THE fine, smooth foliage of the Rhus Vernix render it one of the most elegant of our native shrubs, white its well known poisonous qualities make it an object of aversion, and deter most persons from a near inspection of its structure and characteristics. From Canada to Carolina it is a common tenant of swamps and meadows, usually attaining the height of ten or fifteen feet, but sometimes rising into a tree of twice that altitude. The names of Poison tree, Poison wood, Poison ash, &c. are applied to it in different parts of the United States. In Massachusetts it is universally known by the name of Dogwood. This appellation, being applied throughout the country to Cornus florida, serves to shew the fallacy of depending on vulgar or provincial names for the distinction of plants. A mistake of very injurious consequence might easily arise from the confusion of the English names of two trees so dissimilar in their qualities.
The class Pentandria and order Trigynia; the Linnaean order Dumosae and the Jussieuean Terebintaceae include the genus to which this shrub belongs. The generic character consists in an inferior, five-parted calyx, a corolla of five petals, and a berry with one seed. The Rhus vernix has its leaves annual, pinnate, glabrous; its leafets oblong, entire, acuminate; its panicle lax, and its flowers dioecious.
The trunk of the poison sumach is from one to five inches in diameter, branching at top, and covered with a pale greyish bark. The wood is light and brittle, and contains much pith. The ends of the young shoots and the petioles are usually of a fine red colour, which contributes much to the beauty of the shrub. The leaves are pinnate, the leafets oblong or oval, entire, or sometimes slightly sinuate, acuminate, smooth, paler underneath, nearly sessile, except the terminal one. The flowers, which appear in June, are very small, green, in loose axillary panicles. Where they appear not axillary, it is because the leaf under them has been detached. The barren and fertile flowers grow on different trees. The panicles of barren flowers are the largest and most branched. They are furnished with short, oblong bractes, and downy pedicels. The calyx has five ovate segments, and the corolla five oblong, sigmoid petals. The stamens are longer than the petals, and project through their interstices. The rudiment of a three-cleft style is found in the centre.—In the fertile flowers, the panicles of which are much smaller, the calyx and petals resemble the last, while the centre is occupied by an oval germ, ending in three circular stigmas. The fruit is a bunch of dry berries or rather drupes of a greenish white, sometimes marked with slight purple veins, and becoming wrinkled when old. They are roundish, a little broadest at the upper end, and compressed; containing one white, hard, furrowed seed.
A tree, supposed to be the same with the Rhus Vernix, grows in Japan, and furnishes the celebrated black varnish of that country.
A controversy respecting the identity of the Japanese and American species, was carried on in the forty ninth and fiftieth volumes of the London Philosophical transactions, by Mr. Philip Miller and Mr. John Ellis. The mass of evidence seems to justify the belief, that notwithstanding the remoteness of their situation, they are one and the same species. The description of the oriental tree, given in Kaempfer's Amoenitates exoicae, agrees very closely with that of the American species.
[Note G.] [The following is Kaempfer's description taken from his Amoenitates Exotica, p. 791. His accompanying figure resembles the American Rhus vernix, except, that the end of the branch and bud are larger in proportion than with us.
"Sitz, vel. Sitzdsju, i. e. Sitz planta, vulgo Urus seu Urus no ki, Arbor vernicifera legitima, folio pinnato Juglandis, fructu racemoso ciceris facie.(lots more latin bumpf snipped)]
Like our native Rhus, the Japanese tree possesses a poisonous influence, and frequently causes a severe cutaneous affection in those who approach or gather it. It only remains to shew, that a varnish may be obtained from the American Rhus vernix, to furnish strong presumptive evidence of the identity of the two.
If an incision be made in the bark of our Rhus vernix in the spring or autumn, a quantity of thick viscid fluid immediately exudes, and sometimes with such rapidity as to drop off before it can be collected. This juice has an opaque, whitish appearance, and a strong, penetrating, disagreeable smell. On exposure to the atmosphere, its colour soon changes to a deep black. It is extremely slow in drying, and permanently retains its black colour.
In the month of October, 1814, with the assistance of Dr. Pierson, whose case is afterwards described; I collected several ounces of this juice from a thicket of trees in Brighton. Being collected in a phial, it retained its whitish colour, except at the surface, where it turned black from its contact with the air in the upper part. This juice was kept for more than two years without any change in its appearance. In cold weather it was extremely viscid, and flowed with difficulty.
Different portions of this juice were submitted to chemical examination. It was perfectly insoluble in water, although upon boiling with it, it formed a thick emulsion. Alcohol dissolved it sparingly, and the solution was rendered turbid by water. Aether combined with it more largely, forming a thick, opaque compound. Strong sulphuric acid combined with it, producing a black solid mass. Alkalies also combined with it, and a strong solution of pearl ash dissolved a portion of it, which was afterwards precipitated by sulphuric acid. It had an affinity for metallic oxyds, and powdered litharge, upon being boiled with it, rendered it nearly solid. In distillation at the heat of boiling water, nothing came over except a slight film upon the surface of the water. When the heat was raised to the boiling point of the juice, a quantity of thin, blackish, volatile oil came over, which dried up on being exposed to the air, leaving a slight coating on the surface of the vessel which contained it. The portion remaining in the retort was much inspissated, and upon cooling became nearly solid.
