114 
Tincture  of  Ferric  Chloride. 
f  Am.  Jour.  Pharm. 
1      March,  1886. 
account  of  their  discrepancies  and  advautages,  and  the  offering  of  sug- 
gestions for  improvements  in  the  light  of  newly  discovered  facts. 
Our  accepted  authority^  of  1850,  ordered  the  preparation  of  the 
tincture  by  saturating  a  definite  quantity  of  hydrochloric  acid  with 
subcarbonate  of  iron,  filtering  and  making  up  to  the  requisite  volume 
with  sufficient  alcohol.  This  solution  contained,  generally,  both  fer- 
rous and  ferric  chlorides  in  varying  proportions,  and  when  exposed  to 
atmospheric  influences,  gradually  became  oxidized  with  the  deposition 
of  insoluble  ferric  oxide;  no  free  acid  (HCl)  being  present  to  prevent 
the  change. 
These  objections  were,  in  a  measure,  remedied  by  the  next  revision 
(U.  S.  P.,  1860);  but  it  remained  for  the  following  issue  (U.  S.  P., 
1870)  to  divide  its  manner  of  making  into  two  separate  and  distinct 
changes,  which  consisted  in  the  introduction  of  two  officinal  products. 
The  first  of  these  was  to  be  known  as  ^'  Liquor  Ferri  Chloridi,^'  and 
the  second,  which  was  to  be  made  from  the  first  with  alcohol,  as 
Tinctura  Ferri  Chloridi."  The  Pharmacopoeia  of  1880  retained  these 
later  features,  except  that  in  accordance  with  the  general  plan  of  the 
work,  parts  by  weight  were  substituted,  in  the  formulae,  for  the  volu- 
metric measurement  of  the  liquids. 
The  present  pliarmacopoeial  directions  for  the  preparation  of  the 
liquor,  consist,  first,  in  the  formation  of  ferrous  chloride  with  diluted 
hydrochloric  acid  and  metallic  iron,  and  then  in  the  oxidation  of  this 
ferrous  chloride,  in  slightly  acid  (HCi)  solution,  into  the  ferric  state 
with  nitric  acid,  and  the  direction  to  remove  any  excess  of  the  latter 
reagent  by  heat.  The  tincture  is  ordered  to  be  made  by  simple  admix- 
ture of  the  liquor  and  alcoliol  in  definite  parts  by  weight  and  allowing 
the  mixed  liquids  to  stand  in  a  closed  vessel  for  ''not  less  than  three 
months  prior  to  use."  The  intent  of  the  latter  action,  it  is  said,  is  to 
insure  the  full  production  of  chlorinated  ethers. 
Mr.  R.  Pother,  through  the  ''  Journal,"^  presents,  in  a  very  able  and 
interesting  communication,  some  critical  remarks  upon  ''Ferric  Chlo- 
rides" in  general  and  the  "Liquor"  (U.  S.  P.,  1880)  and  "Tincture" 
(U.  S.  p.,  1880)  in  particular.  He  claims,  principally,  that  the  present 
method  pursued  in  preparing  the  liquor  is  radically  wrong  and  defec- 
tive in  structure,  if  its  object  is  to  obtain  extreme  purity  of  the  finished 
product,  through  the  impossibility  of  evaporating  off  the  excess  of  nitric 
1  U.  S.  Pharmacoi^oeia. 
2  "American  Journal  of  Pharmacy,"  August.  1884,  p.  407. 
