456 
ON  THE  DETECTION  OF  PICROTOXINE. 
Other  powerful  oxydizing  agents  will  produce  the  same 
result  but  not  with  equal  facility ;  chlorine  passed  over  the 
moistened  crystals,  slowly  dissolves  them,  and  if  we  pour  the 
alkaline  solution  upon  them  we  obtain  the  same  color,  or  we  may 
substitute  chlorate  of  potassa  for  the  nitrate,  the  objection  to 
the  use  of  this,  however,  will  be  found  in  its  tendency  to  explode 
when  coming  in  contact  with  the  acid. 
This  color,  however  produced,  is  not  permanent,  but  will 
slowly  disappear  with  a  rapidity  proportioned  to  the  amount  of 
substance  taken,  but  it  will  always  appear  with  great  distinct- 
ness when  first  adding  the  alkaline  solution  if  any  picrotoxine  is 
present. 
It  is  extremely  probable  that  this  color  is  produced  from  a 
trace  of  some  nitrogenous  body  which  pertinaciously  adheres  to 
the  picrotoxine,  as,  on  analysis,  traces  of  nitrogen  can  be  de- 
tected ;  but  this  body  powerfully  resists  all  attempts  at  sepa- 
ration, for  when  repeatedly  crystallized  the  picrotoxine  still  re- 
tains a  minute  portion  of  it.  It  can  be  obtained  perfectly  free 
from  nitrogen  only  by  dissolving  it  in  potassa,  and  precipitating 
it  by  acids.  When  thus  prepared  its  properties  are  the  same  as 
before,  with  the  exception  of  the  purple  color  produced  by  oxy- 
dation  and  subsequent  treatment  with  alkalies. 
There  is  no  substance  at  present  known  to  the  writer  which 
gives  this  shade  of  color  under  these  circumstances.  There  are 
two,  however,  which  communicate  a  brownish-yellow  to  the  fluid, 
and  would,  if  present  as  an  impurity,  interfere  with  the  distinct- 
ness of  the  reaction  ;  these  are  sugar  and  strychnia  ;  from  the 
first  we  need  suffer  no  inconvenience  as  it  is  perfectly  separated 
in  the  ordinary  method  used  for  isolating  the  alkaloids ;  from 
the  latter,  picrotoxine  is  most  completely  removed  by  treating 
an  acidulated  aqueous  solution  of  the  two  bodies  with  ether,  the 
strychnia  remaining  as  a  salt  dissolved  in  the  water  and  the 
ether  containing  all,  or  nearly  all,  of  the  picrotoxine.  To  prove 
this  the  following  experiment  was  tried.  A  quart  of  ordinary 
ale  was  divided  into  equal  portions  ;  into  one  045  gram,  of  pi- 
crotoxine and  a  little  strychnia  were  introduced,  the  other  was 
unadulterated  ;  both  were  acidulated  with  hydrochloric  acid 
and  agitated  with  ether ;  the  ethereal  solutions  on  evaporation 
yielded,  in  the  first  case,  small  microscopic  crystals  of  picrotox. 
