342  Constituents  of  Gehemium  Sempervirens.    |  '^'"juij^'ig^'"'"* 
Conclusions. — It  is  needless  to  add  that  the  only  conclusion  from  the 
foregoing  comparative  results  is  that  the  principles  examined  are  very 
different  substances.  Hence  the  name  gehemic  add.  will  be  retained 
provisionally  for  the  gelsemium  principle. 
Gelsemine. — As  supplementary  to  our  former  paper  on  the  subject, 
some  of  the  more  important  properties  and  reactions  of  gelsemine  may 
be  mentioned. 
In  its  pure  state  gelsemine  is  a  colorless,  odorless  solid,  having  a 
persistent  bitter  taste.  It  has  not  yet  been  obtained  in  the  crystalline 
state.  At  something  below  100°C.  it  fuses  to  a  colorless  liquid.  Gel- 
semine completely  neutralizes  acids,  forming  salts,  most  of  which  are 
freely  soluble  in  water  and  alcohol. 
The  pure  alkaloid  is  soluble,  under  ordinary  conditions,  in  644  parts 
of  water.    It  is  freely  soluble  in  ether  and  in  chloroform. 
The  most  characteristic  reactions  of  the  solid  alkaloid  are  the  fol- 
lowing : 
1.  Sulphuric  acid  dissolves  gelsemine  with  a  reddish  or  brownish 
color  to  a  solution  which  after  a  time  assumes  a  pinkish  hue.  If  the 
solution  be  warmed  on  a  water-bath,  it  acquiires  a  more  or  less  purple 
or  chocolate  color. 
If  a  small  crystal  of  potassium  bichromate  be  slowly  stirred  in  the 
sulphuric  acid  solution,  reddish-purple  streaks  are  produced  along  the 
path  of  the  crystal.  If  the  potassium  salt  be  used  in  the  form  of 
powder,  or,  as  advised  by  Sonnenschein  and  Robbins,  be  replaced  by 
eerie  oxide  (CeO^  formerly  Cefi^),  the  purplish  or  reddish-purple  color- 
ation  manifests  itself  more  promptly  and  strongly,  and  may  be  obtained 
from  even  the  one  ten-thousandth  grain  or  less  of  the  pure  alkaloid. 
For  the  detection  of  these  minute  quantities,  however,  it  is  essential 
that  only  very  minute  quantities  of  the  acid  and  powder  be  employed. 
This  reaction  of  gelsemine — as  remarked  by  Sonnenschein  and  Rob- 
bins,  who  first  observed  it  with  the  cerium  compound — resembles 
somewhat  that  of  strychnine ;  but  these  alkaloids  could  not  thus  be 
confounded. 
2.  Nitric  acid  causes  gelsemine  to  assume  a  brownish-green,  quickly 
changing  to  a  deep  green,  color,  which  slowly  diffuses  itself  through  the 
liquid.  Almost  the  least  visible  quantity  of  the  alkaloid,  if  touched 
with  only  a  very  minute  drop  of  the  acid,  will  yield  this  green  colora- 
tion in  a  marked  degree. 
