Amsep"r;iSrm'}        Preparation  of  Oak  Tannins.  437 
tered  and  the  clear  filtrate  was  diluted  with  water  as  long  as  pre- 
cipitation took  place.  This  dilution  separated  much  of  the  anhy- 
drides. The  filtrate  from  these  was  of  a  clear  red  color  and  yielded 
no  further  precipitate  on  the  addition  of  water.  It  was  agitated 
successively  with  acetic  ether.  The  acetic  ether  portions  were 
mixed  and  the  solvent  recovered  by  distillation  under  reduced 
pressure,  which  yielded  the  tannin  in  a  porous  or  "puffed  up" 
condition.  The  product  was  then  treated  with  cold  water,  and, 
after  filtration,  was  again  separated  by  agitation  with  acetic  ether. 
This  process  was  continually  repeated  until  the  tannin  was  readily 
and  completely  soluble  in  water.  The  tannin  then  possessed  con- 
siderable odor  of  acetic  ether,  which  was  removed  by  solution  in 
official  ether,  sp.  gr.  0*750,  and,  after  filtering  clear,  distilling  off 
the  solvent  under  reduced  pressure.  The  product  was  then  digested 
with  absolute  ether,  which  dissolved  the  small  amounts  of  adhering 
resin  and  crystalline  principles  which  occur  along  with  it  in  the 
bark  or  result  from  decomposition  when  working  it,  and  the  tannin 
remained  behind  nearly  pure,  and  readily  and  completely  soluble 
in  water. 
This  process  was  carried  out  on  barks  from  the  following  species 
of  oaks :  Quercus  alba,  Q.  coccinea  and  its  variety  tinctoria,  Q. 
falcata,  Q.  paluslris,  Q.  Prinus,  Q.  bicolor,  Q.  stellata,  Q.  Phellos  and 
Q.  rubra.  It  was  found  in  some  cases  that  by  dissolving  the  acetone 
residue  in  a  mixture  of  four  parts  water  and  one  part  alcohol, 
instead  of  water  alone,  that  there  was  less  formation  of  anhydrides. 
A  few  trials  were  made  with  a  modification  of  the  purification 
process  in  which  the  first  acetic  ether  residue  was  dissolved  in  water 
and  filtered  through  a  freshly  prepared  lead  compound  obtained  by 
precipitating  a  portion  of  the  aqueous  solution  of  the  bark  with 
lead  acetate. 
In  some  instances,  the  resulting  filtrate  was  nearly  colorless,  but 
the  loss  of  tannin  was  such  as  not  to  warrant  the  adoption  of  the 
process  for  general  use.  It  might,  however,  be  applied  in  certain 
cases  with  satisfactory  results.  From  the  colorless  filtrate  the  tannin 
should  be  removed  by  agitation  with  acetic  ether,  and  the  remainder 
of  the  general  purification  process  then  carried  out. 
Betame  and  Choline  were  obtained  by  E.  Jahns  from  Levant  worm- 
seed.    ^Ber.  d.  D.  Chem.  Gesell.,  1893,  1493.) 