Being desirous to try the effect of this juice, employed as a varnish, I applied a coating of it with a brush to different surfaces of wood, glass, tinned iron, paper, and cloth. These were exposed to the air and light during the whole of the months of July and August, at the expiration of which period they had not become dry. Each of the coatings was half fluid and adhesive, and had collected much dust. Upon the cloth and paper the juice had spread extensively, giving them an oily appearance.
Concluding from this experiment that the juice could not be usefully employed in its crude state, I endeavoured to render it more drying by the addition of litharge. The compound, which resulted from boiling with this oxyd, became dry in a short time, but was not distinguished for any remarkable degree of lustre.
The third and last experiment proved more satisfactory. A quantity of the juice was boiled alone, until nearly all the volatile oil had escaped, and the remainder was reduced almost to the state of a resin. In this state it was applied while warm to several substances, which after cooling exhibited the most brilliant, glossy, jet black surface. The coating appeared very durable and firm, and was not affected by moisture. It was elastic and perfectly opaque, and seemed calculated to answer the purposes of both paint and varnish.
The chemical constitution of the juice of the Rhus vernix seems, from the foregoing experiments, to be most analogous to that of the balsams, consisting chiefly of a resin and an essential oil. The oil dissipates slowly at low temperatures, approaching in this and some other respects to the character of a fixed oil. The resin, when procured in contact with the atmospheric air, is black, opaque, and solid, rendered very adhesive, and at length fluid by heat.
A very distressing, cutaneous disease, it is well known, ensues in many persons from the contact, and even from the effluvium of this shrub. The poisonous influence which produces this affection is common to several other trees and plants, such as the Poison vine or Poison ivy, (Rhus radicans,) the Cashew nut, (Anacardium occidentale,) and the Manchineel, (Hippomane mancinella.) Even the garden Rue, and common Oleander, are said to affect some persons in a similar manner.—The Rhus vernix is the most formidable of this tribe which is found among us, and occasionally produces the most severe effects. It is however extremely various in its action, upon persons of different idosyncrasies. Some cannot come within the atmosphere of the shrub, without suffering the most violent consequences. Others are but slightly affected by handling it, and some can even rub, chew, and swallow the leaves without the smallest inconvenience.
The most formidable cases in persons subject to this poison, usually commence within twenty four hours after the exposure. The interval is sometimes longer, but more frequently shorter. The symptoms are generally ushered in by a sense of itching and a tumefaction of the hands and face. The swelling gradually extends over various parts of the body, assuming an erysipelatous appearance. The inflamed parts become more elevated, acquiring a livid redness, attended with a painful burning sensation. Small vesicles now appear upon the surface, which extend and run into each other. They contain a transparent fluid, which by degrees becomes yellow, and at length assumes a purulent appearance. A discharge takes place from these vesicles or pustules, giving rise to a yellowish incrustation, which afterwards becomes brown. In the mean time an insupportable sensation of itchiug and burning is felt. The inflamed parts become excessively swollen, so that not unfrequently the eyes are closed, and the countenance assumes a shapeless and cadaverous appearance, which has been compared to that in malignant small pox. The disease is usually at its height from the fourth to the sixth day, after which the skin and incrustations begin to separate from the diseased parts, and the symptoms gradually subside. It is not common for any scars or permanent traces of the disease to remain. Notwithstanding the violent character which it sometimes assumes, I never knew an authenticated case of its terminating fatally. It is however capable of occasioning the most distressing symptoms. Kalm, in his travels in North America, mentions a person who, by the simple exhalation of the Rhus Vernix, was swollen to such a degree, that "he was stiff as a log of wood, and could only be turned about in sheets." Dr. Thacher mentions a case, in which the head and body were swollen to a prodigious degree, so as to occasion the loss of sight for some time; and the patient recovered at the end of several weeks with the loss of his hair and nails.
