12     CHEMICAL  COMPOSITION  OF  GELSEMIUM  SEMPERVIRENS. 
but  it  is  very  freely  soluble  both  in  chloroform  and  in  ether;  one 
part  of  the  alkaloid  immediately  enters  into  solution  when 
agitated  with  twenty-five  parts  of  the  latter  liquid. 
If  a  drop  of  concentrated  sulphuric  acid  be  added  to  a  small 
quantity  of  gelseminine,  or  of  any  of  its  colorless  salts,  it  causes 
it  to  assume  a  reddish-brown  color,  and  dissolves  it  to  a  reddish- 
colored  solution.  If  this  solution  be  moderately  heated^  it  ac- 
quires a  beautiful  purple  color.  This  coloration  manifests  itself 
from  1-lOOth  of  a  grain  of  the  alkaloid.  Bichromate  of  potash 
stirred  in  the  sulphuric  acid  solution  of  the  base,  produces  no 
marked  change. 
iVzYnV  readily  dissolves  the  alkaloid,  under  the  production 
of  a  greenish  color,  to  a  greenish  or  greenish-yellow  solution. 
Hydrochloric  acid  dissolves  it  with  a  yellow  coloration  to  a 
colorless  or  faintly  yellow  solution. 
Caustic  potash  has  little  or  no  effect  upon  the  dry  powder. 
At  a  temperature  somewhat  below  212°  E.,  gelseminine  fuses 
to  a  colorless  viscid  liquid,  which  on  cooling  solidifies  to  a  trans- 
parent vitreous  mass.  At  a  higher  temperature  the  alkaloid  is 
dissipated,  without  residue,  in  the  form  of  white  fumes.  If  these 
vapors  be  received  on  a  warmed  piece  of  glass,  they  condense  in 
the  form  of  minute  drops. 
Reactions  of  solutions  of  gelseminine. — Solutions  of  the  salts 
of  gelseminine,  when  pure,  are  nearly  or  altogether  colorless,  and 
have  the  peculiar  bitter  taste  of  the  alkaloid.  This  bitter  taste 
is  well  marked  in  a  single  drop  of  a  1000th  solution  of  the  base. 
1.  Potash,  as  well  as  the  other  caustic  alkalies,  precipitates 
the  alkaloid  from  tolerably  strong  solutions  of  its  salts,  in  the 
form  of  a  white  amorphous  deposit,  which  is  insoluble  in  excess 
of  the  precipitant.  One  drop  of  a  100th  solution  of  the  base 
yields  a  rather  copious  flocculent  precipitate.  After  some  hours 
the  precipitate  acquires  a  reddish  or  brick-red  color. 
2.  Bichromate  of  potash  throws  down  from  solutions  of  salts 
of  the  alkaloid,  when  not  too  dilute,  a  copious  yellow  amorphous 
precipitate,  which  is  slowly  soluble  in  acetic  acid. 
3.  Carhazotic  acid  produces  a  yellow  amorphous  precipitate. 
1-lOOth  of  a  grain  of  the  alkaloid,  in  one  grain  of  fluid,  yields  a 
very  copious,  bright  yellow  deposit ;  1-lOOOth  grain  yields  a 
greenish-yellow  deposit. 
