Amsipt^"i87h7!rm'}  Preparation  and  Composition  of  Emetina.  461 
nitrate  is  added  until  a  precipitate  ceases  to  fall,  and  the  mixture  is  set 
aside  for  24  hours. 
The  abundant  blackish-brown  pitchy  deposit  consists  of  nitrate  of 
emetina  and  coloring  matter.  The  precipitate  is  purified  by  washing 
three  or  four  times  with  a  small  quantity  of  water,  and  will  be  found 
to  weigh  about  200  grams.  The  precipitate  is  dissolved  in  a  little  hot 
alcohol,  and  thrown  into  a  thick  milk  of  lime  containing  200  grams  of 
calcic  hydrate. 
The  mixture  is  evaporated  to  dryness  on  a  water  bath  with  constant 
stirring,  the  mass  powdered  and  placed  in  a  flask  containing  sulphuric 
ether.  After  some  hours  the  ethereal  solution  has  a  clear  yellow  color, 
and  contains  all  the  emetina.  The  residue  is  washed  once  or  twice 
with  ether,  the  solution  mixed,  and  the  ether  recovered  by  distillation. 
The  residue  in  the  retort  is  a  yellowish-brown  syrup.  It  is  treated 
with  water  acidulated  with  sulphuric  acid,  and,  on  filtering,  a  solution 
of  sulphate  of  emetina,  free  from  resin,  is  obtained.  Ammonia  causes 
in  it  a  voluminous  yellowish-white  deposit  of  emetina,  which  is  washed 
and  dried  at  a  low  temperature.  It  may  be  obtained  still  purer  by  dis- 
solving it  again  in  ether  and  evaporating  in  a  vacuum.  This  process 
is  decidedly  the  best  yet  published. 
The  idea  that  emetina  is  uncrystallizable  has  arisen  from  the  fact 
that  impure  specimens  have  been  operated  on.  The  authors  have  pre- 
pared crystals  of  it  varying  in  size  from  that  of  a  millet-seed  to  a  small 
lentil,  and  composed  of  minute  needles,  radiating  from  a  common 
center. 
Composition  of  Emetina. — The  result  of  several  analyses  of  a  material 
dried  in  a  vacuum  give  the  following  figures  : 
C28  .            .            .            .  69-41 
N  .  .             .             .             .  5.78 
H20  .....  8*i6 
Os  ....  1665 
M.  Gl^nard's  formula  is  C30NH22O4,  but  his  analyses  were  made  on 
a  specimen  dried  at  a  temperature  of  no°  to  I20°C,  at  which  tem- 
perature emetina  changes  rapidly. — Chem,  and  Drug. ,  July  14,  1877. 
