Aspidium Rigidum.

Botanical name: 


From an Inaugural Essay.

This fern is indigenous to the Pacific coast, where it is found in rocky canons and on hill-sides. It is confined principally to the eastern slope of the coast range, extending northward to Oregon and southward to Mexico. The following description of the plant is given by Professor Eaton: Root-stock short, stout, ascending or erect; fronds in a crown, on chaffy stalks, half evergreen, firm-membranaceous, smooth and green above, paler and more or less glandular beneath, 1 to 3 feet high, ovate-lanceolate or triangular-lanceolate, usually fully bipinnate; pinnae broadly oblong-lanceolate, the lowest ones broadest .and scarcely shorter than the middle ones; pinnules oblong, incised or doubly serrate, with spinulose teeth, conspicuously veiny; sort large, nearer the mid-rib than the margin; indusia firm, convex, orbicular, with a very narrow sinus, the edge bearing short-stalked glands."

The rhizomes which I have seen are from 4 to 10 inches in length, closely covered with the remnants of stipes, and with these from an inch to an inch and a half thick. They are covered with a brown chaff, and densely beset with wiry rootlets. The rhizomes deprived of the stipes are from one-half to nearly an inch in diameter, and show, upon the transverse section, an arrangement very similar to that of Filix mas, the main difference being that the vascular bundles, found in a circle, are about six in number. It has a peculiar aromatic odor and a sweetish taste, which becomes acrid, bitter and astringent.

This California fern has as yet established only a local reputation as a medicinal agent, but, judging from the verdict of several physicians who have employed the drug, it deserves a more extended use. Prof. H. Behr, of San Francisco, has long used the Aspidium rigidum in this practice in the treatment of taenia, and with better results than he has been able to obtain from any other vermifuge. In 1863 he called the attention of the late Dr. J. B. Trask to its medicinal value, and for many years the doctor used it in his practice, and with such good results that he considered it a specific in the treatment for tape-worm. Prof. Behr employed the fresh rhizome, which he found more effectual than the dried. The fact of its having been used in the fresh state may, in some degree, account for the superior effects obtained from it.

Believing an analysis of the rhizome of this fern desirable, in order to establish the relation of its medicinal constituents to those existing in Filix mas, I have made some investigations, of which the following is an account: From a quantity of the rhizome, carefully dried, the stipes and all the outer brownish portions were removed, and the powdered rhizome exhausted with ether, sp. gr. .750. The ethereal solution was of a reddish-brown color with a greenish tinge. The greater part of the ether having been distilled off, and the residue exposed in a capsule until the remainder of the ether had evaporated, an oleoresin of thick oily consistence was obtained, having a greenish-brown color, an aromatic odor and the bitter, nauseous and somewhat acrid taste of the drug. On standing, it soon deposited a resin, which was separated and treated with alcohol. After evaporation of the alcohol the resin was of a reddish-brown color, but darkened on long-exposure to air, and became hard and brittle; it possessed an aromatic odor and disagreeable bitter taste, was readily soluble in ether, alcohol, turpentine, ammonia, potassa and carbonate of potassium, and was heavier than water. The alcoholic solution gave an acid reaction,, and the resin was evidently similar to that obtained by Luck from Aspidium filix mas.

The ethereal extract of the rhizome, after standing a few days, deposited yellow crystals on the sides of the containing vessel. A portion of the extract with the contained yellow crusts was diluted with, ether-alcohol, then with two measures of water at about 40°C., and ammonia water added until the liquid smelled of ammonia; the whole was then shaken. After allowing it to stand, the lower brown layer was separated from the supernatant oil, filtered and precipitated with hydrochloric acid, the precipitate quickly balling together to a soft, plaster-like mass. This was kneaded with warm water, and crystallized from boiling stronger alcohol, the crystals washed with alcohol of 80 per cent., and purified by dissolving them in ammonia watery-precipitating with hydrochloric acid, washing with alcohol of 80 per cent., and finally recrystallizing from boiling stronger alcohol. The result was a light bright yellow crystalline powder, having a slight nauseous taste and in ethereal solution an acid reaction. When heated it yielded an oily distillate, smelling of butyric acid. It burned with a luminous flame when heated on platinum foil, and left a shining-charcoal. Heated with ammonia water it quickly assumed a dark brown-yellow color. It was insoluble in water, sparingly soluble in aqueous alcohol, soluble in boiling absolute alcohol, in fixed oils, and very soluble in sulphide of carbon and volatile oils. It is probably identical with Luck's filicic acid.

Treatment with Alcohol.—The drug, exhausted with ether and dried, was next macerated and percolated with alcohol. The alcoholic percolate was of a reddish-brown color, and had an acid reaction. The greater portion of the alcohol was distilled off, and the residue evaporated over a water bath to the consistence of honey. The liquid obtained was transparent, of a reddish color, and had a sweet and strongly astringent taste. An endeavor was made to crystallize cane-sugar from the solution, but was unsuccessful. The syrupy liquid was dissolved in water, filtered, and a portion of the filtrate treated with a dilute solution of gelatin, which gave a milky precipitate; another portion gave a greenish-black precipitate with ferric chloride. The remainder of the solution was precipitated by acetate of lead, and filtered, the excess of lead removed by H2S, and the filtrate tested for glucose by Fehling's solution, a brick-red precipitate of cuprous oxide indicating its presence. The precipitates by ferric chloride and by gelatin denote the presence of tannin.

Treatment with Cold Water.—The drug, after having been treated with ether and alcohol, was dried and macerated with water for several days, and strained. A turbid liquid, having a slight acid reaction, was obtained. On boiling, filtering, concentrating and adding alcohol, a flocculent precipitate of gum separated, which was soluble in water, and was precipitated from the aqueous solution by acetate and subacetate of lead.

Treatment with Boiling Water.—The drug, after having been exhausted with cold water, was next treated with boiling water. The liquid, strained and evaporated to a low bulk, deposited on cooling a brown jelly-like substance, which was insoluble in cold water, and is probably pectin. A portion treated with iodine gave a distinct blue color, showing the presence of starch.

The constituents, the presence of which was ascertained, are resin, filicic acid, fat, tannin, glucose, gum, pectin and starch.

The American Journal of Pharmacy, Vol. 53, 1881, was edited by John M. Maisch.