ACTION  OF  CARBONIC  ACID  UPON  QUININE,  ETC. 
239 
the  other  merely  cinchonine.  Crystallized  carbonate  of  quinine 
is  very  readily  obtained  in  this  manner  by  the  following  process : 
10  grms.  of  sulphate  of  quinine  are  dissolved  in  distilled 
water,  to  which  a  few  drops  of  sulphuric  acid  have  been  added. 
The  addition  of  ammonia  to  the  solution  precipitates  the  quinine, 
which  is  collected  on  a  filter  and  washed,  and  then  diffused,  whilst 
still  moist,  through  a  litre  of  water.  The  milky  fluid  is  put  in- 
to a  glass  vessel,  into  which  well-washed  carbonic  acid  gas,  pro- 
duced by  the  action  of  muriatic  acid  upon  marble,  is  passed. 
The  quinine  is  entirely  dissolved  in  less  than  an  hour.  The  so- 
lution, although  supersaturated  with  acid,  retains  an  alkaline 
reaction. 
Quinine  combines  directly  with  carbonic  acid  without  dissolv- 
ing, when  it  is  not  suspended  in  a  sufficient  quantity  of  water. 
By  the  process  just  described,  a  perfectly  limpid  solution  is  ob- 
tained, from  which,  after  a  short  exposure  to  the  air,  crystals  of 
carbonate  of  quinine  are  deposited  ;  these  continue  increasing 
in  size  for  twenty  or  twenty  four-hours.  After  this  no  more  is 
deposited,  although  the  liquid  still  contains  the  salt.  Spontane- 
ous evaporation  only  furnishes  quinine,  which  is  also  instantly 
precipitated  by  ammonia,  potash  and  soda.  Lime-water  pro- 
duces the  same  effect,  with  formation  of  a  deposit  of  carbonate 
of  lime. 
The  solution  of  carbonate  of  quinine  consequently  furnishes 
at  first  crystals  of  the  saline  compound,  whilst  afterwards  this 
compound  is  destroyed,  giving  rise  to  carbonic  acid  and  quinine. 
There  is  a  complete  analogy  between  these,  phenomena  and 
and  those  presented  by  a  solution  of  carbonate  and  cinchonine. 
The  latter  never  furnishes  crystals,  because  the  salt  is  present 
in  very  small  quantity ;  this  no  doubt  depends  on  the  solubility 
of  cinchonine  in  water  being  very  little  increased  by  the  inter- 
vention of  carbonic  acid. 
Carbonate  of  quinine  forms  transparent  acicular  crystals  which 
soon  effloresce  when  exposed  to  the  air ;  they  are  soluble  in  al- 
cohol, but  insoluble  in  ether  ;  they  render  reddened  litmus-paper 
blue.    With  acids  they  produce  a  brisk  effervescence. 
At  a  temperature  of  230°  F.  they  are  decomposed ;  carbonic 
acid  is  evolved,  and  the  quinine  remains  without  alteration.  It 
only  fuses  at  338°  F.    The  decomposition  of  carbonate  of  qui- 
