Messrs. Allen and Pepys on Respiration . 427 
could have been expected in the first gasometer of 250 after 
respiration, supposing the whole of the common air had been 
expelled, but we detected 112,50, or an increase of 48,22 
cubic inches in fifteen minutes. 
The second gasometer before it was connected with the glass 
A, contained but 16,50 cubic inches of azote ; we found how- 
ever about 26, and what is remarkable, in the last gasometer 
there was no increase at all. 
Calculation for Carbonic Acid. 
No. 1. 
250. 
15 
min. 
100 : 6,5 
: 250 : 
16,25 
2, 
250. 
13 
min. 
100 : 7,5 
: 250 ; 
18,75 
3 - 
250. 
17 
min. 
100 : 6 
: 250 : 
15 
66. 
- 
100 : 6 
. 66 : 
3’9S 
4 5 53’9® 
The quantity of carbonic acid evolved in 45 minutes was 
therefore 53,96 cubic inches, or at the rate of 1,19 cubic in- 
ches per minute. 
The foregoing experiments seem to prove, 
1. That when atmospheric air alone is respired, even by an 
animal subsisting wholly upon vegetables, no other change 
takes place in it, than the substitution of a certain portion of 
carbonic acid gas, for an equal volume of oxygen. 
2. That when nearly pure oxygen gas is respired, a por- 
tion of it is missing at the end of the experiment, and its place 
supplied by a corresponding quantity of azote ; the portion 
evolved in a given time, being greater in the early than in 
the later periods. 
3. That the same thing takes place when an animal is 
made to breathe a mixture of hydrogen and oxygen, in which 
