400  Ferrous  Syrup  of  the  Hypophosphites.  {Am- Jour- Pharm> 
Aug.,  1891. 
always  to  interfere  with  the  attempt  to  prepare  a  stable  syrup.  It 
not  being  possible  to  separate  the  CaS04  by  filtration  or  other 
means,  an  excess  of  calcium  hypophosphite  was  added  to  the  fer- 
rous solution,  on  which  addition  the  greater  portion  of  it  is  pre- 
cipitated. 
The  following  formula  is  based  on  this  method  : 
Ferrous  sulphate,  crystallized,  64  grs. 
Calcium  hypophosphite,  40  grs. 
Dissolve  each  separately  in  12  drams  of  distilled  water,  mix,  and 
allow  the  CaS04  to  precipitate.  Exposure  to  cold  aids  the  precipi- 
tation. Filter,  and  to  the  filtrate  add  calcium  hypophosphite  180 
grs.,  aiding  the  solution  of  the  salt  by  an  addition  of  5  grs.  citric 
acid  or  2  drams  of  10  per  cent,  hypophosphorous  acid. 
Allow  to  stand  from  12  to  24  hours,  in  ivhich  time  the  greatest 
portion  of  the  calcium  sulphate  will  precipitate,  and  add  60  grs. 
each  of  potassium  and  sodium  hypophosphite.  Filter,  and  in  the 
filtrate  dissolve  5  oz.  avoir,  of  sugar,  by  agitation  without  heat. 
By  this  method  all  but  a  slight  amount  of  CaS04  is  precipitated 
out,  and  merely  slight  traces  are  found  in  the  finished  syrup.  An 
excess  of  acid  is  necessary  to  dissolve  a  small  amount  of  ferric 
hydrate  formed  during  the  operation,  due  to  impurities  in  the  com- 
mercial calcium  hypophosphite.  If  this  addition  be  omitted,  the 
syrup  will  gradually  deposit  a  brown  precipitate  of  ferric  hydrate. 
When  citric  acid  is  employed,  the  finished  syrup  will  be  of  a  light 
green  color,  with  gradual,  very  slight  precipitation. 
If,  on  the  other  hand,  diluted  hypophosphorous  acid  be  substi- 
tuted, the  syrup  will  be  colorless,  very  much  of  the  appearance  of 
the  officinal  syrup  of  the  hypophosphites.  As  in  the  case  of  the 
ferric  salt,  ferrous  hypophosphite  turns  bright  green  in  the  presence 
of  soluble  citrates.  If  an  addition  of  an  equal  weight,  correspond- 
ing to  the  amount  of  ferrous  hypophosphite  present,  of  potassium 
or  sodium  citrate  be  made  to  the  syrup,  a  handsome  bright  green 
color  is  communicated  to  it. 
This  addition  does  not,  however,  increase  the  stability  of  the 
preparation. 
Neither  of  the  syrups,  prepared  in  this  manner,  gives  any  indi- 
cation of  the  presence  of  ferric  iron.  It  may  be  fair  to  assume,  that 
ferrous  hypophosphite,  in  the  form  of  a  syrup,  unless  subjected  to 
