CONDITIONS INFLUENCING THE EXCRETION OF CO.,. 



259 



lactate of soda), are injected into the blood, the taken in, and the C0 2 

 given off, undergo a considerable increase (Ludwig and Scheremetjewsky). 

 Alcohols, tea, and ethereal oils, diminish the C0 2 (Prout, Vierordt). 

 [Ed. Smith found that the effects produced by alcoholic drinks varied 

 with the nature of the spirituous liquor. Thus brandy, whisky, and 

 gin diminish the amount, while pure alcohol, rum, ale, and porter tend 

 to increase it.] 



8. The Number and Depth of the Respirations have practically no 

 influence on the formation of C0 2 , or the oxidation-processes within the 

 body, these being regulated by the tissues themselves, by some mechanism 

 as yet unknown (Pfliiger). They have a marked effect, however, upon 

 the removal of the already formed CO., from the body. An increase in 

 the number of respirations (their depth remaining the same), as well as 

 an increase of their depth, the number remaining the same, cause an 

 absolute increase in the amount of CO., given off, which with reference 

 to the total amount of gases exchanged, is relatively diminished. The 

 following example from Vierordt illustrates this : 



9. Exposure to a bright light causes an increase in the C02 given off in 

 frogs (Moleschott, 1855); in mammals and birds (Selmi and Piacentini); even in 

 frogs deprived of their lungs (Fubini); or in those whose spinal cord has been 

 divided high up (Chasanowitz). The consumption of O is increased at the same 

 time (Pfliiger and v. Platen). The same results occur in blind persons, although 

 to a less degree. Bluish-violet light is almost as active as white light, while red 

 light is less active (Moleschott and Fubini). 



10. The experiments of Grehant on dogs, seem to show that intense inflamma- 

 tion of the bronchial mucous membrane influences the COo given off. 



11. Amongst poisons, thebaia increases the C0 2 given off, while morphia, 

 codeia, narcein, narcotin, papaverin, diminish it (Fubiui). 



128. Diffusion of Gases within the Lungs. 



The air within the air-vesicles contains most C0 2 and least 0, and as 

 we pass from the small to the large bronchi and onwards to the trachea, 

 the composition of the air gradually approaches more closely to that of 

 the atmosphere (Allan and Pepys). Hence, if the air expired be 

 collected in two portions, the first half (i.e., the air from the larger air- 

 passages), contains less C0 2 (3'7vols. per cent.) than the second half 

 (5*4 vols. per cent.). This difference in the percentage of gases gives 



