Am.  Jour.  Pliarai. ) 
Jan.,  1882.  / 
An  Incompfdihle  Ili.vture. 
19 
powder  left  floating  in  the  supernatant  liquid.  Pursuing  further,  I 
omitted  the  perchloride  of  mercury  as  well  as  the  bark  ;  an  almost 
■complete  solution  is  then  obtained.  The  iodide  of  potassium  helps 
to  dissolve  the  sulphate  of  quinine  without,  it  is  stated,  double 
decomposition  occurring,  as  there  is  much  less  insoluble  matter  left 
than  when  the  iodide  also  is  omitted  from  the  mixture.  In  place  of 
omitting  the  perchloride  of  mercury  I  next  omitted  the  iodide  of 
potassium;  this  gives  a  mixture  containing  a  quantity  of  flocculent 
precipitate  of  the  double  salt,  chloro-mercurate  of  quinine,  with  an 
excess  of  sulphate  of  quinine.  Then  I  dispensed  the  mixture  with- 
out the  chloroform,  using  rectified  spirit  vice  spirit  of  chloroform, 
and  proof  spirit  vice  tincture  of  cinchona  as  before.  The  result  was 
a  soft  resinous  deposit,  not  oily,  but  in  other  respects  like  that  con- 
taining the  chloroform.  Omitting  the  spirit  and  tincture  both, 
merely  using  the  salts,  rubbing  the  quinine  with  a  little  water,  and 
adding  the  perchloride  and  iodide  mixed  in  solution,  the  result  was, 
as  one  would  suppose,  a  mixture  containing  a  flocculent,  curdy, 
white  precipitate,  readily  diffusing  itself  through  the  mixture  on 
agitation. 
On  looking  at  the  prescription  one  perceives  that  the  potassio- 
mercuric  iodide  fWmed  would  act  as  a  precipitant  to  quinine  as  Avell 
as  other  alkaloids,  if  present.  lodo-mercurate  of  quinine,  a  salt 
which,  so  fiir  as  I  know,  has  not  yet  been  described,  or  some  com- 
pomid  of  iodoquinine,  is  probably  here  precipitated  in  the  presence 
of  excess  of  sulphate  of  quinine  in  a  weak  alcoholic  fluid  containing 
also  chloroform.  The  alcohol  renders  the  precipitate  viscid,  and  the 
chloroform,  having  greater  affinity  for  it  than  the  weak  alcoholic  » 
solution,  coml)ines  with  and  dissolves  this  precipitate  and  the  sul- 
phate of  quinine,  and  forms  an  oily  deposit.  The  prescription  is 
tliorougldy  incompatible,  but  not  so  incompatible  but  that  with  an 
addition  the  difficulty  may  be  overcome.  I  first  tried  mucilage  of  aca- 
cia, using  IJ  fluidounce  in  place  of  the  same  quantity  of  water.  On 
rubbing  the  quinine  in  a  mortar  with  the  mucilage,  adding  gradually 
and  stirring  during  the  addition  tlie  iodide  and  perchloride  previously 
dissolved  in  J  ounce  of  water,  pouring  these  into  the  bottle,  adding 
the  tincture,  and  lastly  the  spirit  of  chloroform,  and  shaking  well,  a 
presentable  but  not  an  elegant  mixture  is  obtained.  It  is  too  alcoholic 
to  hold  in  c()nq)lete  solution  the  gum,  which  forms  a  clotty  deposit, 
