^Stembe^iS?"}    Senega,  Euonymus  and  Quillaja.  437 
before  the  observer.  The  bast  cells  would  also  serve  to  distinguish 
euonymus  from  senega. 
medullary  ray. 
After  having  established  these  points  of  difference  between  senega 
and  its  adulterants,  numerous  samples  of  powdered  senega  were 
examined,  but  no  adulteration  was  discovered.    It  would  appear 
a 
Fig.  g.  Senega  powder  magnified  75  diameters  ;  a,  suber ;  b,  parenchyma  ;  c, 
tracheae  (rarely  found  in  No.  60  powder). 
from  this  that  powdered  senega  is  not  difficult  to  secure  in  the 
pure  condition. 
The  drawings  accompanying  this  are  supposed  to  be  self-explana- 
