Am.  Jour.  Pharm.  "1 
September,  1894.  J 
The  Opium  Assay  Method. 
445 
occupies  a  long  time.  The  correction  by  the  lime-water  test  is  more 
satisfactory,  since  the  coloring  matter  precipitated  from  alkaline 
solution  is  not  likely  to  dissolve  in  lime-water  ;  to  what  extent  the 
salts  yielding  the  ash  are  dissolved  by  it  is  not  known,  but  the 
lime-water  solution  of  morphine  gave,  in  every  case,  the  test  for 
meconicacid  when  acidified  with  hydrochloric  acid  and  ferric  chloride 
added,  in  Nos.  I,  4  and  5,  where  the  quantity  of  ash  was  trifling, 
care  had  to  be  exercised  so  as  to  avoid  an  excess  of  the  reagents 
which  were  found  to  interfere  with  the  test. 
As  for  narcotine,  which  is  sometimes  stated  to  be  precipitated  in 
this  assay  method,  the  ignition  method  and  Stilwell's  method 
will  record  narcotine  as  pure  morphine,  as  narcotine,  like  morphine, 
leaves  no  ash ;  and  again,  both  are  soluble  in  alcohol ;  the  lime- 
water  test  rejects  all  but  traces  of  it,  so  that  this  again  forms  the 
best  test.  E.  Dieterich,  in  examining  morphine  for  narcotine,  uses 
ether,  which  is  a  much  better  solvent  for  the  latter  than  for  the 
former. 
The  lime-water  test  is  very  easily  applied  so  as  to  prevent 
frothing,  which  prevents  the  solvent  action  of  the  lime-water 
upon  those  particles  entangled  in  the  froth,  by  moistening  0-5 
gram  morphine  very  thoroughly  with  5  cubic  centimetres  lime- 
water,  and  then  adding  the  balance  of  45  cubic  centimetres ;  the 
contents  are  not  to  be  violently  agitated,  but  simply  to  be  rotated 
frequently  during  half  an  hour,  when  the  solution  and  precipitate,  if 
any,  are  filtered  through  a  pair  of  counterbalanced  filters,  the  latter 
washed  with  5  cubic  centimetres  of  lime-water,  then  with  5  cubic 
centimetres  distilled  water,  pressed  between  bibulous  paper  and 
dried  at  the  same  temperature  at  which  the  morphine  was  dried  ; 
if  the  drying  was  effected  at  ioo°  C,  the  .lime-water  residue  must 
be  subtracted  before  the  calculation  is  made  changing  anhydrous 
into  crystallized  morphine. 
From  the  foregoing  will  be  seen  the  necessity  for  the  following 
suggestions,  embracing  corrections  and  original  investigations  for 
the  perfection  of  the  official  process : 
(1)  A  test  for  the  purity  of  the  weighed  morphine. 
(2)  Information  as  to  the  necessary  time  for  the  maximum  pre- 
cipitation of  morphine. 
(3)  Information  as  to  the  quantity  of  morphine  left  in  the  mother- 
liquor. 
