AmAuoMi"t'  Si?111'}  Preservatives  in  Syrup  of  Iron  Iodide.  359 
taken  place.  In  the  tabulation  below  the  appearance  on  these  two 
dates  of  each  sample  is  noted: 
No.  1. — Proportions  of  the  U.  S.  P.  formula,  but  without  any 
preservative.  On  December  18th  this  sample  was  slightly  yellow. 
It  is  now  of  a  pale  green  color  and  appears  to  be  in  perfect  condition. 
No.  2. — U.  S.  P.  8th  formula  without  any  variation.  On  Decem- 
ber 18th  this  sample  was  very  pale  but  perfectly  clear.  It  was  noted 
that  the  green  color  had  gradually  faded  out  and  the  sample  was 
much  lighter  in  color  than  when  first  prepared.  This  is  in  accord- 
ance with  the  observations  on  this  formula  that  had  been  previously 
reported. 
This  sample  is  now  of  a  light  yellow  color  and  there  is  evidence 
of  some  change  in  the  sugar,  the  change  that  we  have  commonly 
considered  as  caramelizing  which  takes  place  in  the  presence  of 
hypophosphorous  acid  to  a  moderate  extent. 
No.  3. — Proportions  of  the  U.  S.  P.  with  the  addition  of  0.05 
per  cent,  of  tartaric  acid.  This  sample,  on  December  18th,  had 
assumed  a  distinct  yellow  color.  It  has  now  faded  until  it  is  almost 
colorless. 
No.  4. — Proportions  of  the  U.  S.  P.  formula  with  0.1  per  cent, 
of  tartaric  acid.  On  December  18th  this  sample  had  retained  the 
light  green  color  about  the  same  tint  as  when  first  prepared.  It  now 
shows  no  change  and  appears  to  be  in  perfect  condition. 
No.  5. — Proportions  of  the  U.  S.  P.  formula  with  the  addition  of 
0.05  per  cent,  of  citric  acid.  On  December  18th  this  sample  was  of 
a  very  light  green  color  and  preservation  appears  to  have  been  per- 
fect.   It  now  shows  no  further  change. 
No.  6. — Proportions  of  the  U.  S.  P.  formula  with  the  addition 
of  0.1  per  cent,  of  citric  acid.  On  December  18th  this  sample  had 
retained  its  original  pale  green  color,  and  at  this  time  preservation 
appears  to  have  been  perfect. 
Conclusions. — If  syrup  of  iron  iodide  is  carefully  made  and  with 
the  proper  amount  of  sugar,  no  preservative  whatever  is  needed. 
However,-  to  overcome  the  careless  manipulation  on  the  part  of  some 
druggists,  it  has  been  deemed  advisable  to  add  a  preservative. 
Hypophosphorous  acid  has  the  advantage  of  a  reducing  value  which 
is  not  possessed  by  the  organic  acid  suggested  for  this  purpose.  It 
has,  however,  the  disadvantage  that  in  the  strength  directed  it  will 
act  upon  sugar  in  strong  solutions  and  darken  the  syrup.  This  could 
be  overcome  by  substituting  glycerin  for  a  portion  of  the  sugar 
directed  in  the  formula. 
