508 
Assay  of  Opium  for  Morphia, 
Am.  Jour.  Pharm. 
Nov.,  1876. 
The  process  of  Mohr  which  has  been  adopted,  with  slight  modifica- 
tions, by  the  compilers  of  the  B.  P.,  consists  in  exhausting  opium  with 
water,  mixing  with  milk  of  lime  and  boiling  ;  the  filtered  liquid  is 
mixed  with  hydrochloric  acid  and  concentrated.  It  is  then  made 
exactly  neutral  with  ammonia,  filtered,  and  mixed  with  exeess  of 
ammonia  ;  the  precipitate  dried  and  weighed.  This  process,  if  pro- 
perly and  carefully  carried  out,  is  one  of  the  best,  as,  by  the  use  of 
lime,  the  resin  and  meconate  of  calcium,  also  meconic  acid,  is  removed 
from  solution.    The  objections  to  it  are  : 
1.  That  the  large  quantity  of  water  used  and  the  subsequent  evap- 
orations cause  loss  of  morphia. 
2.  That  no  account  is  taken  of  the  loss  of  morphia  by  non-precipi- 
tation. 
The  modifications  I  would  introduce  are  as  follows  : 
1.  The  opium  should  be  first  treated  with  bisulphide  of  carbon  or 
benzin. 
2.  The  dried  residue  should  then  be  mixed  with  its  own  weight  of 
lime  and  two  or  three  times  its  bulk  of  some  inert  powder,  such  as 
pumice  or  glass.  It  is  then  to  be  percolated  with  water,  the  first  part 
of  percolate  being  returned  as  fast  as  it  runs  through.  ,  By  this  means 
much  less  water  will  be  required  to  exhaust  the  opium  than  would 
otherwise  be  the  case.  After  the  opium  is  exhausted,  which  will  be 
known  by  the  liquid  dropping  through  devoid  of  taste,  the  solution 
should  be  exactly  neutralized  with  dilute  sulphuric  acid  and  filtered  and 
the  precipitate  washed.  The  clear  solution  is  then  to  be  evaporated 
over  a  water-bath  until  its  bulk  is  about  half  an  ounce,  and  again 
filtered  if  requisite  ;  then  ammonia  is  to  be  added  in  slight  excess,  and 
the  liquid  allowed  to  stand  twenty-four  hours.  The  precipitate  can 
then  be  collected,  washed  with  ether,  and  dried,  and  to  the  amount 
found  must  be  added  the  amount  corresponding  to  the  quantity  of 
water  used  in  precipitating  and  washing.  The  morphia  obtained  by 
this  process  is  of  a  dull  white  color,  crystalline,  perfectly  soluble  in 
alcohol,  acids  and  alkalies. 
In  concluding  these  few  remarks,  which  I  hope  may  prove  useful, 
-as  indicating  which  methods  are  most  likely  to  give  correct  results,  I 
beg  to  state  that  I  do  not  consider  the  subject  in  any  way  exhausted, 
and  that  I  still  intend  to  work  upon  opium  analysis,  and  hope  to  com- 
municate further  results  at  another  meeting  of  the  Conference. 
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