Am.  Jonr.  Pharm. 
May,  1913. 
Liquor  Ferri  Iodidi. 
197 
Association),  proposed  the  use  of  Glycerin  as  a  preservative  for 
Solution  of  Ferrous  Iodide,  and  in  the  year  following,  Henry 
Thayer  (American  Journal  of  Pharmacy,  1858,  page  390),  pro- 
posed that  the  ferrous  iodide  should  be  prepared  or  formed  in  the 
presence  of  Glycerin.  At  the  semi-centennial  celebration  of  the 
A.  Ph.  A.  in  1902,  there  was  on  exhibition  a  sample  of  Glycerole 
of  Ferrous  Iodide  made  by  Prof.  William  Procter,  Jr.,  January  15, 
1865,  and  although  at  that  time  more  than  thirty-seven  years  old, 
it  was  in  an  excellent  state  of  preservation.  It  is  to  be  remembered 
that  the  title  Liquor  Ferri  Iodidi  in  those  early  days  was  applied 
to  an  entirely  different  preparation  from  what  we  are  now  desig- 
nating under  the  same  title.  The  solutions  of  that  period  were  much 
weaker  and  were  commonly  preserved  with  Glycerin,  Honey  or 
Sugar,  and  these  preceded  and  were  displaced  by  the  formula  for 
Syrup  of  Ferrous  Iodide  which  was  subsequently  made  official.  The 
value  of  Glycerin  as  a  preservative  for  ferrous  salts,  and  likewise 
of  iodide  solutions,  is  now  fully  recognized.  Its  use  is  proposed 
in  the  pharmacopceial  formulas  for  Diluted  Hydriodic  Acid  and  for 
the  Syrup  of  Hydriodic  Acid,  and  likewise  in  a  number  of  the  N.  F. 
formulas  for  Elixirs  containing  iron  salts.  I  have  found  it  of  value 
as  a  preservative  in  Iron  Iodide  Solutions  and  in  the  formula  sub- 
mitted herewith,  it  is  used  along  with  Hypophosphorous  Acid  in 
proper  amount  to  render  the  solution  permanent.  In  this  concen- 
trated Solution  of  Iron  Iodide  the  Glycerin  serves  another  useful 
purpose,  namely,  it  prevents  the  crystallizing  out  of  the  salt,  thus 
assuring  solution. 
The  following  formula  is  submitted  for  a  concentrated  Solution 
of  Iron  Iodide  of  such  a  strength  that  one  volume  diluted  with 
fifteen  volumes  of  Syrup  will  produce  a  Syrup  of  Ferrous  Iodide 
practically  identical  in  strength  with  the  Syrup  of  Ferrous  Iodide 
now  official.  The  strength  of  1  in  16  has  been  retained,  because  of 
its  present  extensive  use  and  likewise  to  maintain  the  leg"al  standard 
of  much  of  the  Solution  of  Iron  Iodide  that  is  already  in  commerce. 
An  aqueous  solution  containing  107.8  Gm.  of  Ferrous  Iodide 
(Fe  I2  —  309.69)  in  each  100  Cc, 
Iron,  in  the  form  of  fine,  bright  wire,  cut  into  small 
Liquor  Ferri  Iodidi. 
Solution  of  Ferrous  Iodide. 
pieces 
250.  Gm. 
