LIQUOR  FERRI  PERSULPHATIS. 
35 
ounce,  and  one  drachm  to  each  part,  with  convenience  and  ad- 
vantage, and  also  on  a  scale  of  33  J  lbs.  av.  of  sulphate,  but  here 
some  modification  in  the  management  was  necessary. 
The  late  suggestion  of  M.  Monsel,  that  a  small  proportion  of 
linseed  oil  be  added  to  the  solution,  and  shaken  with  it  occasion- 
ally during  some  days,  has  been  tried  without  any  notable  ad- 
vantage, except  that  when  the  solution  is  dried  on  plates,  it 
renders  the  salt  rather  less  obstinately  adherent  to  the  plates. 
The  writer  has  succeeded  only  with  great  trouble  and  loss  in 
making  the  scales  or  hydrated  solid  salt  described  by  M.  Monsel, 
and  could  never  obtain  anything  like  an  elegant  or  easily  ma~ 
nagable  preparation,  in  consequence,  first,  of  the  sticking  to  the 
plates  when  dry,  and  next,  in  consequence  of  the  deliquescent 
character  of  the  salt.  The  anhydrous  salt  is  easily  and  con- 
veniently obtained  by  painting  the  solution  quickly  upon  a  heated 
iron  plate.  When  thus  managed  it  dries  very  quickly  in  the 
form  of  light  yellow,  spongy,  brittle  scales,  resembling  tannic 
acid.  This  form  is  also  deliquescent,  but  much  less  so  than  the 
hydrated  salt.  In  view  of  the  character  of  these  solid  forms, 
it  is  fortunate  that  they  are  not  at  all  important  practically, 
since  the  solution  fulfils  all  useful  indications. 
The  remaining  new  preparation  proposed  to  be  noticed  in  this 
paper  is  the  Pyrophosphate  of  Iron,  in  the  combination  originally 
proposed  by  M.  E.  Robiquet,  of  Paris. 
In  view  of  the  chemical  character  and  physical  properties  of 
this  compound,  and  influenced  by  the  statements  in  regard  to  it 
made  by  a  Commission  of  the  French  Acade'mie,  the  writer 
about  a  year  ago,  offered  it  to  the  medical  profession  here  for 
trial,  and  subsequently  brought  it  to  the  notice  of  the  New  York 
Academy  of  Medicine.  From  the  first  introduction  of  it  here, 
several  hundred  pounds  of  the  syrup  has  been  used,  with  such 
effect  that  its  value  has  been  established  here  as  a  ferruginous 
tonic.  Its  advantages  over  other  ferruginous  tonics  are,  briefly, 
that  it  does  not  produce  constipation,  but  commonly  an  opposite 
tendency, — that  it  does  not  excite  the  vascular  system  or  produce 
nausea,  headach  or  tinitus, — that  it  is  nearly  tasteless,  and  may 
be  easily  administered  to  all  classes  of  patients, — and  finally 
that  in  common  with  the  Lactate  of  Iron,  and  the  Tartrate  of 
Iron  and  Potassa,  it  appears  to  be  assimilated  without  decompo- 
