THE TANNINS. 
SECTION I. 
THE DISCOVERY OF THE TANNINS. 
The history of tannin as a proximate principle takes 
its beginning in France during the period between 1790 
and 1800. Previous to that time the histories of leather, 
galls, and oak-bark are our only sources of information 
regarding the development which led to the discovery 
of tannin. 
Great discoveries are rarely made without some 
warning; in reviewing their origin we see that they 
have had a gradual birth, and the exact date which in¬ 
dicates the beginning of their existence cannot be deter¬ 
mined. In these evolutions of a discovery there are 
sometimes periods of comparative inactivity, succeeded 
by sudden and great advances. The history ot tannin 
has not been an exception to the rule of gradual dis¬ 
covery, for we find among the earlier writers on the 
subject a disposition to attribute the astringency of galls 
and oak-bark to some peculiar principle, which, how¬ 
ever, they did not separate or name. 
Dr. William Lewis, in his “ Philosophical Com- 
of the Arts,'London, 1763,” calls attention to 
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