AmA{g"ri87h6arm'}  Powdered  Drugs  under  the  Microscope.  345 
the  grains  are  flattened  out  by  pressure,  it  is  found  that  the  markings 
are  really  rather  irregular  six-sided  meshes.  The  same  thing  can  be 
seen,  at  a  few  points  at  a  time,  after  the  grains  have  been  carefully 
brought  into  focus. 
Each  grain  consists  of  a  single  cavity  or  cell,  surrounded  by  a  double 
membrane.  This  is  hard  to  demonstrate,  but  can  sometimes  be  seen 
by  crushing  beneath  the  thin  glass  cover.  The  outer  membrane  or 
bag  is  thicker  and  brittle,  and  bears  the  markings  ;  the  inner  is  thinner 
and  more  elastic  and  is  smooth.  Within  the  membrane  is  a  thick 
liquid  with  drops  of  oil.  The  latter  are  easily  recognized  under  the 
microscope.  They  have  a  spherical  form,  and  appear  bright,  especially 
at  the  center,  because  the  light  is  highly  refracted  by  them. 
Lycopodium  has  the  reputation  of  being  frequently  adulterated,  but 
the  writer,  in  the  numerous  samples  he  has  examined,  has  always  found 
it  pure,  except  in  one.  This  contained  potato  starch,  easily  recognized 
by  its  turning  blue  with  iodine,  and  by  its  microscopical  characters.  In 
the  case  mentioned,  fully  one-third  of  the  powder  was  starch. 
The  adulterations  given  by  Soubeiran  and  others  will  be  given  and 
briefly  described,  as  they  may  be  met  in  the  United  States.  Ground 
wood  can  be  recognized  by  its  microscopical  structure.  It  can  be  sep- 
arated by  a  fine  sieve.  Ground  talc  can  be  recognized  by  its  shining^ 
flaky  fragments,  needing  a  microscope  to  distinguish  them  when  ground 
fine.  It  can  be  separated  by  water,  in  which  the  talc  sinks  and  the 
lycopodium  floats.  Sulphur  consists  of  irregular  or  crystalline  frag- 
ments, which  have  its  characteristic  yellow  color.  When  lycopodium, 
with  it  as  an  adulterant,  is  burned,  an  odor  of  sulphurous  acid  is  given 
off.  When  adulterated  with  dextrin,  it  becomes  lumpy  when  exposed 
to  moisture.  Benj.  Lillard  has  detected  this  adulteration  in  this  coun- 
try. Lycopodium  is  also  sometimes  adulterated  with  pollen.  That 
of  the  pines  is  characterized  by  being  three-lobed — the  larger,  arched^ 
middle  lobe  connecting  the  two  others.  With  this  adulteration,  the 
powder  has  a  slight  odor  of  pine.  It  does  not  seem  to  be  injured  for 
the  uses  to  which  it  is  put.  One  such  adulteration,  found  in  Ann 
Arbor,  has  been  reported  to  me.  The  pollen  of  cat-tail  flag,  or  Typbar 
is  said  to  be  also  employed.  The  powder  is  then  less  inflammable,  and 
has  a  deeper  yellow  color.  The  grain  of  pollen  consists  of  four  equal 
lobes. 
