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SCIENTIFIC AND APPLIED PHARMACOGNOSY 



oidical starch grains about 0.003 to 0.008 mm. in diameter, or with 

 calcium oxalate either in rosette aggregates or prisms from 0.010 

 to 0.020 mm. in diameter. 



Powder. (Fig. 178.) Light brown to olive-brown; consisting 

 largely of groups of bast fibers with their associated crystal fibers, 

 the latter being usually distinguished with difficulty, unless the 

 material has been mounted in a solution of hydrated chloral and 

 thoroughly cleared by boiling; almost equally numerous are the 

 groups of stone cells which are frequently associated with paren- 

 chyma containing large rhombohedra of calcium oxalate; frag- 



FIG. 178. Rhamnus Purshianus: B, BF, bast fibers; CF, crystal fibers; Ca, 

 calcium oxalate crystals; S, starch grains; P, parenchyma; MR, medullary 

 rays; St, stone cells; C, thick-walled, parenchyma of outer cortex; K, cork. 



ments of parenchyma and medullary ray cells colored red upon the 

 addition of solutions of the alkalies; starch grains either free or 

 in parenchyma cells, the individual grains being somewhat spheroidal, 

 from 0.003 to 0.008 mm. in diameter; calcium oxalate in monoclinic 

 prisms or rosette aggregates from 0.010 to 0.020 mm. in diameter; 

 occasional fragments of yellowish- or reddish-brown cork. 



Constituents. The nature of the active constituents of this 

 drug is not known. It may contain the glucoside cascarin (pur- 

 shianin), which on hydrolysis yields emodin and one or more active 



