256 



DAILY QUANTITY OF GASES EXCHANGED. 



125. Daily Quantity of Gases Exchanged. 



As under normal circumstances more is absorbed than there is 

 CO given off (equal volumes of and C0 2 contain equal quantities of 

 0), a part of the must be used for other oxidation-processes in the 

 body. According to the extent of these latter processes, the ratio of 

 the taken in to the C0 2 given out 



O906 normally) must vary. 



The amount of C0 2 given off may be less than the " mean " above 

 stated. The quantity of C0 2 alone is not a reliable indication of the 

 entire exchange of gases during respiration ; we must estimate simul- 

 taneously the amount of absorbed, and the C0 2 given off. 



126, Review of Daily Gaseous Income and 



Expenditure. 



Income In 24 hours. 



Oxygen 



744 grms. = 516'500c.cmtr. (Vierordt) 



(At 0C and mean barometric 

 pressure. ) 



Expenditure in 24 hours. 

 Carbonic Acid 



900 grms. = 455500 c.cmtr. (Vierordt). 



36 grms. ]>er hour (Scharling). 



32'S-33'4 grms. ,, (Liebermeister). 



34 grms. . ,, . (Panum). 



31-5-33 grms. ,, . (Ranke). 



Water 640 grms. . . (Valentin). 



330 ,, . . (Vierordt). 



127, Conditions Influencing the Gaseous Exchanges. 



The formation of C0 2 , in all probability, consists of two distinct 

 processes. First, compounds containing C0 2 seem to be formed in 

 the tissues which are oxidation products of substances containing carbon. 

 The second process consists in the separation of this C0 2 , which, how- 

 ever, takes place without the absorption of O. Both processes do not 

 always occur simultaneously, and the one process may exceed the other 

 in extent (L. Hermann, Pfliiger). 



According to Schmiedeberg, the oxidation in the tissues depends upon a 

 synthesis with the liberation of H 2 0, the blood supplying the necessary 0. 



The following affect these processes : 



1. Age. Until the body is fully developed, the C0 2 given off increases, 

 but it diminishes as the bodily energies decay. Hence, in young persons 

 the absorbed is relatively greater than the C0 2 given off ; at other 

 periods both values are pretty constant. Example : 



