ON  LIQUOR  FERRI  IODIDI. 
25 
iodide  of  iron,  until  the  whole  of  it  is  decomposed  into  sesquiox- 
ide  of  iron  and  iodohydric  acid  ? 
I  will  here  state  a  fact,  that  I  have  no  where  seen  mentioned, 
and  which  I  can  prove  beyond  a  doubt :  it  is  that  iodine  unites 
with  sugar  to  form  a  chemical  combination,  which  I  will  call  iodide 
of  sugar. 
This  new  therapeutic  agent,  as  white  and  as  agreable  to  the 
taste  as  the  simple  syrup,  stable  in  its  composition,  no  doubt 
will  some  day  take  the  lead  among  the  preparations  of  iodine. 
This  metalloid,  however,  has  but  a  slight  affinity  for  sugar  ;  but 
that  they  do  unite  together,  the  three  accompanying  bottles 
marked  syrup  of  iodide  of  sugar  will  prove.  These  bottles  con- 
tain respectively  one,  two  and  four  grains  of  iodine  to  the 
ounce  by  weight. 
From  this  fact  I  draw  the  inference,  that  the  sugar,  which  is 
the  very  substance  that  preserves  the  iodide  of  iron  intact,  is 
also  the  cause  of  its  decomposition  to  a  certain  point ;  and  from 
it  I  deduct  my  theory,  which  is,  that  in  the  liquor  ferri  iodidi, 
the  sugar  by  affinity  decomposes  a  small  portion  of  the  iodine 
and  protoxide  of  iron,  and  when  this  liquor  is  warmed  or  expos- 
ed to  the  sun's  rays,  the  iodine  combines  with  the  sugar  to  form 
iodide  of  sugar,  and  the  protoxide  of  iron  probably  combines 
also  with  the  sugar,  or  dissolves  in  the  syrup,  so  as  to  form  a 
syrup  of  protoxide  of  iron. 
In  the  other  instance,  when  to  a  newly  made  liquor  a  slight 
excess  of  iodine  is  added,  and  the  whole  exposed  to  the  heat  as 
above,  the  sugar  combines  with  that  small  portion  of  iodine,  and 
its  affinity  for  the  metalloid  is  lessened,  so  much  that  it  has  no 
more  power  to  decompose  the  iodide  of  iron,  which  will  therefore 
remain  permanent. 
These  two  assertions  prove  conclusively  also,  that  there  can 
be  no  iodate  of  iron  formed,  as  has  been  advanced  by  some,  and 
that  this  ferruginous  liquor  can,  and  ought  to  be,  kept  in  the 
sun's  light. 
[Note. — The  above  paper  was  accompanied  by  seven  specimens  ;  four 
of  syrup  of  iodide  of  iron,  and  three  of  "  iodide  of  sugar,"  so  called.  The 
iodide  of  iron  preparations  were  thin,  syrupy,  light  green  liquids,  perfectly 
transparent.  The  vials  of  "  iodide  of  sugar  "  were  nearly  colorless  solu- 
tions of  sugar,  having  an  acid  reaction.    One  of  them  slowly  deposited  a 
