CHEMICAL  TESTS  FOR  STRYCHNIA. 
459 
an  element  of  the  Materia  Medica  with  which  he  may  be  sup- 
posed to  be  especially  familiar. 
To  those,  however,  who  have  not  repeated  for  themselves  the 
tests  by  which  it  may  be  infallibly  recognized,  or  to  those  who, 
having  done  so,  are  yet  in  doubt  as  to  their  delicacy,  the  follow- 
ing may  not  be  unwelcome. 
It  is  not  intended  to  offer  any  opinion  as  to  whether  strychnia, 
after  its  exhibition  as  a  poison,  and  when  death  has  ensued  from 
a  minimum  quantity — when  that  quantity  has  been  so  nicely 
adjusted  that  the  whole  is  absorbed  before  death  takes  place,  or 
whether,  when  the  body  is  in  a  state  of  advanced  decomposition, 
it  may,  or  may  not,  be  always  extracted,  but  simply  to  assert 
the  extreme  delicacy  of  the  chemical  tests  ;  such  delicacy  indeed 
do  they  possess,  that  it  may  be  fairly  stated,  that  in  every  case 
where  these  give  no  indications,  one  of  three  things  must  obtain 
— either  that  no  strychnia  has  been  taken,  or,  that  it  cannot  al- 
ivays  be  extracted,  or,  that  the  process  adopted  for  its  elimina- 
tion was  faulty. 
Organic  poisons,  as  a  class,  are  admitted  on  all  hands  to  be 
less  readily  recoverable,  and  even  when  obtained,  to  be  with 
much  less  certainty  distinguished  than  the  inorganic.  Every 
practical  Chemist  knows,  that  when  some  of  these  have  entered 
into  combination  with  other  substances,  more  especially  gallic  or 
tannic  acids,  they  are  separated  with  the  utmost  difficulty.  The 
detection  of  strychnia,  however,  is  less  uncertain  ;  perhaps  there 
is  no  substance  with  which  the  toxicologist  has  to  deal,  not  ex- 
cepting arsenic,  which  displays  such  distinct  and  constant  fea- 
tures as  this. 
The  principle  of  the  tests  is  the  supply  of  nascent  oxygen ; 
almost  any  substance,  therefore,  which  will  supply  this  element, 
when  acted  on  by  sulphuric  acid,  is  suitable  for  the  purpose. 
The  same  in  principle  is  the  application  of  the  galvanic  current 
as  proposed  by  Dr.  Letheby,  which,  moreover,  has  the  advantage 
of  being  free  from  all  fallacy  dependent  upon  the  presence  of 
other  bodies. 
There  are  two  conditions  necessary  to  the  success  of  the  test 
— that  the  strychnia  should  be  obtained  in  the  state  of  dryness, 
and  that  the  sulphuric  acid  employed  should  be  concentrated,  not 
