550 
TESTING  FOR  STRYCHNIA,  BRUCIA,  ETC. 
part  bichromate  of  potash  dissolved  in  fourteen  parts  of  water, 
to  which  is  afterwards  added  two  parts  in  bulk  of  strong  sulphu- 
ric acid. 
The  circumstances  connected  with  Palmer's  trial  induced  me  to 
make  a  series  of  experiments,  and,  as  I  possessed  a  large  quantity 
of  the  just-named  precipitant,  I  resolved  to  try  its  effects  upon 
a  solution  of  strychnia,  which,  to  my  surprise,  was  entirely  pre- 
cipitated in  the  form  of  a  beautiful  golden-colored  and  insoluble 
precipitate. 
It  will  form  a  beautiful  experiment  to  witness  the  complete 
decolorization  of  a  solution  of  either  the  chromate  or  bichromate 
of  potash  by  the  gradual  addition  of  a  solution  of  the  acetate  of 
strychnia,  chromate  of  strychnia  being  immediately  precipitated ; 
and,  if  the  experiment  be  well  conducted,  scarcely  a  trace  of 
bitterness  will  be  left  in  the  supernatant  or  filtered  liquor. 
I  do  not,  however,  claim  as  an  original  discovery  the  use  of  a 
chromic  salt  and  an  acid  liquor,  because  they  have  been  already 
suggested  by  Professor  Otto,  and  have  been  in  use  for  some  time  ; 
but  the  point  to  which  I  wish  to  call  your  attention  is  the  es- 
sential difference  in  the  mode  of  their  application.  In  short, 
such  is  the  extreme  range  of  sensibility  which  I  have  attained, 
that  it  is  no  vain  assertion  on  my  part  in  saying  that  it  is  just- 
as  much  out  of  the  power  of  any  human  being  to  define  its  limits, 
as  it  would  be  for  a  person  to  count  the  sand  on  the  sea-shore, 
or  to  measure  the  drops  of  the  ocean  surrounding  it;  and  with- 
out an  experiment  in  point,  you  would  not,  perhaps,  believe  it 
possible. 
I  will  therefore  take  say  thirty  drops  of  this  solution  of  strych- 
nia, containing  half  a  grain.  I  will  dilute  it  with  four  drachms 
of  water.  I  now  take  this  dropping  tube,  and  charging  it  with 
a  solution  of  bichromate  of  potash,  I  will  drop  in  say  six  drops. 
You  observe  that  I  have  no  sooner  added  one  drop  than  crystals 
begin  to  form  at  the  bottom  ;  and  on  the  addition  of  five  drops 
more,  and  stirring  the  mixture,  the  decomposition  is  complete. 
I  have  now  split  up  the  half  grain  of  strychnia  into  millions  of 
atoms  of  minute  crystals,  each  of  which,  could  they  be  separated, 
would  as  effectually  demonstrate  the  chemical  characteristics  of 
strychnia  as  though  I  had  operated  on  a  pound  weight  of  the 
same.    I  have  now  to  show  you  the  chemical  reaction  with  those 
