Uses—The ethereal extract has been prescribed for all kinds of intestinal worms; but recent experience goes to prove that its effects are chiefly exhibited in cases of tapeworm. It is equally and thoroughly efficacious in the three kinds respectively termed Tænia solium, T. medio-cannellata and Bothriocephalus latus.
Substitution—The rhizomes of Asplenium Filix fœmina Bernh., Aspidium montanum Vogl. (A. Oreopteris Sw.) and A. spinulosum Sw. may scarcely be mistaken for that of A. Filix mas. The best means of distinguishing them is afforded by transverse sections of the leaf-bases. In Filix mas, the section exhibits 8 vascular bundles,—in the other ferns named, only 2,—a difference easily ascertained by examination under a lens. Practically, no other indigenous fern than A. Filix mas affords a rhizome of sufficient bulk so as to be remunerative. We are not acquainted with that of the American Aspidium marginale Swartz, the section of which shows 6 vascular bundles; its extract is stated by Cressler (1878) to be perfectly active.
Thallogens.
LICHENES.
LICHEN ISLANDICUS.
Iceland Moss; F. Lichen ou Mousse d’Islande; G. Isländisches Moos.
Botanical Origin—Cetraria islandica Acharius.[2738]—It is abundant in high northern latitudes, as Greenland, Spitzbergen, Siberia, Scandinavia and Iceland, where it grows even in the plains. It is found in the mountainous parts of Great Britain, France, Italy, and Spain, in Switzerland (in elevations of nearly 10,000 feet), and in the Southern Danubian countries. It also occurs in North America and in the Antarctic regions.
History—In the North of Europe, this lichen has long been used under the general name of Mosi, Mossa or Mus,[2739] as an article of food. It is the Muscus crispæ Lactucæ similis of Valerius Cordus,[2740] and was also mentioned by Ole Borrich, of Copenhagen (1671), who called it Muscus catharticus, under the notion that in early spring it possesses purgative properties.[2741] The pharmaceutical tariff of the same city, of the year 1672, likewise quotes Muscus catharticus islandicus.[2742] Its medicinal employment in pulmonary disorders was favourably spoken of by Hjärne in 1683,[2743] but it is only since 1757 that it has come into general use as a medicine, chiefly on the recommendation of Linnæus and Scopoli.
Description[2744]—The plant consists of an erect, foliaceous, branching thallus, about 4 inches high, curled, channelled or rolled into tubes, terminating in spreading truncate, flattened lobes, the edges of which are fringed with short thick prominences. The thallus is smooth, grey, or of a light olive-brown; the under surface is paler and irregularly beset with depressed white spots. The apothecia (fruits), which are not very common, appear at the apices of the thallus, as rounded boss-like bodies, ²/₁₀ to ³/₁₀ of an inch across, of a dark, rusty colour. The colour and mode of division of the thallus vary greatly, so that many varieties of the plant have been distinguished.
In the dry state, Iceland moss is light, harsh and springy; it absorbs water in which it is placed to the extent of a third of its weight, becoming soft and cartilaginous; it ordinarily contains about 10 per cent. of hygroscopic water. It is inodorous, but when wetted has a slight seaweed-like smell; its taste is slightly bitter.