400      Dialysed  Iron  as  an  Antidote  for  Poisoning,  { ^"JJS*"' 
case  I  allowed  the  mixture  to  remain  together  for  about  one  minute 
only,  and  on  collecting  the  precipitated  oxide  of  iron  and  washing,  I 
found  that  already  it  had  absorbed  some  of  the  arsenious  acid.  A 
second  mixture  I  kept  together  for  one  hour  at  the  temperature 
already  mentioned.  I  then  found  that  about  40  per  cent,  of  the  acid 
was  taken  up.  This  I  consider  proves  beyond  doubt,  that  a  dose  suffi- 
ciently large  of  dialysed  iron  solution,  preceded  by  a  dose  of  a  solution 
of  bicarbonate  of  soda  or  of  magnesia  (to  neutralize  the  acidity  of  the 
stomach,  and  using  an  excess),  is  an  antidote  in  poisoning  by  arsenious 
acid. 
According  to  Dr.  Maclagan  at  least  twelve  parts  of  moist  peroxide 
of  iron  prepared  with  ammonia  are  required  for  one  of  arsenious  acid, 
from  which  we  can  conclude  that  three  volumes  (at  least)  of  the 
dialysed  iron  solution  (2  gr.  in  fgi)  are  required  for  one  volume  of 
either  of  the  arsenical  solutions  of  the  B.P.  But  as  yet  I  can  give  no 
proof  as  to  the  correctness  of  this  statement. 
Pereira  says  that,  "  moist  ferric  oxide  is  only  an  antidote  where 
solutions  of  arsenious  acid  have  been  used,  and  not  when  the  solid 
acid  has  been  taken."  But  as  the  arsenic  must  enter  into  solution 
with  the  liquid  contained  in  the  stomach,  it  stands  to  reason  that  the 
antidote  is  as  good  in  one  case  as  in  the  other,  especially  as  the  arsenic 
has  no  action  in  the  solid  form. 
In  conclusion,  I  must  add  that  the  advantages  over  the  ordinary 
method  of  administering  the  antidote  are  as  follows : 
Firstly,  the  solution  of  perchloride  of  iron  has  to  be  largely  diluted 
in  order  to  make  it  palatable,  whereas  dialysed  iron  does  not  require 
much  water,  as  it  can  almost  be  taken  as  it  is,  and  moreover  it  can  be 
given  in  large  doses  with  greater  safety  than  ferric  chloride  solution. 
Secondly,  the  amount  of  magnesia  or  alkaline  carbonate  in  the  case 
of  dialysed  iron  is  but  small,  as  it  has  only  to  overcome  the  acidity  of 
the  stomach  before  acting  upon  the  antidote,  but  with  ferric  chloride 
solution  it  is  much  larger,  for  in  addition  to  the  acidity  spoken  of,  the 
alkali  has  to  overcome  the  acid  of  the  ferric  chloride  solution  used. 
And  lastly,  as  few  chemists  keep  moist  ferric  oxide  ready  prepared, 
and  even  if  they  did  it  would  have  become  inactive  by  keeping,  whilst 
nearly  all  have  dialysed  iron,  this  supplies  the  most  rapid  mode,  and 
also  the  best  way  of  administering  the  antidote  for  this  most  painful 
poison. — Phar.  Jour,  and  Trans.,  June  15,  1878. 
