26 
THE TANNINS. 
water and tested for pyrogallol and catechol, according 
to the following: 
One pee cent. Solutions op 
Pyrogallol. 
Catechol. 
Ferric chloride . . . 
Red color, turning 
brown. 
Green color. 
Ferric acetate . . . 
Dark-purple color. 
Green color. 
Lime-water .... 
Purple color, turn¬ 
ing brown. 
Clear red color. 
Melting-point . . . 
Pine wood moistened 
131°. 
111°. 
with HC1. 
No change. 
Violet color. 
The above tests will readily distinguish between 
pyrogallol and catechol when either occurs singly or 
mixed with only a small proportion of the other, but 
when they occur in a solution in nearly equal propor¬ 
tions it becomes a matter of much more difficulty. 
The tannin should be free from gallic acid and catechin 
before submitting it to the above operation, or else 
pyrogallol will be obtained from the former and cat¬ 
echol from the latter; this may be Accomplished by 
thorough agitation of an aqueous solution of the tannin 
with ether and separation of the latter, the water is 
then rapidly distilled from the tannin under reduced 
pressure. 
It has been found by the author, in carrying out the 
application of heat to tannins, that there is a practical 
difficulty iu separating the ethereal layer containing 
pyrogallol and catechol when the 5 cc. of glycerin, 
after the application of heat, are dissolved in 20 cc. 
of water and agitated with ether. The emulsion formed 
