322 
Jalap  Resin  and  Jalapin. 
( Am.  Jour.  Pharm. 
t       July,  1887. 
Hume  applied  the  name  jalapine  to  a  supposed  alkaloid  (Med.  and 
Phys.  Jour.,  April  1824,  p.  346).  I  was  unable  to  consult  the  origi- 
nal paper;  but  in  Buchner's  Repertorium  xxxvii,  204,  it  is  stated  that 
this  principle  was  prepared  by  exhausting  the  root  with  concentrated 
acetic  acid  and  precipitating  the  liquid  with  ammonia ;  the  white  sub- 
stance was  totally  insoluble  in  ether,  but  dissolved  readily  in  alcohol. 
Meylink,  (B.  Rep.  xxxii,  446),  could  not  obtain  it  in  crystals.  Subse- 
quently Schweinsberg  (Magaz.  f.  Phar.,)  thought  the  precipitate  con- 
sisted of  ammonio-magnesium  phosphate  with  a  little  calcium  phos- 
phate ;  but  Dulk,  (Berl.  Jahrb.  1825,  xxvii,)  showed  it  to  be  resin 
combined,  as  he  supposed,  with  acetic  acid ;  more  properly  speaking 
it  is  contaminated  with  acetic  acid,  some  of  which  is  persistently 
retained. 
A  communication  from  Van  Mons,  in  1826,  who  had  endeavored 
to  decolorize  resin  of  jalap  by  treating  its  alcoholic  solution  with  gas- 
eous chlorine,  gave  J.  Pelletier,  (Jour,  de  Phar.,  1826,  xii,  143,)  an 
opportunity  to  refer  to  his  long  continued  researches,  undertaken  for 
the  purpose  of  isolating  from  jalap  root  a  purgative  principle  distinct 
from  the  resin  ;  these  researches  were  unsuccessful,  and  the  investiga- 
tion of  this  important  subject  was  stated  by  Pelletier  to  be  connected 
with  great  difficulties. 
About  the  same  time  T.  W.  C.  Martius  ascertained  (Kastner's  Ar- 
xihiv,  1826,  vi,  286),  and  soon  afterwards  L.  A.  Planche  confirmed 
the  observation  (Jour,  de  Phar.  1827,  xiii,  167),  that  jalap  resin  may 
be  completely  decolorized  by  treatment  with  animal  charcoal,  without 
depreciating  its  purgative  properties ;  the  latter  obtained  similar  re- 
sults also  with  two  other  hydragogue  cathartic  convolvulaceous 
resins,  those  of  scammony,  and  of  the  herb  of  Convolvulus  Solda- 
.nella,  Lin.  A  modification  of  the  process  for  decolorizing  jalap  resin, 
was  published  by  Martius  in  1835,  (JBuch.  Rep.  li,  367). 
In  1831,  A.  Buchner  and  J.  E.  Herberger  announced  (Buch.  Rep. 
xxxvii.,  203-212)  the  isolation  of  the  supposed  alkaloid  jalapine  by 
dissolving  the  brownish-yellow  resin  of  jalap  in  alcohol,  and  precipitat- 
ing an  acid  with  lead  acetate,  after  which  water  would  precipitate  suba- 
cetate  of  jalapine;  by  treatment  with  a  little  sulphuric  acid,  and  subse- 
quently with  lead  hydrate,  the  supposed  alkaloid  was  obtained  as  a 
colorless  transparent  mass,  pulverizable,  totally  insoluble  in  ether,  sol- 
uble in  alcohol,  also  in  concentrated  acetic  acid,  and  less  freely  in  strong 
mineral  acids,  usually  with  decomposition.  The  lead  compound  precipi- 
