ON  SOME  CONSTITUENTS  OF  RHUBARB.  867 
After  having  determined  the  leading  properties  of  the  deposit 
by  the  above-named  experiments,  its  composition  was  investigated 
in  the  following  manner  : — A  considerable  quantity  of  the  sub- 
stance was  pulverized  as  finely  as  possible,  and  treated  repeatedly 
with  boiling  spirit  of  wine  (of  86  per  cent.)  until  it  no  longer 
dissolved  anything  ;  the  insoluble  residue,  which  constituted  by 
far  the  greater  bulk  of  the  deposit,  will  be  treated  of  hereafter. 
The  dark  yellow  solution  was  filtered  while  hot,  and  concentrated 
by  partially  distilling  off  the  alcohol ;  the  concentrated  solution, 
on  cooling,  deposited  a  flocculent  matter  of  a  yellow  color.  This 
deposit,  after  being  several  times  dissolved  in  alcohol,  and  allowed 
to  deposit  therefrom,  became  crystalline,  and  exhibited  all  the 
properties  of  Qhrysophane. 
In  accordance  with  the  method  adopted  by  Schlossberger  and 
Dopping,*  in  their  analysis  of  rhubarb,  the  mother-liquor  of  the 
chrysophane  was  mixed  with  about  an  equal  volume  of  ether, 
when  a  bulky  brown  precipitate  was  formed.  This  was  allowed 
to  stand  for  a  while,  and  the  clear  supernatant  liquor  tested  with 
a  fresh  portion  of  ether,  in  order  to  ascertain  whether  any  more 
precipitate  could  be  thrown  down.  After  the  precipitation  was 
ascertained  to  be  complete,  the  deposit  was  separated  by  filtra- 
tion, and  set  aside.  The  filtrate  was  concentrated  by  distilling 
off  the  greater  part  of  the  ether,  and  was  then  allowed  to  evapo- 
rate spontaneously  to  dryness.  The  dry  residue  was  again  dis- 
solved in  alcohol,  and  the  solution  treated  with  ether,  which  again 
caused  a  precipitation ;  the  filtered  solution  was  then  concentrated, 
and  allowed  to  evaporate  to  dryness  ;  and  these  operations  were 
repeated  as  long  as  ether  caused  any  precipitate  in  the  alcoholic 
solution.  Lastly,  by  evaporating  the  alcoholic  solution  to  dry- 
ness, we  obtained  a  small  quantity  of  a  substance  which  did  not 
show  any  signs  of  crystallization  ;  it  had  a  brown  resin-like 
appearance,  and  when  powdered  became  yellow  ;  it  dissolved 
readily,  with  a  turmeric  tint,  in  alcohol,  ether,  and  benzol,  and 
gave  a  deep  red  solution  with  ammonia  and  the  fixed  alkalies,  and 
exhibited  the  other  characteristic  properties  of  Erythroretin, 
The  brown  deposit  separated  by  ether  from  the  solution  of 
erythroretin,  after  repeated  solution  in  alcohol  and  precipitation 
*  Ann.  Ch.  Pharm.  1.,  219. 
