4S4 On Respiration. 



Thus we know that 52*14 cubic inches of azote were in the 

 vessel with the animal at the be- 

 ginning of the experiment, and 

 that, of the 250 cubic inches of 

 mixed gases passed in the first 

 fifteen minutes, only 184 could 

 be expelled into gasometer C, 

 (100 : 66 : : 184 : 12-14) which 



contained only 12*14 



making together 64*28 of azote, which was all that 

 could have been expected in the first gasometer of 230 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 16'30 cubic inches of azote; we 

 found, however, about 26, and what is remarkable, in the 

 last gasometer there was no increase at all. 



Calculation for Carbonic Acid. 

 No. 1. 250. ISmin. 100 : 6*5 : : 250 : 16.25 

 2; 250. 13min. 100 : 7*5 :: 250 : 18*73 

 3. 250. 17min. 100 : 6 :: 250 : 15 



66. - 100 : 6 : : 66 : 3*96 



45 33*96 



The quantity of carbonic acid evolved in 45 minutes was 

 therefore 53*96 cubic inches, or at the rate of 1*19 cubic 

 inches per minute. 



The foregoing experiments see-m 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 the former is in nearly the same proportion to the 

 latter, as azote to oxygen in atmospheric air. 



4. That an animal is capable of breathing a mixture of 



78 parts 



