Ana.  Jour.  Pharm.  \ 
December,  1894.  J 
Rnbiis  Villosus. 
587 
liquid  a  yellowish  crystalline  substance  which  was  shown  by  the 
following  tests  to  be,  most  likely,  gallic  acid  : 
Potassium  cyanide,  bright-red  color. 
Aqueous  solution  of  picric  acid  followed  by  ammonia,  deep-brownish  color. 
Ammonio-silver  nitrate,  immediate  reduction. 
Lead  acetate,  yellowish-white  precipitate. 
Ferric  chloride,  greenish-black  color. 
Ferrous  sulphate,  no  change  ;  but  on  exposure,  gradually  acquired  a  bluish 
color. 
Action  of  Heat — 0-3  gram  of  tannin  was  heated  with  5  c.c.  of 
glycerin  at  1600  C,  for  twenty  minutes,  and  then  raised  to  2000  C, 
after  which  it  was  allowed  to  cool.  The  mixture  was  repeatedly 
shaken  with  stronger  ether,  which,  on  evaporation,  left  a  yellowish- 
brown,  crystalline  residue.  An  aqueous  solution  of  the  latter  gave 
the  following  reactions  : 
Calcium  hydrate,  reddish-brown  ppt.,  soluble  in  excess  of  reagent. 
Ferric  chloride,  deepening  of  color. 
Ferric  acetate,  grayish-brown  ppt.,  with  greenish  fluorescence. 
Fehling's  solution,  reduced. 
Ammoniacal  picric  acid  solution,  deepening  of  color. 
Lead  nitrate,  faint  cloudiness. 
Lead  acetate,  faint  cloudiness. 
Tartar  emetic,  faint  cloudiness. 
Ferrous  sulphate,  no  change  at  first,  but  solution  gradually  acquired  a  bluish 
color,  which  was  lost  upon  standing. 
With  some  differences,  the  above  tests  correspond  to  those  for 
pyrogallol. 
Action  of  Acids  {Hydrolysis). —  0-5  gram  of  the  tannin  was 
dissolved  in  100  c.c.  of  two  per  cent,  (absolute  gas)  hydro- 
chloric acid,  and  this  solution  boiled  under  an  upright  condenser  for 
three  hours.  The  solution  was  allowed  to  stand  for  twenty-four 
hours,  and  then  filtered,  to  remove  the  blackish  precipitate  produced 
by  the  action  of  the  acid.  This  substance  was  insoluble  in  both 
cold  and  hot  water,  but  readily  soluble  in  alcohol,  and  in  alkali 
hydrate  solutions,  with  a  deep-brown  color. 
The  alcoholic  solution  was  not  precipitated  on  pouring  it  into  an 
excess  of  water. 
The  reddish-brown  filtrate  was  shaken  with  successive  portions 
of  ether,  sp.  gr.  -725,  which  were  mixed  and  set  aside  to  evaporate. 
A  yellow,  crystalline  residue,  which  contained  gallic,  and  probably 
ellagic  acids,  was  obtained.    The  aqueous  solution  was  warmed  to 
