NOTE UPON TANNIN. 
233 
•Aqueous solution of nut galls and extraction of the 
tannin which it contains. 
{&. Nut galls in fine powder, 4 oz. 
Distilled water, 8 " 
Mix. After two hours, pour the mixture upon a paper 
filter placed in a funnel. Place under it a vessel to receive 
the liquid which filters through, and when it has ceased to 
run, add two ounces of sulphuric ether to the solution ob- 
tained, the quantity of which will be about four ounces. 
Shake the mixture for a few minutes; pour it into a funnel 
with a stop cock. After standing a few moments, the liquid 
tannin which forms, will occupy the lower portion of the ves- 
sel. Separate it, and repeat the operation until no more liquid 
tannin is formed. Dry what has been obtained by the heat 
of a stove, carried to 100° C. 
By this method the whole of the tannin contained in the 
solution of nut galls cannot be obtained. About two-thirds 
remain in solution, a fact which depends upon some circum- 
stance to be determined. 
Theory of the extraction of Tannin by ether. 
M. Pelouze, in the memoir cited, thus expresses himself 
upon the subject of the extraction of tannin. 
" Of all the substances which constitute nut galls, that 
which is most soluble in water, and which has the greatest 
affinity for this liquid, is tannin. 
" When, therefore, nut galls in fine powder are brought in 
contact with ether containing water, the tannin seizes upon 
the water contained in the ether, forms with it and a certain 
quantity of ether a very dense syrup, which by degrees is 
pushed from the filter into the decanter by the upper layers of 
ether, which in this case perform the office of a piston. A re- 
markable fact, which equally explains itself ; the liquids are 
scarcely colored, while if the residue of the nut galls be treat- 
ed with distilled water, there is extracted a reddish-brown 
vol, vi. — NO. III. 
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