406 Messrs. Allen and Pepys on Respiration. 
here the deficiency was greater than we had ever remarked 
before ; but on passing an equal quantity of common air from 
the water gasometer, and registering it in the mercurial ones, 
we were satisfied that the apparatus was quite perfect. It is, 
however, to be considered, that the respiration in this case 
was not natural, and that some small degree of force was re- 
quired when the inspirations and expirations were made in 
the mercurial gasometers, which renders this experiment 
rather different from those which had preceded it ; and it ap- 
pears to us probable, that a portion of air was forced into the 
extremities of the bronchea, which could not be suddenly ex- 
pelled by the strongest attempts at expiration. Hence also, 
perhaps, the constant though smaller deficiency, even when 
the air was only once passed through the lungs ; but when 
the process is continued for a much longer time, it is probable 
that the vessels recover their tone, and are able to expel nearly 
the whole of the volume admitted. 
The air expired in the present instance, being examined in 
the manner described in our last paper, we found that 100 
parts from each of the gasometers contained the following 
proportions : 
No. i. i o carbonic acid 
21 azote 
69 oxygen 
100 
No. 2. 10 carbonic acid 
1 1 azote 
79 oxygen 
100 
