RADIX ABRI. 189 



not always well marked. As it is often mixed in the Indian bazaars 

 with true liquorice, he thinks the latter may have sometimes been 

 mistiiken for it. 



Microscopic Structure — On a transverse section the bark ex- 

 hibits some layers of cork cells, loaded with brown colouring matter, 

 and then, within the middle zone of the bark, a comparatively thick 

 layer of sclerenchymatous tissue. Strong liber fibres are scattered 

 through the interior of the cortical tissue, but are not distributed so as 

 to form wedge-shaped rays as met with in liquorice. In the latter the 

 sclerenchyme (thick-walled cells) is wanting. These differences are 

 sufficient to distinguish the two roots. 



Chemical Composition — The concentrated aqueous infusion of the 

 root of Abrus has a dark brown colour and a somewhat acrid taste 

 accompanied by a faint sweetness. When it is mixed with an alkaline 

 solution of tartrate of copper, red cuprous oxide is deposited after a 

 short time : hence we may infer that the root contains sugar One drop 

 of hydrochloric or other mineral acid mixed with the infusion produces 

 a very abundant flocculent precipitate, which is soluble in alcohol. If 

 the infusion of Abrus root is mixed with a very little acetic acid, an 

 abundant precipitate is likewise obtained, but is dissolved by an excess. 

 This behaviour is similar to that of glycyrrhizin (see p. 181). 



Berzelius observed, so loner ago as 1827, that the leaves of Abrus 

 contain a sweet principle similar to that of liquorice. 



Uses — The root has been used in the place of liquorice, for which 

 it is in our opinion a very bad substitute. 



SET^ MUCUNiE. 



Dolichi puhes vel setce ; Cowhage, Cow-itch * ; F. Pois a gixitter, Pais 

 pouillieux ; G. Jitxhhorsten. 



Botanical Origin — Muciina pruriens DC. (Dolichos pmriens L., 

 Stizolobium pruriens Pers., Mucuna 2^11'untct' Hook.), a lofty climbing 

 plant ^ with large, -dark purple papilionaceous flowers, and downy 

 legumes in size and shape not unlike those of a sweet pea, common 

 throughout the tropical regions of both Africa, India and America. 



History — The earliest notice we have found of this plant is that of 

 Parkinson, who in his Theater of Plants, published in 1640, names it 

 " Phaseolus siliqud hirsutd, the Hairy Kidney-Beane called in Zurrate 

 [Surat] where it groweth, Conhage." It was subsequently described by 

 Ray (1686), who saw the plant raised from West Indian seeds, in the 

 garden of the Hatton family in Holborn.^ Rheede figured it in the 

 Hortus Malabaricus* and it was also known to Rumphius and the 

 other older botanists. We find it even in the pharmaceutical tariff of 

 the county of Nurnberg, A.D. 1714.' 



^ These names and the following are also ' Hist. Plant, i. 887. 



applied to the entire pods, or even to the * Tom. viii. (1700) tab. 35, sub nom. 



plant. Ncii Corana. 



^ Fig. in Bentley and Trimen, Meil. * Fluckiger, Documente znr Geschic/Ue der 



Plants, part 13 (1876). Pharmacie, Halle, 1876. 84. 



