MARSHMALLOW 



315 



presence of bast fibres that have been liberated by the scraping, and 

 bears brownish scars of lateral roots. The bark, which can readily 

 be removed in long strips, is tough and fibrous, but the wood breaks 

 with a short granular fracture ; internally the root is whitish and 

 starchy. It can easily be cut, and the transverse section exhibits 

 a bark of moderate thickness, separated by a yellow sinuate cambium 

 line from the wood. Both bark and wood possess a radiate structure 

 that is more distinct when the surface of the section is moistened ; 

 numerous cells containing a translucent mucilage then also become 

 visible. 



The drug has a faint but characteristic odour, and a mawkish, 

 mucilaginous taste. To improve its appearance it is sometimes 

 limed, but this sophistication can easily be detected by rinsing the 

 drug with 1 per cent, hydrochloric acid, filtering, and adding 

 excess of sodium carbonate, when the 

 liquid should remain clear. 



The student should observe 



(a) The fibrous bark, 



(b) The yellow cambium line, 



(c) The radiate structure of the wood, 



(d) The presence of mucilage ; 



and should compare the root with 



Belladonna root, which closely re- 

 sembles unpeeled marsh mallow root, 

 but may be distinguished by the non- 

 fibrous nature of the bark, by the 

 absence of mucilage, and by the 

 scarcely radiate structure of the wood. 



Constituents. The principal constituent is mucilage, of which 

 the root is said to contain as much as 25 to 35 per cent., but these 

 figures require confirmation. The drug contains also an abundance 

 of starch together with asparagin and a substance allied to lecithin. 

 Asparagin, C 4 H 8 N 2 O 3 , is the amide of aspartic (amidosuccinic) acid, 

 and is found in many plants, especially in marshmallow root and 

 in etiolated plants. 



Uses. Marshmallow root is used as an emollient and demulcent. 



FIG. 159. Marshmallow 

 root. Transverse section. 

 Magnified. (Moeller.) 



LIQUORICE ROOT 



(Radix Glycyrrhizae) 



Source, &C. The chief plants that yield the liquorice root of 

 commerce are GlycyrrMza glabra, Linne, G. glandulifera, Waldstein 

 and Kitaibel, and G. glabra, var. /3-violacea. The British Pharma- 



