BARBERRY 235 



or brownish translucent points ; their presence is often very 

 characteristic (canella bark). 



Calcium oxalate is generally visible as colourless points or lines 

 (cusparia bark) ; if present in large quantities the tissue itself may 

 appear white (canella). 



BARBERRY BARK 



(Cortex Berberidis) 



Source, &C. The common barberry, Berberis vulgaris, Linne (N.O. 

 Berberidece) , is a shrub about 2 metres high, with three-lobed thorns 

 at the bases of the tufts of leaves. It occurs scattered over Great 

 Britain, and over the greater part of Europe and temperate Asia. 

 The yellow flowers, in elegant drooping racemes, are succeeded by 

 oblong scarlet fruits. 



The stem bark is collected by shaving, and dried. 



Description. Small, thin, nearly flat pieces not often exceeding 

 5 cm. in length or 1 cm. in breadth, dark in colour, with a decided 

 yellow or yellowish grey tinge. The outer layer (cork) is dark yellowish 

 grey, and marked with shallow, longitudinal furrows or deeper 

 fissures, becoming ultimately scaly ; it frequently bears the minute 

 black apothecia of small inconspicuous lichens. The inner surface 

 is dark yellowish brown, longitudinally striated and fibrous, 

 and occasionally has fragments of yellow wood adhering to 

 it. The fracture is short in the outer portion (cork and cortex), 

 but fibrous and strongly laminated in the inner (bast). The trans- 

 verse section exhibits under the lens a narrow cork and a dark brown 

 bast traversed by paler, yellow medullary rays. The bast rays 

 contain narrow, tangentially elongated bundles of bast fibres, which 

 easily separate from the bast parenchyma in strands and produce 

 the laminated appearance and fracture. The bark has a bitter 

 taste, and colours the saliva yellow. 



Constituents. Barberry bark contains several alkaloids, of which 

 berberine is the most important. 



Oxyacanthine and berbamine are colourless alkaloids that have 

 been obtained from the bark of barberry root, and doubtless exist 

 also in that of the stem. 



Berberine, C 20 H 19 NO 5 , crystallises in brilliant yellow needles with four or six 

 molecules of water, and melts when anhydrous at 145 ; it forms well crystallised 

 compounds with acetone and chloroform, and is coloured in aqueous solution 

 blood-red by chlorine water. Berberine is one of the few alkaloids that occur 

 in plants belonging to several different natural orders (Berberidece, Ranun- 

 culacece, Rutacece, Leguminosce). 



Uses. Barberry bark is sometimes employed as a remedy for 

 fevers, and as a tonic. 



