436 
particularly  to  the  numerous  and  easily  observed  prismatic  crystals 
of  calcium  oxalate.  Any  or  all  of  these  clearly  mark  the  powder  of 
quillaja,  and  would  at  once  betray  its  presence  in  the  powder  of 
senega. 
Fig.  5.  Cross-section  Quillaja ;  «,  parenchyma  ;  b,  medullary  rays ;  c,  bast 
fibres. 
Again,  in  the  case  of  the  powder  derived  from  the  root  bark  of 
euonymus,  we  encounter  elements  that  serve  as  points  of  distinction 
between  it  and  the  other  drugs  here  considered.    In  this  instance 
Fig.  6.  Longitudinal-radial  section  of  Quillaja ;  a,  sclerotic  cells ;  b,  medul- 
lary rays  ;  c,  bast  fibres  ;  d,  cork  cells. 
the  most  marked  characteristic  is  the  fragment  of  large-celled  sub- 
erous  tissue,  which  so  frequently  exhibits  a  concentric  arrangement. 
In  addition,  the  fragments  of  cortical  parenchyma,  crossed  by  the 
narrow  remains  of  medullary  rays,  appear  numerously  and  distinctly 
a 
c 
Fig.  7.  Longitudinal-tangential  section  of  Quillaja  ;  a,  sclerotic  cells  ;  b,  bast 
fibres ;  c,  crystal ;  d,  medullary  ray. 
