124 
Citrate  of  Iron  and  Quinine. 
{Am.  Jour.  Pharm. 
March,  1885. 
between  a  triquinic  citrate  and  a  citric  acid  molecule.  This  view  would 
consider  it  a  super  acid  quinium  citrate.  However,  according  to  either 
construction,  the  union  partakes  of  that  subvalent  nature  wherein  the 
chemical  compact  cannot  be  represented  by  unit  bonds. 
The  first  of  these  citrates  is  the  least  soluble  of  them  and  forms  as 
a  voluminous  curdy  mass. 
The  second  has  a  more  crystalline  character  and  is  also  slightly  more 
soluble. 
The  third  crystallizes  in  voluminous  collections  of  delicate  satiny 
needles.  It  is  by  far  the  most  soluble  of  these  salts,  imparting  a  very 
decided  bluish  fluorescence  to  the  cold  aqueous  solution,  and  is  much 
more  freely  soluble  in  hot  water.  Although  this  monoquinic  citrate 
appears  to  be  more  soluble  than  the  ordinary  sulphate,  it  is  remarkably 
less  bitter.  Besides  the  process  already  mentioned,  it  can  also  be  pre- 
pared by  double  decomposition  between  436  parts  of  diquinic  sulphate 
and  monosodic  citrate  derived  from  210  parts  of  citric  acid  and  84 
parts  of  sodium  bicarbonate.  The  resulting  magma  is  heated  with 
sufficient  water  to  dissolve  it,  and  the  solution  set  aside  to  crystallize. 
Til  is  method  is,  however,  somewhat  wasteful,  owing  to  the  marked 
solubility  of  this  salt. 
The  monoquinic  citrate  is  apparently  the  most  practically  applicable 
salt  in  the  preparation  of  the  new  sodio-ferric  quinium  citrate.  If  not 
procurable  as  such  in  the  market,  it  can  be  readily  compounded  by 
directly  uniting  the  quinine  and  citric  acid  employed  in  the  working 
formula  of  the  double  salt.  As  already  intimated,  the  union  is  more 
speedily  and  easily  effected  by  this  manner  of  compounding  than  by 
the  incorporation  of  the  quinine  last.  The  tendency  of  the  alkaloid 
to  fuse  into  resinous  ma.sses  is,  in  the  case  of  the  new  salt,  by  no  means 
as  pronounced  as  in  the  old  official  process,  yet  it  can  be  wholly 
obviated  as  above  suggested. 
If  the  Pharmacopoeia  intends  to  employ  anhydrous  quinine  in  its 
formulas,  it  should  not  have  adopted  a  hydrite  at  all.  Had  an  anhy- 
drite been  directed,  the  operator  would  either  have  employed  the 
trihydrous  quinine  in  the  proportion  of  378  to  324  or  he  would  have 
appropriately  heated  378  parts  of  the  trihydrite  until  only  324  parts 
remained. 
The  preparation  of  a  pure  trihydrous  quinine  is  not  so  easy  as  it 
might  seem.  It  is  especially  difficult  when  the  sulphate  is  used.  On 
pouring  the  solution  of  the  acid  sulphate  into  the  alkaline  precipitant 
