THE  AMERICAN 
JOURNAL  OF  PHARMACY. 
OCTOBER,  1877. 
LABORATORY  NOTES. 
By  Albert  B.  Prescott. 
I.  Solubility  of  Quinia  Precipitate  in  Water-washing. 
On  precipitating  quinia  sulphate  acidulate  solution  with  sodium  or 
with  ammonium  hydrate,  and  washing  on  the  filter  with  water  until 
the  washings  gave  no  cloudiness  with  solution  of  barium  salt,  Mr.  W. 
J.  Holloway  found  a  loss  of  11 '6  per  cent,  of  the  quinia.  The  weight 
of  quinia  sulphate  taken  was  0*250  gram  ;  two  operations,  one  with 
each  alkali,  giving  the  same  result.  Two  other  operations  were  made, 
the  precipitates  respectively  by  sodium  hydrate  and  by  ammonium 
hydrate  being  set  aside  for  20  hours  before  filtering,  and  then  each 
washed  with  18*4  cc.  of  water.  The  precipitate  by  soda  had  wasted 
2*9  per  cent,  of  the  alkaloid,  that  by  ammonia  io*6  per  cent.  The 
filtrate  from  one  of  the  precipitates  by  ammonia  (added  in  very  slight 
excess)  was  made  turbid  by  adding  soda,  and  the  dilute  washings  of  this 
same  precipitate  were  made  turbid  by  ammonia  (though  the  first  filtrate 
was  not  so  affected).  Apparently  the  solvent  power  of  water  upon  the 
alkaloid  was  diminished  by  presence  of  a  very  small  proportion  of 
ammonia,  though  it  is  increased,  as  is  well  known,  by  presence  of  more 
ammonia.  A  change  in  the  proportion  of  the  same  solvent  reverses  its 
effect,  just  as  dilute  sulphuric  acid  dissolves  less  lead  sulphate  than  either 
water  or  concentrated  sulphuric  acid. 
Mr.  A.  S.  Lobb  washed  0*280  gram  of  dried  quinia  on  the  filter 
with  a  half  liter  of  water,  dropped  from  a  burette,  at  about  87°F.,  and 
found  the  alkaloid  had  lost  50  per  cent,  of  its  weight,  each  cc.  of  the 
water  having  dissolved  0*000216  gram  of  quinia.  In  all  these  cases 
the  filtrates  gave  a  precipitate  with  potassium  mercuric  iodide. 
The  solubility  of  quinia  precipitate  in  sodium  sulphate  solution  becomes  of 
interest,  because  this  solution  is  the  filtrate,  in  the  use  of  the  best  preci- 
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