ACTION  OF  IODINE,  BROMINE  AND  CHLORINE  UPON  SUGAR.  307 
ACTION   OF  IODINE,  BROMINE   AND   CHLORINE  UPON 
SUGAR. 
Translated  and  communicated  for  this  Journal  by  the  author.* 
I  do  not  know  of  any  work  upon  chemistry, f  or  of  any  chem- 
ist, having  described  the  action  of  iodine  upon  sugar;  yet  the 
changes  which  take  place  between  these  two  bodies  deserve  being 
studied  by  scientific  men. 
I  have  only  to  report  a  series  of  facts,  the  result  of  my  ex- 
periments since  1866,  in  the  preparation  of  tbe  syrup  of  the 
iodide  of  iron,  which  led  me  to  study  the  action  of  iodine, 
bromine,  &c,  upon  sugar. 
I  have  observed  the  two  following  facts  : 
1st.  The  partial  spontaneous  decomposition  of  the  syrup  of 
iodide  of  iron  by  exposure  to  the  air,  is  arrested  at  a  certain 
point,  and  does  not  go  further,  even  if  exposed  for  several 
months,  in  a  capsule  only  covered  with  paper. 
2d.  This  syrup,  lightly  decomposed,  or  even  colored  by  the 
addition  of  a  small  quantity  of  iodine,  becomes  perfectly  white 
after  a  long  exposure  to  the  sun's  rays  or  to  a  moderate  heat  • 
replaced  in  the  dark,  it  resumes  its  amber  color. 
However,  two  vials  hermetically  sealed,  each  containing  the 
syrup  of  iodide  of  iron,  one  colored  by  natural  decomposition, 
the  other  by  the  addition  of  a  small  quantity  of  iodine,  were 
exposed  for  a  year  to  the  sun's  rays,  then  both  syrups  were 
colorless  ;  and  they  remained  so  for  more  than  a  year,  though 
they  were  left  in  a  dark  cellar,  and  in  half-filled  bottles. 
The  first  fact  reverses  the  old  theory  of  the  decomposition  of 
the  syrup  of  iodide  of  iron,  which  was  explained  by  the  forma- 
tion of  a  protoxide  of  iron  and  iodohydric  acid,  by  means  of  the 
decomposition  of  the  water  into  its  two  elements,  and  by  the 
transformation  of  the  protoxide  of  iron  into  sesquioxide  of  iron 
by  the  oxygen  of  the  air.  Evidently,  should  the  decomposition 
of  the  water  and  of  the  iodide  of  iron  operate  thus,  this  process 
should  continue  to  that  point  when  all  the  iodide  of  iron  is  de- 
composed ;  this  does  not  take  place. 
*  Repertoire  de  Pharmacie,  Bouchardat,  Decemb.,  1859,  et  Union  Phar- 
maceutique,  par  Dorvault,  January,  1860,  &«• 
[|  See  Gmelin's  Handbook,  vol.  xv.  252. — Ed.  Am.  Jour.  Ph.] 
