344 
Book V. 
Putrefac 
tion. 
Action ot 
sulphuric 
acid, 
Nitric acid, 
ANIMAL SUBSTANCES. 
When the solution of urea in water is kept in a boil 
ing heat, and new water is added as it evaporates, the 
urea is gradually decomposed, a very 
great quantity of 
carbonat of ammonia is disengaged, and at the same 
time acetous acid is formed, and some charcoal precipi 
tates*. 
When a solution of urea in water is left to itself for 
some time, it is gradually decomposed. A froth col 
lects on its surface ; air bubbles are emitted which have 
a strong disagreeable smell, in which ammonia and ace 
tous acid are distinguishable. The liquid contains a 
quantity of acetous acid. The decomposition is much 
more rapid if a little gelatine be added to the solution. 
In that case more ammonia is disengaged, and the pro 
portion of acetous acid is not so greatf. 
When the solution of urea is mixed with one-fourth 
of its weight of diluted sulphuric acid, no effervescence 
takes place ; but, on the application of heat, a quantity 
of oil appears on the surface, which concretes upon 
cooling ; the liquid which comes over into the receiver 
contains acetous acid, and a quantity of sulphat of am 
monia remains in the retort dissolved in the undistil 
led mass. By repeated distillations, the whole of the 
urea is converted into acetous acid and ammoniaf. 
When nitric acid is poured upon crystallized urea, a 
violent effervescence takes place, the mixture frothes, 
assumes the form of a dark red liquid, great quantities 
of nitrous gas, azotic gas, and carbonic acid gas, are 
disengaged. When the effervescence is over, there re 
mains only a concrete white matter, with some drops of 
reddish liquid. When heat is applied to this residuum, 
F Ann. de Chim. xxxi. 96. 
Ibid. 
t Ibid. p. 104.