Atmospheric Air and Oxygen Gas by Respiration. 2 79 
On account of an accident we cannot give the proportions 
contained in 2 to 10 ; but the contents of the first and last 
gasometers confirm the former experiment, and shews that 
the proportion of azote continues to diminish, as the experi- 
ment proceeds, and also that there is a larger proportion of 
carbonic acid given off when oxygen is employed, instead of 
atmospheric air. 
In this recital of experiments, which have occupied a con- 
siderable portion of time, and attention, we have endeavoured 
to give a plain statement of facts, from which every one may 
draw conclusions for himself ; we shall here, however, take 
the liberty of briefly recapitulating the principal of those facts, 
and submitting what seems to us the most obvious inferences. 
1 . It appears that the quantity of carbonic acid gas emitted 
is exactly equal, bulk for bulk, to the oxygen consumed, and 
therefore there is no reason to conjecture that any water is 
formed by a union of oxygen and hydrogen in the lungs. 
2. Atmospheric air once entering the lungs, returns charged 
with from 8 to 8.5 per cent, carbonic acid gas, and when the 
contacts are repeated almost as frequently as possible, only 10 
per cent, is emitted. 
The 12th and 13th experiments prove, that when the in- 
spirations and expirations are more rapid than usual, a larger 
quantity of carbonic acid is emitted in a given time, but the 
proportion is nearly the same, or about 8 per cent. The pro- 
portions of carbonic acid gas, in the first and last portions of 
a deep inspiration, differ as widely as from 3.5 to 9.5 per cent. 
3. Considering the 11th as a standard experiment, it appears 
that a middle sized man, aged about thirty-eight years, and 
whose pulse is seventy on an average, gives off' 302 cubic 
