CHEMICAL  COMPOSITION  OF  GELSEMIUM  SEMPERVIRENS.  9 
brown  deposit,  which  after  a  time  assumes  a  dark  green  color. 
The  precipitate  is  insoluble  in  acetic  acid. 
Solutions  containing  more  than  1-lOOth  of  their  weight  of  the 
acid  will  also  yield  precipitates  with  the  soluble  neutral  salts  of 
lime,  nickel,  cobalt  and  tin. 
II.  Gelseminine. 
Preparation. — Gelseminine  may  be  extracted  from  the  con- 
centrated extract  from  which  gelseminic  acid  has  been  extracted 
by  ether,  by  rendering  the  liquid  slightly  alkaline  with  potash, 
and  then  repeatedly  agitating  it  with  chloroform,  which  will  dis- 
solve the  alkaloid  together  with  more  or  less  foreign  matter. 
For  this  purpose,  about  two  volumes  of  chloroform  may  at  first 
be  employed,  and  after  this  has  been  separated,  the  operation 
repeated  with  a  similar  quantity  of  the  fluid,  when  finally  the 
alkaline  solution  is  washed  with  about  its  own  volume  of  the 
liquid.  It  sometimes  happen,  especially  if  the  mixture  has  been 
violently  agitated  for  some  minutes,  that  the  liquids  form  an 
emulsion  from  which  the  chloroform  does  not  entirely  separate 
for  many  hours.  The  separation  may  usually  be  facilitated  by 
moderately  warming  the  mixture  and  gently  agitating  it. 
The  chloroform  employed  for  these  extractions  is  collected  in 
a  dish  and  evaporated  at  a  very  moderate  temperature,  when  it 
will  leave  a  hard,  gum-like,  yellowish  or  brownish-yellow  residue. 
This  is  treated  with  a  small  quantity  of  water  and  the  mixture 
slightly  acidulated  with  hydrochloric  acid,  which  will  dissolve  the 
alkaloid  together  with  more  or  less  foreign  matter.  This  solu- 
tion is  filtered,  and  the  filtrate  concentrated  to  about  one-six- 
teenth the  volume  of  the  original  fluid  extract  operated  upon. 
On  now  treating  the  concentrated  liquid  with  slight  excess  of 
caustic  potash,  the  alkaloid  will  be  precipitated  in  the  form  of 
a  more  or  less  white  deposit.  This  is  collected  on  a  filter,  washed 
with  a  small  quantity  of  pure  water,  then  allowed  to  dry  at  the 
ordinary  temperature.  On  drying,  the  precipitate  will  shrink 
greatly  in  volume  and  acquire  a  dark  color. 
For  the  purpose  of  further  purifying  the  alkaloid,  the  dry 
mass  is  pulverized  and  the  brownish  powder  dissolved,  by  the 
aid  of  a  few  drops  of  hydrochloric  acid,  in  a  small  quantity  of 
