Origin

This is the inner bark of Cerasus serolina, or wild-cherry, a large indigenous tree, growing abundantly in the Middle and Western States. The officinal name originated in the mistaken supposition, that the Prunus Viryiniana of Linnaeus was the tree in question; whereas, according to Torrey and Gray, that title really belongs to the choke-cherry (Cerasus Virginiana of the N. American Flora), a small tree or shrub, inhabiting the Northern States. The bark is obtained from the root, stem, and branches of the tree; but that from the root is preferred. It should be collected in the autumn, when it is strongest. The recently dried bark is more efficacious than that which has been long kept.

Sensible Properties. Wild-cherry bark, as found in the shops, is usually destitute of epidermis, of a reddish-yellow colour, brittle, and easily pulverized, yielding a fawn-coloured powder. When fresh, or treated with water, it has the odour of peach-leaves. The taste is agreeably bitter, astringent, and somewhat aromatic. It yields its bitterness to water, to which it imparts a reddish-brown colour like that of Madeira wine.

Active Constituents. Among the active principles existing in the bark are amygdalin and tannic acid. There is probably also some emulsin, a kind of nitrogenous or albuminous matter, found in the bitter almond, where it plays an essential part in changes, analogous if not identical with those which are now to be noticed as occurring in wild-cherry bark. When this bark conns in contact with water, a reaction takes place, under the influence of the emulsin operating as a ferment, between the water and the amygdalin of the bark, whereby the latter is converted into a peculiar volatile oil and hydrocyanic acid, which may be obtained together by distillation, constituting a product which is probably identical with the volatile oil of bitter almonds. When, therefore, wild-cherry bark is used in the form of infusion, it is not merely the amygdalin and tannic acid which act, but the new product also, which is essentially, in relation to its effects on the system, the hydrocyanic acid; for the volatile oil which attends it has little effect. When the medicine is taken in the form of powder, it is highly probable that the same change takes place in the stomach, under the reagency of the water there. It is a question whether the bark does or does not contain a bitter principle distinct from amygdalin. I believe that it does so, not only from its tonic effects, which cannot be ascribed either to the volatile oil or hydrocyanic acid, but from an experiment made at my request by Professor Procter, which appears to determine the question.* Though boiling water will extract the active matters existing in the bark, yet cold water is medicinally the best solvent; for the emulsin is coagulated and rendered inert at a high temperature, and the formation of hydrocyanic acid consequently prevented.

* A portion of the bark was exhausted by alcohol, and the tincture evaporated to an extract. This contained the amygdalin, and whatever bitter matter and tannic acid existed in the bark. The extract was triturated with water, and with gelatin to remove the tannic acid. The liquor being then filtered, was mixed with an excess of the emulsion of sweet almonds, containing of course the emulsin necessary for causing reaction between the amygdalin and water. A strong odour of hydrocyanic acid was produced, which had not previously existed in the solution of the alcoholic extract. As the emulsin was in excess, the whole of the amygdalin must have been destroyed. The liquid was evaporated to a soft extract, and mixed with water. Sweet almond emulsion now added generated no more hydrocyanic acid.

Effect* on the System. Wild-cherry bark is, through its bitter principle, a gentle stimulant to the digestive and probably to the nutritive function; while the hydrocyanic acid, evolved by the reaction of water with the amygdalin, renders it sedative to the nervous system, and, when freely taken, to the general circulation. Dr. Eberle states that, in his own person, he has "several times reduced his pulse from seventy-five to fifty strokes in the minute by copious draughts of the cold infusion, taken several times a day, and continued for twelve or fourteen days." {Mat. Med. and Therap., 4th ed., i. 301).

