One  hundred  grains  of  the  bark,  exhausted  by  stronger  alcohol,  gave 
a  rich,  reddish-brown  tincture,  possessing  an  acrid  taste.  Upon  the 
evaporation  of  this  tincture  there  remained  18  grains  (18  per  cent.)  of 
extract,  which  was  insoluble  in  water,  thus  showing  its  resinous  nature, 
and  which  possessed  a  very  acrid  taste. 
About  one  third  of  this  extract  was  dissolved  when  submitted  to  the 
action  of  ether,  this  part  possessing  a  more  acrid  taste  than  the  remain- 
ing portion. 
The  portion  which  was  insoluble  in  ether  was  soluble  in  alkaline 
solutions. 
The  acrid  taste  of  the  bark,  therefore,  is  due  to  two  resins,  which 
are  very  similar  in  taste  to  the  resin  obtained  from  Pellitory  root.  The 
bark  contains  pectin,  which  was  obtained  from  the  acid  decoction  by 
treating  with  milk  of  lime,  when  a  large  quantity  of  this  substance 
was  precipitated. 
By  the  following  process  the  bitter  principle  of  the  bark  was 
obtained. 
Four  troyounces  of  the  bark  were  exhausted,  with  successive  por- 
tions of  water  and  muriatic  acid  ;  milk  of  lime  was  then  added,  which 
precipitated  the  pectin. 
The  filtrate  from  this  was  then  evaporated  to  a  syrupy  consistence 
and  a  mixture  of  equal  parts  of  alcohol  and  ether  added.  Upon  the 
evaporation  of  the  alcohol  and  ether  the  bitter  substance  was  left  in 
the  form  of  a  yellowish,  semi-transparent  mass.  A  small  quantity  of 
the  mass  was  then  dissolved  in  a  little  distilled  water  and  the  filtered 
solution  set  aside.  On  the  evaporation  of  the  liquid  no  crystals  could 
be  discovered  in  the  residue. 
It  was,  therefore,  redissolved  in  water  slightly  acidulated  with  muri- 
atic acid  and  again  evaporated,  when  the  mass  was  still  found  to  be 
amorphous. 
It  was  finally  dissolved  in  water  and  the  acid  solution  tested  with  the 
reagent  for  alkaloids  (Mayer's  solution),  with  the  result  of  giving  a 
very  decided  precipitate.  I  also  succeeded  in  isolating  this  principle 
from  the  bark  by  the  following  process,  which  is  somewhat  different 
from  the  above  : 
Four  troyounces  of  the  bark  were  exhausted  with  alcohol  and  two 
pints  of  tincture  obtained.  This  was  evaporated  to  four  fluidounces, 
an  equal  bulk  of  water  added,  which  precipitated  all  the  resinous  matter. 
