228 
ON  THE  COLOR-TESTS  OF  STRYCHNIA,  ETC. 
an  imperative  reason  for  a  further  investigation  of  the  subject ; 
as  the  suicide  or  murderer  can  destroy  all  traces  of  his  work,  by 
simply  combining  an  excess  of  morphia  with  a  poisonous  dose 
of  strychnia.  The  former  will  not  delay  the  fatal  action  of  the 
latter,  but  on  the  contrary,  will  rather  aid  it. 
With  the  view  of  determining  the  important  question,  whether 
strychnia  is  actually  decomposed  when  treated  with  test-agents 
in  the  presence  of  morphia,  or  whether  it  is  merely  masked  by 
such  presence,  I  have  performed  more  than  a  hundred  experi- 
ments, of  which  an  account  of  a  few  of  the  most  valuable 
and  satisfactory  is  now  submitted.  Premising  that,  in  the  ex- 
amination of  minute  portions  of  strychnia,  success  or  failure  de- 
pends entirely  upon  the  care  given  to  the  details.  In  all  of  my 
experiments  I  employed  crystals  of  the  pure  alkaloids,  and  of 
their  salts. 
The  »  color-tests  "  referred  to  in  this  paper,  are  those  fur- 
nished by  bichromate  of  potassa,  or  by  the  ferricyanuret  of 
potassium  (red  prussiate  of  potassa),  when  added  to  a  portion  of 
strychnia  previously  dissolved  in  a  drop  of  strong  sulphuric  acid. 
The  discrepancies  in  the  results  of  the  published  experiments 
of  different  observers  depends,  I  think,  in  a  great  measure,  on 
their  diverse  modes  of  procedure,  and  therefore  I  feel  justified 
in  giving  a  precise  account  of — 
The  Mode  of  Testing. — In  every  instance  the  material  to  be 
tested  was  employed  in  the  solid  form,  such  as  the  pure  alka- 
loids or  their  salts.  If  it  existed  in  solution,  it  was  reduced  to 
a  solid  consistence  by  evaporation  in  a  test  capsule,  spontaneously, 
or  by  a  very  gentle  heat.  Having  thus  procured  a  solid  sub- 
stance, a  small  portion  of  it  was  placed  upon  a  white  plate,  a 
drop  of  strong  pure  sulphuric  acid  was  added,  and  trituration 
was  carefully  made  with  a  glass  rod  until  the  substance  was  dis- 
solved. Then  a  small  quantity  of  powdered  bichromate  of 
potassa,  or  of  powdered  ferricyanuret  of  potassium,  was  deposit- 
ed on  the  plate,  near  the  aeid  mixture  but  not  touching  it,  and 
to  the  powder  a  minute  drop  of  water  was  added — just  enough 
to  partly  dissolve  it — and  then,  with  a  pointed  glass  rod,  a  little 
stream  was  drawn  from  each  of  the  solutions  in  such  a  direction 
as  to  cross  each  other.  Immediately  at  the  point  of  intersection 
the  play  of  test-colors  was  beautifully  manifested.    When  the 
