154 
ON  RUMICINE. 
ses ;  but  he  adopted  another  mode  of  purification,  because  by 
Riegel's  method  he  only  obtained  the  substance  in  a  very  impure 
state. 
The  coarsely  pounded  roots  of  Rumex  obtusifolius  (Radix 
lapatJti  acuti  of  the  shops)  were  extracted  by  anhydrous  ether 
in  a  displacement  apparatus,  and  the  combined  extract  distilled 
on  the  water-bath,  until  only  a  small  residue  was  left.  On  cool- 
ing, a  (hirk  brown  mass  separated  from  this,  which  was  filtered, 
washed  with  a  little  ether,  and  then  dried  between  several  folds 
of  filtering-paper.  When  dried,  it  was  boiled  with  alcohol  of 
spec.  grav.  0*833  and  filtered  ;  a  dark  brown  body  remained  on 
the  filter,  whilst,  on  the  cooling  of  the  hot  filtrate,  a  dingy 
greenish-yellow  mass  separated  therefrom,  which  remained 
greenish  after  repeated  solution  in  alcohol  and  separation,  and 
only  exhibited  traces  of  crystallization.  As  the  green  resin 
could  not  be  separated  in  this  way,  the  alcoholic  solution  of  the 
substance  was  precipitated  by  a  large  quantity  of  water ;  the 
flocculent,  yellow  precipitate  was  separated  by  filtration,  and, 
after  drying,  dissolved  again  in  alcohol  of  spec.  grav.  0-83B, 
when  a  small  quantity  of  a  brown  body  remained  undissolved. 
This  operation  was  twice  repeated,  but  the  substance  still  con- 
tinued impure. 
The  final  purification  was  effected  by  the  author  in  accord- 
ance with  the  process  of  Rochleder  and  Held,  employed  by 
them  in  their  investigation  of  the  lichens. 
For  this  purpose  the  substance  was  treated  with  a  mixture  of 
ammonia  and  weak  alcohol,  the  filtered  solution  diluted  with 
water,  and  neutralized  by  acetic  acid ;  the  yellow  precipitate 
was  completely  washed  with  water,  and  the  same  operation  was 
repeated ;  the  last  precipitate  obtained  was  dried  and  recrystal- 
lized  from  alcohol ;  the  crystalline  mass  deposited  was  again 
dissolved  in  ether,  and  the  solution  left  standing  in  a  loosely 
covered  vessel,  in  which  the  rumicine  slowly  crystallized  as  the 
ether  evaporated. 
The  rumicine  thus  obtained  formed  a  shining  crystalline  mass 
of  a  light  golden-brown  color,  which  was  seen  under  the  micro- 
scope to  consist  of  distinct,  yellow,  transparent  prisms,  appa- 
rently belonging  to  the  monoclinohedric  system,  and  exhibit  a 
golden-yellow  color  by  reflected  light.    By  crystallization  from 
