Viscum. Viscum album, Mistletoe. Phoradendron flavescens, American mistletoe.

Viscum. Viscum album L. Mistletoe. Gui de Chene, Gillon, Fr. Mistel, G. (Fam. Loranthaceae.)—A European evergreen, parasitic shrub growing on various trees, particularly the apple and other fruit trees, and forming a pendent bush from two to five feet in diameter. The plant is famous in the history of Druidical superstition. In the religious rites of the Druids, the mistletoe of the oak was employed, and hence was afterwards preferred when the plant came to be used as a remedy; but it is in fact identical in all respects with those which grow upon other trees. (P. J., 1897, 289.) The fresh bark and leaves have a peculiar, disagreeable odor, and a nauseous, sweetish, slightly acrid and bitterish taste. Viscin, which forms the glutinous constituent in the berries, leaves, and stalks of the mistletoe, is the principal constituent of birdlime. Crude viscin may be obtained by kneading the finely bruised mistletoe bark with waiter, as long as anything is dissolved, and removing the ligneous impurities mechanically. A purer product may be obtained by boiling the crude product in strong alcohol, macerating the residue with ether, evaporating the ethereal extracts, purifying these extracts by kneading first with alcohol and then with water. The formula C20H48O8 (C20H32 + 8H2O) has been given to it by Reinsch. Pawlevsky (Bull. Soc. Chim. (2), 34, 348) obtained from mistletoe a crystallizable acid, slightly soluble in water, insoluble in alcohol and ether, fusing at from 101° to 103° G. (213.8°-217.4° F.), to which he gave the formula CH3O3.OH. The berries, which are white, and about the size of a pea, abound in the peculiar viscid principle, and are sometimes used in the preparation of birdlime, of which this principle is the basis. Mistletoe is said to be productive of vomiting and purging when largely taken. The berries caused in a child three years old vomiting and prostration, coma, a fixed and somewhat contracted pupil, and convulsive movements. [Ann. Ther., 1859, 36.) A fatal case is recorded. (M. T. G., 1867, 26.) The plant was formerly looked upon as a, powerful nervine, but it is now out of use. The leaves and wood were given in the dose of a drachm (3.9 G-m.) in substance. Viscum has been recommended by Gaultier (S. M., 1907) for the reduction of high blood pressure in arteriosclerosis and other conditions of excessive arterial tension. But Dossin (A. I. P. T; 1911, xxi, p. 432) finds that the lowering of blood pressure is of but short duration and is preceded by a rise and concludes, therefore, that the drug is not clinically useful for this purpose. Gaultier employed a watery extract in doses of 3 grains (0.2 Gm.) daily. According to P. Riehl (D, M. W., xxvi, 1900), viscin affords an excellent basis for the making of applications to the skin, a benzene viscin solution mixed with starch affording an excellent plaster mass.

The American Mistletoe is the Phoradendron flavescens (Pursh) Nutt. It is a woody parasite, growing upon the branches of deciduous trees from New Jersey to Florida and westward. It is probably the plant reported as growing upon the elm, by which several children were poisoned. (Henry Dye, Memphis Med. Recorder, iv, 344.) The prominent symptoms were vomiting and great thirst followed by frequent discharge of bloody mucus from the bowels, with tenesmus. One of the children was found in a collapsed state, in which death took place. Dye states also that, in other instances, as he had been informed, children had eaten the berries without any ill effect. In the western part of the United States Arceuthobium Americanum Nutt., and Phoradendron juniperinum Englm., are also known under the name of mistletoe. Crawford (J. A. M. A., 1911, lvii) has found that the extract of P. flavescens or the P. juniperinum, when injected into the blood stream, produces a sharp rise in the blood pressure similar to that produced by epinephrine. He also succeeded in isolating an active base, the composition of which, however, he did not satisfactorily determine, but suggests that it may be phenylethylamine. W. H. Long, confirmed by Lee Payne (North Carolina Med. Journ., vol. vii, 253) asserts (New Prep; ii, 31) that the American mistletoe is a very certain oxytocic, and very efficacious in arresting post-partum and other varieties of uterine hemorrhage. He gives a fluidrachm (3.75 mils) of the fluidextract every twenty minutes in labor until the effect is produced; every four to six hours in menorrhagia. Dalassus proposes a formula for an aqueous extract of mistletoe. Five hundred parts of the ground, dry, young twigs and leaves are infused for 12 hours in 3000 parts of boiling water, expressed and the residue treated with 1500 parts of boiling water. The united liquids are then evaporated to the consistence of an extract. Syrup of mistletoe is made by dissolving 1 part by weight of the above extract in 10 parts by weight of boiling water and adding 990 parts of simple syrup.

The Dispensatory of the United States of America, 1918, was edited by Joseph P. Remington, Horatio C. Wood and others.