1881.] On the Influence of Altitude upon Respiration. 423 



If altitude, or a fall of atmospheric pressure, with which I couple 

 increased dryness of the atmosphere, exerted no influence on the 

 amount of carbonic acid expired, independently of temperature, the 

 combustion within the body would be regulated by the temperature 

 of the air only, all other circumstances supposed to be similar ;* in 

 that case the weight of carbonic acid at Yvoire and at Courmayeur, 

 reduced to equal temperatures, would have been the same. We find, 

 however, that such is not the case, and that, after reducing the 

 carbonic acid for Yvoire to the temperature corresponding to that of 

 Courmayeur, a marked excess of carbonic acid is expired at Cour- 

 mayeur, and that this applies to both of us, as is clearly seen in the 

 following table : — 



Table showing the theoretical excess of C0 2 expired at Courmayeur 

 over that expired at Yvoire (difference of altitude, 2,715 feet) for 

 equal temperatures. 



Myself (Courmayeur, 1st Series). 



C0 2 at Courmayeur (1st Series) 0"494 . . t. air 76°'l 



C0 2 at Yvoire (2nd Series) 0'572 . ". t. air 60 c> 3 



C0 2 at Yvoire (2nd Series) reduced for 1 n.^g a ^ 75° i 

 temperature 



Increase of C0 2 expired at Courmayeur 8*3 per cent. 



Myself (Courmayeur, 2nd Series). 



C0 2 at Courmayeur (2nd Series) 0492 . . t. air 77°'0 



C0 2 at Yvoire (2nd Series) 0-572 . . t. air 60°'3 



C0 2 at Yvoire (2nd Series) reduced for) a a aq h^o A 



. , > U*44io . . at 7/ '0 



temperature J 



Increase of C0 2 expired at Courmayeur 8*9 per cent. 



M. David (Courmayeur, 1st Series). 



C0 2 at Courmayeur (1st Series) 0727 . . t. air 7F'2 



C0 2 at Yvoire 0776 . . t. air 61°-6 



C0 2 at Yvoire reduced for temperature. .. . 0*671 .. at 71°"2 

 Increase of C0 2 expired at Courmayeur 7" 7 per cent. 



M. David (Courmayeur, 2nd Series). 



C0 2 at Courmayeur (2nd Series) 0727 . . t. air 72°- 2 



C0 2 at Yvoire 0776.. t. air 6l°-6 



C0 2 at Yvoire reduced for temperature. . . . 0*662 . . at 72° - 2 

 Increase of C0 2 expired at Courmayeur 8*9 per cent. 



* There exist apparently other circumstances besides food and temperature of the 

 air exerting an influence on the amount of carbonic acid expired, but neutralising 

 each other in a series of experiments. 



VOL. XXXI. 2 H 



