64 
CITROMEL  AND  TARTROMEL  OF  IODIDE  OP  IRON. 
a  more  complicated  problem  than  was  supposed  so  long  as  no 
isomeric  sugar  was  known.  Indeed,  the  processes  by  which  such 
a  sugar  might  be  produced,  unless  they  are  discovered  by  chance 
and  by  accident,  must  rest  on  the  comparative  study  of  these 
different  isomeric  principles,  and  furnish  the  general  law  of  their 
formation — London  Chemist,  Oct.,  1858,  from  Comptes  Bendus, 
Aug.  2,  1858, 
CITllOMEL  AND  TARTEOMEL  OF  IODIDE  OF  IRON. 
By  Mr.  John  Horncastle. 
So  many  able  experimentalists  have  been  engaged  in  the  pro- 
duction and  improvement  of  the  preparations  of  iodide  of  iron, 
that  I  feel  some  diffidence  in  inviting  attention  to  two  new  com- 
binations, fearing  I  might  lay  myself  open  to  the  charge  of 
wishing  to  increase  their  number,  without  adequate  advantage 
in  the  improvement  of  their  quality.  But  as  all  the  prepara- 
tions at  present  in  use  are  in  some  respects  defective,  especially 
as  regards  their  stability,  I  feel  confident  that  my  investigations 
have  been  directed  to  a  useful  object,  and  hope  the  results  will 
be  interesting  to  the  Members  of  the  Pharmaceutical  Society. 
About  six  years  ago  I  was  informed  by  Mr.  C.  F.  Palmer,  of 
Birmingham,  that  citric  acid  would  prevent  the  spontaneous  de- 
composition of  solutions  of  iodide  of  iron.  Conceiving  that  this 
property  of  the  acid  might  be  made  available  for  preserving  so- 
lutions for  officinal  use,  I  commenced  a  series  of  experiments,  to 
ascertain  the  extent  of  its  preservative  powers,  and  likewise 
whether  the  other  common  vegetable  acids,  viz.,  the  tartaric  and 
acetic,  possessed  similar  properties. 
Six  solutions  were  made,  each  containing  five  grains  of  iodide 
of  iron  in  a  fluid  ounce  of  distilled  water,  and  to  five  of  them 
citric  acid  was  added,  in  proportions  varying  from  one  to  five 
grains.  All  the  solutions  were  perfectly  clear  and  colorless — 
They  were  put  into  ounce-and-half  phials,  not  corked,  but  the 
mouths  covered  with  paper,  to  keep  out  the  dust,  and  placed  in 
a  window  where  they  were  freely  exposed  to  the  light,  though 
usually  shaded  by  a  blind  from  the  direct  rays  of  the  sun.  They 
were  examined  and  tested  with  starch  paper  at  intervals  of  a 
few  days.    The  solution  which  contained  no  citric  acid  had  de- 
