had passed some time at Fort-Pitt, was known to have collected the plant for the purpose. I believe it to be a fact sufficiently established, that the basis (or perhaps rather the most active part) of Martin's powder was the oxyd of arsenic. This has been shown by a chemical examination of the powder*, and by other circumstances nearly as decisive. Thus comatose affections (such as are known to be induced by arsenic) have been induced by the powder of Martin, even when externally applied in cancerous ulcers. A case of this kind came under the notice of a physician† in Philadelphia. The patient seemed to fall a victim to the application of the medicine.

BUT the powder of Martin did not consist entirely of the oxyd of arsenic. This is certain. This is certain. I believe it to be certain also, that he combined with the arsenic, a vegetable matter; and from what has been said, it would seem not entirely improbable, that this vegetable was the Orobanche Virginiana.

IT may be said, and it is not impossible, that Martin added the vegetable matter merely to disguise the arsenic, reposing, at the same time, all his confidence in the arsenic alone. I think it more probable, however, that the superior efficacy of Martin's powder, and of the powders in the hands of other empirical practitioners, has been, in part, owing to the addition of something to the arsenic. If there be no foundation for this suspicion, how has it happened, that in the management of cancers, the empirical practitioners have often succeeded so much better with their medicines than the regular physicians

*See Dr. Rush's paper on the subject, in the Transactions of the American Philosophical Society. Vol. II. No. xxvi.

† Dr. Adam Kuhn, from whom I received the fact.

have done?

Both use arsenic.

Some of the cancer powders, employed by empirics, in Europe, are known to have been composed, in part, of arsenic and a vegetable matter. The celebrated powder of Plumked was made up of arsenic, the root of a species of Ranunculus, or Crow-foot; and sulphur.

WHATEVER may have been the vegetable which Martin used in combination with arsenic, it is certain, that the powder of the Orobanche, or Cancer-root, has been of great service (in Philadelphia, &c.) externally applied to obstinate ulcers, some of which had resisted the applications that are commonly made use of in such cases. It would be well to try the effects of this vegetable in those dreadful ulcerations (by some writers deemed cancerous), which are too frequently the consequence of the use of mercury, when it has been given in large quantity. Cases of the kind I allude to, are recorded by Dr. Donald Monro, Mr. Adams, in a valuable work*, and other writers. I have had occasion to see some ulcerations of the same kind in Philadelphia. They often refuse to yield to stimulating or to mild applications.

WITH the view to encourage further inquiry into the nature and properties of the Orobanche Virginiana, I may here mention, that one of the European species of this genus, the Orobanche major, or Greater Broom-rape, is a very powerful astringent, and is said to have been found useful, externally applied, in cases of ulcers. This I mention on the respectable authority of Sir John Floyer. The activity of the European plant may even be inferred from the fact mentioned by Shreber, that cattle * Observations on Morbid Poisons, Phagedæna, and Cancer, &c. p. 65, &c. London: 1795.

† Pharmacobasanos, or The Touchstone of medicines, &c. p. 159. London: 1687.

do not eat it. We must pay, perhaps, no regard to certain other powers which have been ascribed to it. "Dicunt autem facere, ut taurum vacca appetat*." I have not been able to learn whether the Orobanche Virginiana is eaten by the horned cattle, or other quadrupeds.

SECTION II. TONICS.

I SHALL open this section with a few notices concerning some indigenous Bitter vegetables, which seem well entitled to the attention of physicians. At the same time, I avail myself of an opportunity of observing, that the tonic quality of vegetables does not so much consist in bitterness as some celebrated writers † have imagined. It will not be denied that many of the bitters (even those which have their bitterness unmixed with astringency) are some of the most useful tonics with which we are acquainted. But, it must be allowed, that certain other bitter vegetables have but a feeble claim to the character of tonics. And it would not be a difficult task to show, that some of the most valuable tonics are (strictly speaking) neither bitter nor astringent. It is not easy, therefore, to say, in what the tonic property of medical agents does especially consist. It will hardly be doubted, however, that every tonic exerts a stimulant effect upon the system, though, on many occasions, it may be difficult, or impossible to measure the intensity or degree of the sti

* Alberti v Haller Historia Stirpium Indigenarum Helvetia inchoata. Tom. i. p. 130.

† Dr. Cullen, particularly. See his Treatise of the Materia Medica. Vol. II. P. 55, &c.

mulus applied, merely by an attention to the pulse. THE

PULSE IS OFTEN A VERY UNCERTAIN OR FALLACIOUS TEST OF THE OPERATION OF STIMULANT AGENTS.

THE Zanthorhiza apiifolia* of L'Heritier, or Parsleyleaved Yellow-root, is a native of North and South Carolina, and Georgia. It is a small shrub, which flowers early in the spring. This vegetable has long been known; but it is only within a very few years that it has excited the attention of physicians.

THE bark of the root is intensely bitter; I think more so than the root of Columbo. This bitter property pervades the wood of the root, as well as the bark: but in the former it is, unquestionably, weaker than in the latter. The bark of the stem is also bitter, perhaps but little less so than that of the root. The sensation of bitterness that is left in the mouth, when the bark has been chewed, is very durable and adhesive. It continues, to a considerable degree, even after the mouth has been repeatedly washed with cold water. There does not seem to be combined with the bitterness, any very considerable degree of a foreign acrimony. However, upon holding the bark for some time in the mouth, it evidently communicates to it a sense of pungency, or acrimony. I think there is less of this pungency in the bark of the stem than in that of the root.

THE infusion of the bark of the root, in hot water, had a disagreeable and somewhat virose smell. From this, however, it ought not to be inferred, that the Zanthorhiza is a deleterious plant. A similar smell belongs

Zanthorhiza simplicissima of Marshall, and Zanthorhiza tinctoria of Woodhouse. The specific named apiifolia should be preferred.

to many other bitter vegetables, even to some of those which appear, from the experience of many ages, to be entirely innoxious. I am not ignorant, indeed, that a poisonous quality has been supposed to be necessarily attached to every bitter. I cannot help thinking, that this theory has been the result of a very limited view of the subject of bitters, and of their effects. The evil effects of the Portland powder, and other similar articles, in gouty affections, have, I am persuaded, been greatly exaggerated by Dr. Cullen*, and some other writers: and the real bad effects of these articles must, perhaps, be ascribed to the long-continued repetition of a stimulant powder, by which the energies of the system are wasted, and irregularities occasioned in the circulation of the blood.

THE Zanthorhiza, so far as we are enabled to investigate its properties, appears to be one of the most pure and unmixed bitters. The addition of the sulphat of iron to an infusion of the bark of the root in boiling water, did not produce the least perceptible change in the colour of the infusion, even when the two articles were suffered to stand for a considerable time, after the addition. In this respect, as well as in others, it appears to make a very near approach to the Columbo. But I am inclined to think, that the Zanthorhiza is the least pure of the two †.

To the saliva, the bark, when it is chewed, communicates the most beautiful yellow colour. The infusion in hot water is also very fine. If its colour could be fixed, the Zanthorhiza would be one of the most important of all the yellow plantæ tinctoriæ with which we are acquainted.

*A Treatise of the Materia Medica. Vol. II. p. 64, 65, 66.

† See Elements of Botany, &c. Explanation of the Plates. Page 26.