Iceland Moss

ICELAND MOSS, Lichen islandicus, lichen (Cetraria islandica), growing in northern Europe, in Iceland, in the mountains of central and southern Europe, in Siberia and arctic America. Its thallus, up to 10 cm in height, is ascending or erect, and branches repeatedly dichotomously. In the fresh state, it is membranous-leathery, on the light-exposed side olive-green, sometimes covered with blood-red spots, on the shaded side white or greenish-white with spots. The branches of the thallus gradually widen upward, their edges are furnished with dense, stiff cilia, in which the spermogonia are located; oval or almost round flat apothecia appear singly or in pairs at the ends of the branches. In the dry state, the thallus is cartilaginous, dark-colored, with a very weak characteristic odor and bitter taste. I. m. contains up to 70% lichenin (C₆H₁₀O₅)_n, about 11% dextrorotatory lichenin, an isomer of the first but, in contrast to it, colored blue by iodine; 2% cetrarin, a crystalline substance soluble in alcohol and alkaline water, to which different authors give different formulas, for example C₈₀H₃₀O₁₂ (Hilger, Buchner); the bitter taste of I. m. is due to cetrarin; 1% lichenosterinic acid (C₄₃H₇₀O₁₃); in small quantities, essential oil, gum, sugar, fumaric acid, and traces of iron. Due to the significant content of starch-like substances in I. m., it was formerly used as food by local residents. I. m. is taken internally as a bitter stomachicum and as an enveloping agent in the form of an infusion (1:10-15) or in the form of jelly that forms from the decoction upon cooling (Lich. isl. 30.0, Aq. 1,000.0, Sacchar. 3.0, to boil down to 100.0) 1-2 tablespoons per day. Previously, jelly from I. m. was recommended as a strengthening remedy for tuberculosis and exhausted subjects, however, its benefit in these cases is doubtful due to the small amount of nutrients in this preparation; to attribute any specific action to it is not sufficiently justified. Bread, prepared from I. m., was proposed by various authors as a substitute for starchy food substances in diabetes, but the tolerance of such a preparation by a diabetic must be checked in each individual case. Cetrarin, isolated from I. m. in pure form, was recommended (A. Gigon) as a remedy for vomiting in pregnant women, hysterical patients, after chloroform anesthesia, in seasickness, etc. (0.1-0.2 per dose in powders or in a 2% alcoholic solution).

M. Likhachev