Am.  Jour.  Pharm. 
July,  1887. 
Jalap  Resin  and  Jalapin. 
323 
tated  from  the  resin  on  being  treated  with  H2S,  yielded  a  brown  mass, 
which  was  readily  soluble  in  alkalies,  also  in  ether  and  in  acids.  This 
acid  and  the  jalapine  were  regarded  as  uniting  to  a  subsalt,  and  thus 
constituting  the  natural  resin. 
While  examining  scammony,  Clamor  Marquart  noticed  in  1836, 
(Archiv  d.  Phar.  lvii,  236,)  that  in  certain  solutions  precipitates 
were  obtained  with  tannin  ;  likewise  in  certain  solutions  of  jalap  resin, 
and  the  presence  of  alkaloids  was  inferred  in  both  products. 
The  elementary  analysis  of  jalap  resin  made  by  Johnston  in  1839 
(Philos.  Trans,  ii,  342)  proved  the  presence  of  C,  H  and  O,  and  the 
absence  of  nitrogen.  A  similar  result  had  already  been  obtained  by 
O.  F.  Goebel  in  1821  (Buck.  Rep.  xi,  84.) 
Cadet  de  Gassicourt  first  observed  (Jour,  de  Phar.,  1817,  iii)  that 
jalap  resin  may  be  separated  by  means  of  ether  into  two  portions ;  one 
hard  and  resin-like,  insoluble  in  ether,  soluble  in  warm  alkalies  and 
from  these  solutions  not  precipitated,  or  merely  very  slightly  so,  on  the 
addition  of  a  mineral  acid ;  the  other  portion  soft,  plaster-like,  soluble 
in  ether,  and  likewise  in  warm  alkalies,  but  from  the  latter  solution 
precipitated  by  acids  in  the  same  manner  as  the  crude  resin.  It  is  the 
portion  insoluble  in  ether  which  was  subsequently  called  jalapine  by- 
Hume,  Buchner  and  Herberger,  though  by  them  erroneously  supposed 
to  be  an  alkaloid. 
The  insolubility  of  the  hard  and  soft  portion  of  jalap  resin  in  oil  of 
turpentine  appears  to  have  been  first  noticed  by  Trommsdorff  (Neues 
Jour.  d.  Phar.,  1833,  xxv)  and  was  by  him  and  others  recommended 
as  a  convenient  test  for  proving  the  absence  of  agaric  resin,  colophony 
and  others,  with  which  jalap  resin  was  sometimes  adulterated.  Bley 
afterwards  found  (1839,  Bueh.  Rep.  Lxv,  374)  that  ordinary  oil  of 
turpentine  would  dissolve  a  little  jalap  resin,  but  the  freshly  rectified 
oil  take  up  merely  a  trace  of  the  latter. 
During  his  investigations  of  the  resins  of  jalap  and  orizaba  root,  (1844, 
Annalen  li,  81)  G.  A.  Kayser  observed  their  solubility  in  strong  sul- 
phuric acid  with  the  production  of  a  red  color,  and  regarding  this  re- 
action as  characteristic  introduced  the  names  rhodeoretin  and  pararho- 
deoretin,  the  former  for  the  hard,  white,  in  ether  insoluble  resin  of  tuber- 
ous jalap,  the  latter  for  the  similar,  but  in  ether  soluble,  resin  of  fusi- 
form jalap.  Kayser  proved  also  that  the  resins,  which  have  a  neutral 
reaction  on  litmus,  on  being  dissolved  in  warm  alkalies,  are  converted 
into  acids  soluble  in  water.    The  ether-soluble  resin  of  tuberous  jalap 
