324 
Jalap  Resin  and  Jalapin. 
(Am.  Jour.  Pharro. 
\       July,  1887. 
has,  however,  an  acid  reaction  and  retains  the  peculiar  odor  and  acrid 
taste  of  jalap.  B.  Sandrock  (1850,  Arch.  d.  Phar.  cxiv,  160)  obtained 
it  of  a  yellow  color,  soft,  tough,  not  becoming  hard  and  brittle  on  dry- 
ing, precipitated  by  lead  acetate,  soluble  in  alkalies  and  after  prolonged 
boiling  of  this  solution  converted  into  a  peculiar  acid  somewhat  sol- 
uble in  water.  He  named  this  soft  resin  "  gani ma-resin,"  and  regarded 
the  ether-insoluble  resin  as  consisting  of  "  alpha-"  and  "  beta-resin," 
which,  however,  were  soon  shown  to  be  not  materially  distinct.  Per- 
eira  (Mat.  Med.,  Amer.  edit.  1854,  p.  520)  retained  for  this  resin  the 
name  jalapin,  and  called  jalapic  acid  the  portion  soluble  in  ether. 
F.  Holl  (1846,  Arch.  d.  Phar.,  xcviii,  45.)  and  others  had  shown 
that  the  color  reaction  observed  by  Kayser  with  sulphuric  acid  is  by 
no  means  characteristic  for  the  jalap  resins,  but  in  his  first  researches 
Wm.  Mayer  retained  (1852,  Annalen,  lxxxii,  121)  the  name  rhodeore- 
tin,  until  after  having  extended  them  to  the  resin  of  fusiform  jalap  (1856, 
Annalen,  xcv,  129),hevery  unfortunately  adoptedforthe  pureresiuof  the 
latter  the  name  jalapin,  while  the  ether-insoluble  resin  of  tuberous  jalap 
which  is  the  most  important  active  principle  of  this  drug,  was  designated 
convolvulin.  The  ether-soluble  resin  accompanying  the  latter  was  not 
investigated  by  Mayer.  The  pure  resin  of  scammony,  at  first  called 
seammonin,  was  through  the  researches  of  F.  Keller  and  H.  Spirgatis 
(1857-1860,  Annalen,  civ,  63;  cix  209;  cxvi,  289;  Buck.  N.  Rep.,  viir 
9,  511)  shown  to  be  identical  with  the  jalapin  of  the  orizaba  root. 
It  is  very  difficult,  if  not  impossible,  to  ascertain  now  by  whom  the 
name  jalapin  was  first  applied  to  the  soft  resin  of  true  jalap,  with 
which  Mayer's  jalapin  has  nothing  in  common  except  the  solubility  in 
ether ;  but  it  is  thus  designated  in  several  English,  French  and  German 
works.  The  confusion  is  thereby  increased,  for  the  name  jalapin  which 
was  originally  given  to  the  ether-insoluble  resin  of  true  jalap  root,  is 
now  occasionally  applied  to  the  more  or  less  decolorized  natural  resin 
of  jalap,  the  greater  portion  of  which  is  insoluble  in  ether ;  2.,  to  the 
ether-soluble  portion  of  this  resin,  soft  at  ordinary  temperature,  readily 
fusible  and  not  becoming  brittle  even  after  prolonged  exposure  to  a 
heat  of  100°  C;  and  3.,  to  the  pure  white  resin  of  Orizaba  jalap  and 
of  scammony,  brittle  at  ordinary  temperature,  and  melting  at  about 
150°  C. 
In  answer  to  the  question  as  to  what  is  sold  commercially  as  jalapin^ 
attention  may  be  drawn  to  a  paper  recently  published  in  Phar.  Jour, 
and  Trans.,  Feb.  12,  1887,  pp.  650-652  in  which  eight  samples  were 
