132 



RESPIRATION. 



LECT. VI. 



experiments. It was invariably found that the hydrogen or 

 azote was absorbed, and in its place carbonic acid and 

 azote were exhaled. In pure azote, it was carbonic acid 

 only. By introducing, by a syringe, a mixture containing 

 more oxygen than exists in atmospheric air, after having 

 exhausted the lungs by a syringe, it was observed that the 

 exhaled carbonic acid was in greater proportion than that 

 which is disengaged by respiring air. Frogs produce car- 

 bonic acid in hydrogen and in azote, even when they have 

 been deprived of their lungs. 



Conclusion. From all that has been stated, we cannot 

 hesitate to conclude, that the respiratory function is a purely 

 physico-chemical phenomenon ; that the gases dissolved in 

 venous blood are set free by the absorption of other gases ; 

 that a portion of the carbonic acid of venous blood is ex- 

 haled by the absorption of atmospheric oxygen by this 

 blood ; that it is not in the lungs, at least for the most part, 

 that the expired carbonic acid is formed ; that this gas exists 

 dissolved in venous blood, and is set free, during the act 

 of respiration, by the presence of oxygen, which is intro- 

 duced in the same manner as is done by azote or hydrogen 



gen almost exactly agreed with those reckoned according to the law of the 

 diffusion of gases : 



Chemical Gazette, vol. ii. 1844, p. 159. J. P. 



