A Discussion on the interchange of Gases in the Lungs. 



By 

 R. J. Anderson. 



A discussion on passage of oxygen from the air cells of the lungs 

 to the blood took place at the Autumn meeting of the British Medical 

 Association. 



The discussion was opened by Professor John J. Charles who 

 pointed out that there were two rival theories 



1. The so called difiusion theory, and 



2. The vitalistic theory, in which the secretion of oxygen by the 

 Endothelium plays an important part, in addition to diffusion and the 

 affinity of the Haemoglobin. 



Pflüger and others showed that experiments with the aerotono- 

 meter and gas pump led to the conclusion that the tension of the 

 oxygen in the air cells is greater than that in the blood in the lungs, 

 and that the gas thus pases inwards. Bohr found by using the 

 haematäerometer that the tension in Arterial blood exceeds that of the 

 air in the Trachea. Hiifner and Fredericq thought that the results 

 were susceptible of a different explanation. Haldane and Lorraine 

 Smith caused animals to breathe air containing Carbon monoxide 

 until the saturation of Haemoglobin remained constant, they then 

 drew some blood, in the case of a man, from the finger and de- 

 termined by titration with carmine the per centage saturation of the 

 Haemoglobin. 



The oxygen tension is established from the knowledge of the 

 Carbon monoxide tension. The tension of oxygen in alveolar air is 



