386         COLOR  TEST  FOR  THE  DETECTION  OF  STRYCHNIA. 
recognition  of  the  alkaloid.  The  cause  seems  obvious.  The 
proportions  of  the  salt  and  acid  used  are  always  too  great  to- 
wards the  quantity  of  strychnia  tested  if  it  exists  in  very  minute 
proportions  or  traces.  It  is  required  to  add  to  the  acid  pre- 
viously^dropped  upon  the  suspected  spot  a  fragment  of  a  crystal 
of  bichromate  of  potash,  but  if  the  alkaloid  is  minute,  however 
small  the  crystal  may  appear,  the  oxidation  will  take  place  so 
rapidly  as  to  either  fail  altogether  in  making  an  impression  upon 
the  optic  nerve,  or  merely  produce  a  momentary  flash  of  blue 
without  any  subsequent  play  of  colors,  the  absence  of  which 
cannot  be  received  as  sufficient  evidence  to  prove  the  positive 
presence  of  strychnia.  In  testing  for  minute  portions  of  the  alka- 
loid it  is  a  desideratum  to  use  a  reagent,  the  proportionate  relations 
andf superior  sensitiveness  of  which  will  admit  of  the  successful 
demonstration  of  traces  of  the  poison.  In  experimenting  to- 
wards [that  end  I  have  found  that  a  solution  of  one  grain  of 
permanganate  of  potassa  in  2000  grs.  of  sulphuric  acid  is,  par 
excellence^  the  test  for  that  purpose.  In  delicacy  of  reaction, 
brilliancy  of  colors  and  duration,  I  have  found  it  to  be,  in 
parallel  experiments  made  with  the  bichromate  of  potassa  and 
sulphuric  acid  test,  greatly  its  superior. 
While  I  do  not  claim  priority  of  discovery  of  a  valuable  re- 
agent in  the  use  of  the  permanganate, — an  honor  which  duly 
belongs  to  Wm.  A.  Guy,  of  London,  and  to  whose  valuable  in- 
vestigations on  alkaloids  and  their  tests  I  take  pleasure  in  re- 
ferring,*— I  w^ould  simply  state  that  I  was  not  cognizant  of  its 
use  as  a  test  for  alkaloids  prior  to  the  time  when  I  first  tried  it ; 
but  becoming  acquainted  with  that  fact,  I  henceforth  relinquished 
all  claim.  Believing  it  to  be  a  valuable  reagent,  I  determined 
to  [test  its  value.  Considering  a  solution  of  the  permanganate 
in  sulphuric  acid  proper,  and  preferable  to  a  solution  in  water, 
inasmuch  as  the  water  can  act  only  as  a  diluent,  and  therefore 
must  prove  to  some  degree  detrimental  to  the  sensibility  of  the 
test.  Further,  a  solution  of  the  permanganate  in  w^ater  (10  grs. 
to  3I)  possesses  a  deep  purple  color,  which  might  possibly  be- 
*  On  Color  Tests  of  Strychnia  and  the  Diagnosis  of  the  Alkaloids.  By 
William  A.  Guy,  M.D.  Cantab.,  vol.  2  and  3,  pp.  558,  602.  11  and  12 
Pharm.  Journ.  and  Trans. 
