554 



SCIENTIFIC AND APPLIED PHARMACOGNOSY 



Tubercles which have a specific gravity less than 1.275 and are 

 white internally should be rejected. 

 INNER STRUCTURE. See Fig. 237. 



FIG. 237. Transverse section of jalap: Ph, cork cells; Se, resin-secretory cells; 

 0, rosette aggregates of calcium oxalate; Si, sieve cells; G. tracheae; C 1 , 

 primary cambium; C 2 , secondary cambium. After Meyer. 



Powder. (Fig. 238.) Dark yellow or light brown; crystals of 

 calcium oxalate in rosette aggregates, 0.010 to 0.035 mm. in diam- 

 eter; starch grains ellipsoidal and ovoid, with somewhat excentral 

 lamellae, from 0.005 to 0.035 mm. in diameter, 1- to 3-compound 



