AmAug.^"iS12arm'}      Constituents  of  Angostura  Bark.  413 
line  precipitate,  which  is  insoluble  in  water  and  alcohol;  it  melts  at 
1820.  The  methiodide,  C19H17NOsMeI,  is  prepared  by  heating  cus- 
paridine  with  excess  of  methyl  iodide  for  three  hours  at  100°  in  a 
sealed  tube ;  after  recrystallizing  from  water,  it  forms  a  pale-yellow, 
crystalline  powder,  soluble  in  water  and  alcohol,  insoluble  in  ether. 
It  has  a  very  bitter  taste  ;  its  color  changes  to  brown  on  exposure 
to  the  air  or  light,  and  it  melts  at  1490. 
The  four  alkaloids  are  tertiary  bases ;  their  reactions  with  the 
various  alkaloidal  reagents  are  described. 
The  essential  oil  of  angostura  bark,  which  was  extracted  by  means 
of  ether,  was  freed  from  alkaloids  by  dilute  sulphuric  acid,  and  then 
remained  as  a  dark-colored  liquid.  From  100  kilos  of  the  bark, 
1*5  kilos  of  oil  was  obtained.  It  has  an  aromatic  odor  ;  the  sp.  gr. 
at  1  5°  is  0  956,  and  it  dissolves  in  ether,  alcohol,  chloroform,  light 
petroleum,  and  glacial  acetic  acid  ;  it  reddens  litmus.  It  is  free 
from  sulphur  and  nitrogen,  and  does  not  react  either  as  a  phenol,  a 
ketone,  or  an  aldehyde.  Distilled  under  a  pressure  of  35  mm.,  it 
commences  to  boil  at  1 5 3 °;  the  greater  part  distilled  between  2000 
and  2200;  the  last  portions  became  solid  when  cooled  with  a  mix- 
ture of  sodium  sulphate  and  hydrochloric  acid. 
The  bitter  principle  angosturin,  is  insoluble  in  ether,  but  soluble 
in  alcohol,  and  is  found  therefore  in  the  alcoholic  extract  of  the  bark; 
it  is  obtained  free  from  alkaloids  after  the  alcoholic  extract  has  been 
rendered  alkaline  with  sodium  carbonate  and  extracted  with  ether. 
The  bitter  principle  is  difficult  to  obtain  pure.  The  residue,  after 
separating  the  alkaloids,  was  dissolved  in  water,  and  an  excess  of 
tannin  added;  the  precipitate  was  washed  with  water,  and  dissolved 
in  alcohol ;  lead  acetate  was  added,  and  the  precipitate  first  washed 
with  alcohol  and  then  with  boiling  water.  The  angosturin  was 
further  purified  by  dissolving  it  in  water,  precipitating  with  char- 
coal, extracting  with  alcohol  and  finally  evaporating  the  latter.  It 
remained  as  a  transparent,  pale-yellow  mass,  which  is  soluble  in 
water,  alcohol,  and  glacial  acetic  acid.  The  addition  of  ether  to  the 
solution  in  acetic  acid  precipitated  the  angosturin  quite  white ;  it 
melts  at  580. 
The  angostura  bark  contains  a  glncoside,  which  may  be  separated 
from  the  bark,  after,  exhausting  it  first  with  ether,  and  then  with 
alcohol,  by  extraction  with  water.  The  solution  fluoresces  and 
reduces  Fehling's  and  other  metallic  solutions.  The  glucoside  was 
not,  however,  obtained  pure 
