Ulmus. U. S.
Ulmus. U. S.
Elm. [Elm Bark, Slippery Elm]
"The bark of Ulmus fulva Michaux (Pam. Ulmaceae), deprived of the outer corky layer and dried." U. S.
Red Elm, Moose-elm, and Indian Elm; Cortex Ulmi Interior, Ulmi Cortex; Orme Fauve, Fr. Cod.; Ecorce d'Orme, Fr.; UImenrinde, Ruaterrinde, G.
The slippery elm (Ulmus fulva), is a lofty tree, fifty or sixty feet in height, with a trunk fifteen or twenty inches in diameter. The bark of the trunk is brown, that of the branches rough and whitish. The leaves are petiolate, oblong-ovate, acuminate, nearly equal at the base, unequally serrate, pubescent, and very rough on both sides. The buds, a fortnight before their development, are covered with a dense russet down. The flowers, which are apetalous, appear before the leaves, are sessile, and in clusters at the extremities of the young shoots. The clusters of flowers are surrounded by scales, which are downy like the buds. The calyx is also downy. The stamens are five, short, and of a pale rose color. The fruit is a membranaceous capsule or samara, enclosing in the middle one round seed, destitute of fringe.
Ulmus fulva is indigenous, growing in all parts of the United States north of the Carolinas, but most abundantly west of the Alleghany Mountains. It extends westward to the Dakotas and northward to western Quebec and Lake Huron. It flourishes in open, elevated situations, and requires a firm, dry soil. From the white elm (U. americana L.) it is distinguished by its rough branches, its larger, thicker, and rougher leaves, its downy buds, and the character of its flowers and seeds. Its period of flowering is in April. The inner bark, separated from the cortex, is the part used. Large quantities are collected in the Lower Peninsula of Michigan.
Fremontia californica Torr., or California Slippery Elm, is not botanically allied to Ulmus fulva; its bark is said, however, to have the same properties as slippery elm bark, and to be used for a similar purpose.
Properties.—Elm bark is officially described as follows:
"Usually in bundles consisting of flat, oblong pieces, about 30 cm. in length and from 10 to 15 cm. in width; outer surface of a light brown or buff color with occasional dark brown patches of adhering cork, longitudinally striate and with detachable bundles of bast-fibers, and colored blackish upon the addition of a very diluted iodine T.S.; inner surface light yellowish-brown, nearly smooth and finely striate, only slightly darkened upon the addition of a very diluted iodine T.S.; fracture fibrous with projecting bast-fibers, the broken surface porous, due to the large mucilage cells; odor distinct; taste mucilaginous. The powder is very light brown; under the microscope it shows mostly fibrous fragments, and a finely granular portion made up of small starch grains, the latter being immediately colored bluish-black upon the addition of iodine T.S.; starch grains mostly spherical or more or less polygonal, usually about 0.003 mm. in diameter, but also attaining a diameter of 0.025 mm.; bast-fibers very long, about 0.02 mm. in diameter, with rather thin, slightly lignified walls; calcium oxalate in monoclinic prisms, mostly in crystal fibers, the individual crystals from 0.01 to 0.025 mm. in diameter; fragments of large mucilage cells with adhering starch grains. Macerate 1 Gm. of powdered Elm with 40 mils of distilled water for an hour and forcibly strain; the solution is of a mucilaginous consistence." U. S.
Ulmus abounds in mucilaginous matter, which it readily imparts to water. The mucilage is precipitated by solutions of lead acetate and subacetate, but not by alcohol. It contains a variety of tannin which colors iron solutions green, in amount about 6.5 per cent. according to Rink, or, according to Davy, a little less than 3 per cent.
Much of the bark brought into the market is of inferior quality, imparting comparatively little mucilage to water. It has the characteristic odor of the genuine bark, but is much less fibrous and more brittle, breaking abruptly when bent, instead of being capable, like the better kinds, of being folded lengthwise without breaking. To what this inferiority is owing, whether to difference in the species or the age, or to circumstances in the growth of the tree producing it, we are unable to state. Ground elm bark is said to be adulterated, usually with substances containing starch. Roberts found commercial specimens which possessed considerable of a brownish outer bark still adhering to them. One specimen was partly mouldy and had considerable adhering wood. (Proc. Penn. Ph. Assoc., 1913, p. 85.) The following test, devised by Geo. M. Beringer, seems to have practical value: Ten grains of ground or pulverized elm bark, thoroughly shaken with one fluidounce of water, will, if pure and of good quality, in fifteen minutes form a thick jelly-like mass of a fawn color.
C. W. Wright, of Cincinnati, in a communication to the Western Lancet, states that slippery elm bark has the property of preserving fatty substances from rancidity, and that this fact was known to the Indians, who prepared bear's fat by melting it with the bark, in the proportion of a drachm of the latter to a pound of the former, keeping them heated together for a few minutes, and then straining off the fat. Wright tried the same process with butter and lard, and found them to remain perfectly sweet for a long time. (A. J. P., xxiv.)
Uses.—Elm bark is an excellent demulcent, applicable to all cases in which this class of medicines is employed. It is especially recommended in dysentery, diarrhea, and diseases of the urinary passages. Its mucilage is reputed to be nutritious.
It is commonly used as a drink in the form of infusion. (See Mucilago Ulmi.) The powder may be used stirred in hot water, with which it forms a mucilage more or less thick according to the proportion added. The bark also serves as an emollient application in cases of external inflammation. For this purpose the powder may be formed into a poultice with hot water, or the bark itself may be applied, previously softened by boiling. McDoweIl, of Virginia, recommended slippery elm bark for the dilatation of fistulas and strictures (Med. Examiner, i, 244); subsequently H. R. Storer, of Boston, used it advantageously for dilating the os uteri (B. M. S. J., liii, 300), and A. Abbe of the same place, succeeded in curing with it a case of stricture of the rectum, (B. M. S. J., liv, 349).
Off. Prep.—Trochisci Ulmi, N. F.