PRECIPITATION BY ANIMAL CHARCOAL. 
203 
ART. XL—ON THE PRECIPITATION OF DIFFERENT ORGANIC 
AND INORGANIC SUBSTANCES BY ANIMAL CHARCOAL. 
By F. Weppen. 
From the fact that animal charcoal precipitates a number 
of very different colouring matters from their solutions, it 
was presumed that this effect was not limited to colouring 
matters, and the presumption has been substantiated by the 
following experiments, which show that animal charcoal 
likewise precipitates bitter substances, resins, and substances 
containing tannin. The charcoal used for these experi- 
ments was obtained from bone-black by repeatedly boiling 
it with muriatic acid; afterwards well washing it, and then 
exposing it to moderate red heat. 
1. Organic Substances. 
1. Bitter Substances. — Ten grains of the substance were di- 
gested with two ounces of boiling water, and the filtered infu- 
sion shaken with the charcoal, until the bitter taste had entirely 
disappeared. 
Names of the bitter substance. Quantity of charcoal. 
Wormwood 30 grains. 
Colocynth - - - 30 
Gentian Root - 20 
ColumboRoot - - - 10 
Quassia - 30 " 
Cascarilla Bark - 30 
Menyanthes trifoliata 30 " 
A solution of two grains of extract of aloes in two ounces of 
water, became quite tasteless with forty grains of charcoal. 
2. Resins. — One drachm of the tincture of guaiacum and of 
the tincture of jalap were respectively diluted with as much al- 
cohol; the first required thirteen grains, and the latter twenty- 
five grains of charcoal to precipitate the resin contained there 
