Action of Tannin on Organic Salifiable Bases, fyc. 231 
Hence the composition of these salts is : 
Organic Bitannates. Atoms. 
Tannin. 
Alkaloid. 
" Cinchonine, 
71,48 
72,84 
28,52 
27,16 
" Morphine, j 
" Codeine, j 
" Strychnine, j 
59,81 
62,— 
63,93 
38, 
40,19 
36,07 
" Brucine, 
60,45 
39,55 
This combination of the vegetable bases probably often 
occurs in nature, at least as regards part of the alcaloid ; 
in the Peruvian barks for example, an analogous compound of 
quinine and cinchonine with the red colouring matter (a kind 
of tannin) constitutes the abundant deposit which takes place 
on the cooling of hot decoctions of bark. This may be re- 
garded as a species of bitannate. 
The organic salts of tannic acid and the vegetable bases 
may be obtained by carefully adding a solution of pure tan- 
nin, or infusion of nut galls, to one of the alkaloid. The pre- 
cipitate, being collected and drained, when dried in the open 
air, is a white, pvlverulent, hydrated bitannate, if exposed to 
100° C. it assumes a resinous appearance and is anhydrous. 
Method of Extracting tlie Alkaloids by means of Tannin. — 
The vegetable bases exist in nature, principally in a state of 
combination with different acids, and form salts which are 
more or less soluble in water: sometimes this solubility is 
only sensible on the addition of another acid ; and it is on a 
plan analogous to that I have described for the preparation of 
sulphate of quinine, that all the vegetable alkalies may be ex- 
tracted. 
It is well known that these bodies being for the most part 
almost insoluble in water, are precipitated from their acid so- 
lutions by the addition of a slight excess of a mineral alkali, 
as potash, soda, lime, magnesia, or ammonia, when the alka- 
