COMPOSITION OF TANNIC ACID. 
95 
dant evolution of hydrochloric acid. The gallic acid 
is converted into a yellow powder, which is washed by 
decantation with several portions of absolute ether. 
“ The ether is removed from the residue by gentle 
warming and then dissolved in a small quantity of 
water. After twelve hours’ standing the gallic acid 
crystallizes out and is removed, and to the yellowish- 
red solution is added sufficient common salt to saturate 
it, causing a separation of the resin-like mass, which is 
easily separated from the liquid and washed twice with 
saturated salt solution. 
“ The resin-like mass is dried under reduced press¬ 
ure, dissolved in a small quantity of absolute alcohol, 
to remove salt, and to the clear alcoholic solution is 
added an equal volume of ether, filtered, the solvent 
distilled off, and the amorphous residue dried in a 
vacuum. 
“The varnish-like, nearly colorless residue gives 
similar reactions, solubility, physical properties, taste, 
etc., which are considered characteristic of tannic acid. 
“ It is the first absolutely sugar-free tannic acid.” 
The amorphous residue was entirely reconverted into 
gallic acid on boiling with hydrochloric acid, and this 
gallic acid again converted into the amorphous acid by 
the phosphorus oxychloride. 
Two elementary analyses gave the following: 
i. n. 
C. 51.7 52.3 
H. 3.8 4.1 
The question in regard to the nature of tannic acid 
was answered as follows : 
