320   HYPOPHOSPHITE  OF  IRON  AND  SYRUP  OF  HYPOPHOSPHITES. 
pophosphorous  acid  as  hypophosphite  of  lime,  this  syrup  con- 
tains five  grains  of  the  combined  hypophosphites  in  each  fluid 
drachm,  about  f  of  a  grain  of  which  is  hypophosphite  of  pro- 
toxide of  iron.  There  is  necessarily,  a  trace  of  sulphate  of  lime 
in  this  syrup,  which  will  be  gradually  deposited  in  the  course  of 
two  or  three  days,  after  which  it  may  be  entirely  separated  by 
filtration  through  porous  paper. 
The  hypophosphites  of  commerce  nearly  all  contain  impurities, 
unavoidable  in  their  preparation  on  a  large  scale  ;  such  is  free 
lime,  soda  and  potassa  and  their  carbonates ;  all  of  which  are 
brought  into  a  state  of  combination,  by  the  free  hypophosphor- 
ous  acid  used  in  this  preparation. 
Since  the  foregoing  was  written  I  have  made  a  modification 
in  the  formula  by  which  the  syrup  is  free  from  the  objection  of 
containing  sulphate  of  lime.  The  modified  formula  is  as  follows  : 
Take  of  Hypophosphite  of  lime,       .       .      256  grains. 
Hypophosphite  of  soda,    .       .     - .  192  « 
Hypophosphite  of  potassa,  .       .       128  " 
Protosulphate  of  iron,  crystallized,   .  185  " 
Carbonate  of  soda,     .       .       .       240  « 
Hypophosphorous  acid,  sp.  gr.  1.036,    3j  fl.  ounces. 
Sugar  12  ounces. 
Dissolve  the  [protosulphate  of  iron  and  carbonate  of  soda, 
each  separately,  in  four  fluid  ounces  of  water,  and  mix  the  solu- 
tions. Wash  the  precipitated  carbonate  of  iron  thoroughly  with 
sweetened  water  and  drain  it  on  a  muslin  filter.  Having  placed 
the  salts  of  lime,  soda  and  potassa  in  a  suitable  porcelain  dish, 
add  about  two  fluid  ounces  of  water  and  one  fluid  ounce  of  hy- 
pophosphorous acid ;  heat  the  mixture  gently,  and  add  the  moist 
carbonate  of  iron,  in  small  portions,  from  time  to  time,  alter- 
nately with  the  hypophosphorous  acid,  until  the  solution  is  com- 
plete. Add  water  enough  to  make  the  whole  measure  ten  fluid 
ounces ;  pour  it  into  a  bottle  containing  the  sugar  and  agitate 
as  before  Jour,  and  Trans,  of  Maryland  College  of  Pharm. 
June,  1858. 
