Amjune^imarm'}     Chemical  Examination  of  Ipomcea  Purpurea.  261 
no  coloration  with  ferric  chloride,  but  yielded  precipitates  with  solu- 
tions of  silver  nitrate  and  lead  acetate.  It  appeared  to  be  identical 
with  an  acid  which  was  subsequently  obtained  in  larger  amount  by 
the  fusion  of  the  alcohol  extract  of  the  resin  with  potash,  and  which 
proved  to  be  azelaic  acid.  The  mother-liquor  from  this  acid  de- 
posited an  exceedingly  small  amount  of  a  crystalline  substance 
which  gave  the  above  described  coloration  with  ferric  chloride,  but 
it  could  not  be  obtained  in  a  pure  state. 
Treatment  with  Dilute  Alcoholic  Sulphuric  Acid. — Thirty  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 
in  a  reflux  apparatus  on  the  water-bath  for  about  four  hours,  after 
which  the  alcohol  was  removed,  and  the  residue  subjected  to  distil- 
lation in  a  current  of  steam.  The  distillate,  which  contained  a  small 
amount  of  oil  floating  on  the  surface,  was  extracted  with  ether,  the 
ethereal  liquid  being  first  washed  with  a  little  water,  and  then 
shaken  with  a  solution  of  sodium  carbonate  in  order  to  remove  any 
acids  present.  After  this  treatment  the  ethereal  liquid  was  dried 
with  calcium  chloride  and  the  ether  removed,  when  a  small  amount 
of  a  dark  green  oil  was  obtained.  This  was  first  distilled  under  a 
pressure  of  10  mm.,  and  then  at  the  ordinary  pressure,  but  as  the 
range  of  temperature  at  which  it  passed  over  was  very  wide,  it  was 
evidently  a  complicated  mixture.  The  amount  of  neutral  oil  thus 
obtained  was  i-8  grammes.  It  was  a  pale  yellow  liquid,  having  a 
rather  agreeable  odor. 
The  alkaline  liquid  obtained  by  extraction  of  the  original  oily 
product  with  sodium  carbonate  was  acidified,  and  extracted  with 
ether,  the  ethereal  liquid  being  washed,  dried  with  calcium  chloride, 
and  the  solvent  removed.  A  small  amount  of  an  oily  acid  was  thus 
obtained,  which  was  converted  into  an  ammonium  salt,  and  from  this 
a  silver  salt  was  prepared.  The  latter  was  washed,  dried  in  a 
vacuum  over  sulphuric  acid,  and  analyzed. 
o  1288  of  salt  gave  on  ignition  0  0498  Ag.    Ag  =  38  7 
C10H]9O2  Ag  requires  Ag  =  387  per  cent. 
The  figures  obtained  by  this  analysis  are  seen  to  be  in  exact 
agreement  with  those  required  for  the  silver  salt  of  a  decylic  acid, 
although  it  is  probable  that  the  acid  was  a  mixture. 
