ANTIDOTE  AT  ONCE  FOR  PRUSSIC  ACID,  ETC. 
13 
oxide,  and  which  is  far  more  easily  prepared  and  kept.  This  is 
also  a  preparation  of  the  British  Pharmacopoeia. 
The  action  of  this  antidote  for  prussic  acid  is  based  on  its 
capability  of  instantly  forming  Prussian  blue  with  that  acid. 
When  the  antidote  is  used,  the  solution  of  carbonate  of  soda  is 
first  swallowed,  and  immediately  afterwards  the  mixture  of  sesqui- 
chloride  and  protosulphate  of  iron,  so  that  a  mixture  of  sesqui- 
and  protoxide  of  iron  in  a  nascent  gelatinous  state  is  formed  in  the 
stomach,  and  this  renders  the  poison  inert,  by  forming  Prussian 
blue.  Owing  to  the  fact  that  carbonic  acid  is  eliminated  in  the 
use  of  the  alkaline  carbonate,  and  that  this  acid  interferes  witli 
the  action  of  the  test,  a  large  excess  of  the  antidote  is  considered 
necessary  by  MM.  Smith  to  insure  its  activity. 
"  When  the  poisoning  has  been  caused  by  cyanide  of  potassium, 
in  which  the  prussic  acid  is,  as  it  were,  united  to  a  base,  the 
alkaline  solution  forming  one  part  of  the  antidote  does  not  of 
course  require  to  be  given,  although  the  antidotal  action  would 
not  be  prevented  by  giving  it  in  the  way  recommended." 
A  considerable  portion  of  the  paper  is  taken  up  with  discuss- 
ing the  preparation  and  action  of  hydrated  sesqui-oxide  of  iron 
as  an  antidote  to  arsenious  acid,  embodying  the  facts  that  were 
examined  twenty  years  ago  in  this  country  and  in  Germany,  and 
which  are  noticed  in  the  14th  and  25th  volumes  of  this  Journal, 
and  which  was  noticed  in  the  2d  volume  of  the  "  Pharmaceutical 
Journal."  The  numerous  instances  in  which  the  hydrated  oxide 
have  been  successfully  employed  in  the  United  States  have 
caused  it  to  be  much  relied  upon  here,  where  the  poison  has  not 
been  too  long  ingested.  t 
The  Messrs.  Smith  have  exte-Med  t/heir  experiments  to  tartar 
emetic,  and  find  the  sesqui-oxiw3  to  act  equally  well  as  an  antidote ; 
the  sequel  will  show  their  results^-  It  seems  needless  to  recom- 
mend the  solution  of  sesqui-*Vhioride  of  iron  for  the  purposes 
mentioned,  when  the  tersulpilate  of  sesqui-oxide  of  the  Pharma- 
copoeia is  toore  easily  prepared,  cheaper,  and  contained  in  both 
the  British  and  U.  S.  Pharmacopoeias, — and  especially  as  one  part 
of  Smith's  antidote  is  protosulphate  of  iron,  which  of  course  gives 
a  resulting  sulphate  of  soda.  Our  experience  with  hydrated 
oxide  is  greatly  in  favor  of  ammonia,  which  is  always  ready,  can 
