112 



Dr. W. Marcet. On the Chemical 



[Jan. 15, 



Table showing the Volumes of Air and Weights of C0 3 expired in 

 the final stage of the experiment compared with the corresponding 

 volumes and weights expired normally. 



This table shows unmistakably that the respiration had again 

 become normal before or by the end of the last stage of the ex- 

 periment ; the C0 2 is all but exactly the same, while there is a very 

 slight increase by 3'6 per cent, in the volume of air expired, indicat- 

 ing that there was perhaps an instinctive tendency to continue 

 breathing a volume of air slightly larger than usual, although the 

 COo expired was the same as in normal respiration. 



The following are the results obtained from the present inquiry : 



1. On re-breathing air in a closed vessel less carbonic acid is expired 

 within a given time than in ordinary breathing. 



2. Those persons who emit most CO 2 in re-breathed air are those 

 who expire most air and COo in the same time in ordinary breathing, 

 and mce versa 



3. On re-breathing 35 litres of air in a closed vessel for a period 

 of five minutes, the volume of this air undergoes a slight reduction. 



4. When fresh air is taken into the lungs immediately after re- 

 breathing air in a closed vessel, the volumes of air breathed and 

 weights of C0 2 expired are greater than in ordinary breathing. 



5. The effects produced on the chemical phenomena of respiration 

 by re-breathing 35 litres of air in a closed vessel for a period of 

 five minutes have passed away in less than six minutes after the 

 breathing of fresh air has been resumed. 



It may be added that the number of experiments is insufficient to 

 admit of any inquiry into the influence of barometric pressure on 

 respiration. 



The tables showing the general results of the experiments are as 

 follows : 



