298         Atropine  Periodides  and  Iodomercurates.    {Am i^l'Jm^ 
determined  in  two  separate  portions.  For  mercury  the  substance  is 
dissolved  in  a  little  warm  alcohol  and  a  little  water  added;  the  solu- 
tion is  then  acidulated  with  a  few  drops  of  dilute  hydrochloric  acid 
and  saturated  with  hydrogen  sulphide.  The  mercuric  sulphide  is 
then  dried  and  weighed  in  the  usual  way.  For  the  determination 
of  iodine  the  substance  is  treated  with  a  hot  solution  of  potassium 
hydroxide  (1  :  10),  diluted  with  water,  filtered,  and,  when  completely 
cold,  neutralized  with  acetic  acid.  The  iodine  is  now  precipitated 
with  silver  nitrate  and  nitric  acid  and  determined  as  silver  iodide  in 
the  usual  way. 
In  the  following  analyses  the  standard  silver  nitrate  solution  was 
made  to  correspond  with  one  per  cent,  of  iodine  and  the  ammonium 
thiocyanate  solution  to  correspond,  cubic  centimeter  per  cubic  centi- 
meter, with  the  silver  nitrate  solution.  The  standard  solution  of 
iodine  contained  1  per  cent,  of  iodine,  and  the  sodium  thiosulphate 
solution  corresponded,  cubic  centimeter  per  cubic  centimeter,  with 
the  iodine  solution. 
Analysis  of  the  Atropine  Enncaiodide  not  Re  crystallized :  Volu- 
metric estimation  for  total  iodine, 01 5225  gramme  required  12-2  c.c. 
of  the  silver  nitrate  solution. 
For  the  iodine  removed  by  reduction,  O*  19255  gramme  required 
137  c.c.  of  the  thiosulphate  solution. 
Calculated  for 
C17H23N03.HI.Is.  Found. 
Iodine  by  reduction  70*88  7i'!5 
Total  iodine  .  7974  80*13 
In  the  gravimetric  estimation  from  0  218  was  obtained  0-3207 
silver  iodide. 
Calculated  for 
C17H23N03.HI.Is.  Found. 
Total  iodine  7974  79'43 
Analysis  of  the  Atropine  Enneaiodide  Recrystallized from  Alcohol: 
The  methods  employed  were  the  same  as  with  the  non-crystallized 
compound  and  the  standard  solutions  of  the  same  strength. 
In  the  volumetric  estimation  of  total  iodine,  o 12685  gramme 
required  10  I  c.c.  of  the  silver  nitrate  solution.  For  the  iodine 
removed  by  reducing  agents,  0  23  105  gramme  required  16-4  c.c.  of 
the  thiosulphate  solution. 
Calculated  for 
C17Hs3N03.HI.I8.  Found. 
Total  iodine   7974  79'62 
Iodine  by  reduction  70"S8  70*98 
