330        THE  SOLUBILITY  AND  ESTIMATION  OF  QUININE. 
several  different  makers,  and  exposed  in  the  same  manner.  All 
were  more  or  less  similarly  affected,  but  nevertheless  the  results 
varied  considerably.  In  some  cases  the  salt  was  even  more  de- 
cidedly affected  than  my  own  had  been  ;  but  in  others  the  result 
was  less  injurious,  and  when  the  scales,  after  insolation,  were 
treated  with  water,  although  they  became  white  and  opaque, 
their  ultimate  solution  took  place  readily.  Portions  of  these 
exposed  specimens  were  wrapped  up  and  put  away  in  a  dark 
place  for  some  time ;  upon  subsequently  examining  them,  they 
had  to  a  great  extent  passed  back  to  their  original  condition.  It 
has  often  happened  that  samples  of  this  salt  have  been  disparaged 
on  account  of  their  difficult  solubility ;  from  these  results,  how- 
ever, it  would  appear  possible  that  this  defect  has  not  been  so 
much  due  to  any  fault  in  the  manufacture  as  to  some  accidental 
circumstance  in  .the  preservation  of  the  product.  Should  time 
and  opportunity  offer,  I  hope  on  some  future  occasion  to  investi- 
gate more  fully  the  nature  of  the  change  which  thus  occurs  in 
citrate  of  iron  and  quinine  by  exposure  to  light. — Pharm.Jour.^ 
Lond.,  May,  1869. 
THE  SOLUBILITY  AND  ESTIMATION  OF  QUININE. 
M.  Fausto  Sestini  (Bulletin  de  la  Societe  Chimique,  Fevrier,- 
1869)  has  made  some  new  determinations  of  the  solubility  of 
quinia  in  pure  water.  He  finds  that  one  part  of  quinia  requires 
1667  parts  of  water  at  20  C,  and  902  parts  at  100  C.  for  its 
solution.  One  part  of  the  hydrate  of  quinia  (with  SHa  0)  re- 
quires 1428  parts  at  20°,  and  773-4  at  100°  0.  The  alkalies 
diminish  the  solubility  of  quinia,  and  soda  to  a  greater  extent 
than  potash ;  a  ley  containing  one-sixth  of  soda  dissolving  none. 
The  author  has  analysed  several  arseniates  of  quinia,  in  which 
he  estimated  the  alkaloid  by  the  following  method ;  The  salt  is 
dissolved  in  water  acidulated  with  sulphuric  acid,  and  the  qui- 
nia precipitated  by  a  solution  of  carbonate  of  soda ;  the  liquor 
is  evaporated  to  dryness  without  filtering,  the  residue  treated 
with  water,  the  quinia  collected  on  a  filter,  washed  until  the 
filtrate  ceases  to  react  with  nitrate  of  silver,  and  then  dried  at 
100  C,  and  weighed.   The  filtered  liquor  and  washings  are  eva- 
