AVo°vu>r'i87hSrm'}      Assay  of  Opium  for  Morphia.  499 
our  knowledge  of  the  physiological  effects  of  opium  and  its  constitu- 
ents is  sufficiently  complete  to  enable  us  to  affirm  that  all  the  objects 
for  which  opium  is  prescribed  can  be  attained  equally  well  by  the  use 
of  its  alkaloids.  Among  these  only  three  can  be  said  to  have  any 
practical  importance,  viz.,  morphia,  codeia  and  narceina,  which  are  all 
hypnotics,  and  seem  to  differ  from  one  another  mainly  in  the  amount 
required  to  produce  the  desired  effect.  The  other  bases  are  either  inert 
in  ordinary  doses,  or  exist  in  such  minute  quantities  that  the  proportion 
of  them  in  a  large  dose  of  laudanum  could  only  produce  a  physiologi- 
cal effeet  in  the  imagination  of  a  homoeopathist. 
I  believe  that  the  chief  work  of  pharmaceutical  chemistry  for  a 
long  time  to  come  will  consist  in  the  perfecting  of  processes  for  the 
isolation  of  the  active  principles  of  the  vegetable  remedies,  so  that  in 
due  time  all  the  mediaeval  tinctures  and  decoctions  of  the  "  Pharmoco- 
poeia  "  will  become  obsolete,  and  be  superseded  by  preparations  of  defi- 
nite and  invariable  strength.  It  is  my  sincere  hope  that  this  paper, 
meagre  and  imperfect  though  it  is,  may  in  some  small  measure  be  the 
means  of  hastening  such  a  desirable  consummation. — Pharm.  four,  and 
Trans.  [Lond.],  Sept.  16,  1876. 
REPORT  OF  AN  ASSAY  OF  OPIUM  FOR  MORPHIA. 
BY  EDWARD  LAWRANCE  CLEAVER,  F.C.S. 
In  order  to  thoroughly  criticize  the  different  processes  in  present  use 
for  the  estimation  of  morphia  in  opium  it  is  necessary  to  have  a  thorough 
knowledge  of  the  following  points  : 
1.  What  are  the  constituents  of  opium  ? 
2.  In  what  state  of  combination  do  they  exist  ? 
3.  The  action  of  solvents  and  reagents  on  these  principles. 
4.  The  action  of  solvents  on  opium. 
5.  The  action  of  alkalies  on  solutions  of  opium. 
6.  The  action  of  heat,  acids,  etc.,  on  morphia. 
This  paper  will  therefore  be  divided  into  two  parts.  The  first  con- 
sists of  remarks  on  the  foregoing  heads  ;  the  second  of  the  application 
of  these  remarks  to  point  out  the  advantages  and  disadvantages  of  the 
existing  processes  used  for  opium  analysis. 
Part  I. — The  principal  constituents  of  opium  are  as  follows  :  Mor- 
phia, narcotina,  narceina,  codeina,  thebaina,  papaverina,  a  substance 
