578        ON  SOME  PRINCIPLES  OF  CONVALLARIA  MAJALIS. 
most  of  the  crystals  behind.  The  ethereal  solution  yields  more 
crystals  on  evaporation,  but  mixed  with  a  syrupy  liquid,  from  which 
they  may  be  liberated  either  by  digesting  with  water,  agitating 
the  separated  resin  with  ether,  dissolving  the  insoluble  residue 
in  alcohol,  digesting  with  animal  charcoal,  filtering  and  evapo- 
rating ;  or  the  acid  reaction  of  the  syrup  is  neutralized  by  soda, 
the  liquid  evaporated  and  the  residue  treated  with  ether,  then 
with  water,  and  at  last  with  alcohol,  which  latter  solution,  after 
being  decolorized  by  animal  charcoal,  is  evaporated. 
The  aqueous  solution  obtained  by  any  one  of  the  above 
methods  is  decolorized  by  animal  charcoal,  precipitated  by  a 
watery  solution  of  tannic  acid,  and  the  precipitate,  after  filtering 
and  expressing,  is  digested  with  alcohol ;  the  tincture  is  now 
treated  with  hydrated  lime,  filtered,  and  distilled  to  one  half. 
Carbonic  acid  is  passed  through  the  residue  to  precipitate  the 
excess  of  lime,  the  liquid  is  evaporated  and  the  dry  mass  digest- 
ed with  ether.  To  obtain  the  bitter  principle  in  a  perfectly 
pure  state,  it  must  be  redissolved  in  water  and  treated  as  be- 
fore. 
Properties.  Convallarin  crystallizes  in  colorless  rectangular 
prisms,  is  scarcely  soluble  in  water,  but  sufficiently  to  impart  to 
it  its  acrid  taste,  and  to  foam  like  soap  water  when  shaken. 
It  is  easily  soluble  in  alcohol,  which  solution  produces  an  intensely 
acrid  sensation  in  the  throat,  and  is  rendered  turbid  by  water 
and  ether.  If  heated  to  312°  F.,  it  remains  unaltered,  but  it 
fuses  at  a  higher  temperature  and  is  decomposed.  It  dissolves 
in  ammonia  and  is  deposited  again  on  evaporation ;  potassa  dis- 
solves and  decomposes  it  ;  concentrated  mineral  acids  dissolve 
it,  and  yield  with  water  a  flocculent  precipitate  which  is  now 
soluble  in  ether. 
The  composition  of  convallarin  is  C34  H31  On.  By  digestion 
with  diluted  acids,  sugar  is  procured  and  a  new  body  convallare- 
tin  C28  H26  06,  which  is  soluble  in  ether,  yellowish  white,  crys- 
talline and  of  a  resinous  taste. 
Convallamarin  is  a  white  powder,  of  a  very  bitter,  subsequent- 
ly sweetish  taste,  soluble  in  water  and  alcohol,  not  in  ether ;  it 
dissolves  in  ammonia  without  decomposition,  but  is  decomposed 
by  potassa.  The  moist  powder  is  colored  violet  by  concentrated 
sulphuric  acid,  which  color  disappears  by  the  addition  of  water, 
