48 
DETECTIVE  POWER  OF  THE  MICROSCOPE. 
terated  article,  under  the  microscope,  that  the  presence  of  foreign 
substances  in  the  adulterated  powder,  can  be  distinguished  ; 
because,  as  previously  stated,  the  form  of  the  starch  granules, 
the  shape  of  the  cells  of  each  organic  substance,  have  a  charac- 
ter peculiar  to  themselves,  by  which  their  source  may  be  deter- 
mined. 
By  a  similar  process,  the  question  can  be  answered,  when  it  is 
thus  ascertained  that  a  drug  has  been  adulterated — -by  what  sub- 
stance or  substances  has  this  drug  been  contaminated? 
The  investigator  will  know,  from  previous  experience,  those 
materials  which  are  most  suitable  for  the  sophistication  of  the 
genuine  article,  and  by  rendering  himself  familiar  with  their 
appearances  in  a  pulverized  state,  when  viewed  by  the  microscope, 
he  will  readily  detect  their  presence  in  the  adulterated  powder, 
and  be  able  to  refer  them  to  their  origin.  But  in  this  instance, 
and  all  others,  he  must  learn  the  microscopical  characteristics  of 
any  substance  whose  detection  is  desirable,  from  specimens,  the 
genuineness  of  which  he  can  vouch  for. 
To  avoid  a  constant  repetition  of  the  examination  of  every 
substance,  whose  microscopical  characteristics  it  may  be  desirable 
to  be  acquainted  with,  and  which  are  difficult  to  commit  to  me- 
mory, it  will  be  advisable,  for  the  purpose  of  reference,  to  obtain 
drawings  of  them,  which  is  most  readily  and  perfectly  accom- 
plished by  the  aid  of  the  camera  lucida. 
Moreover,  it  should  be  borne  in  mind,  that  the  microscope  can 
never  supplant  chemical  analysis  in  detecting  the  admixture  or 
adulteration  of  such  drugs  as  opium,  scammony,  and  others, 
which  are  the  concrete  juices  or  exudations  of  plants ;  but  for 
powders  of  barks,  roots,  leaves,  and  such  organised  substances  as 
consist  of  cellular  tissue,  ligneous  fibre,  &c,  it  is  in  the  highest 
degree  superior  to  every  other  known  or  available  means  for  the 
discovery  of  their  sophistication. 
In  conclusion,  it  may  be  remarked  that,  although  investiga- 
tions by  the  aid  of  the  microscope  require  less  time  for  their 
performance,  and  certainly  not  greater  ability  for  the  acquire- 
ment of  the  necessary  skill,  than  chemical  analysis,  yet  no  one 
can  expect  to  be  au  fait  in  the  application  of  this  instrument 
for  the  purposes  described,  except  by  the  devotion  of  much  time 
and  attention  to  its  study. — Annals  of  Pharmacy,  Jan,  1852. 
