384 
VARIETIES. 
communication affords for transmitting secret messages, an apparently- 
blank piece of paper was produced, on which a message had been impress 
ed invisibly before the meeting of the Section, and by brushing it over 
with a solution of prussiate of potass the writing became instantly legible. 
— Ibid, from Report of British Association in the Athenozum. 
Occurrence of Mercury in Corsica. — An abundant deposit of pure cinna- 
bar, which furnished 80 per cent, of mercury on analysis, has been dis- 
coveredin the above island. — Chem. Gaz., July, 1851, from Journ. de Pharm., 
March, 1851. 
On a new Cinchona Bark containing Quinoidine. By Dr. F. L. Winckler. 
■ — Among some samples of barks recently received from London, was one 
labelled Bark from Maracaibo. The author has examined this bark, and 
has obtained the remarkable result, that it contains kinovate of quinodine 
in combination with a very peculiar yellow coloring substance, which 
produces no precipitate or alteration in perchloride of iron, and a consider- 
able amount of quinate of lime, but only an exceedingly small quantity of 
quinotannine, and not a trace of quina-red. 
The hot decoction of bark obtained by treating 100 grs. with 4 oz. of dis- 
tilled water, when strained hot, was perfectly clear, pale reddish-brown, 
and did not become turbid on cooling. It had an exceedingly disagreeable 
bitter taste, not at all like bark, and could be easily filtered. The filtered 
solution, on being tested with tannin, showed the presence of a considerable 
amount of alkaloid ; perchloride of iron colored the decoction slightly 
greenish-brown, without rendering it turbid; oxalic acid precipitated lime. 
The sulphate of copper gave no precipitate, although the bark contains a 
large quantity of kinovic acid. The author explains this by assuming that 
it is firmly combined with the coloring principle and the quinoidine. In 
the alcoholie extract of the bark, the decomposition of this substance is 
not even effected by lime. — Chem. Gaz. } April, 1851, from Buchner's Be_pert., 
vol. v. p. 194. 
On the Acrid Substance of the Boot of Iris tuberosa. By M. Landerer. — 
The acrid principle of 7m tuberosa is volatile. It separates upon the water 
distilled from the root as a stearoptene, in nacreous scales. When extracted 
from the root by means of ether, this evaporation furnishes an acrid ex- 
tract, which, upon being rubbed upon the skin, produces considerable 
inflammation. — Chem. Gazette, April, 1851, from Archiv. der Pharm., 
lxv. p. 302. 
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