b.  If  instead  of  the  substance  being  '  red-
dened '  by  strong  sulphuric  acid,  no  particular
action  ensues  in  the  cold,  it  contains  either
Conia  or  Strychnia;  if  a  small  fragment  of
bichromate  of  potassa  being  now  dropped  in,
produces  a  rich  violet  colour,  it  is  SiBTOHlflA ;
if  the  original  matter  on  being  heated,  or
treated  with  solution  of  potassa,  evolves
a  penetrating,  disagreeable  odour,  somewhat
analogous  to  that  from  'hemlock,'  or  to  a
mixture  of  those  from  tobacco  and  mice,  it  is
Conia.
"  Seactions  with  ceroso-ceric  oxide.  This
oxide  exhibits  characteristic  colours  with  several
alkaloids,  especially  with  stetohnine.  When
strong  sulphuric  acid  is  poured  upon  strychnine,
and  then  a  small  quantity  of  ceroso-ceric  oxide
added,  a  fine  blue  colour  is  produced,  similar
to  that  which  strychnine  exhibits  with  potas-
sium bichromate,  but  much  more  permanent.
The  blue  colour  gradually  changes  to  cherry-
red,  and  then  remains  unaltered  for  several
days.  This  reaction  is  capable  of  detecting
one  part  of  strychnine  in  a  million  parts  of
liquid.  Bettcine  similarly  treated  acquires
an  "orange-colour,  gradually  changing  to
yellow ;  MOEPHINE,  olive-brown,  finally  brown ;
NAEcotine,  brown  cherry  red,  finally  wine-red ;
codeine,  olive-green,  finally  brown ;  QUININE,
pale-yeUow ;  cinchonine  and  theine  remain
colourless;  TEEATEINE  becomes  reddish-brown;
ATEOPINE,  dingy  yellowish-brown ;  SOLANINE,
yellow  at  first,  finally  brownish ;  emetine,
brown;  COLCHICINE,  first  green,  then  dirty
brown  ;  aniline,  after  a  long  time,  acquires  a
blue  colour  extending  from  the  edges  inwards  ;■
CONINE  becomes  light-yeUow.  Pipeeine  co-
lours the  sulphuric  acid  blood-red,  and  is  turned
dark -brown,  almost  black  by  the  cerium  oxide"
(Sonnenschein).
