196 
Liquor  Ferri  Iodidi. 
Am.  Jour.  Pharm. 
May,  1913. 
As  a  matter  of  fact,  both  of  these  statements  are  incorrect.  The 
N.  F.  Ill  formula  is  directed  to  yield  1000  Cc.  of  product;  if  this 
be  changed  and  the  finished  product  made  1000  Gm.  then  the  solu- 
tion will  contain  81  per  cent,  of  Ferrous  Iodide. 
The  manufacturers  have  quite  generally  adopted  for  the  Solu- 
tion of  Ferrous  Iodide  a  strength  of  sixteen  times  by  volume  that 
of  the  official  Syrup  of  Iron  Iodide.  That  is,  their  labels  direct  that 
to  prepare  Syrup  Iron  Iodide,  1  fluidounce  of  the  Liquor  be  mixed 
with  15  fluidounces  of  Syrup.  This  is  only  another  evidence  that 
the  American  physicians,  druggists  and  manufacturers  persist  in 
using  the  apothecaries'  measure  and  think  in  its  terms  rather  than 
in  the  decimal  terms  of  the  metric  measure.  The  intent  of  the 
National  Formulary  evidently  was  to  supply  a  formula  for  a  prepa- 
ration of  the  same  strength  as  supplied  in  the  trade. 
Several  other  minor  defects  in  the  N.  F.  formula  should  be 
considered.  The  direction  to  filter  the  boiling  solution  of  ferrous 
iodide  through  paper  is  a  manipulative  error  that  brings  trouble. 
In  my  experience,  hot  solutions  of  ferrous  iodide  of  the  strength 
directed  invariably  eat  right  through  paper  filters,  even  if  of  several 
thicknesses.  Either  the  solution  has  to  be  diluted  greatly  or  cooled 
before  filtering  through  paper  or  else  the  hot  solution  must  be 
filtered  through  glass  wool  or  asbestos  wool,  returning  the  first  por- 
tion of  the  filtrate  until  it  comes  through  clear. 
The  amount  of  Hypophosphorous  Acid  directed  to  be  used  in 
the  formula  is  not  the  equivalent  of  that  directed  as  a  preservative 
in  the  official  formula  for  the  Syrup.  Consequently,  the  Solution 
is  prone  to  undergo  change  if  kept  in  bottles  that  are  opened  fre- 
quently, as  is  apt  to  be  the  case.  Hence,  the  Solution  should  be 
preserved  in  small  glass  stoppered  bottles,  which  should  be  com- 
pletely filled  and  kept  tightly  stoppered. 
The  proposition  has  now  been  made  that  the  U.  S.  P.  IX  should 
direct  that  Syrup  of  Ferrous  Iodide  be  prepared  from  a  concentrated 
liquor,  and,  consequently,  a  formula  for  a  concentrated  Solution  of 
Ferrous  Iodide  will  have  to  be  adopted  as  a  new  admission  in  the 
Pharmacopoeia.  Our  concern  is,  that  the  most  satisfactory  formula 
be  adopted. 
The  value  of  Glycerin  as  a  preservative  for  solutions  of  iron 
salts  has  long  been  recognized  by  the  practical  pharmacists  and  the 
manufacturers  of  the  various  solutions  of  ferrous  salts.  As  early 
as  1857,  J.  C.  Learning  (Proceedings,  American  Pharmaceutical 
