HENBANE, Hyoseyamus, a genus of plants of the natural order solanacece, having a five-toothed calyx, an irregular funnel-shaped corolla, and a capsule opening by a lid, and inclosed in the hardened calyx. The species arc mostly annual and biennial herbaceous plants, and natives of the countries near the Mediterranean sea. The only species found in Britain is the COMMON HENBANE (H. niger), which is not uncommon in waste places, and in the neighborhood of towns and villages, particularly in calcareous soils, and on the sandy shores of Scotland. It is an annual or biennial plant, somewhat bushy, about two feet high; with large sinuated or sharply-lobed leaves without leaf stalks, and large dingy yellow flowers, with brownish-red or purple veins. The whole plant is covered with unctuous hairs, and has a nauseous smell, which gives warning of its strong narcotic poisonous quality. Cases of poisoning by henbane are, however, not rare; but are more frequently owing to the proceedings of quacks, than to any mistake of the plant for an esculent.
The seeds contain in largest quantity the peculiar alkaloid on which the properties of the plant chiefly depend, ligoscyarnia or Ikyosegamine, which crystallizes in stellated acicular crystals of a silky luster. The symptoms of poisoning by henbane are similar
to those produced by other narcotic poisons, and the proper treatment is the same as in cases of poisoning by opium. In medicine, henbane is employed both externally and internally. The leaves are the part commonly used; they are gathered and quickly dried when the plant is in full flower. Fomenuttions of henbane are applied to painful glandular with and often found to afford relief. An extract of henbane is sometimes employed instead of belladona to dilate the pupil of the eye. Tincture and extract of henbane are often administered in cases of annoying cough, spasmodic asthma, and other diseases requiring sedatives and anti spasmodics. Henbane is also employed to calm mental irritation, and to induce sleep. For many cases, it has one great advantage over laudanum, in not producing constipa tion. The smoke from the burning seeds of henbane is sometimes introduced into a carious tooth, to relieve toothache.
The other species of henbane possess similar properties. The dried stalks of cans are used by smoking in Greece to allay toothache.