ON  THE   PHARMACY  OF   THE  PHOSPHATES. 
113 
ly  yet  been  fully  investigated  ;  and  it  is  worthy  the  attention  of 
physicians  who  prescribe  the  phosphates  in  this  manner,  to  ob- 
serve the  relative  effects  of  treatment  by  phosphatic  mixtures, 
with  and  without  the  free  acid  ;  more  especially  in  reference  to 
the  excretions. 
The  following  recipe  will  yield  an  acid  solution  of  the  phosphates 
of  protoxide  of  iron  and  soda,  viz. 
Take  Protosulphate  of  Iron,  (cryst.)      a  drachm. 
Phosphate  of  Soda,  (cryst.)  two  drachms. 
Glacial  Phosphoric  Acid,  two  scruples. 
Syrup  of  Orange  peel,  two  fluid  ounces. 
Water,  two  fluid  ounces 
Triturate  the  salts  with  the  acid  in  a  wedgewood  mortar  until 
a  syrupy  liquid  is  produced  by  their  reaction,  then  gradual- 
ly add  the  water,  filter  the  solution  through  a  piece  of  lint,  or 
muslin,  and  mix  it  with  the  syrup.  Of  this  mixture  the  dose 
may  be  a  dessert  spoonful,  or  a  table  spoonful,  according  to  cir- 
cumstances. 
The  reactions  that  occur  when  the  solid  ingredients  are  tritu- 
rated together,  are  the  production  of  phosphate  of  iron  and  sul- 
phate of  soda,  and  the  solution  of  the  former  by  the  free  phos- 
phoric acid,  the  liquefaction  arising  from  the  water  of  crystalli- 
zation of  the  salts,  both  of  which  are  strongly  hydrated.  The 
presence  of  the  small  amount  of  sulphate  of  soda  formed  may 
be  looked  upon  as  unimportant,  yet  it  would  be  more  appropri- 
ate to  employ  the  proto-chloride  of  iron  as  in  the  following  for- 
mula, when  the  resultant  would  be  common  salt  instead  of  sul- 
phate of  soda. 
Take  of  Proto-chloride  of  Iron,  (in  crystals,)  gj. 
Chloride  of  Calcium,  (fused,)  3iss, 
Phosphate  of  Soda,  (crystallized,)  Jvij. 
Phosphate  of  Potassa,  jj. 
Glacial  Phosphoric  acid, 
Syrup  of  Lemons, 
Distilled  water,  of  each  four  fluid  ounces. 
Triturate  the  chlorides  of  iron  and  calcium,  six  drachms  of  the 
phosphate  of  soda,  and  the  phosphoric  acid,  together  with  a  little 
water,  until  a  homogeneous  liquid  is  obtained,  and  then  add  the 
rest  of  the  water  gradually.    Dissolve  the  phosphate  of  potassa 
