Am  Jc°tur-i9^arm-}        Determination  of  Morphine.  703 
Experiment  15. — The  question  was  raised  as  to  whether,  when 
starch  is  precipitated  by  barium  hydroxide  in  the  presence  of  mor- 
phine salts,  any  morphine  is  carried  down  in  the  gelatinous  pre- 
cipitate. 
A  paste  was  made  by  the  action  of  hot  water  on  one  Gm.  of 
starch.  To  this  was  added  20  Cc.  of  a  stock  solution  of  morphine 
hydrochloride,  then  10  Gm.  of  barium  hydroxide  dissolved  in  hot 
water.  The  mixture  was  cooled,  diluted  to  100  Cc.  and  filtered 
through  a  dry  paper.  From  the  filtrate  50  Cc.  was  taken,  acidified, 
and  mixed  with  25  Cc.  of  standard  iodine  solution.  The  mixture 
was  diluted  to  100  Cc.  and  filtered.  An  aliquot  portion  of  the  filtrate 
(50  Cc.)  was  titrated  with  sodium  thiosulphate  solution. 
Volume  of  sodium  thiosulphate  solution  used  =  3.6  Cc.  In  a 
blank  experiment  the  corresponding  result  was  3.4  Cc. 
The  difference  corresponds  to  0.001 1  Gm.  of  anhydrous  mor- 
phine in  the  fraction  titrated,  or  0.0044  Gm.  of  the  total  original 
amount. 
Combined  Action  of  Lead  Salts  and  Barium  Hydroxide  on  Mor- 
phine. Experiment  16. — A  few  Cc.  of  basic  lead  acetate  solution 
was  added  to  25  Cc.  of  the  same  stock  morphine  hydrochloride  solu- 
tion used  in  Experiment  15:  Barium  hydroxide  solution  was  added 
in  excess  till  the  total  volume  was  250  Cc.  The  mixture  was  filtered. 
One  hundred  Cc.  of  the  filtrate  was  acidified  and  25  Cc.  of  standard 
iodine  solution  was  added,  then  enough  water  to  make  up  to  250  Cc. 
The  periodide  was  filtered  out  and  125  Cc.  of  the  filtrate  titrated 
with  standard  sodium  thiosulphate  solution.  A  blank  determination 
of  morphine  was  made  at  the  same  time. 
Sodium  thiosulphate  solution  required 
(  i)  In  main  experiment   7.6  Cc. 
(ii)  In  blank  experiment   3.4  Cc. 
Since  1  Cc.  Na2S2Q3  sol.  =  1.0638  Cc.  iodine  solution  and  1  Cc. 
iodine  solution  =  0.008285  Gm.  of  anhydrous  morphine. 
10  Cc.  of  the  stock  solution  of  hydrochloride  used  above  =  0.1464 
Gm.  of  anhydrous  morphine,  of  which  amount  0.0735,  or  niore  than 
half,  was  precipitated  by  the  lead  in  the  foregoing  experiment. 
The  Action  of  Ammonium  Salts  on  Morphine.  Experiment  ij. 
— Crystallized  morphine  (0.3000  Gm.)  was  dissolved  in  standard 
sulphuric  acid  and  the  solution  was  titrated  with  standard  sodium 
