INFLUENCE OF TIME ON CHEMICAL. BODIES. 51 
ART. XII.— ON THE INFLUENCE OF TIME UPON THE. 
FORMATION OF CHEMICAL BODIES. 
By Prof. J. Liebig. 
When effloresced oxalic acid is mixed with an equal 
weight of alcohol, this liquid takes up a certain quantity 
of it, far more at a high than at the ordinary temperature. 
When the alcohol is saturated hot with it, a portion of the 
oxalic acid again separates on the cooling of the liquid. 
These facts are so well known, that they would scarcely 
deserve special mention, did not this solution gradually lose 
the above properties. In fact, when a boiling saturated 
solution of oxalic acid in alcohol, which consequently on 
cooling deposits a large amount of crystals, is kept for some 
time at a temperature of 104° to 122°, the quantity of the 
crystals deposited on cooling decreases after some days, and 
in the course of several months this liquid no longer affords 
any crystals. Long before this time a considerable amount 
of oxalovinic acid and oxalic ether may be detected in the 
solution ; and at last so much of the latter, that on the 
addition of water it separates in the usual heavy oily drops. 
On saturating the liquid with chalk, a quantity of lime re- 
mains in solution as oxalovinate ; on mixing it with am- 
monia, a considerable quantity of oxamide is obtained. 
Hippuric acid behaves in exactly the same manner. From 
a hot saturated alcoholic solution this acid crystallizes in 
the well-known long needles; but if the solution be kept 
for several weeks in a warm place, the form of the deposited 
crystals varies perceptibly, the needles become shorter and 
shorter, and the acid subsequently separates in cauliflower- 
like masses, without any distinct form. At last crystals are 
formed, which melt like an oil at a gentle heat, and possess 
all the properties of hippuric ether. 
