PEOCEEDINGS OF 



THE ROYAL SOCIETY. 



Section B. — Biological Sciences. 



The Causes of Absorption of Oxygen by the Lungs in Man. 



[Preliminary Communication.) 

 By C. Gordon Douglas, B.M., Fellow of St. John's College, and. 

 J. S. Haldane, M.D., LL.D., F.R.S., Fellow of New College, Oxford. 



(Received February 23— Read March 23, 1911.) 



In a previous communication* we gave a short account of experiments on 

 mice, showing, by the carbon monoxide method of determining the partial 

 pressure of oxygen in the arterial blood, that when want of oxygen is pro- 

 duced by administering to these animals a relatively high percentage of 

 carbon monoxide in the air breathed, active secretion of oxygen inwards 

 through the lung epithelium occurs, although in resting animals the passage 

 inwards of oxygen is apparently due to nothing but simple diffusion. 



It was very desirable to extend these experiments to man, as the main 

 chemical factors in respiration can be much more satisfactorily investigated 

 in man than in lower animals, and we have now succeeded in obtaining a 

 number of results in man. In the case of a man it would require many 

 hours to complete an experiment made by exactly the same method as was 

 employed for mice and rabbits. We have therefore adopted the plan of 

 first rapidly administering sufficient carbon monoxide to bring the blood to 

 the required degree of saturation with the gas, and then allowing the subject 

 to breathe into a closed space of about 15 litres, in the air of which the 

 carbon dioxide is absorbed and the oxygen kept constant on the principle 

 of Regnault and Reiset. The partial pressure of carbon monoxide in this 

 air becomes equal in a few minutes to that in the blood, and part of 

 this air is thereafter used for saturating the sample of the subject's blood, 

 * ' Eoy. Soc. Proc.,' B, 1910, vol. 82, p. 331. 

 VOL. LXXX1V. — B. B 



