CASCARA SAGRADA 



247 



The 



been applied to the bark of the closely allied R. Purshianus. 

 latter has been much used as a laxative since 1883. 



The bark is collected in the spring and early summer, and dried 

 in the shade ; if left till later in the year it adheres so firmly to the 

 wood that it has to be cut off, and then brings shavings of wood 

 with it. 



Description. Cascara sagrada occurs in straight, stiff, single quills 

 or in channelled pieces. The quills vary from 5 to 

 25 mm. or more in diameter, whilst the channelled 

 or sometimes flattish pieces may be as much as 

 10 cm. wide ; commonly the drug is seen in pieces 

 about 10 to 20 cm. long, 2 cm. wide, and from 1-5 to 

 4 mm. thick, the thinnest being most esteemed. 



The outer layer is a smooth, dark purplish 

 brown cork marked with transversely elongated 

 whitish lenticels. The bark, however, is usually 

 more or less completely covered with silvery grey 

 patches of lichens which conceal the purple cork 

 and the lenticels and give to the drug its pervading 

 greyish white colour. The inner surface is of a 

 dark, or even very dark, reddish brown colour 

 and longitudinally striated, with faint transverse 

 corrugations. 



The fracture is short, that of the bast being 

 shortly fibrous. The section exhibits under the lens 

 a narrow purplish cork, a yellowish grey cortex in 

 which darker translucent points (groups of scleren- 

 chymatous cells) can be distinguished, and a brown- 

 ish yellow bast in which wavy, somewhat distant 

 medullary rays may sometimes be discerned. ^ 12 6 Cascara 



The bark has a characteristic though not strong Sagrada bark, 

 odour, and a persistent, nauseously bitter taste. Natural size. 



Like alder buckthorn bark, this drug should be 

 kept for at least a year before it is used medicinally ; the action is 

 then milder and less emetic. It also shares with alder buckthorn 

 bark the property of imparting a yellow colour to the paper in which 

 it is kept. 



Microscopical Characters. The structure of cascara sagrada closely resembles 

 that of alder buckthorn bark, the chief differences being in the contents of the 

 cork cells which are reddish brown, and the presence of groups of sclerenchymatous 

 cells in the cortex and secondary bast. 



The student should observe 



(a) The purplish cork and the grey lichens covering it, 

 (6) The groups of sclerenchymatous cells in the cortex, 

 (c) The characteristic odour and taste ; 





