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dark brown precipitate. This was collected on a cloth filter, strongly 

 compressed, and washed with a little cold water to free it as much as 

 possible from adhering impurities. The precipitated tannin, when 

 boiled with dilute sulphuric acid, did not yield a trace either of grape- 

 sugar or gallic acid, but was changed into a dark brown substance 

 nearly insoluble in water. It dissolved pretty readily in alcohol, 

 forming a dark brown solution, from which, however, no crystals 

 could be obtained. 



Oak-bark from Quercus pedunculata. 



A decoction of oak-bark gave a dark brown precipitate with ace- 

 tate of lead. This was decomposed by sulphuretted hydrogen. The 

 filtered solution, when boiled with sulphuric acid, yielded grape-sugar 

 and a reddish-brown precipitate, but no gallic acid. The reddish- 

 brown precipitate dissolved with difficulty in spirit of wine, but gave 

 no crystals on standing. Rochleder has stated that tea and oak- 

 bark contain the same species of tannin. They certainly resemble 

 each other in their general characters ; but as the tannin of oak-bark 

 yields sugar when boiled with dilute sulphuric acid, while that of tea 

 does not yield a trace of sugar, it is clear that the two tannins are 

 not identical. 



Falonia, the acorn of the Quercus ^Egilops. 



This species of tannin, which has a bright yellow colour, when 

 treated in the way already described, yielded sugar, but no gallic acid. 



The tannin of pomegranate rind also gave abundant indications of 

 sugar, but no gallic acid. 



The tannin of Myrobalans, the fruit of Terminalia Chebula, gave 

 similar results. 



Tannins which give green precipitates with per salts of Iron. 



Salix triandra and Salix undulata (the willows generally used for 

 basket making). A quantity of the bark of these two willows, when 

 boiled with water, yielded a dark brown solution. This, when treated 

 with acetate of lead, gave a copious precipitate of a brownish-yellow 

 colour. This lead-salt was decomposed by sulphuretted hydrogen ; 

 and the clear filtered liquid, when boiled with sulphuric acid and 