Of the cases which have fallen under my notice, the following affords a fair instance of the operation of this poison, as it ordinarily effects those who are constitutionally liable to it. On the 27th of October, 1814, Dr. A. L. Pierson, then a student of medicine, accompanied me to Brighton for the purpose of collecting the juice of the Rhus vernix, growing at that place. He had always supposed himself constitutionally exempt from liability to the poison. The day proved warm, and the effluvium from the incisions we had made in the trees was very powerful. We were engaged in the collection for upwards of an hour, during which he was less exposed than myself, being absent a part of the time. His own account of the symptoms which followed this exposure is as follows:
"I felt no unpleasant effects for six or seven hours after returning to Boston. About 8 o'clock P. M. I perceived the backs of my hands were swollen and puffy, but without pain or itching; my forehead and upper lip were soon in the same state. On the morning of the 28th the tumefaction had increased, and I discovered various other parts of my body to be infected. The backs of my hands and wrists, which were the most advanced, began to show small watery vesicles. No applications were made till the noon of this day. I then applied cloths dipped in lead water to one hand and wrist, and in a spirituous solution of the the corrosive muriate of mercury to the other. From this and subsequent trials, I am induced to prefer the lead. The parts began to itch—the tumefaction increased—vesication began to take place on the swollen surface—small pustules formed and ran into each other, and at last some were formed as large as nutmegs. On the 29th, my eyes were nearly closed, in consequence of the swelling of my forehead, eyebrows and cheeks. The contents of the vesicles were perfectly limpid—inoculation from them to other parts had no effect—neither in this nor any subsequent stage. On the evening of the 30th, the inflammation appeared at its height. The burning sensation and itching were intolerable. I could scarcely discern any object. On the 31st, the pustules began to appear a little milky—and before night the inflammation was evidently on the decline. I this day applied an ointment, composed of Ung. Stramonii, 1 oz.—Subm. Hyd. c. Ammonia (white precipitate) 1 dr. mixed—with a very pleasant effect. It was now soothing, although before it had seemed to irritate, and produced pain when applied. November 1st, a very free desquamation began, first on my forehead, hands and wrists. And in just a fortnight I was enabled to leave my chamber, blessed with a new cuticle from the root of the hair on my forehead to my breast, from the middle of my forearm to the tips of my fingers, and on the whole inside of my thighs. The constitutional effects of this thorough vesication were but slight. During the first five days, my pulses were increased from ten to twenty strokes in the minute. The time of duration of the inflammatory symptoms in this case accords pretty well with the account of Prof. Barton, who states, I think, the height of it to be on the fifth day. It is worth observing, that the operation of the poison seemed to have a considerable effect in relieving me from dispeptic symptoms, with which I had been previously troubled, and also benefitted a chronic inflammation of my eyes. I am still subject to an eruption of watery pustules between my fingers, which dry up, and the cuticle peels off." Letter dated July, 1815.
Many constitutions are but slightly, or not at all, affected by the poison of the Rhus vernix. This I find to be my own case. After the same exposure, which occasioned the case just detailed, I experienced no ill consequence, except a slight vesicular eruption on the backs of the hands and about the eyes, which disappeared in a short time, without farther inconvenience. The same slight affection I have felt upon several subsequent exposures, particularly when making, from a recent specimen, the drawing which accompanies this account.
I apprehend that a majority of persons are not liable to the injurious effects of the poisonous sumacs. Among persons residing in the country, exposures must occur very frequently from the abundance of these shrubs, especially of the Rhus radicans, by roadsides and elsewhere. Very few however, in proportion to the number exposed, have personal experience of their deleterious effects. In those on the contrary, in whom a constitutional liability to the poison exists, the disease frequently returns several times during life, notwithstanding the utmost precaution in avoiding its causes. A gentleman residing in the country informed me, that he had been seven times poisoned to the most violent degree. In such constitutions a slight exposure is sufficient to excite the disease. I have known individuals badly poisoned in winter from the wood of the Rhus Vernix, accidentally burnt on the fire. Others have made the same observation.
Some farther remarks on the poison of these shrubs, and on the treatment of the disease occasioned by them, will be made in a future part of this work, under the head of Rhus radicans.
Many interesting observations on the properties of these species of Sumach, will be found in an inaugural dissertation, by Dr. Thomas Horsfield of Bethlehem, Pa. a work of much industry and merit.
In the New York Medical Repository is an account of a swarm of bees, which, having alighted on the branches of the Rhus vernix, were the next day found dead, with their bodies black and swollen. This is a remarkable circumstance. There is certainly no instinctive aversion in these animals for the tree. In the flowering season the blossoms, which are very fragrant, are always thronged with a multitude of winged insects in quest of their honey.
The introduction of the juice into the arts will not perhaps take place among us, during the present high price of labour, and the general prejudice which exists against the shrub. In some future period, it is probable that a substance, which is found so valuable in the eastern countries, will not be neglected among us. It might safely be procured by persons not subject to the poison, and, with proper precautions, would injure no one during its preparation and use. A pound of the juice in a day might be collected by an individual. When thoroughly dry, it ceases to emit an effluvium, and nothing farther is to be apprehended from its effects.
Rhus vernix Linnaeus, Sp. pl.
Aiton, Hort. Kew. i. 366.
Michaux, i. 183.
Pursh, i. 205.
Pennated toxicodendron Ellis, Phil. trans. abr. xi. passim.
American toxicodendron Miller, ibid.
Toxicodendron carolinianum foliis pinnatis, &c. Mazeas, ibid. x. 595.
Toxicodendron foliis alatis, fructu rhomboideo, Dill. Elth. 390, t. 292, f. 377.
Arbor Americana alatis foliis, sueco lacteo, venenato, Plukenet, phyt. t. 145. f. 1.
Dudley, Phil. trans. abr. vi. 507.
Sherard, ditto. 508.
Kalm, travels, i. 77.
Marshall, arbust. 130.
Cutler, Amer. Acad. 427.
Barton, Coll. 24.
Thacher, Disp. 321.
Horsfield, Inaugural Dissertation.
American Medical Botany, 1817-1821, was written by Jacob Bigelow, M. D.