Am.  Jour.  Pharm. 
March.  1898. 
The  Rhubarbs  and  a  Probable  Adulterant. 
133 
which  a  more  careful  study  adds  the  fragments  of  pitted  vessels,  and 
crystals  of  chrysophanic  acid.  The  cell  walls  of  the  parenchyma 
hardly  appear  at  all,  and  when  present  are  mere  fragments.  These 
common  elements  offer  little  means  for  basing  a  distinction  between 
the  two  Rheums,  since  in  size  and  form  they  differ  so  little.  The 
only  distinction  observed  was  the  greater  number  of  starch  grains 
in  the  rhaponticum  ;  but  this  could  hardly  be  used  as  point  of  dis- 
tinction, since  it  is  such  a  variable  character.  Numerous  measure- 
ments of  starch  grains  and  the  calcium  oxalate  crystals  were  made 
and  gave  the  following  averages  :  Starch,  Chinese,  -02646  mm.  {Fig. 
Fig.  5. — Chinese  Rhubarb,   x  450  diameters,   a,  starch  ;  b,  fragments  of  pitted 
vessel  ;  c,  calcium  oxalate  ;  d,  chrysophanic  acid. 
5);  rhaponticum,  -0216  mm.  {Fig.  6);  Calcium  oxalate  crystals, 
Chinese,  -0716  mm.;  rhaponticum,  -0683  mm.  Both  elements  are 
thus  seen  to  be  larger  in  the  Chinese  form,  but  the  difference  is  not 
such  a  one  as  could  be  used  as  a  test. 
The  powder  of  Rumex  hymenosepalus  is  marked  particularly  by 
the  size  and  form  of  the  starch  grains  {Fig.  f).  These  are  long  and 
slender  in  form,  and  exhibit  a  long,  branching  hylum,  which  extends 
throughout  the  major  portion  of  the  long  diameter.  The  presence 
of  these  in  a  sample  of  rhubarb  powder  would  at  once  show  that  it 
was  adulterated  with  canaigre,  since  they  differ  entirely  in  form  and 
