AND MAGNUS. 547 



from ^ to -j^o cubic inch of carbonic acid in 

 from 6 to 12 hours, in gases that contain no 

 oxygen ; or nearly as much as they generate 

 in atmospheric air. (Elements of Physiology, 

 p. 339.) 



But it is impossible to reconcile these results 

 with the experiments of Mr. Ellis, who found that 

 carbon (not carbonic acid,) was exhaled from the 

 stigmata of bees and other insects, after all the 

 oxygen of the air in which they were confined 

 was consumed. (Inquiries, Sections 133, 137, 

 and 671.) The formation of carbonic acid in the 

 blood is also disproved by the fact, that variable 

 proportions of carbon and hydrogen are given 

 off by venous blood while passing through the 

 lungs, as shown by their diminished quantity in 

 arterial blood, according to the analyses of Mi- 

 chaelis. 



That different gases may exist in a state of me- 

 chanical mixture with the blood, and be separated 

 from it by means of the air pump, has been shown 

 by the experiments of Magnus, who found the 

 proportions of carbonic acid, oxygen, and nitro- 

 gen, in the arterial and venous blood of the horse 

 and calf, as follows ; making from 10 to 12^ per 

 cent, of gaseous matter by volume. 



Horse. Calf. 



Arterial. Venous. Arterial. Venous. 



Carbonic acid 17.7 18.8 16.4 16.3 



Oxygen 6.3 4.8 6.5 2.8 



Nitrogen 2.5 2.8 4.2 1.9 



