Arnjine?i903arm*}     Chemical  Examination  of  Ipomcea  Purpurea.  269 
which,  when  collected  and  dried,  was  found  to  weigh  3  grammes. 
This  resin,  when  again  dissolved  in  alcohol  and  treated  with  basic 
lead  acetate  as  before,  yielded  a  further  small  quantity  of  a  precipi. 
tate  from  which,  after  treatment  with  hydrogen  sulphide,  about  1 
gramme  of  dry  resin  was  obtained.  The  filtrate  from  this  second 
precipitation,  after  removal  of  the  lead,  yielded  finally  2  grammes 
of  resin,  the  alcoholic  solution  of  which  was  no  longer  precipitated 
by  basic  lead  acetate. 
The  result  of  the  above  experiment  would  appear  to  indicate  that 
the  alcohol  extract  of  the  resin,  notwithstanding  the  various 
methods  of  purification- to  which  it  had  been  subjected,  was  still  not 
a  homogeneous  or  individual  substance. 
Destructive  Distillation  of  the  Resin  under  Diminished  Pressure. — It 
was  thought  of  some  interest  to  ascertain  the  character  of  the  prod- 
ucts afforded  by  the  dry  distillation  of  the  purified  alcohol  extract 
of  the  resin,  especially  when  this  operation  was  conducted  under 
greatly  diminished  pressure.  For  the  purpose  of  this  experiment 
10  grammes  of  the  dry  resin  were  brought  into  a  small  distillation 
flask,  which  was  connected  with  a  receiver,  and  the  apparatus  evac- 
uated to  a  pressure  of  20  mm.  On  heating  gently,  the  resin  first 
melted,  then  fumes  were  evolved,  and,  on  gradually  increasing  the 
temperature,  a  viscid  red  liquid  passed  over,  until  finally,  at  2800 
C./20  mm.,  the  distillation  was  stopped.  The  amount  of  this 
liquid  was  2  grammes,  or  one-fifth  of  the  weight  of  resin  employed, 
the  remainder  having  been  chiefly  converted  into  a  brittle,  black 
mass.  The  distillate  was  almost  entirely  soluble  in  ether,  and  on 
shaking  the  ethereal  liquid  with  a  solution  of  sodium  carbonate  the 
greater  portion  of  the  dissolved  substance  was  removed,  thus  indi- 
cating it  to  be  of  an  acidic  nature,  while  a  further  small  amount 
was  removed  by  subsequent  extraction  with  a  solution  of  sodium 
hydroxide,  a  little  finally  remaining  in  the  ethereal  liquid.  The 
amount  of  these  products  was  not  sufficient  for  their  further  exam- 
ination, and  they  did  not  appear  to  be  of  sufficient  interest  to  justify 
the  use  of  larger  quantities  of  the  resin  in  this  manner.  It  may  be 
noted  in  this  connection  that  Klimenko  and  Bandalin1  have  recorded 
an  experiment  in  which  they  subjected  600  grammes  of  "jalapin" 
to  dry  distillation,  and  obtained  therefrom  285  grammes  of  a  viscid, 
1  Ber.  d.  deutsch.  chem.  Ges.,  1893,  26,  IV,  591. 
