EXAMINATION OF THE SUBSTANCE OF WENS. 159 
or after being extinguished with cold water, into an acid 
solution of sulphate of copper, the metal is gradually depo- 
sited upon the charcoal until it may be entirely recovered. 
In neutral or alkaline liquors the reaction is not so well per- 
formed. In Barreswill’s liquor, for instance, the copper 
deposited upon the charcoal has a very beautiful iridescent 
appearance. When nitric acid, hydrochloric acid, or sul- 
phuric acid is used to acidify the solutions, the effect is the 
same, only that it is clearest with sulphuric acid. 
2d. I have observed that the metallic salts of organic 
acids are less easily decomposed than those which contain 
mineral acids. 
3d. The solutions of silver in nitric acid, whether neutral 
or acid, and chloride of silver dissolved in ammonia, are 
easily decomposed by freshly calcined wood charcoal. The 
silver is soon seen to cover the charcoal in the most beautiful 
manner ; it sometimes appears crystallized. 
4th. Copper may, by this same means, be precipitated 
from ammoniacal solutions; but if these solutions likewise 
contain silver, the latter w T ill be first reduced. 
5th. Finally, incandescent wood charcoal plunged in 
Fowler’s solution, acidified with sulphuric acid, produces a 
very agreeable ether which I intend to examine. It w ill be 
easy to make in this way, by varying the acids, nitric, acetic, 
sulphuric ethers, &c. 
6th. Zinc, iron, platinum, lead, and mercury may be pre- 
cipitated by wood charcoal, but they re-dissolve in acid 
liquors; this does not occur at all w 7 ith silver, and with 
copper not until twenty-four hours after the operation. — 
Comptes Rendus and Chemist. 
CHEMICAL EXAMINATION OE THE SUBSTANCE OF WHICH 
WENS ABE COMPOSED. 
By J. L. Lassaigne. 
We generally know by the name of wens encysted tumours, 
situated under the skin, circumscribed, moveable, and capable 
of attaining to a considerable size. These tumours, according 
to the nature of the matters which they contain, bear in 
pathology, various names. 
In a work undertaken in 1852, by Dr. Legrand, that 
physician having furnished us with numerous opportunities 
of chemically examining several of these tumours, which he 
