194     PREPARATION  OF  DEODORIZED  TINCTURE  OF  OPIUM. 
tillation  I  made  numerous  experiments,  and  finally  discovered 
a  method  by  which  the  object  may  be  accomplished  at  a  trifling 
cost,  and  with  little  trouble.  Upon  the  addition  of  a  caustic 
alkali  to  the  etherial  solution  the  odorous,  resinous,  and 
coloring  matters  are  nearly  all  withdrawn,  and  the  ether  is  fitted 
for  future  use  as  a  deodorizer.  The  process  is  as  follows :  Take 
of  common  caustic  potassa  one  troy  ounce;  place  it  in  one  pint 
of  the  ethereal  solution,  having  previously  added  two  fluid- 
ounces  of  water,  and  agitate  occasionally  for  twenty-four  hours. 
Decant  the  ether,  mix  it  with  four  fluidounces  of  distilled 
water,  allow  it  to  separate ;  again  remove  the  ether  and  keep  it 
for  further  use. 
While  engaged  in  the  foregoing  manipulations,  I  conceived 
the  idea  of  substituting  for  the  ether  the  light  product,  obtained 
in  the  rectification  of  petroleum,  known  as  "  benzine."  A  trial 
of  this  solvent  convinced  me  of  its  applicability,  and,  after  a 
series  of  carefully-  conducted  experiments,  I  became  convinced 
of  its  decided  superiority.  The  results  of  my  investigation, 
with  the  attending  advantages,  may  be  stated  as  follows : — 
The  odorous  and  resinous  matters  in  the  aqueous  solution  of 
opium  are  more  completely  removed  by  benzine,  while  the 
morphia  is  not  dissolved  to  a  greater  extent  than  by  the  use  of 
ether. 
Benzine  does  not  extract  codeia  or  narcotina ;  ether  removes 
the  former  partially,  and  the  latter  altogether,  from  the  solu- 
tion. A  practical  advantage  in  the  use  of  benzine  is  the  facil- 
ity with  which  it  may  be  separated  from  the  deodorized  solu- 
tion. It  is  only  necessary  to  pour  the  mixture  on  a  moistened 
paper  filter,  when  the  watery  extract  will  rapidly  pass,  ad- 
mixed with  but  a  trace  of  benzine,  which  may  be  expelled  by 
.  a  comparatively  slight  application  of  heat.  Economically  con- 
sidered, (its  cost  being  but  ^  that  of  ether,)  the  advantage  of 
using  benzine  is  important,  as  its  use  may  exert  an  influence 
on  the  general  employment  of  deodorized  tincture  of  opium. 
The  following  formula,  involving  the  use  of  benzine,  is  nearly 
in  the  language  of  the  Pharmacopoeia. 
Deodorized  Tincture  of  Opium. 
Take  of  opium,  dried,  in  moderately  fine  powder,  2 J  troy- 
