AmAJjustPi887.m'}    Mixture  of  Quinine  and  31ercuric  Chloride.  403 
ROTE  ON  A  MIXTURE  CONTAINING  SULPHATE  OF 
QUININE  AND  BICHLORIDE  OF  MERCURY. 
By  T.  H.  Powell. 
The  incompatibility  of  sulphate  of  quinine  and  bichloride  of  mercury 
is,  I  think,  not  very  generally  known,  and  was  first  brought  to  my 
notice  a  few  weeks  ago  when  dispensing  a  prescription,  of  which  the 
following  is  a  copy  : — 
Tine,  ferri  perch  lor   3  vj 
Quin.  disulph  gr.  xlviij 
Acid,  hydrochlor.  dil  q.  s. 
Liq  hydrarg.  perchlor  .   iv 
Aq.  dest ...  ad  %  xij 
M. 
The  quinine  (Howard's)  was  dissolved  in  the  tincture  of  perchloride 
of  iron  and  half  a  drachm  of  dilute  hydrochloric  acid  added ;  this  was 
diluted  with  water,  and  finally  the  solution  of  perchloride  of  mercury 
poured  in,  a  perfectly  clear  straw-colored  mixture  resulting.  After 
standing  a  few  minutes,  however,  a  heavy  granular  precipitate  began 
to  form,  a  considerable  quantity  ultimately  collecting  at  the  bottom  of 
the  bottle,  and  remaining  undissolved  after  the  addition  of  a  drachm 
more  dilute  acid.  The  same  result  followed  when  the  mixture  was 
made  a  second  time,  the  sulphate  of  quinine  being  first  dissolved  in  an 
increased  quantity  of  acid.  On  examination  I  found  the  clear  liquid 
still  gave  evidence  of  bichloride  of  mercury  in  solution,  and  the  pre- 
cipitate, as  might  have  been  expected,  proved  to  be  a  double  chloride 
of  mercury  and  quinine.  We  may  perhaps,  infer,  as  the  dispenser  is 
directed  to  use  "a  sufficient  quantity"  of  dilute  hydrochloric  acid, 
that  the  writer  of  the  prescription  was  aware  of  the  formation  of  a 
precipitate,  but  believed  it  was  merely  due  to  the  inability  of  the 
tincture  to  retain  the  quinine  salt  in  solution ;  the  addition  of  the  acid, 
however,  does  not  effect  the  desired  result.  I  find  no  mention  of  the 
incompatibility  of  these  salts  in  Squire's  '  Companion,'  and  Pereira 
merely  says  a  salt  of  quinine  is  precipitated  on  the  addition  of  tannic 
acid,  ammonia,  perchloride  of  mercury  and  perchloride  of  platinum,  a 
statement  likely  to  mislead  when  the  character  of  the  respective  pre- 
cipitates is  taken  in  consideration. 
I  would,  therefore,  draw  attention  to  the  fact  that  when  mercuric 
chloride  and  quinine  salts  are  combined  in  a  mixture  they  form  a  very 
sparingly  soluble  double  chloride,  which,  unless  the  quantities  are 
