Am.  Jour.  Pharm.  \ 
October,  1900.  / 
Syrup  Ferrous  Iodide. 
469 
To  prove  that  glucose  does  reduce  iodine  and  forms  hydriodic 
acid,  we  carried  out  the  following  :  A  glucose  solution,  neutral  reac- 
tion, was  taken  and  solution  of  iodine  added  until  a  slight  color  was 
imparted  to  the  glucose ;  a  gentle  heat  was  then  applied,  color  dis- 
appearing. Reaction  was  then  found  to  be  acid  to  litmus ;  with 
starch  paste  no  color  was  noted,  while  upon  the  addition  of  a  small 
quantity  of  chlorine  water  a  deep  blue  color  was  obtained.  We  then 
took  10  c.c.  of  the  solution,  added  NH4OH  to  neutralization,  and 
titrated  with  decinormal  AgN03V.  S.  (using  a  few  drops  K2Cr04  T.  S. 
as  indicator)  until  we  obtained  a  permanent  pink  tint,  which  required 
5*5  c.c.  of  the  AgN03  V.  S.,  corresponding  to  y2  per  cent,  absolute 
HI.  We  conclude  that  hydriodic  acid  is  formed  as  a  product  of 
reduction,  and  that  while  the  syrup  is  constantly  kept  of  a  light 
color,  it  is  none  the  less  true  that  hydriodic  acid  is  being  formed. 
This  being  true,  we  ultimately  have  a  preparation  which  partakes 
to  a  degree,  at  least,  of  the  nature  of  an  iodine  preparation,  medi- 
cinally, as  well  as  an  iron  preparation ;  granting,  of  course,  that  this 
change  is  an  exaggerated  incident,  as  such  change  would  require  a 
long  period  for  consummation,  and  is  merely  cited  to  impress  the 
chemistry  of  the  action  of  glucose. 
NOTE. — Should  a  preparation  of  10  per  cent,  ferrous  iodide  in  a  glucose  solu- 
tion, specific  gravity  1*40,  be  kept  so  long  as  to  permit  of  the  glucose  exercising 
its  limit  of  reducing  influence  upon  iodine  liberated,  we  would  have  a  prepa- 
ration containing  hydriodic  acid  about  yz  per  cent.,  ferrous  iodide,  9*358  per 
cent.  Thus  :  10  per  cent,  by  weight  of  ferrous  iodide  would  contain  14 
grammes  in  100  c.c.  (specific  gravity  glucose  solution,  1*40),  of  which  11*467 
grammes  would  be  iodine.    Thus  : 
Mol.  Mol. 
Wgt.  Wgt. 
Fel2  :    I2     ::  14  grammes  :  X  (gramme  I). 
308-94  :  253-06  :  :  14  grammes  :  X  (=  11-4677  grammes  I  in  14  grammes  Fel2). 
308-94  X  =  3542 -84  grammes. 
X  =    11*4677  grammes  I. 
In  %.         cent.  HI  in  glucose  (specific  gravity,  1*40)  we  would  have  07 
gramme  HI  (absolute)  in  100  c.c.  solution. 
Then: 
Mol.  Atom. 
Wgt.  Wgt. 
HI    :    I     :  :  0*7  gramme  :  X  (gramme  I). 
127-53  :  126-53  :  :  °'7  gramme  :  X  (=  -69451  gramme  I  in  0-7  gramme  HI). 
This  being  the  limit  to  the  reducing  power  of  glucose  upon  iodine. 
Then  : 
11  "4677  grammes  I  in  10  per  cent.  Fel2  (100  c.c.)  less 
•6945  gramme  I  in  12  per  cent.  HI   (100  c.c.)  equals 
I0'773*  grammes  I  remaining  as  Fel2. 
