AmVuner,'i908arm'}     Chemical  Examination  of  Ipomcea  Purpurea.  283 
acid,  which  was  obtained  by  the  above-described  treatment  was 
present  in  the  extract  in  the  form  of  a  glucoside,  the  latter  would 
have  yielded  on  hydrolysis  an  amount  of  glucose  corresponding  to 
3  8  grammes.  It  is  evident,  therefore,  that  practically  the  entire 
amount  of  glucose  found  resulted  from  the  hydrolysis  of  the  gluco- 
sides  of  ipurolic  and  hydroxylauric  acids.  On  the  other  hand,  as 
the  5-5  grammes  of  crystalline  acids  obtained  would  correspond  to 
about  9  grammes  of  the  respective  glucosides,  and  as  the  weight  of 
alcohol  extract  of  the  hydrolyzed  resin  which  was  treated  with 
sulphuric  acid  was  25  grammes,  it  follows  that  this  extract  con- 
tained a  considerable  proportion  of  a  substance  which  was  not  a 
glucoside. 
The  liquid  which  had  been  freed  from  sulphuric  acid  by  means 
of  baryta,  as  described  above,  contained,  besides  glucose,  a  consider- 
able quantity  of  a  barium  salt,  but  this  did  not  separate,  even  when 
the  liquid  was  concentrated  to  the  consistency  of  a  thick  syrup  and 
allowed  to  stand  for  a  long  time.  The  acid  contained  in  this  salt 
was  evidently  highly  oxygenated,  and  doubtless  represented  that 
constituent  of  the  alcohol  extract  of  the  hydrolyzed  resin  which 
was  not  glucosidic  in  character.  Numerous  attempts  were  made 
to  isolate  this  soluble  organic  acid,  but  without  success.  A  deter- 
mination of  the  amount  of  barium  in  the  liquid  showed,  however, 
that  the  soluble  non-glucosidic  acid  yielded  by  '25  grammes  of  the 
alcoholic  extract  of  the  hydrolyzed  resin  corresponded  to  4-15 
grammes  Ba. 
SUMMARY  AND  PHYSIOLOGICAL  TESTS. 
As  the  details  of  the  preceding  investigation  are  necessarily  some- 
what extended,  it  appears  desirable  that  the  more  important  results 
should  be  briefly  summarized. 
The  material  employed,  consisting  chiefly  of  the  aerial  stems  of 
Ipomcea  purpurea,  Roth,  was  kindly  supplied  to  us  by  Mr.  J.  Medley 
Wood,  Director  of  the  Natal  Botanic  Gardens,  Durban,  South 
Africa.  When  extracted  with  alcohol,  and  the  resulting  extract 
distilled  with  steam,  an  amount  of  essential  oil  was  obtained  cor- 
responding to  0-018  per  cent,  of  the  weight  of  the  drug.  This 
essential  oil  was  a  pale  yellow  liquid,  having  a  strong,  characteristic 
odor  and  the  following  constants:  d  20°/20°  ==  0-9085  ;  aD  —  4°52/ 
in  a  1  dcm.  tube.    After  the  removal  of  the  volatile  substances 
