Henbane , (hyoscyamus, Tournefort), a somewhat rare but highly dangerous weed, belonging to the nightshades (solanaceoe), seen in waste places and on rubbish heaps, and on the sites of old houses; remarkable for the singular beauty of its flowers, as well as for its fetid, viscid stems, and clasping, sinuate-toothed, and angled leaves. There are many species of henbane, but the one most common in the United States is an adventitious weed from Europe, H. niger. Its seeds are small, flat, kidney-shaped, resembling beans, and suggesting the classic name of hyoscyamus, i. e., swine beans, being, it is said, eaten with impunity by the hog, though avoided by other creatures. - Hyoscyamus is used in medicine in the form of a tincture, extract, and fluid extract. Its action is very similar to that of belladonna and stramonium, at first diminishing and then increasing the frequency of the pulse, and producing dryness of the throat, headache, delirium, and dilated pupils. The tendency of large doses to produce coma, and of small ones to cause sleep, seems, however, somewhat greater than with belladonna, though by no means equalling opium in this respect.
It is used, though not very extensively, in certain nervous affections, as in some forms of neuralgia and insomnia, and occasionally to diminish the irritability that leads to cough. It may be regarded as a suc-cedaneum of opium, though far inferior in power to that drug, and having less action upon the secretions. It is sometimes used in place of belladonna for dilating the pupil. Its activity is due to an alkaloid, hyoscyamia, which is white and crystalline, and forms crystallizable salts with the acids. The dose of the tincture is a fluid drachm or less; of the solid extract, two or three grains; of the fluid extract, five to ten drops.
Henbane (Hyoscyamus niger).