Myrica cerifera. Wax Myrtle.
Almost every region of the United States produces varieties of the Wax myrtle. Michaux considers them all as belonging to one species, a conclusion which is warranted by the great number of intermediate sizes, and forms of leaf, which may be observed between the different extremes. Pursh, however, has chosen to distinguish three species which bear wax, and which he names cerifera after Linnaeus, Caroliniensis from Willdenow, and Pennsylvanica from Lamarck. The Wax myrtle or Bayberry, as it is often called, which is common in New England, varies in height from one to seven or eight feet. It is found in every kind of soil from the borders of swamps to the tops of barren hills, and is very much influenced in its size and appearance, by the place in which it happens to grow.
The genus Myrica belongs to the class Dioecia, and order Tetrandria. It is also ranked among the Amentaceae of Linnaeus and Jussieu.
The generic character consists in an imbricated ament; the scales without a corolla; the barren flowers containing four anthers, the fertile ones two styles. Fruit, one seeded.
—The specific character, as given by Michaux, is as follows. leaves wedge-lanceolate, with a few serratures at top; barren aments lax; fruit spherical, naked, distinct.
The Wax myrtle is found bearing fruit at every size, from the height of one foot, to six or eight. In Louisiana, it is said to grow to twelve feet. The top is much branched, and covered with a grayish bark. The leaves are wedge-lanceolate, varying in width, sometimes entire, but more frequently toothed, particularly toward the end. They are somewhat pubescent, a little paler beneath, and generally twisted, or revolute in their mode of growth. They are inserted in a scattered manner by short petioles. The flowers appear in May before the leaves are fully expanded. The barren ones grow in catkins, which are sessile, erect, about half an inch or three quarters long; originating from the sides of the last year's twigs. Every flower is formed by concave rhomboidal scale, containing three or four pairs of roundish anthers on a branched footstalk. The fertile flowers, which grow on a different shrub, are less than half the size of the barren ones, and consist of narrower scales, with each an ovate germ, and two filiform styles.
To these aments succeed clusters or aggregations of small globular fruits resembling berries, which are at first green, but finally become nearly white. They consist of a hard stone inclosing a dicotyledonous kernel. This stone is studded on its outside with small black grains resembling fine gun-powder, over which is a crust of dry white wax, fitted to the grains and giving the surface of the fruit a granulated appearance. Botanically speaking, this fruit has been improperly called a berry, and a drupe; since it is always dry and never invested with a cuticle, or any thing but the grains and wax.
Every young part of the Wax myrtle has a fragrant, balsamic smell, which it communicates to the fingers when rubbed by them. This appears to be derived from a resinous exudation, which may be seen in minute points of a bright transparent yellow, covering the young shoots and under surface of the leaves. In the berries this resinous substance is within the wax.
The bark and leaves of the Myrica cerifera contain gallic acid, tannin, resin, and a small quantity of mucilage, which are manifested by their usual tests.
The wax of the Myrica is obtained for common purposes by boiling large quantities of the berries in kettles with water enough to cover them to the depth of several inches. The berries, which float at first, gradually subside to the bottom when the wax is melted off, which latter substance floats on the surface. When the boiling has been continued long enough to divest the berries of most of their wax, the liquid is suffered to cool, and the wax concretes on the top. It is purified by melting it anew, and is then cast into masses.
In this state it is of a greenish gray colour, with a consistence which is intermediate between that of bees wax and tallow, being brittle and not remarkable for adhesiveness or unctuosity. It burns with a white flame, which is less vivid than that of tallow or whale oil.
The chemical properties of this wax have been examined by M. Cadet, in France, and Dr. Bostock, in England. From their experiments, we learn that water has no action on the Myrtle wax, either cold or at the boiling heat. Dr Bostock informs us that alcohol, at the ordinary temperature of the atmosphere, has no action upon it; but one hundred parts by weight of the fluid, when boiling, dissolve about five parts of the wax. About four fifths of this is deposited by cooling, and the rest is slowly deposited in a few days, or may be precipitated by water. Of the mass of wax, a certain portion remains insoluble in alcohol.
Sulphuric ether, according to Dr. Bostock, dissolves but little of the wax, when cold, but acts upon it rapidly, when boiling, taking up somewhat more than one quarter of its own weight. Upon evaporation, the wax is deposited in a crystalline or lamellated form, its texture resembling that of spermaceti.
Rectified oil of turpentine, when assisted by heat, dissolves about six per cent of its own weight, most of which is deposited on cooling.
Pure potash, in water, renders the wax colourless by boiling, and forms a soap with a small part, which may be decomposed by an acid, and affords the wax nearly unchanged.
The sulphuric acid, assisted by heat, dissolves about one twelfth of its own weight, and forms a dark brown mass. The nitric and muriatic acids exert very little action upon it. Dr. Bostock considers the Myrtle wax to be a fixed vegetable oil, rendered concrete by oxygen.