Therapeutic Application

The joint tonic and sedative properties of this bark admirably adapt it to the treatment of cases of general debility, with enfeebled digestion, an irritable state of the nervous system, and excessive frequency of pulse. Long before its chemical peculiarities were discovered, experience had established this application of the remedy. In the treatment of pulmonary consumption, it has for many years been a favourite in this country, and, before cod-liver oil came into notice, was probably more relied on than any other single medicine. It was employed not only in the advanced stages when hectic fever had set in, but from the beginning, and often as a preventive, in cases in which a strong tendency to the disease seemed to be displayed. It was given with the view of imparting tone to the digestive organs and system generally, and thereby modifying the tuberculous diathesis, and was preferred to other tonics, because it was thought to produce these effects with less danger of undue excitement. Now that it is known to be positively sedative to the heart, and to the nervous system, we can better understand its usefulness in that complaint. In other forma of scrofulous disease, presenting a similar complication of debility of the digestive and nutritive functions with frequency of the pulse, it is equally indicated. Few remedies are better adapted to hectic fever, from whatever source it may proceed. In the debility of convalescence from fevers, and other severe acute diseases, when attended, as it often is, with night-sweats, a frequent pulse, and sleeplessness, restlessness, or other functional nervous disorder, the wild-cherry bark is also an excellent remedy. Perhaps the tannic acid it contains may contribute to its usefulness in correcting the excessive sweating in these cases; but I am not inclined to attribute much to that principle in estimating the virtues of the bark.

It has been recommended also in simple dyspepsia, and as an antiand there was none of the peculiar odour of that product; yet the taste was decidedly bitter, proving the existence in the bark of a bitter principle distinct from amygdalin.

periodic in intermittents; but in the former it is much inferior to the pure bitters, and in the latter, though sometimes successful, it very often also fails, and is not comparable in efficacy with Peruvian bark. It may be employed, however, in cases of convalescence from miasmatic fevers, in which there is a strong tendency to relapse, and in which a long continuance of the preventive influence may be necessary for the eradication of the predisposition. In such cases, though less effectual than sulphate of quinia, it may perhaps be safer.

I have employed the remedy much in functional and organic disease of the heart, attended with a frequent, perhaps irregular, but rather feeble pulse, with an anemic or otherwise debilitated state of system; and consider it one of our best remedies in such cases, combined, if anaemia exist, with the use of the chalybeates. As the infusion, however, contains tannic acid, it is better not to add the preparation of iron to it, but to administer the two separately.

Administration

The bark may be given in the form of powder, infusion, or syrup. The powder is seldom used, because less convenient, more apt to oppress the stomach, and less likely to undergo those chemical changes which are essential to the characteristic effects of the remedy. The dose is from thirty grains to a drachm, which may be repeated three or four times daily.

The Infusion made with cold water (Infusum Pruni Virginianae, U. S.) is the most appropriate form. It is made in the proportion of half an ounce to the pint of water, and is best prepared by the proce-percolation. Any one can perform this process. Introduce an ounce of the bark, in the state of powder, into a common funnel, pack it somewhat closely, and pour upon it a quart of cold water; the point of the funnel being inserted into the mouth of a glass decanter. When the water has all passed, pour it back into the funnel, and repeat this measure until the liquid acquires the colour of Madeira wine. Two fluidounces of the infusion, thus prepared, may be given three or four times a day, or more frequently when a strong impression is desired.

A Syrup (Syrupus Pruni Virginianae, U. S.) is directed by our Pharmacopoeia. It is an elegant preparation, and, where there is no contraindication, from delicacy of stomach or other cause, to the use of so much saccharine matter, may be substituted without disadvantage for the infusion. The dose is half a fluidounce, to be repeated as directed for the other forms.

A Fluid Extract (Extractum Pruni Virginians Fluidum, U. S.) was introduced into the last edition of the Pharmacopoeia. It is prepared according to a very ingenious process suggested by Professor Procter, by which the virtues of the bark are obtained in a very concentrated form. The dose is one or two fluidrachms, equivalent to half a drachm or a drachm of the bark in substance. (See U. S. Dispensatory, 11th ed., p. 628).

Wild-cherry bark should not be prepared in the form of tincture, extract, or decoction. In reference to the two latter, independently of the chemical objection above stated, there is another in the volatile character of the hydrocyanic acid, which, if formed, would be driven off, to a greater or less extent, in the processes for their preparation.