^'"Mar".'i88L  "'"|  AustvaUan  Alstonia  Bark  115 
colored  darker,  and  finally  of  a  coffee-brown  color  in  consequence  of 
the  loss  of  water,  which  occurs  rapidly  by  heating  to  80°C. 
The  author  first  applied  ammonia  for  the  precipitation  of  the  alka- 
loid, but  it  was  found  to  precipitate  alstonina  very  incompletely.  For 
the  alkaloid  precipitated  by  ammonia  the  formula  C2iH2oN204-[-H20 
had  previously  been  determined,  while  now  the  alstonina  precipitated 
by  caustic  soda  and  dried  at  120°C.  gave  the  formula,  C21H20N2O4. 
Alstonina,  freshly  precipitated,  is  readily  soluble  in  chloroform,  but 
less  readily  when  previously  dried;  it  dissolves  also  readily  in  alcohol, 
but  sparingly  in  ether,  particularly  in  the  dried  form.  Its  hydrate 
(containing  3J  H2O)  melts  below  100°,  while  the  anhydrous  alkaloid 
melts  near  195°C.  (uncorr.) 
Alstonina  is,  in  opposition  to  the  statements  of  Palm,  a  strong  base, 
and  forms,  therefore,  salts  with  the  acids.  Some  of  them  were  pre- 
viously (1865)  examined,  and  the  platinum  salt,  as  formed  by  the  pre- 
cipitation of  a  solution  of  hydrochlorate  of  alstonina  by  platinum 
solution,  has  now  again  been  analyzed,  the  results  of  which  correspond 
to  the  formula  (C2iH2oiS'20,)2.PtCl6H2+4H20. 
In  regard  to  the  salts  of  alstonina,  it  may  be  added  that  its  sulphate, 
hydrochlorate,  tartrate  and  oxalate  are  readily  soluble  in  water,  but 
that  an  excess  of  the  acids  precipitates  the  salts  as  brown  flocculent 
masses.  The  same  behavior  as  these  acids  is  shown  by  an  acid  con- 
stituent of  the  Australian  alstonia  bark,  which  is  obtained  in  brown 
amorphous  flakes,  and  which  forms  with  alstonina  an  indifferent,  diffi- 
cultly soluble  compound.  The  author  considers  it  very  probable  that 
Palm's  alstonin  consists  of  the  compound  just  mentioned. 
Porphyrina. — Ks>  previously  mentioned,  petroleum  ether  extracts 
from  the  carbonic  acid  solution  several  substances,  which  may  be  taken 
up  from  the  former  by  acetic  acid ;  the  latter  then  assumes  a  magnifi- 
cent blue  fluorescence,  and  gives  with  an  excess  of  ammonia  a  reddish- 
white,  flocculent  precipitate.  This  precipitate  was  dissolved  in  ether 
and  the  solution  treated  with  animal  charcoal,  Avhich  absorbed  not 
only  a  small  residual  amount  of  alstonina,  but  also  another  basic  sub- 
stance, which  could  be  extracted  from  the  animal  charcoal  by  means  of 
■dilute  acetic  acid.  The  acid  becomes  colored  thereby  of  a  magnificent 
purplish-red,  and  gives  then,  with  an  excess  of  ammonia,  a  flesh-col- 
ored, amorphous  precipitate,  which,  however,  soon  changes  by  expos- 
ure to  the  air.    This  latter  circumstance  induced  the  author  to  aban- 
