COLOR  TESTS  FOR  STRYCHNIA,  ETC. 
523 
into  two  leading  groups,  of  which  one  continued  without  color, 
and  the  other  underwent  changes  of  color  more  or  less  charac- 
teristic. In  the  instance  of  meconine  and  of  aconitina,  the 
colors  developed  proved  to  be  peculiar  to  these  substances,  so 
as  to  lead  at  once  to  their  elimination  from  the  rest. 
Bj  raising  still  further  the  temperature  of  the  acid  solutions 
to  a  point  at  which  vapor  was  given  off,  a  further  separation 
into  distinct  groups  or  classes  was  found  to  take  place.  The 
six  substances  which  stand  first  in  order  in  Table  I.  still  re- 
mained colorless,  while  the  remainder  assumed  tints  more  or 
less  characteristic.  Esculine  and  atropia ;  picrotoxia,  santo- 
nine  and  narcotina  ;  amygdaline  and  naphthaline,  formed  them- 
selves into  three  distinct  groups  ;  while  strychnia,  brucia  and 
morphia  gave  indications  of  color  less  distinct  and  character- 
istic. 
By  this  triple  test  of  sulphuric  acid,  cold,  warmed  and  heated, 
the  active  principles  contained  in  this  division  (Table  I.)  have 
been  either  eliminated,  or  split  up  into  manageable  groups, 
awaiting  the  application  of  further  tests.  It  seemed  natural  to 
select  as  the  next  test  in  order  nitric  acid — a  known  character- 
istic test  of  brucia  and  morphia.  By  applying  this  test  to  the 
several  members  of  the  table  in  succession,  codeia  was  isolated 
from  the  group  of  six  to  which  it  belonged  by  the  distinct  yel- 
low color  assumed  by  the  acid  solution.  Emetia  was,  in  like 
manner,  isolated  from  the  other  members  of  the  same  group  of 
six,  by  yielding  with  the  acid  a  yellow-brown  color.  Atropia, 
again,  was  distinguished  from  esculine  by  giving  a  negative 
result,  while  esculine  assumed  a  distinct  yellow  color.  In  the 
same  way  narcotina  was  detached  from  its  group  of  three,  and 
naphthaline  from  its  group  of  two.  Again,  morphia  was  dis- 
tinguished by  the  rich  orange  hue  given  by  the  acid,  together 
with  the  red  fumes  of  nitrous  acid  ;  and  brucia  was  effectually 
distinguished  from  strychnia  by  the  intense  red  of  the  former 
contrasting  with  the  faint  tinge  of  red  imparted  to  ordinary 
specimens  of  the  latter.  For  the  next  eliminating  test  I  have 
selected  sulphuric  acid  followed  by  a  solution  of  permanganate 
of  potash,  in  the  proportion  of  10  grains  of  the  salt  to  ^j.  of 
water.  The  effect  of  this  test  on  strychnia  was  to  develop  its 
characteristic  colors,  strongly  contrasted  with  the  altogether 
different  colors  given  with  brucia,  and  still  more  with  the  brown 
