502  Assay  of  Opium  for  Morphia.  {AmNo0vl!!**i8P76arm' 
effect  of  mixing  opium  with  chalk,  and  then  adding  water,  and  per- 
colating. 
ioo  grains  of  opium,  as  before,  yielded  45  per  cent,  of  extract,  which 
gave  ii*9  per  cent,  of  brown  crystalline  morphia. 
The  difference  in  extract  yielded  by  the  plan  is  due  to  the  fact  that 
the  free  acid  being  neutralized  by  the  chalk,  the  meconic  acid,  part  of 
resin,  the  whole  of  the  meconate  of  calcium,  and  part  of  narcotina,  are 
removed  from  solution  and  so  diminish  the  weight  of  extract  obtained. 
The  results  obtained  by  this  process,  compared  with  others,  will  be 
given  further  on. 
Action  of  Alkalies  on  Infusion  and  Tincture  of  Opium. 
Ammonia. — If  excess  of  solution  of  ammonia  be  added  to  infusion 
of  opium  a  precipitate  is  obtained,  which  consists  chiefly  of  morphia, 
but  contains  small  quantities  of  narcotina  and  other  alkaloids,  meconate 
of  calcium  and  resin.  This  precipitate  is  either  crystalline  or  amor- 
phous, accordingly  as  a  solution  was  hot  or  cold  when  precipitated.  If 
the  solution  be  concentrated  until  about  equal  to  twice  the  weight  of 
opium  employed,  and  ammonia  added  to  the  boiling  liquid,  with  constant 
stirring,  the  resin  is  precipitated,  melts  and  adheres  firmly  to  the  sides 
of  the  containing  vessel  or  to  the  glass  rod  used  for  stirring.  The  liquid 
can  then  be  poured  off  immediately,  when  the  morphia,  etc.,  will  begin 
to  be  precipitated  owing  to  the  change  of  temperature.  The  crystals 
so  obtained  are  free  from  the  resin  and  light-brown  in  color.  The 
morphia  is  not  entirely  precipitated  by  ammonia  from  infusion  of  opium, 
owing  to  the  solubility  of  morphia  in  water  and  in  ammonia.  If  the 
ammonia  be  added  in  slight  excess  only,  and  the  liquid  allowed  to  stand 
until  the  smell  of  the  ammonia  has  disappeared,  then  the  amount  of 
morphia  left  in  solution  should  correspond  to  the  amount  of  liquid  used,, 
unless  there  be  any  constituent  in  the  infusion  of  opium  which  prevents 
the  complete  precipitation  of  morphia.  This,  according  Prof.  Dragen- 
dorff,  is  the  case.  The  following  experiments,  however,  tend  to  prove 
that,  provided  the  excess  of  ammonia  be  nearly  driven  off,  the  amount, 
of  morphia  left  in  solution  is  in  direct  accordance  with  its  solubility  in 
water. 
6*48  grams  of  dried  Turkey  opium  were  exhausted  with  water,  and 
concentrated  to  35  cc.  It  yielded  *8oo  gram  of  morphia.  The  solu- 
tion, which  with  the  wash  water  measured  70  cc,  was  shaken  repeat- 
edly with  fusel  oil;  fusel  oil  removed  and  evaporated.    The  residue 
