Am'june?i908arm'}     Chemical  Examination  of  Ipomoea  Purpurea.  271 
The  acids  remaining  in  the  aqueous  distillate  after  extraction  with 
ether  were  converted  into  a  barium  salt,  of  which  13  5  grammes 
were  obtained.  This  salt  afforded  reactions  which  established  the 
presence  of  formic  and  butyric  acids.  After  drying  at  no°  C.  it 
was  analyzed  with  the' following  result: 
o  5178  of  the  dried  salt  gave  04532  BaS04  .  Ba  =  5 -1-5. 
(CH02)2  Ba    requires  Ba  =  60  4  per  cent. 
(C4H702)2  Ba       «      Ba  =  441    "  « 
From  these  results  it  may  be  inferred  that  this  salt  consisted  of 
barium  formate  and  butyrate  in  nearly  equal  proportions. 
The  liquid  remaining  in  the  distillation  flask  after  the  removal 
of  the  volatile  acids  by  steam  was  very  light  in  color,  and  contained 
practically  no  resin.  It  was  extracted  with  ether,  the  ethereal  liquid 
being  washed,  dried  with  calcium  chloride,  and  the  ether  removed, 
when  a  small  amount  of  an  oily  liquid  was  obtained,  which,  on  cool- 
ing, solidified  to  a  crystalline  mass.  The  substance  was  acid  to 
litmus,  and  also  soluble  in  a  solution  of  sodium  carbonate.  It  was 
recrystallized  from  water,  from  which  it  separated  in  small,  colorless 
plates,  melting  at  103-1040  C.  On  analysis  it  gave  the  following 
result : 
0-0956  gave  0-2020  C02  and  0-0754  H20.    C  =  57-6;  H  =  8.8 
C9H1604  requires  C  =  574;  H  =  8  5  per  cent. 
A  silver  salt  of  the  acid  was  also  prepared  and  analyzed  : 
0-0268  of  salt  gave  on  ignition  0*0144  Ag.    Ag  =  53-7 
C9H1404  Ag2  requires  Ag  =  53  7  per  cent, 
It  is  evident  from  these  results  that  the  above-described  substance 
is  a  dicarboxylic  acid,  corresponding  in  its  composition  and  proper- 
ties to  azelaic  acid. 
Treatment  with  Dilute  Alcoholic  Sulphuric  Acid. — Forty  grammes 
of  the  resin  were  dissolved  in  alcohol,  and  such  an  amount  of  sul- 
phuric acid  added,  with  a  little  water,  that  the  total  liquid  contained 
about  5  per  cent,  of  its  weight  of  acid.  The  liquid  was  then  heated 
on  a  water-bath  in  a  reflux  apparatus  for  four  hours,  after  which  the 
alcohol  was  removed,  and  the  residue  subjected  to  distillation  with 
steam.  The  distillate  was  extracted  with  ether,  the  ethereal  liquid 
being  shaken  with  a  solution  of  sodium  carbonate,  then  washed  with 
water,  dried  with  calcium  chloride,  and  the  ether  removed.    A  very 
