THE  AMERICAN 
JOURNAL  OF  PHARMACY. 
JUNE,  1876. 
POWDERED  DRUGS  UNDER  THE  MICROSCOPE. 
BY  MARK  W.  HARRINGTON,  M.A. 
Assistant  Professor  of  Botany  in  the  University  of  Michigan. 
I.  PRELIMINARY. 
The  writer  proposes,  in  this  and,  perhaps,  several  succeeding  arti- 
cles, to  point  out  to  pharmacists  the  utility  of  the  microscope  as  a 
means  of  identifying  powdered  drugs,  and  of  ascertaining  their  purity. 
He  does  this  because  he  is  convinced  that,  notwithstanding  the  writings 
of  Hassall,  Pocklington,  Fliickiger,  Planchon  and  some  others,  the 
practical  usefulness  and  ready  availability  of  the  microscope  as  a  means 
of  organic  analysis,  is  not  fully  appreciated. 
This  instrument  is  especially  useful  in  the  examination  of  organic 
bodies.  One  would  expect  that  when  two  parts  of  plants  differ  in 
external  appearance,  corresponding  differences  would  exist  in  the 
minute  structure  as  well,  and  such  is  found  to  be  the  case.  It  is  not 
too  much  to  say  that,  for  those  having  the  necessary  previous 
knowledge,  it  is  no  harder  to  distinguish  two  powders  under  the  micro- 
scope than  it  is  to  distinguish  the  two  bodies  from  which  the  powders 
are  derived.  There  is  no  more  difficulty  in  telling  ground  mustard 
from  ground  horse-radish,  and,  where  they  are  mixed,  in  picking  the 
one  out  from  the  other,  than  there  is  in  telling  the  mustard-seed  and 
the  horse-radish-root.  Wherever  any  powdered  drug  has  traces  of 
organic  structure,  the  microscope  can  identify  them  and  ascertain  their 
source.  In  these  cases  the  use  of  the  microscope  can  properly  accom- 
pany the  work  of  chemical  analysis.  It  can  precede  and  indicate  what 
the  chemist  is  to  look  for,  or  it  can  follow  and  verify  the  results  of 
his  work.  In  some  cases,  indeed,  microscopical  analysis  can  do 
successful  labor  in  fields  where  chemistry  is  powerless.  Chemistry, 
for  instance,  cannot  distinguish  between  the  various  starches — wheat- 
starch,  corn,  potato,  arrow  root,  sago  starch,  etc.;  it  can  only  show 
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