360 
place ; but such modification does not prove that it 
is essential to every change. The present state of 
chemical science does not enable us to trace the mo- 
difications of change which the varied application of 
the agents, concerned in the decomposition of ani- 
mal substances, would produce ; but many examples 
might be stated wherein such substances have under- 
gone remarkable changes, in situations from which 
the atmosphere was entirely excluded. 
671. So, likewise, animal substances undergo spon- 
taneous changes which enable them to afford carbon, 
when they are confined in elastic fluids deprived 
of oxygen gas. Thus, M, Huber found, that bees, 
when confined in air, afforded carbon after all the 
oxygen was consumed (133.), and this substance 
then combined with the residual nitrogen, in the 
same manner as when it was afforded by vegeta- 
bles ; facts which afford direct proof that carbon 
escapes from animal substances, in consequence of 
the spontaneous changes which they undergo, and 
that the attractive force of oxygen is not necessary 
to effect its separation. 
672. In support of the foregoing facts, the follow- 
ing experiments may, likewise, be stated. A piece 
of fresh mutton was placed in a jar containing about 
fifteen cubic inches of atmospheric air, inverted over 
mercury. The meat was supported on a small hoop 
that was fixed about half way up the jar, and, be- 
neath the hoop, a glass cup, containing water of po- 
tassa, was placed. The air gradually diminished in 
volume, and, by the third day, the mercury had 
risen to about one-sixth of the height of the jar, at 
