finds he can employ many other remedies with at least equal advantage.

From the history of the bark, it appears to have been introduced as a remedy for intermittent and remittent fevers of warm climates. When brought to Europe it was not less successful; not that former plans had failed, but vernal intermittents had been considered as salutary, and autumnal ones as peculiarly obstinate. The fever was supposed to be the means of concocting the matter; and, when this was effected, it was supposed that nature would discharge it. On this principle the use of the bark was opposed by regular physicians, and it was accused of producing infarctions of the liver, dropsy, etc.; while its supporters alleged that these were the effect of the disease, and, in reality, owing to its not being checked more early. Truth, as usual, probably lay between the two extremes. We are confident that these inconveniences have been derived from the injudicious use of the bark, though they may, and often do, arise from the disease itself, as will appear in its proper place.

As the bark seems to act as a tonic in consequence of its astringency, we may suspect that, from this power, it would be occasionally injurious, and it is certainly found so. The admirers of this remedy contend that it cannot be an active astringent, since it is useful in relieving glandular tumours arising from obstruction, and that it does not stop the spitting in the confluent small pox. Such assertions, which we find in the former edi-lions of this dictionary, are owing to the want of discrimination, so frequent in its authors. When increased evacuations or obstructions arc owing to, or connected with debility, the astringent power of the bark corrects the cause, and only by degrees lessens the effect. We have already noticed even a stronger case, where it is useful in peripneumonia notha arising from atonic gout, and shall have occasion to point out its efficacy in the putrid peripneumony. But when it is contended that it has been given to women successfully in the quantity of a drachm every three hours, two days after delivery, the event is certainly misrepresented, or the circumstances concealed. We have had occasion to witness very opposite effects; and though it may not greatly lessen the usual flow of the menses in some cases of excessive critical evacuations from the uterus, it has been highly injurious by checking them. The expectoration, except where connected with debility, it certainly lessens; the discharge of bile it checks; and frequently the perspiration. In short, its use demands much more minute discrimination than it seems yet to have enjoyed.

In intermittents its power is generally acknowledged; and it is in these a medicine of great importance, as we can often, with certainty, prevent an expected fit. This power is more valuable, as those species which attack the head would be fatal in the recurrence of another paroxysm. Yet, where we can wait the operation of laxatives, it is always safest to premise them, for reasons which we shall afterwards explain. (See intermittents.) The young practitioner must not, however, too confidently expect constant success. We have often found the bark ineffectual in curing agues, in whatever way it has been tried; but usually to succeed is no common praise. In remittents the bark is equally useful; and in the malignant ones indispensable, when the irritability of the stomach will admit of its exhibition.

In every kind of continued fever, except the inflammatory, or the inflammatory stages of fever, the bark is said to be extremely useful, though this general axiom is not supported by our own experience. When the bowels are thoroughly emptied, it is not injurious: when debility or putridity comes on, it is useful. Yet in many cases of febrile debility, wine and suitable aliment are at least equally effectual, and the practitioner should be aware that bark, by checking the discharges from the liver and other glands of the intestines, produces an apparent debility, which purgatives alone will remove. In the yellow fever, it is lately said by Dr. De la Fuente, a Spanish physician, that it is a specific, given in large doses: six or eight ounces of bark are to be taken in the first forty-eight hours of the disease.