SYRUPUS   FEE, HI  PYROPHOSPHATE.  41 
dlrous  pyrophosphate  of  iron,  or  nearly  two  grains  of  the  com- 
pound salt. 
M.  E.  Robiquet,  of  Paris,  with  whom  this  particular  method 
of  using  this  most  soluble  and,  probably,  most  available  com- 
pound of  the  two  popular  tonics,  iron  and  phosphorus,  published 
so  meagre  and  indefinite  a  description  of  his  process  of  prepara- 
tion, that  those  who  wished  to  make  it  would  have  to  go  over 
the  whole  ground  from  the  beginning,  with  much  labor  and  ex- 
periment that  he  might  have  saved  them.  The  effect  of  such 
publications  upon  those  who  seek  practical  information  from 
them,  is  very  much  like  that  of  a  compromise  between  legiti- 
mate pharmacy  and  the  quackery  of  proprietory  medicines, — 
that  is  the  preparation  is  made  known  with  advantages  that  se- 
cure its  coming  into  use  for  trial,  whilst  the  ambiguous  insuffi- 
cient publication  pretty  effectually  confines  the  supply  to  the 
one  source,  because  few  would  take  the  time  and  trouble  to  work 
it  out  thoroughly. 
In  the  foregoing  formula  and  processes  the  writer  has  brought 
forward  some  practical  illustrations  of  what  he  believes  would  be 
the  great  advantages  in  point  of  accuracy  of  manipulation,  and 
results  by  dispensing  with  measures  of  capacity  or  volume,  and 
substituting  weights  in  the  formula  and  processes  of  the  Phar- 
macopoeia. 
The  second  point,  namely,  the  substitution  of  parts  by  weight 
for  the  definite  weights,  is  also  illustrated,  but  not  so  fairly, 
since  the  inconvenience  of  weighing  large  quantities  of  men- 
strua does  not  occur  in  these  instances. 
Nevertheless,  in  view  of  the  direction  in  which  Pharmacy  is 
advancing  toward  fluid  extracts  and  saturated  tinctures  as  sub- 
stitutes for  the  old  dilute  preparations,  and  when  percolation  is 
coming  into  so  general  and  effective  use,  these  circumstances 
would  be  less  felt. 
In  the  first  formula  the  equivalent  number  of  the  principal 
ingredient,  namely,  Fe  0,  So3  +  7  HO,=  139,  is  adopted  as  the 
indicator  upon  which  the  ratio  is  based,  and  on  close  inspection 
the  advantage  of  equivalent  proportion  expressed  in  equivalent 
numbers  will  hardly  fail  to  be  apparent. 
In  the  second  formula,  where  the  same  materials  are  used, 
