Atmospheric Air and Oxygen Gas by Respiration. 281 
7. No hydrogen, nor any other gas, appears to be evolved 
during the process of respiration. 
8. The general average of the deficiency in the total amount 
of common air inspired, appears to be very small, amounting 
only to about 6 parts in 1000, and we are inclined to attribute 
it in great measure to the difficulty in exhausting the lungs as 
completely after an experiment as before it ; the first expira- 
tion being made into the open air, the last into the apparatus. 
9. The experiments upon oxygen gas prove that the quan- 
tity of air remaining in the lungs and its appendages is very 
considerable, and that, without a reference to this circum- 
stance, all experiments upon small quantities of gas are liable 
to inaccuracy. 
Other important conclusions might perhaps be drawn from 
the facts related in this paper, but having already trespassed 
largely upon the time of the Society, we shall abstain from 
any farther remarks, until we bring forward a new series 
of experiments. 
O o 
MDcccvnr, 
