70 



Dr. Marcet. Absorption of Oxygen and [June 4, 

 Mr. Eussell under experiment. 



On a consideration of the foregoing tables it will be seen that the 

 C0 2 expired (per cent, of air expired) does not represent the CO 2 

 exhaled from the blood, but the figure is much higher, as it includes 

 the CO 2 inspired, which is expired together with the proportion 

 exhaled. The volume of CO 2 actually exhaled from the blood can 

 be calculated by subtracting the proportion of CO 3 in the air 

 inspired from the corresponding proportion of C0 2 in the air expired. 

 The volumes of C0 3 actually found in the expired air have not been 

 entered in the following table (p. 71), but the figures represent these 

 volumes less the corresponding proportions of CO 2 in the air inspired, 

 and they show that the C0 2 actually exhaled from the blood is very 

 much less than in ordinary respiration. 



It will therefore be observed that nearly half the C0 2 which would 

 have been expired in natural breathing has been retained in the 

 body. Of course this is assuming that no C0 2 has been absorbed 

 directly at the lungs. Hence there must be a very great accumula- 

 tion of C0 2 in the blood when air containing C0 2 is inspired. 



It follows from this inquiry on the respiration of air containing 

 from 2*5 to 4 per cent, of C0 2 



1st. That the proportion of oxygen in 100 of air expired exhibits 

 a slight increase beyond its proportion in ordinary breathing. 



2nd. That the relation between the oxygen consumed and C0 2 pro- 

 duced is very much smaller than in ordinary respiration, amounting 

 to a mean of 0*654 for myself and 0'567 for Mr. Eussell, against a 

 total mean of 0'871 for both of us in ordinary breathing. 



