206 HERBS 



The drug has no marked odour ; the taste is at first bitter, but after- 

 wards sweetish. 



The student should observe 



(a) The alternate scars, 



(b) The glabrous, glossy surface, and hollow centre, 



(c) The bitter-sweet taste. 



Bitter-sweet has been reported to contain the amorphous glucoside 

 dulcamarin to which the bitter-sweet taste is due, and also the 

 glucosidal alkaloid solanine (which is also contained in the berries and 

 young shoots of the potato, 8. tuberosum, Linne) and other Solanaceous 

 plants. According to Masson (1912) dulcamarin consists of two acid 

 saponins, dulcamaretic acid which is non-glue osidal and dulcamaric 

 acid which is glucosidal ; the glucosidal alkaloid present resembles, 

 but is not identical with, the solanine of potatoes, and is better termed 

 solaceine. 



>. Bitter-sweet was formerly given in rheumatic and cutaneous 

 affections, but is now seldom prescribed. 



WHITE HOREHOUND 

 (Herba Marrubii) 



Source, &C. White horehound, Marrubium vulgar e, Linne (N.O. 

 Labiatce), is an erect herbaceous plant with perennial root, widely 

 distributed over Europe, but not very common in England. It is, 

 however, cultivated as well as collected wild in various parts of the 

 country for medicinal use, and is also imported from the south of 

 France. The Romans esteemed horehound as one of the most valuable 

 drugs, but at present it is used only as a domestic remedy and that 

 not to any great extent. The plant is cut when in flower, and dried. 



Description. White horehound grows to a height of about 50 cm., 

 and possesses a quadrangular, branching stem densely clothed with 

 white woolly hairs. The leaves are from 3 to 5 cm. long, opposite and 

 petiolate ; the lower rounded-ovate, the upper ovate-acuminate, 

 with dentate or dentate-crenate margin. They are much wrinkled, 

 and both the upper and under surfaces, but especially the latter, are 

 covered with white felted hairs. 



The flowers are arranged in dense verticillasters in the axils of the 

 upper leaves. The hairy calyx is provided with ten recurved, hooked 

 teeth ; the whitish bilabiate corolla is characterised by its small, 

 erect, cleft upper lip. 



The drug has an agreeable though not powerful odour, and a some- 

 what aromatic but very bitter taste. 



