AmaJuaryPSm  }     Action  of  Sulphuric  Acid  Upon  Strychnine.  19 
under  these  conditions,  partially  destroy  the  alkaloid,  or  by  hydroly- 
sis or  in  some  other  way  so  change  it  that  its  presence  could  not  be 
discovered  by  ordinary  reagents.  The  object  of  these  investiga- 
tions was  to  determine,  if  possible,  to  what  extent  this  process 
affected  the  delicacy  of  the  tests  for  the  detection  of  strychnine. 
The  method  employed  for  separation  of  an  alkaloid  from  organic 
matter  is  usually  that  of  Stas,  modified  by  later  investigators  as 
the  conditions  of  the  case  may  suggest.  For  the  separation  of 
strychnine,  the  best  method  has  been  found  to  be  to  acidulate  with 
acetic  acid,  and  digest  at  a  moderate  temperature  with  diluted 
alcohol.  This  alcoholic  solution  is  then  evaporated  and  an  aqueous 
solution  is  obtained,  which  is  made  alkaline  with  caustic  potash  and 
shaken  with  chloroform  several  times ;  the  chloroform  solution  is 
separated,  and  evaporated  to  dryness, and  the  residue,  dissolved  in  a 
drop  of  dilute  acetic  acid,  is  tested  for  strychnine  by  the  appropriate 
reagents.  If  this  residue  is  still  impure,  it  will  become  colored 
when  the  sulphuric  acid  is  added  to  it,  on  account  of  the  decompo- 
sition of  organic  matter,  for  pure  strychnine  salts  and  sulphuric  acid 
give  no  coloration,  or  only  the  very  faintest  trace  of  color. 
The  color  tests  for  strychnine  are  considered  very  satisfactory  if 
carefully  performed,  and  in  connection  with  the  precipitation  by 
alkaloid  reagents  and  the  examination  of  the  crystals  by  the  micro- 
scope, and  with  the  physiological  test  also,  they  can  be  depended 
upon  to  identify  the  alkaloid.  Our  experience  has  been  that  the 
most  delicate  tests  could  be  made  by  the  use  of  sulphuric  acid  and 
potassium  bichromate.  In  this  case  the  succession  of  colors,  blue, 
purple  and  red  is  very  characteristic.  The  color,  with  some  other 
oxidizing  agent,  as  manganese  dioxide,  is  frequently  of  value  as  a 
confirmatory  test,  especially  in  the  presence  of  other  substances, 
such  as  caffeine.  With  this  latter  reagent  the  color  reactions  appear 
more  slowly,  but  are  just  as  definite  finally. 
In  these  experiments  the  delicacy  of  the  color  reaction  with  sul- 
phuric acid  and  potassium  bichromate  was  first  established.  In  order 
to  do  this,  solutions  of  strychnine  of  various  strengths  were  prepared 
by  dissolving  a  known  weight  of  the  alkaloid  in  acetic  acid  and 
water.  The  strength  of  these  solutions  varied  from  1  grain  of  strych- 
nine dissolved  in  1,000  c.c.  of  water  to  1  part  in  1,000,000.  One- 
tenth  of  a  cubic  centimetre  of  the  solution,corresponding  to  one-tenth 
the  weight  of  strychnine  in  1  cubic  centimetre,  was  evaporated  to 
