ON  TINCTURA  FERRI  CHLORIDI. 
21 
are,  its  permanent  character  and  its  being  a  pure  sesquichloride* 
It  is  the  solution  which  I  prefer  keeping  for  making  the  muri- 
ated  tincture  and  other  preparations. 
The  formula  is  as  follows,  with  some  unimportant  exceptions : 
Take  of  Iron  wire  free  from  rust,  gii. 
Muriatic  acid,  fl.  §viii. 
or  sufficient  quantity, 
Water,       .       .  3  v. 
Mix,  and  digest  with  a  gentle  heat,  adding  more  acid,  if 
necessary,  until  all  the  iron  has  disappeared,  when  the  solution 
is  complete  add  to  it  half  as  much  more  muriatic  acid,  previously 
diluted  with  3  oz.  of  water,  then  raise  the  temperature  to 
boiling  or  nearly  so,  and  pour  in  by  successive  portions  about 
2  fl.  3,  of  nitric  acid,  or  until  a  drop  tested  with  a  dilute  solution 
of  red  prussiate  of  iron,  gives  neither  a  green  or  blue  precipi- 
tate.* Evaporate  with  a  gentle  heat,  until  upon  cooling  it 
begins  to  crystallize,  add  6  oz.  water,  and  if  any  iron  oxide  has 
separated,  add  enough  muriatic  acid  to  re-dissolve  it  with  the 
aid  of  a  gentle  heat.  Again  evaporate  to  6  fl.  3.,  and  finally 
add  water  to  make  the  whole  measure  10i  fl.  The  sp.  gr.  of 
this  solution  is  144,  and  is  of  the  same  strength  as  the  so- 
lution previously  spoken  of,  and  can  be  made  into  the  muri- 
ated  tincture  in  the  same  manner. 
As  connected  with  this  subject  I  may  here  remark,  that  a 
Syrup  of  Perohloride  of  Iron,  which  is  occasionally  prescribed, 
may  be  readily  and  extemporaneously  made  as  follows : 
J£.  Liq.  Ferri  Sequichloridi  fl.  3i. 
Syrupi         .       .       .  fl.  Ix. 
Misce. 
This  is  identical  with  that  prepared  by  Beral's  formula,  which 
is  made  by  dissolving  one  part  dry  chloride  of  iron  in  23  parts 
of  syrup. 
*The  first  part  of  this  process  is  best  effected  in  a  flask  ;  after  the  iron 
is  dissolved,  transfer  the  solution  to  an  evaporating  dish,  which  should 
not  be  more  than  one-fourth  full,  on  account  of  the  extrication  of  nitrous 
vapors  towards  the  close,  occasioning  sometimes  considerable  frothing  up 
of  the  materials. 
