526 
WHAT  IS  OPIUM  ? 
enumerated  at  the  outset  as  peculiar  to  opium*  are  contained  in 
the  alcoholic  tincture,  and  besides  them  sugar,  a  very  small  quan- 
tity of  resin,  and  coloring  matters.  This  portion  of  opium, 
representing  the  largest  part  of  it,  appears  certainly  to  deserve 
the  most  attentive  examination.  I  am  sorry  to  state  that  I  have 
not  yet  succeeded  in  isolating  from  it  any  new  principle  in  a 
state  of  sufficient  purity.  The  coloring  matter,  for  instance,  is 
extremely  alterable. 
Water  dissolves  chiefly  mucilage  from  powdered  opium,  which 
has  been  previously  exhausted  by  benzol  and  alcohol.  The  mu- 
cilage is  precipitated  by  neutral  acetate  of  lead,  but  not  by  sili- 
cate of  soda  ;  I  have  not  found  in  opium  any  gum  analogous  to 
gum  arable.  This  fact,  if  confirmed  by  the  examination  of  large 
quantities  of  good  commercial  opium,  would  enable  one  to  say 
that  any  opium  containing  gum  must  necessarily  be  adulterated. 
After  the  action  of  the  water,  acetic  acid  removes  some  salts 
and  a  little  coloring  matter,  all  in  small  proportion. 
Finally,  ammonia  acts  very  manifestly  upon  the  residue  of 
the  preceding  operations.  The  powder  swells  and  yields  a  brown 
liquid,  which,  being  viscid,  cannot  easily  be  filtered.  On  the  ad- 
dition of  an  acid,  of  alcohol  or  even  of  chloride  of  sodium,  a 
thick  jelly  at  once  separates.  The  pectie  acid,  thus  obtained, 
lias  not  yet  been  found  by  other  observers,  as  far  as  I  can  see, 
though  I  think  that  it  must  henceforth  be  considered  as  one  of 
the  regular  constituents  of  opium.  I  met  with  it  in  several  sorts 
of  the  drug  which  happened  to  be  at  my  disposal  and  likewise  in 
a  good  standard  opium  from  Asia  Minor,  for  which  I  am  indebted 
to  Mr.  E.  Merck,  of  Darmstadt,  who  furnished  me  with  the  res- 
idues of  the  drug,  which  had  been  previously  exhausted  by  hot 
water  and  by  hydrochloric  acid.  It  would  be  interesting  to  ex- 
amine in  this  respect  the  various  Indian  opiums,  which  I  pre- 
sume to  be  of  a  somewhat  different  composition.  From  all  the 
various  reports  on  them,  it  appears  that  the  Indian  juice  is  more 
fluid  than  that  collected  in  Asia  Minor.  Does  this  partly  de- 
pend upon  the  absence  of  pectic  acid  or  of  mucilage?  This  in- 
vestigation must  be  expected  from  chemists  having  at  their  com- 
*  Narcotine  only  excepted,  as  it  has  been  met  with  in  aconite  tubers 
by  Messrs.  Smith, 
