12  ANTIDOTE  AT  ONCE  K>R  PRUSSIC  ACID,  ETC. 
do  not  contain  a  trace  of  the  volatile  alkaloid,  it  is  only  what 
might  have  been  expecFed ;  but  then  it  was  not  dissipated  ;  it 
merely  did  not  exist  there  previously. 
But  whether  the  toxicodendric  acid  is,  to  greater  or  less 
extent,  lost  in  drying,  I  am  as  yet  unable  to  say  ;  though  such 
a  result  may  be  expected.  As  regards  its  isolation,  it  is  easily 
effected.  The  only  questions  are  whether  it  could  be  procured 
in  sufficiently  large  proportion  to  be  remunerative,  whether  it 
is  not  altered  by  keeping  in  its  pure  state,  and  whether  it  pos- 
sesses any  intrinsic  value  in  its  medicinal  properties.  As  far 
as  our  knowledge  reaches,  I  belive  the  expressed  juice,  pre- 
served by  alcohol,  to  be  the  best  pharmaceutical  preparation. 
Even  in  the  chemical  history  of  this  acid,  nearly  everything 
is  to  be  found  out  yet  by  further  researches.  If  my  time  per- 
mits, I  may  attempt  to  prepare  it  in  larger  quantities,  and  in  a 
more  concentrated  form,  and  to  determine  its  composition. — 
Proc.  Amer.  Pliarm.  Association,  1865. 
ON  AN  ANTIDOTE  AT  ONCE  FOR  PRUSSIC  ACID,  ANT  I. 
MONY,  AND  ARSENIC. 
By  T.  and  H.  Smith,  of  Edinburgh. 
[In  1854,  Messrs.  T.  and  H.  Smith  suggested  the  use  of 
proto-persulphate  of  iron  in  connection  with  an  excess  of  alka. 
line  carbonate,  as  an  antidote  for  prussic  acid,  based  on  ex- 
periments made  on  dogs.  The  difficulty  has  always  been  that 
the  time  required  to  prepare  the  antidote  was  too  great,  in  view 
of  the  energy  of  the  poison,  and  its  rapid  action.  In  this  coun- 
try it  has  for  many  years  been  the  custom  with  some  druggists 
to  keep  a  solution  of  persulphate  of  iron  ready  for  use  with 
ammonia,  for  producing  hydrated  sesqui-oxide  of  iron. 
In  the  "  Pharmaceutical  Journal"  for  October  these  gentle- 
men have  a  very  long  and  elaborate  paper  on  this  subject,  under 
the  above  title,  in  which  they  take  advantage  of  the  officinal 
(British)  solution  of  perchloride  of  iron  as  the  source  of  the 
hydrated  sesqui-oxide,  and  appear  to  consider  it  superior  to  the 
solution  of  tersulphate  usually  employed  as  the  source  of  sesqui- 
