52 LEAVES 



hairs, some of which are simple, but the majority terminate in oval multicellular 

 glands ; the mesophyll contains calcium oxalate chiefly in the form of prismatic, 

 often twin, crystals ; in some specimens small cluster crystals are fairly numerous, 

 and sandy crystals may occur in or near the midrib ; the bundles are bicollateral, 

 and there are no pericyclic or bast fibres. 



The student should observe 



(a) The hairy leaves with sinuate-dentate outline and broad 



midrib, 



(b) The purple veins of the corolla, 



(c) The characteristic fruit (or ovary). 



Constituents. The principal alkaloid in henbane leaves is hyos- 

 cyamine, but it appears to be accompanied by small proportions of 

 atropine and scopolamine (hyoscine). The drug contains much less 

 total alkaloid than either belladonna or stramonium, viz. from 0'045 

 to 0'14 or, exceptionally, 0'2 per cent, (of the dry drug). The cul- 

 tivated plant contains about the same proportion as the wild, but 

 the leaves contain more than the large stems and the extract made 

 from the leaves, more than that made from the stem. The petiole is, 

 however, rather richer than the lamina. Henbane should yield 

 about 8 to 12 per cent, of ash, but commercial samples sometimes 

 afford much more. 



Assay. Henbane may be assayed by the process official for belladonna leaves, 

 using 25 gm. of the powdered drug instead of 10. 



Uses. The action and uses of henbane closely resemble those 

 of belladonna and stramonium, but the drug is distinctly weaker. 

 The extract has a decided laxative and carminative effect, whilst the 

 tincture has a more marked action on the urinary organs. 



Varieties. The first year's leaves of biennial henbane may be 

 recognised by their being longer and relatively narrower, stalked, 

 and free from stem and flower. They are equal in activity to the 

 leaves from flowering plants, and there seems to be no good reason 

 why they should not be used. They are sometimes sold for annual 

 henbane. 



Annual henbane is distinguished by its slender simple stem, smaller 

 leaves, and paler corolla, with less distinct purple venation. As 

 in this case the entire plant is usually cut and dried, portions of the 

 stem as well as leaf and flower are often found in the drug. Much 

 imported henbane is of this variety, and it often arrives in very poor 

 condition, probably mixed with other species of Hyoscyamus. Such 

 henbane contains notably less alkaloid than either the first or second 

 biennial, viz. about 0*03 per cent. English annual henbane consists 

 of such plants as happen under favourable conditions to flower in 

 the first year ; such plants are much stronger than the foreign, and 

 being more carefully dried are richer in alkaloid. 



