264  Assay  of  Opium  and  its  Preparations.  {^'jZll\vm?m' 
solution  used  by  4  and  subtract  the  product  from  the  12  c.c.  of  acid 
used ;  the  remainder  will  be  the  amount  of  acid  consumed  by  the 
morphine,  which  number  must  be  multiplied  by  -030092,  in  turn 
dividing  the  last  product  by  2,  which  will  give  the  per  cent,  of 
morphine  obtained,  but  to  which  should  be  added  -070  as  the  correc- 
tive factor  of  the  loss  of  morphine  during  estimation. 
The  above  calculation  can  be  materially  lessened  by  multiplying 
the  number  of  cubic  centimeters  of  —  acid  consumed  by  the  mor- 
10 
phine  by  1-5046  and  adding  -070  to  the  product. 
ASSAY  OF  THE  TINCTURE  OF  OPIUM. 
"  Add  5  c.c.  of  5  per  cent.  KOH  solution  "  to  40  c.c.  of  the  tinct- 
ure contained  in  a  tared  evaporating  dish  and  evaporate  about  8 
grammes,  add  2  grammes  of  freshly  slaked  dry  lime  and  triturate 
to  uniform  mixture.  Transfer  to  a  graduated  cylinder,  rinsing  cap- 
sule with  water,  using  the  tipped  rod  to  facilitate  same,  until  30  c.c. 
are  obtained.  Drop  upon  the  surface  of  the  liquid  5  to  10  drops  of 
ether,  to  destroy  foam  and  air  bubbles.  Add  water  to  exactly  31  c.c, 
close  the  cylinder  with  stopper  and  shake  frequently  during  half  an 
hour,  filter,  and  from  15  c.c.  of  filtrate  proceed  as  under  opium, 
multiplying  the  number  of  cubic  centimeters  of  acid  consumed  by 
•15046  plus  70  and  the  product  will  be  the  number  of  grammes  of 
morphine  in  100  c.c.  of  tincture. 
THE  USE  OF  KOH  SOLUTION. 
The  first  assay  carried  out  after  the  Stevens  method  was  with  the 
tincture  and  after  the  addition  of  the  lime  the  odor  of  ammonia 
was  very  marked  in  some  cases.  The  principle  upon  which  this 
method  depends  is  the  fact  that  morphine  is  soluble  in  solution  of 
calcium  hydroxide  and  is  precipitated  by  the  ammonia  produced  by 
the  action  of  the  alkaline  solution  upon  ammonium  chloride.  The 
presence  then  in  the  opium  or  tincture  of  ammonium  compound 
will  naturally  precipitate  the  morphine  before  filtration  and  thus 
lessen  the  final  result.  Warming  either  opium  or  the  tincture  with 
KOH  decomposes  the  ammonium  compound  and,  as  evidenced  by 
experiment,  the  morphine  content  was  greater  in  those  cases  made 
with  the  previous  addition  of  KOH  than  in  those  made  without  it. 
It  was  further  proven  by  adding  to  solution  of  morphine  of  known 
