of Respiration at different Periods of the Day. 413 



No. 1. 99-5 parts, became 95*5 .'. loss = 4-02 per cent. 

 96-5 do. do. 93- .-. do. 3*62 do. 



2)7-64 



.*. average loss = 3"82 per cent, 

 wliich, corrected for tension, will be 3*93 per cent. 



No. G. Bag. 101 parts, became 95-75 .*. loss = 5-20p.cent. 

 113-5 do. do. 108- .'.do. 4-84 do. 

 126 do. do. 120 .'. do. 5-00 do. 



3)15-04 



.*. average loss = 5*01 p. cent. 

 which, corrected for tension, will be 5*12 per cent. 



These experiments, made during the same day, and at an 

 interval of exactly 12 hours, the one confirming the other, 

 sho5v that an increase of carbonic acid gas is eliminated by 

 protracting the respiratory process, which increase (from the 

 average of the present experiments) amounted to one fourth 

 more than the quantity of carbonic acid gas found in natural 

 respirations. 



These results show at once the expediency of reducing the 

 quantity of carbonic acid gas obtained by the experiments of 

 Messrs. Allen and Pepys by one fifth part. The 8 per cent, 

 will then become 6-4 per cent. 



Considering then that Messrs. Allen and Pepys's opera- 

 tions were carried on at periods of the day in which I have 

 shown the respiration to contain its maximum quantity of car- 

 bonic acid gas, viz, before breakfast, and immediately before 

 dinner, and that, although the absolute volume of respired 

 air upon which they operated was very considerable, yet it 

 was the volume obtained at one period of the day ; and that 

 although their experiments upon this large volume of air 

 were very numerous, yet the volumes themselves were not 

 renewed above thrice ; it appears that we may rely upon 

 their demonstration that the air which they examined would, 

 if respired in the natural manner, have contained 6-4 per cent, 

 of carbonic acid gas, which quantity is almost the maximum 

 that occasionally occurs at the most favourable periods for its 

 production. 



Having very many times examined the air respired by otlier 

 individuals, I have never yet met with a single instance which 

 did not accord with the avei-ages already detailed. 



