Am.  Jour.  Pharm.  \ 
October,  1900.  J 
Syrup  Ferrous  Iodide. 
471 
That  glucose  is  found  in  the  normal  healthy  juices,  being  the 
form  of  sugar  into  which  starchy  and  saccharine  substances  are  con- 
verted by  amylopsin  and  allied  ferments,  that  they  may  become 
soluble,  digestible  compounds. 
For  a  working  formula  for  syrup  ferrous  iodide  with  glycerin  we 
find  that  by  replacing  half  the  syrup  by  glycerin  a  much  more  stable 
preparation  is  obtained  than  by  the  entire  substitution  of  glycerin 
for  syrup.  Then,  too,  heat  in  excess  should  be  avoided  with  the 
finished  preparation,  lest  a  more  or  less  disagreeable  odor  be  devel- 
oped of  an  "  allyl  "  character.  For  these  experiments  we  used  the 
formula  as  prescribed  by  the  U.S.P.,  with  the  changes  noted  above. 
We  do  not  consider  the  use  of  glycerin  at  all  advantageous. 
For  the  formula  for  the  use  of  glucose  we  first  prepared  a  glucose 
solution  of  1-40.  specific  gravity  (as  this  high  specific  gravity  is 
less  likely  to  undergo  acetous  fermentation)  and  used  the  spirit  of 
the  U.S.P.  formula.  First  experiment  showed  in  a  short  time  a  pre- 
cipitate at  first  flocculent,  finally  more  or  less  dense. 
Upon  carrying  out  a  few  tests,  we  discovered  the  presence  of  a 
trace  of  sulphates  and  an  abundance  of  chlorides ;  after  eliminating 
the  chlorides  with  silver  nitrate,  T.  S.  (in  treating  the  glucose 
solution,  with  the  object  of  eliminating  chlorides,  the  solution 
(specific  gravity,  1*40)  was  reduced  to  one  having  a  specific  gravity 
no,  and  titrated  with  Ag.N03,  T.  S.,  until  no  further  trace  of 
chlorides  was  noted;  filtered  and  again  concentrated  to  specific 
gravity  140,  we  again  carried  out  the  above  experiment,  using  the 
glucose  solution;  specific  gravity,  1*40,  reaction  neutral.  The  result 
was  a  clear,  permanent  preparation. 
We  then  tried  half  syrup  and  half  glucose  solution,  with  like 
result ;  yet  this  latter  would  not  necessarily  be  as  permanent  as  the 
preceding. 
After  two  months'  standing  each  specimen  showed  a  slightly  acid 
reaction.  In  closing  this  article,  we  wish  to  make  prominent  a  few 
points  to  be  observed  in  making  the  official  syrup,  the  non-observ- 
ance of  which  is  the  cause  of  much  of  the  decomposition  met 
with  in  practice.  The  sugar  should  be  free  from  ultramarine,  as  this 
will  cause  a  slight  reddening  of  the  finished  syrup. 
The  specific  gravity  should  be  at  least  1-35. 
The  water  used  should  be  distilled  and  free  from  ammonia,  as  fer- 
rous iodide  is  an  excellent  reagent  for  this  gas,  and  with  it  gives  a 
yellowish-brown  coloration. 