M. Cadet, in addition to many of the above characteristics of Myrtle wax, found that it combined readily with the semivitreous oxyde of lead, forming a very hard plaister. When distilled in a retort, the wax was partly decomposed, and a portion which passed over was white and of a soft consistence. Oxygenated muriatic acid bleaches it, but with more difficulty than bees wax.
The experiments which I have made on this substance confirm the preceding statements with the following exceptions. Cold alcohol dissolves a minute portion, which is gradually separated by the addition of water, and floats in perceptible flocci, near the surface. Cold ether dissolves about one sixteenth of its weight. This it does with great rapidity, and if thin shavings of the wax be dropped into a vessel of ether, they disappear almost immediately.
Dr. J. F. Dana has published, in Silliman's Journal, an account of some experiments made to ascertain the proportion of wax, and of the other parts which compose the entire berry. He found the wax to constitute nearly a third of the whole, or thirty two per cent; the kernels 47.00, the black powder 15.00, with about 5.00 of a resino-extractive matter.
There undoubtedly exists, in the berries of this shrub, some interesting constituents beside the wax and insoluble portions, as the following results will show. If water be distilled from the fresh berries, it acquires a slight pearly appearance and a fine aromatic odour and taste. This indicates the presence of a volatile oil, though I have not performed the experiment sufficiently in the large way to obtain any oil separate. The decoction remaining in the retort gives proofs of gallic acid.
When the wax, in a separate state, is boiled in alcohol, a portion is dissolved, which is mostly deposited on cooling, leaving the fluid clear. But if alcohol be boiled upon the berries till a strong solution is formed, it does not give a deposit on cooling, but the solution coagulates into a soft solid and remains afterwards unaltered. This coagulum is readily soluble in cold ether, and melts when exposed to heat. If the berries be boiled in water until the wax is melted and principally detached, the remaining parts still give a coagulating solution with alcohol.
The tincture made by digesting cold alcohol on the bruised berries is considerably coloured, and becomes turbid on the addition of water, but whether the resinous substance thus precipitated is the same in small quantity, which produces the coagulation in a large one; I am not prepared to say.
It appears, then, that there exists in the berries of the Myrica a peculiar vegetable principle, bearing nearly the same relation to alcohol, as starch and gelatin do to water. I have not yet obtained it in a separate state, and cannot therefore give any additional characteristics to those which have been already stated.
The Myrtle wax is useful for many of the purposes for which bees wax and tallow are employed, particularly for candles. It burns with a clear flame, though less vivid than that of common oil, and emits a considerable fragrance. It was formerly much in demand as an ingredient in a species of blacking ball, to which it communicated a temporary lustre and power of repelling water. It has occasionally been used in pharmacy in various compositions intended for external use, and is mild or stimulating according as it is more or less pure and freed from the colouring matter.
In some parts of Europe plantations of this shrub have been raised with a view to the profit to be derived from the wax. In this country, where the shrub abounds, the berries are often neglected, their collection and the separation of the wax being deemed too laborious to compensate the trouble.
In Dr. Thatcher's Dispensatory, we are informed, on the authority of Dr. Mann, that the bark of the root of the Myrica cerifera is emetic. With a view to examining thoroughly its medicinal properties, Dr. S. L. Dana, in 1818, made it the subject of an inaugural dissertation. He found that the powdered bark was acrid and astringent, but did not appear to possess any other qualities than were attributable to those two. Moderate doses of the powder and decoction produced no effect on the stomach or bowels. Large doses, for instance two scruples, were swallowed with difficulty on account of their acrimony, and occasioned heat and nausea at the stomach. Larger doses, of a drachm, produced a powerful burning sensation and vomiting. Costiveness generally followed the use of this medicine. The powder, when snuffed up the nose, proved powerfully sternutatory, and when applied to the fungous granulations of an ulcerated leg, it produced so much pain as compelled the patient to wash it off.
We may then consider the bark of the Myrica as an acrid stimulant and astringent. That it sometimes proves emetic, in large doses, is to be explained in the same way as the operation of mustard and horse-radish, which some of the older physicians employed as emetics. When the stomach is burdened with an undue quantity of stimulus, it naturally tends to relieve itself by vomiting.
On the whole, we are to esteem the Myrica cerifera as more interesting in a chemical, than a medical point of view. The pleasant aroma of the water distilled from the berries, and the application of the wax to some purposes of pharmacy, are all, that this shrub at present offers, much deserving the attention of physicians.
Myrica cerifera, Willd. iv. 745.
Michaux, ii. 227.
Pursh, ii. 620.
Myrtus foliis lanceolatis, &c.
Myrtus brabanticae similis, &c.
Catesby, i. 13?
Medical and Chemical References.
Cadet, translated in Nicholson's Journal, 8vo. vol. iv. 187.
Bostock, in ditto, 129.
Kalm, Travels, i, 129.
Dana, in Silliman's Journal, vol. i.
Thacher, Disp. 288.