AmNJo0v.^87h9arm,}  Analysis  of  Eriodictyon  Calif ornicum.  547 
<no  residue.  Another  part  of  the  same  liquid  was  examined  for  organic 
acids  ;  a  tannic  acid  was  found,  which  precipitated  ferric  salts  green. 
To  separate  the  organic  acids  lead  acetate  in  solution  was  added 
until  further  addition  produced  no  precipitate  ;  filtered  ;  the  filtrate  was 
treated  with  ammonium  hydrate  to  a  still  feeble  acid  reaction,  and  on 
addition  of  acetate  of  lead  no  turbidity  was  produced,  thus  showing 
all  organic  acid  present  were  contained  in  the  leads  precipitate,  which 
is  absolutely  insoluble  in  boiling  water. 
The  lead  precipitate  was  dissolved  in  acetic  acid,  reprecipitated  by 
ammonia,  carefully  washed  and,  whilst  still  moist,  mixed  with  absolute 
alcohol,  and  decomposed  by  means  of  sulphuretted  hydrogen,  filtered, 
and  the  filtrate  evaporated  to  dryness,  at  a  low  temperature  ;  the  tannic 
acid  was  obtained  as  an  amorphous  brittle  substanee,  of  a  clear 
yellowish-brown  color,  having  an  astringent  acidulous  taste.  It  was 
perfectly  soluble  in  alcohol,  yielding  a  turbid  solution  in  water,  which, 
on  addition  of  solution  of  the  alkalies,  turned  to  deep  reddish-brown 
color,  and  became  perfectly  clear. 
Ferric  chloride  gives  a  green  precipitate,  turning  to  a  dirty  gray  on 
standing  ;  it  is  dissolved  by  ammonia,  yielding  a  solution  of  a  dingy 
purple  color,  and  is  decolorized  by  oxalic  acid. 
Sulphate  of  cinchonia  gives  a  copious  white  precipitate. 
Plumbic  acetate  yields  a  golden  yellow  precipitate,  not  dissolved 
by  potassic  hydrate. 
Plumbic  subacetate  yields  a  dingy-yellow  precipitate,  soluble  in  pot- 
assic hydrate. 
Tartar  emetic,  no  precipitate. 
Glue,  no  precipitate. 
Hydric  sulphate  dissolves  it  with  a  deep  crimson,  somewhat  purplish 
color. 
Argentic  nitrate — on  heating,  the  metal  is  partly  reduced  in  the  spec- 
ular form. 
Diluted  hydric  sulphate,  when  added  to  either  alcoholic  or  aqueous 
solutions,  shows  a  peculiar  behavior  by  rendering  the  solution  at  first 
milky  white,  and,  on  short  standing,  a  viscous  brownish  mass  separates. 
Fehling's  solution  then  added,  copper  is  reduced. 
This  decomposition,  effected  by  diluted  sulphuric  acid,  takes  place 
very  rapidly  at  ordinary  temperature,  and  this  fact  and  the  general 
