298  Powdered  Drugs  under  the  Microscope.  } Am  jify r"If76arm* 
white  color,  but  glistening  a  little  when  examined  closely,  crackling 
slightly  when  rubbed,  inodorous  and  insipid. 
The  grains  are  simple,  egg  shaped,  or  oblong.    The  rings  are  fine 
and  concentric  or  eccentric.  The 
nucleus  is  large,  shaped  like  a 
point,  or  a  slit  crossing  the  grain 
or  two  slits  crossing  each  other. 
It  is  in  the  center,  or  nearer  the 
larger  end  of  the  grain.  The 
length  of  the  grains  is  from  itt. 
to  24//. 
Other  varieties  of  arrowroot 
are  described,  from  the  European 
trade,  though  the  writer  has  never 
seen  them  in  the  United  States, 
with  the  exception  of  potato- 
arrowroot,  which  is  occasionally 
found.  It  can  be  easily  distin- 
guished by  the  examination  of  the  starch-grains  already  described. 
Curcuma  arrowroot  is  known  by  starch-grains  which  are  rather  larger 
than  those  of  maranta,  and  which  have  the  nucleus  on  the  margin  of 
the  grain,  frequently  on  a  projecting  point.  Canna-arrowroot,  or  tous 
les  moisy  consists  of  starch-grains  from  16//.  to  50//.,  which  are  there- 
fore about  twice  as  long  as  the  grains  of  maranta.  The  larger  grains 
are  flat  and  more  or  less  egg  shaped,  with  the  nucleus  near  the  smaller 
end.  The  concentric  lines  are  fine,  regular  and  very  numerous. 
Tacca  or  Tahiti  arrowroot  consists  of  grains  \tt.  to  15//.  long,  and 
shaped  much  like  the  grains  of  sago-starch.  They  are  partly  convex, 
partly  with  flat  surfaces,  rather  hemispherical  or  pear-shaped.  The 
nucleus  is  nearly  central,  and  star-shaped.  Arum  or  Portland  arrowroot 
consists  of  very  minute  grains,  something  like  those  of  Tacca,  but 
only  itt.  to  8//.  in  diameter. 
The  above  can  be  considered  in  the  light  of  commercial  varieties. 
Fraudulent  substitutions  or  adulterations  of  maranta  with  any  of  the 
cheaper  starches  may  be  expected.  Potato,  sago  and  tapioca  starches 
are  especially  used  for  this  purpose. 
5.   AMYLUM  (Fig.  5). 
Under  this  name,  the  "U.  S.  Pharmacopoeia"  calls  for  wheat-starch, 
Fig.  4.  Maranta. 
