342  Investigations  of  the  Tannins.  {AmjuOiy^l>03arm' 
The  separation  and  purification  of  the  tannin  was  effected  as 
follows :  The  ground  dried  bark  was  percolated  with  acetone ;  the 
solvent  recovered  and  the  residue  treated  with  water.  The  solution 
was  filtered  clear  and  shaken  with  acetic  ether,  and  as  this  did  not 
remove  the  tannin,  the  watery  solution  was  saturated  with  salt  and 
again  shaken  with  successive  portions  of  acetic  ether.  The  acetic 
ether  solution  was  distilled  to  dryness,  the  residue  taken  up  with 
water,  the  solution  filtered  and  evaporated  to  dryness  under  reduced 
pressure.  This  residue  was  then  dissolved  in  a  mixture  of  alcohol 
and  ether,  and  the  solution  filtered  and  evaporated.  This  method 
of  purification  was  repeated  several  times.  The  tannin  was  finally 
treated  with  absolute  ether  and  dried  at  1200  C.  It  yielded  the 
following  results  upon  combustion : 
Per  Cent.      Oak  Tannin. 
Carbon  60*57  5979 
Hydrogen  ,  5-38  5*08 
Oxygen  ...  .  34-05  35*13 
Pinus  Echinata. — The  materials  for  these  estimations  were  col- 
lected at  St.  David's,  Pa. 
Part. 
Date. 
Moisture. 
Ash  on 
Dry  Basis. 
Tannin  on 
Dry  Basis. 
Remarks. 
Whole  bark  . 
May  12,  '94. 
5-88 
7-29 
8- 20 
June  17. 
8-41 
6-n 
Inner  " 
July  27. 
9*3 
3*84 
9-87 
Whole  " 
Aug.  28. 
66-43 
2-80 
io'66 
Oct.  3. 
8-52 
3-02 
5 '57 
Nov.  4. 
9-81 
279 
6*04 
Dec.  12. 
19-04 
2*06 
6-54 
Jan.  20,  '95. 
8-92 
2-98 
7-905 
Feb.  25. 
7-22 
2-03 
770 
Sap  beginning  to  flow. 
For  the  separation  and  purification  of  the  tannin  the  following 
methods  were  applied  :  The  dried  bark  was  exhausted  with  acetone, 
the  solvent  recovered  and  the  residue  taken  up  in  water  and  filtered. 
The  clear  solution  was  shaken  with  acetic  ether,  but  this  did  not 
remove  the  tannin ;  the  watery  solution  was  saturated  with  salt  and 
again  shaken  with  acetic  ether,  but  still  the  tannin  was  not  removed. 
The  saturated  watery  solution  was  then  shaken  with  acetone,  which 
only  removed  a  part  of  the  tannin.    The  acetone  solution  was 
