Am.  Jour.  Pharm. 
July,  1903. 
Alkaloidal  Color  Tests. 
331 
ALKALOIDAL  COLOR  TESTS,  WITH  THOSE  OF  STRYCH- 
NINE AS  EXAMPLES. 
By  Lyman  F.  Kebler, 
Chief  of  the  Drug  Laboratory,  Bureau  of  Chemistry,  Department  of 
Agriculture,  Washington,  D.  C. 
Before  taking  up  these  tests,  a  brief  review  of  the  general  methods 
for  recovering  the  alkaloids  from  organic  mixtures  might  be  of  ser- 
vice. 
J.  S.  Stas,1  of  Brussels,  in  1 85 1,  first  pointed  out  the  underlying 
principles  for  isolating  alkaloidal  bodies  in  general.  By  this 
method  alkaloids  are  removed  by  treating  the  organic  matter  with 
pure  concentrated  alcohol,  then  render  distinctly  acid  with  tartaric 
or  oxalic  acid.,  heat  to  about  yo°  C,  cool  the  mixture,  filter,  wash 
the  residue  with  alcohol  and  evaporate  the  mixed  filtrates  to  dry. 
ness,  at  a  temperature  not  exceeding  35 0  C.  The  residue  is  then 
digested  with  absolute  alcohol,  the  filtrate  evaporated  at  a  low  tem- 
perature, the  resulting  residue  taken  up  in  a  small  quantity  of  water, 
the  solution  treated  with  a  slight  excess  of  powdered  sodium  carbo- 
nate, and  finally  violently  agitated  with  four  or  five  volumes  of  pure 
ether.  This  operation  dissolves  the  alkaloids  in  a  fairly  pure  state. 
Separate  the  ether  and  evaporate  spontaneously  on  a  watch  glass  as 
occasion  requires.  Volatile  alkaloids  must  first  be  converted  into 
stable  salts  before  the  ether  is  dissipated. 
For  the  extraction  of  many  of  the  vegetable  alkaloids,  the  above 
method  is  quite  applicable,  but  the  operator  must  bear  in  mind  three 
points:  (1)  An  alkaloid  extracted  by  the  above  process  is  very 
liable  to  be  contaminated  with  coloring  matter  and  certain  plant 
principles;  (2)  that  some  of  these  alkaloidal  bodies  are  quite  insoluble 
in  ether  ;  consequently,  with  such  chemicals  the  results  are  either 
only  partially  successful  or  fail  entirely  ;  and  (3)  the  influence  of  the 
presence  of  one  body  on  the  solubility  of  another. 
The  first  difficulty  was  partially  met  by  F.  J.  Otto,2  who  treated 
the  acidulated  solution,  containing  the  alkaloid  in  the  form  of  a  salt, 
with  ether,  in  which  alkaloidal  salts  in  general  are  insoluble,  thus 
removing  undesirable  bodies  from  the  alkaloidal  solution.  After  the 
above   treatment,  the  solution  is  rendered  alkaline  with  a  fixed 
1  Bull,  de  V Academie  de  Medecine  de  Belgique,  9,  304;  Ann.  (Liebig),  84, 
379- 
2 1856,  Ann.  (Liebig),  100,  39. 
