Am.  Jour.  Pharni.  ] 
Nov..  1880.  i 
Syrup  of  Iodine  of  Iron. 
565 
then  filter  through  paper,  and  finally  reduce  by  evaporation  to  its 
original  bulk.  The  syrup  will  then  have  resumed  its  original  appear- 
ance. 
The  strength  of  the  preparation  will  not  have  been  materially  altered 
by  this  treatment,  for  it  takes  a  wonderfully  small  quantity  of  iodine  in 
the  free  state  to  color  a  large  amount  of  liquid.  Thus  it  will  be  found 
that  one  drop  of  liquor  ferri  perchloridi  added  to  half  a  fluidounce  of 
freshly  prepared  syrup  of  iodide  of  iron  will  produce  in  it  the  tint  of 
golden  sherry,  to  be  completely  dissipated  by  a  few  minutes'  boiling. 
There  is,  I  am  aware,  nothing  new  in  this  treatment  by  boiling,  etc.; 
it  has,  I  know,  been  mentioned  already  by  some  writer  whose  name  I 
have  unhappily  forgotten,  but  whose  useful  though  often  unused  sug- 
gestion has  not  escaped  me. 
I  will  now  refer  to  some  experiments  I  have  recently  made  in  the 
same  direction,  and  having  for  their  object  the  avoidance  of  the  delay 
attendant  on  the  process  already  mentioned. 
The  text-books  tell  us  that  when  a  persalt  of  iron  is  brought  in  con- 
tact with  a  soluble  iodide,  the  salt  is  reduced  to  the  proto  condition,  and 
free  iodine  is  eliminated.  It  was  at  one  time  thought  that  under  these 
circumstances  a  per-iodide  was  formed,  but  !VIr.  Squire,  jr.,  some  years 
since  proved  conclusively  that  such  was  not  the  case  by  showing  that 
the  color  could  be  removed  from  such  a  liquid  by  simply  shaking  it 
with  an  ordinary  solvent  for  iodine  such  as  benzin  or  chloroform.  If 
to  such  a  liquid  containing  iodine  in  solution,  caustic  potash  or  soda  be 
added,  precipitation  of  ferric  oxide  will  result,  and  the  iodine  will  com- 
bine with  the  base  of  the  precipitant.  Applied  to  a  discolored  syrup  of 
iodide  of  iron  the  process  does  not  answer,  and  that  in  consequence  of 
the  sugar,  as  it  appears  to  me,  exercising  a  solvent  action  on  the  pre- 
cipitated oxides.    In  fact  it  is  after  filtration  more  discolored  tF.an  ever. 
In  a  paper  published  in  the  ninth  volume,  second  series,  of  the 
Pharmaceutical  Journal "  Preservation  of  Syrup  of  Iodide  of  Iron"), 
I  pointed  out  the  efiVct  produced  by  the  presence  in  the  syrup  of  a 
trace  of  phosphoric  acid,  how  that  by  seizing  at  the  moment  of  its 
formation  the  peroxide  of  iron  and  rendering  it  insoluble,  it  effectually 
prevented  the  reaction  ending  in  the  elimination  of  free  iodine  that 
would  otherwise  have  resulted.  Syrup,  even  dilute,  will  keep  for  years 
after  being  so  treated,  but  of  course  one  gets  instead  of  the  discoloration 
the  slight  turbidity  occasioned  by  the  deposit  of  perphosphate  of  iron; 
this  however,  being  colorless  and  easy  of  removal  by  deposit  or  filtra- 
