1 66  Canaigre  Tannin.  { Am  ijg;  f8h93amK 
water,  became  red.  The  washings  did  not  precipitate  silver  nitrate. 
The  filtrate  was  warmed  to  remove  the  slight  excess  of  bromine. 
The  absence  of  the  latter  in  a  free  state  having  been  proven  by- 
agitating  with  chloroform,  chlorine  water  was  then  carefully  added 
and  upon  agitating  again  with  chloroform,  the  latter  was  colored 
red  showing  bromine  compounds  to  be  present  in  the  liquid.  The 
latter  was  precipitated  by  silver  nitrate,  which  would  indicate 
hydrobromic  acid. 
The  washed  and  reddened  precipitate  was  fused  with  sodium  car- 
bonate which  rendered  the  bromine  capable  of  detection  by  silver 
nitrate  and  by  chlorine  and  chloroform. 
The  tannin  was  then  subjected  to  the  following  examinations  : 
Action  of  Heat. — 0-5  gram  of  the  tannin  were  heated  with  a  few 
cubic  centimetres  of  glycerin  at  1600  C.  for  twenty  minutes  and 
then  raised  to  1900  C.  for  a  few  minutes,  at  which  temperature  con- 
siderable effervescence  occurred.  The  mixture  upon  cooling  was 
shaken  with  several  portions  of  ether,  sp.  gr.  -725,  which  upon 
being  separated  and  evaporated  yielded  a  residue  of  small  square 
yellow  crystals.  But  for  a  small  amount  of  resinous  substance 
soluble  in  alcohol,  the  crystals  were  completely  soluble  in  water  and 
gave  the  following  characteristic  reactions  of  catechol : 
Calcium  hydrate,     .  .  .  .  {  red  color>  turninS  brown  and  gradua% 
I  precipitating. 
Ferric  chloride,    .  .   ,  .  .      brownish-green  color. 
Ferric  acetate,  ......      brownish-green  ppt. 
Ferrous  sulphate,    .  .  .  .  j  no  chan^e'  UPon  standin£  a  slight  blue 
v-     ppt.,  the  liquid  remaining  colorless. 
Action  of  Acids  {Hydrolysis). — Two  grams  were  boiled  with  two 
per  cent,  (absolute  gas)  hydrochloric  acid  for  three  hours,  during 
which  an  amphorous,  red,  insoluble  substance  separated. 
The  contents  of  the  vessel  were  allowed  to  cool,  then  filtered,  the 
insoluble  red  substance  washed  with  water  and  dried  over  sulphuric 
acid.  The  red  filtrate  was  evaporated  to  dryness  on  a  water-bath 
and  the  residue  treated  with  water,  which  it  slightly  colored. 
The  insoluble  red  substance  was  filtered  off,  the  filtrate  shaken 
with  several  portions  of  ether,  sp.gr.  -725,  which  removed  a  color- 
less crystalline  substance,  the  ether  removed  frorrl  the  aqueous 
liquid  by  warming,  the  latter  cooled  and  precipitated  by  basic  lead 
acetate,  filtered,  excess  of  lead  removed  from  filtrate  by  means  of 
