352 
ON  THE  RESIN  OF  JALAP. 
I  could  not  approach  the  site  of  the  spring  to  ascertain  what 
the  temperature  of  it  might  be — probably  it  is  high.  There  are 
hot  springs,  some  forty  or  sixty  miles  off,  on  the  east,  with  a 
temperature  of  120°,  where  the  secondary  overlying  Trap  meets 
with  gneiss  and  granite.* — Pharm.  Jour.,  May  1,  1853. 
Aurungahud.)  Ja,nuary21i  1853. 
ON  THE  KESIN  OF  JALAP. 
By  W.  Mater. 
The  rhizomes  of  Convolvulus  Schiedeanus,  Zucc,  known  asjalap- 
roots,  contain  an  active  principle,  a  resin  which  has  been  re- 
peatedly made  the  subject  of  chemical  investigation  by  Cadet  de 
Gassicourt,  Tromsdorff,  Gobel,  Buchner,  Herberger,  Kayser  and 
Sandrock.  Johnston  examined  the  resin  from  the  rhizome  of  Con- 
volvulus orizabensis,  Pell.  Buchner  and  Herberger  believed  they 
had  detected  a  basic  substance,  jalapine,  and  a  resinous  acid. 
Kayserf  extracted  the  resin  with  ether,  and  found  that  the  insoluble 
residue  had  the  complicated  formula  C42  H35  O20,  was  identical  with 
jalapine,  and  by  treatment  with  bases  was  converted  into  an  acid 
soluble  in  water,  composed  of  C42  HP  02n  +  HO.  He  found,  more- 
over, that  both  this  acid,  which  he  called  hydrorhodeoretine,  and 
the  original  resin,  rhodeoretine,  were  broken  up,  by  treatment 
wTith  hydrochloric  acid,  into  sugar  and  a  neutral  substance  unacted 
upon  by  either  concentrated  potash  or  concentrated  sulphuric  acid. 
He  called  this  body  rhodeoretinole.  Sandrock  obtained  results 
essentially  different  from  those  of  Kayser.  He  considered  the  part 
insoluble  in  ether  to  consist  of  two  resins,  one  of  which  was  pre- 
cipitated by  acetate  of  lead  from  the  alcholic  solution,  the  other 
not.  He  described  both  resins  as  being  converted  by  boiling  with 
alkalies  into  soluble  acids,  of  which  one,  ipomic  acid,  was  pre- 
cipitated by  basic  acetate  of  lead  from  the  neutral  potash  salt ; 
the  other,  jalapic  acid,  not. 
The  resin  extracted  from  the  rhizomes  of  C.  Schiedeanus  by 
*  Mr.  R.  Reynolds  has  determined  this  salt  to  be  compound  of  Soda,  32.8, 
Carbonic  acid,  34.2,  water,  31,  Chloride  of  Sodium,  2,  Alumina,  a  trace,  and 
hence  it  is  a  sesquicarbonate. — See  Pharm.  Jour.,  p.  517,  vol.  xii. 
t  Chera.  Gaz.,  vol.  iii.  p.  15. 
