On Respiration and Animal Heat. 37 
evolution of azote takes place; and another, 
that no carbonic oxide is ever found in re- 
spired gas. | 
In a series of experiments on respiration, 
published in the Phil. Transac. 1809, by the 
same gentlemen, (see also: Nicholson’s Jour- 
nal, vol. 25.) several, curious and interesting 
results are obtained,. Among them are some 
to the following purport; 1.,That when pure 
oxygen is respired, a portion of it is missing 
at the end of the experiment, and its place 
supplied. by a corresponding quantity of azote. 
2. That a mixture of 78 hydrogen and 22 
oxygen may be inspired for an hour or more; 
it tends to produce sleep ; at the end, a defi- 
ciency of hydrogen and corresponding increase 
of azote are obseryed, more than can be as- 
cribed to the uncertain capacity of the lungs. 
3. That the lungs of a middle-sized man con- 
tain more than 100 cubic inches of air, after 
death. 
From these results, it should seem, that 
any air which can be respired would lose a 
portion in the process, and acquire an equal 
portion of azote; this may, perhaps, be occa- 
sioned by the blood parting with the common 
air, which it contains mechanically; that is, 
in the same way that water and other liquids 
gontain it, and receiving a portion of the 
