DECOMPOSITION  05  QUINIA  SALTS  BY  THE  ACETATES.  387 
at  a  boiling  heat,  the  crystals  appearing  on  the  cooling  of  the 
liquid  are  pure  acetate  of  quinia  free  of  sulphate. 
The  solution  of  six  grains  of  quinia  in  half  an  ounce  of  water, 
if  rapidly  and  well  mixed  with  one  or  two  drachms  of  a  nearly 
concentrated  solution  of  acetate  of  any  of  the  alkalies,  is  thick- 
ened by  a  curdy-looking  precipitate,  so  that  the  vessel  may  be 
inverted  without  the  loss  of  a  drop  ;  after  expressing  and  washing 
with  cold  water,  it  contains  neither  alkali  nor  sulphuric  acid, 
but  is  pure  acetate  of  quinia. 
The  precipitates  obtained  from  solutions  of  sulphate  of  quinia 
by  acetate  of  magnesia,  if  washed  until  free  of  magnesia,  do  not 
contain  any  sulphuric  acid. 
Acetate  of  quinia  dissolved  in  acetic  acid  is  not  decomposed 
by  the  sulphate  of  alkalies  and  alkaline  earths.  After  the  fore- 
going experiments  this  last  result  might  have  been  predicted, 
but  the  experiment  was  made  to  entirely  refute  the  assertion 
of  sulphate  of  quinia  being  merely  insoluble  in  the  acetates  ;  if 
this  was  the  case,  a  solution  of  acetate  of  quinia  might  be  expected 
to  be  decomposed  by  a  soluble  sulphate  with  the  separation  of 
crystals  of  sulphate  of  quinia. 
Sulphate  of  quinia  requires  a  considerable  quantity  of  acetic 
acid  to  dissolve  at  ordinary  temperature:  such  a  solution  is  not 
disturbed  by  the  addition  of  acetate  of  potassa,  the  acetic  acid 
necessary  for  dissolving  the  sulphate  of  quinia  being  also  suffi- 
cient to  keep  in  solution  all  the  acetate  of  quinia  that  may  be 
formed. 
Solutions  of  the  bimuriate  of  quinia  are  likewise  precipitated 
by  the  acetates  ;  the  precipitates,  when  well  washed,  are  also 
pure  acetate  of  quinia,  free  of  hydrochloric  acid. 
From  the  above  experiments  it  follows,  that  the  salts  of  quinia 
are  decomposed  by  the  acetates,  and  that  the  decompositions 
may  be  made  complete  at  the  boiling  point  as  well  as  at  ordinary 
temperature,  although,  if  the  solutions  are  not  well  mixed,  the 
precipitate  may  contain,  besides  acetate,  more  or  less  sulphate 
of  quinia.  Accordingly  the  preparation  of  pure  acetate  of  quinia 
is  attended  with  no  difficulty ;  the  solution  of  the  bisulphate  of 
quinia  is  mixed  with  a  boiling  solution  of  any  acetate  in  excess, 
the  crystals  appearing  after  cooling  are  filtered  off  by  linen, 
expressed,  washed  with  cold  water,  dried  and  kept  in  well 
