ON  NITRATE  OF  IRON. 
401 
found  the  true  ter-nitrate  of  sesquioxide  which,  probably  is  the 
result  desired  in  the  officinal  prescription. 
Theoretically,  each  fluid  ounce  of  the  solution  of  nitrate  of  iron 
of  the  Pharmacopoeia  should  contain  32  grains  of  the  salt  Fe2 
03,  3  N05,  but  with  the  greatest  caution,  when  the  true  ter- 
nitrate  is  formed,  it  seldom  reaches  two-thirds  of  that  amount. 
When  ounces  of  nitric  acid  sp.  gr.  1.42  are  saturated  with 
moist  hydrated  sesquioxide  of  iron,  and  diluted  to  thirty  fluid 
ounces,  there  will  be  formed  a  true  and  beautiful  reddish  solution 
of  ter-nitrate  of  sesquioxide  of  the  proper  strength  to  answer  the 
requirements  of  the  Pharmacopoeia.  The  solution  thus  made 
keeps  without  change  a  considerable  time,  and  remarkably  well 
under  the  protection  of  sugar  when  converted  into  a  syrup.  A 
syrup  of  sufficient  density  will  be  formed  by  pouring  the  acid 
solution  of  iron  upon  two  pounds  of  sugar,  and  adding  sufficient 
water  to  make  the  whole  measure  thirty  fluid  ounces.  Either  of  the 
above  would  be  admissible  dispensed  for  solution  of  nitrate  of  iron. 
Syrup  of  proto-nitrate  of  iron  FeO  In05  has  become  a  fa- 
vorite with  many  practitioners  in  this  city,  who  assert  that  its 
effects  are  more  energetic,  that  its  larger  equivalent  of  iron,  its 
greater  stypticity,  render  it  better  suited  to  the  worst  types  of  the 
disease  in  which  it  has  become  so  frequently  the  only  resort.  The 
method  by  which  I  have  succeeded  in  preparing  a  syrup  of  proto- 
nitrate  of  iron  is  the  following  :  Nitrate  of  lime  is  first  formed, 
and  the  solution  decomposed  by  its  proper  equivalent  of  proto- 
sulphate  of  iron  ;  thus,  two  fluid  ounces  of  nitric  acid  sp.  gr.  1.42 
may  be  saturated  with  carbonate  of  lime  and  filtered,  washing 
the  filter  with  sufficient  water  to  make  the  solution  measure  three 
fluid  ounces.    In  ten  fluid  ounces  of  water  dissolve  1485  grains 
of  well  crystallised  proto-sulphate  of  iron,  then  filter;  if  requisite, 
the  two  solutions  are  to  be  mixed  in  a  beaker  glass,  and  poured 
immediately  upon  a  filter  of  muslin  stretched  across  one  end  of  a 
glass  percolator,  and  the  filtrate  allowed  to  fall  upon  two  pounds 
of  sugar,  sufficient  water  being  added  to  make  the  syrup  formed 
measure  thirty  fluid  ounces.    The  sugar  may  be  dissolved  with- 
out the  aid  of  heat,  a  beautiful  emerald  green  syrup  is  the  result 
which  is  not  liable  to  decompose,  and  contains  32  grains  Fe,  0, 
N05  to  each  ounce. 
26 
