390      SOLUTION  OF  PYROPHOSPHATE  OF  SODA  AND  IRON. 
sesquioxide  =  10-99  grm.  2Fe203,3bP05  =  13-36  grm.  2  Fe203- 
3bP05,  9 IIO.  This  latter  amount  is  equal  to  206  troy  grains, 
and  each  fluidrachm  of  the  solution  as  used  by  Persoz  contained 
therefore  1*45  troy  grains  of  hydrated  pyrophosphate  of  iron. 
In  1849,  Dr.  Leras  advocated  the  use  of  the  same  compound,* 
because  he  conceived  that  it  was  the  only  preparation  not  pre- 
cipitated by  the  agency  of  the  food  or  gastric  juice, — a  supposi- 
tion which  I  shall  prove  to  be  incorrect. 
A  few  years  later,  Professor  L.  A.  Buchnerf  again  called 
attention  to  Persoz'  observations.  Based  upon  the  experience 
that  the  bitter  saline  taste  of  the  sulphate  of  soda  formed  pro- 
duces an  aversion  when  used  continually  in  the  recommended 
strength,  Buchner  proposed  to  prepare  it  from  perchloride  of 
iron,  to  dilute  it  so  that  16  ounces  represent  one  grain  of  metal- 
lic iron,  and  to  impregnate  the  solution  with  carbonic  acid.  For 
convenience  he  recommended  a  normal  solution,  containing  in 
each  ounce  one  grain  of  iron,  so  that  the  physician  might  obtain 
a  solution  of  any  desired  strength.  This  preparation,  we  are 
\  informed,  is  still  used  by  many  physicians  of  Munich. 
RobiquetJ  proposed  to  combine  ferric  pyrophosphate  with  ci- 
trate of  ammonia  (or  of  soda),  to  render  it  permanently  soluble 
in  water.  Many  formulas  for  liquid  and  solid  preparations  of 
this  compound  were  subsequently  published  in  the  pharmaceutical 
journals  of  all  countries,  and  the  dry  salt  was  admitted  into  our 
pharmacopoeia. 
In  1859,  A.  F.  Haselden§  and  myself|]  noticed  the  solubility 
of  the  ordinary  ferric  phosphate  in  citrate  of  ammonia,  and  Prof. 
Procter  published  some  formulas^  for  prescribing  extemporane- 
ously the  phosphate  of  iron  in  solution.  I  am  not  aware  that 
the  therapeutic  value  of  ferric  pyrophosphate  was  ever  claimed 
to  be  superior  to  the  ordinary  phosphate,  except  for  its  solubility, 
and  this  at  a  time  when  the  solubility  of  the  latter  was  un- 
*  See  U.  S.  Dispensatory,  1866,  1144. 
f  Kepert.  f.  d.  Pharm.  3  Ser.  vii.  38,  1851. 
%  Gaz.  M6d.  de  Paris,  1857,  No.  7.    See  Am.  Journ.  Ph.  1857,  401. 
§  Pharmaceut.  Jour.  August,  1859. 
||  Ainer.  Jour.  Pharm.  1859,  Sept.,  410. 
\  Ibid,  413. 
