482  American  Pharmaceutical  Association.     { ^ptembef!1!^' 
cose,  traces  of  fatty  matter,  coloring  matter,  and  more  or  less  colored  derivatives 
of  tannin,  according  to  whether  the  sterilization  by  boiling  alcohol  has  been 
properly  done.  Common  salt  was  then  added  to  this  filtrate  to  saturation  and 
the  cafFein  kolatannate  was  completely  precipitated.  It  was  filtered  out  and 
added  to  the  first  residue  of  caffein  kolatannate.  The  reddish-colored  filtrate 
was  then  transferred  to  a  large  separatory  funnel  and  agitated  with  chloroform 
repeatedly  to  remove  alkaloids  and  the  traces  of  fat.  The  dissolved  chloroform 
was  then  separated  by  agitation  with  small  portions  of  ether.  Ethyl  acetate 
was  then  added  to  the  liquid  in  the  funnel,  and  the  liquid  extracted  with  it  as 
long  as  any  tannin  was  removed.  The  united  solutions  of  tannin  in  ethyl  ace- 
tate were  transferred  to  a  distilling  flask,  and  concentrated  to  dryness  under 
reduced  pressure.  The  tannin  residue  in  the  flask  was  a  porous,  pinkish  mass, 
very  friable,  and  easily  and  completely  soluble  in  water.  It  was  redissolved  in 
saturated  salt  solution,  filtered  and  again  shaken  out  with  ethyl  acetate,  which 
was  distilled  off  in  the  way  just  described.  The  tannin  residue  was  next  dis- 
solved in  cold  distilled  water,  and  shaken  out  as  before,  this  process  being 
repeated  as  often  as  necessary.  The  final  tannin  residue,  after  the  ethyl  acetate 
had  been  removed  as  far  as  possible  by  distillation,  was  treated  in  the  distilling 
flask  with  a  small  quantity  of  ether,  which,  after  permeating  the  mass,  was 
removed  by  distillation  under  reduced  pressure,  to  remove  the  odor  of  ethyl 
acetate.  The  tannin  was  then  transferred  to  a  vacuum  desiccator  and  kept  over 
sulphuric  acid  for  several  days  to  remove  the  last  traces  of  ethyl  acetate.  The 
kolatannin  from  caffein  kolatannate  was  prepared  by  decomposing  the  purified 
salt  with  lead  hydroxide.  Freshly  precipitated  lead  hydroxide,  triturated  to  a 
smooth  paste  with  warm  alcohol,  was  added  in  excess  to  a  warm  solution  of 
the  caffein  kolatannate  in  dilute  alcohol.  The  mixture  was  warmed  on  a  water 
bath  for  a  few  minutes,  with  stirring.  The  precipitate  of  lead  kolatannate, 
mixed  with  the  excess  of  lead  hydroxide,  was  allowed  to  subside,  the  superna- 
tant liquid  removed  and  the  precipitate  washed  repeatedly  with  dilute  alcohol 
until  all  caffein  was  removed.  The  precipitate  was  then  suspended  in  dilute 
alcohol  and  treated  with  hydrogen  sulphide  until  the  tannin  was  all  liberated. 
The  lead  sulphide  was  removed  by  filtration,  and  the  filtrate  concentrated  by 
distillation  in  vacuo  to  small  volume.  Eight  or  ten  volumes  of  water  were  then 
added.  This  precipitated  a  reddish  mass,  a  mixture  of  certain  anhydrides  of 
kolatannin,  which  was  filtered  out  and  set  aside. 
The  filtrate  containing  tannin,  together  with  dissolved  anhydrides,  was  now 
shaken  with  ether  once  or  twice,  which  was  thrown  away.  Then  ethyl  acetate 
was  added  and  the  tannin  separated  and  purified  in  the  way  already  described 
under  the  method  of  preparation  of  free  kolatannin.  Kolatannin  is  a  cream-col- 
ored powder,  with  a  slight  pinkish  tinge.  It  is  freely  and  completely  soluble 
in  water,  alcohol,  acetone  and  ethyl  acetate,  sparingly  soluble  in  ether,  insolu- 
ble in  chloroform  and  m  benzene.  In  properties  and  reactions  with  ferric  salts, 
bromine  and  calcium  hydroxide,  it  agrees  with  the  "oak  tannin  group,"  not 
with  the  "gall  tannin  group."  It  precipitates  metallic  salts,  alkaloids  and 
albumen,  and  produces,  with  solution  of  formaldehyde  in  the  presence  of 
a  condensing  agent,  as  hydrochloric  acid,  a  pink  precipitate  which 
becomes  red.  In  empirical  atomic  composition  it  is  homologous  with 
the  caffe tannic  acid  of  Hlasiwetz.  It  purifies  to  perfect  constancy  of  com- 
position, Ql  6H20O8,  as  found  in  repeated  preparations.    The  results  which 
