Am.  Jour.  Pharm. 
July,  1887. 
Jalap  Resin  and  Jalapin. 
325 
examined,  one  of  which  was  completely  soluble  in  ether,  and  consisted 
either  of  Mayer's  jalapin  or  of  taropicin,  the  resin  of  Tampico  jalap 
which  however  has  a  lower  fusing  point  than  the  former,  namely  about 
130°  C.  The  other  samples,  seven  in  number,  were  evidently  resins 
of  true  jalap  and  yielded  between  3*5  and  7*3  per  cent  of  ether-soluble 
resin,  which,  though  stiff  and  tenacious,  and  incapable  of  being  ren- 
dered quite  hard,  was  considered  to  be  identical  with  jalapin ;  its  solu- 
bility in  warm  ammonia  was  not  ascertained. 
"Jalapin ''  does  not  appear  to  be  often  prescribed  in  the  United  States; 
still  it  was  not  difficult  to  procure  under  this  name  two  entirely  dis- 
tinct articles,  one  of  which,  being  of  German  manufacture,  answered  to 
the  characters  of  Mayer's  jalapin  in  being  soluble  in  ether,  while  the 
other  yielded  to  ether  3.3  per  cent,  of  a  soft  brown  resin,  which  had 
an  acid  reaction  and  was  suluble  in  warm  potassa  solution  and  repre- 
cipitated  by  excess  of  acid  ;  warmed  with  ammonia  a  milky  emulsion- 
like mixture  was  obtained,  but  not  a  clear  solution.  This  soft  resin 
was  dissolved  in  absolute  alcohol,  for  several  days  treated  with  animal 
charcoal,  and  the  nitrate  evaporated,  when  a  soft  brownish  yellow  mass 
was  left,  neutral  in  reaction,  leaving  no  residue  when  ignited,  and  giv- 
ing with  warm  ammonia  a  milky  mixture.  A  second  and  third  treat- 
ment with  somewhat  weaker  alcohol,  and  excess  of  animal  charcoal, 
diminished  the  quantity  of  this  soft  mass  very  considerably,  but  with- 
out materially  altering  its  characters.  After  a  fourth  treatment,  only 
a  minute  quantity  of  it  was  left,  the  properties  being  unaltered.  It 
follows  from  these  results  that  this  ether-soluble  portion  is  entirely  dis- 
tinct from  Mayer's  jalapin ;  in  fact,  its  resinous  nature  appears  to  be 
quite  doubtful,  and  it  seems  tp  me  more  nearly  related  to  the  fats  and 
waxes,  and  to  be  absorbed  from  its  solution  by  a  large  quantity  of 
animal  charcoal. 
In  1854  Prof.  L.  A.  Buchner  (N.  Rep.,  iii,  22;  Amer.  Jour. 
Rhar.,  1854,  p.  446)  reported  that  the  ether-soluble  portion  of  jalap 
resin  behaves  like  rhodeoretin  (or  convolvulin)  with  alkalies ;  for  if 
resin  of  jalap  be  dissolved  in  warm  potassa  solution,  and  the  liquid 
supersaturated  with  an  acid,  either  no  change  takes  place  or  only  an 
opalescence  without  real  precipitation,  according  to  whether  the  resin 
had  been  decolorized  by  animal  charcoal  or  not. 
A  somewhat  analogous  observation  has  more  recently  been  pub- 
lished by  Prof.  Fliickiger  (Phar.  Zeitung,  1883,  p.  211),  according  to 
which  resin  of  jalap  decolorized  by  animal  charcoal  is  dissolved  by 
