EXAMINATION OF THE BARK OF MONESIA. 
157 
orown acidulous liquid, of styptic taste at first, then very 
acrid, we placed fragments of parchment, previously well 
washed and softened. 
Tannin, or Tannic Acid. 
After forty-eight hours the organized membrane was swol- 
len and hardened by the combination with tannin. This hav- 
ing been accomplished, the liquid no longer evinced tannin 
with the sulphate of iron. This was filtered anew, at the same 
time washing the parchment, and evaporated to dryness with- 
out loss. The difference of weight of the dry extract, with 
that which it possessed originally, indicates nearly the pro- 
portion of tannin. The extract still preserved its brown color ; 
it was acid from malic acid, and its acrid taste was well 
marked. 
Red Coloring Matter — a kind of Cinchona Red. 
The residue, treated by alcohol, at 25°, completely dissolved 
in this menstruum. An excess of slacked lime was then 
added, in fine powder, or acetate of lead, and immediately 
there was formed a rose gray precipitate, or wine dregs, pro- 
duced by the combination of coloring matter with the oxide 
of calcium or that of lead. 
This substance, which very much resembles what is found 
in catechu, in kino, and especially in the bark of Peru, (red 
cinchona,) was disengaged from its combination with the 
oxide of lead by means of sulphuretted hydrogen and the pro- 
per treatment. It was of a reddish brown color, little soluble 
in strong alcohol, more so in water or alcohol, at 25°. Its 
taste was slightly acrid; and under the influence of potassa, it 
appeared capable of precipitating tannin like gelatine, and be- 
coming black with the sulphate of iron ; properties recognised 
by MM. Pelletier and Caventou in the red insoluble matter 
of cinchona. 
The alcohol, scarcely colored, retained an acrid substance, 
which we proceeded to examine, and which remained after 
the most cautious evaporation of the menstruum. When the 
