POWDERED DRUGS AND FOODS. 



709 



Adulterants. All chocolate products may be adulterated 

 with any of the cereal starches, those of corn, wheat and rice being 

 usually employed. 



157. GUARANA. Dark brown; parenchyma thin-walled, 

 containing nearly spherical, more or less altered starch grains 10 fj. 

 in diameter ; sclerenchymatous cells nearly isodiametric, non-ligni- 



o Q CD 

 t^ (g) 



Fig. 3og. Aconite: T, tracheae with scalariform thickenings or bordered pores, 

 ST, stone cells; P, parenchyma with starch grains; S, starch grains; C, E, cork. 



fied ; sclerenchymatous fibers few, narrow ; tracheae few, narrow, 

 annular or scalariform. (See also Fig. 159.) 



158. PIPER. Dark brown (Fig. 311) ; stone cells nearly iso- 

 diametric, uniformly thickened or with only three walls thick- 

 ened, the contents consisting of yellowish-brown tannin masses, 

 which give a blue reaction with ferric ammonium sulphate solu- 

 tion ; starch grains spherical, i to 2 /i. in diameter; pirenchyma 

 with remains of chromoplastids and reddish-brown tannin masses ; 



49 



