186 



An excess of 

 expired ait. 



Component 

 parts of the 

 expired' gas. 



CHANGES PRODUCED IN AIR BY RESPrRATIQN. 



Here, as usual, the lungs were exhausted both before, an# 

 at the close of the experiment. 



The excess of eleven cubic inches, in this case, no doubt, 

 arose from the person not having been in the habit of ex- 

 hausting his lungs, so that they contained more when he be- 

 gan than when he left off; his lungs appeared to be of 

 greater capacity than those of the usual operator. 



Portions of gas were saved from each of the mercurial 

 gasometers as they were filled, which being mixed together, 

 for the average gave the following results: 



100 parts of the mixture contained 



8*5 carbonic acid 

 12*5 oxigen 

 79 azote. 



100. 



Calculation for Carbonic AcicL 



100 



8-5 



3311 : 281*43. 



Consequently 28 1*43 cubic inches of carbonic acid gag wen;, 



given off in 6| minutes. 



The carbonic ' In this experiment we meet with a remarkable fact, viz. 



ga \-l m » ? lu' that as much carbonic acid gas was given off in 5f- minutes, 

 portidn to the . • 



^ir respired, as in the former experiment in eleven minutes ; so that it 

 -appears, whenever atmospheric air is taken into the lungs, 

 it returns charged with about 8 per cent of carbonic acid. 

 The faster respiration is performed, the more carbonic acid is 

 v given off, and consequently the more oxigen consumed : in 

 this instance it was given off at the rate of fifty-one cubic 

 inches per minute. 



Thirteenth Experiment. 



13th experi- ^ e aow proceeded to carry .on the respiration of common 



ment with a i r for a much longer period than usual, and of course on a 



quantity of much larger quantity. The experiment was made by the 



air. same operator who had performed all the others, except the 



12th. Eleven mercurial gasometers having been filled, 



taken off, and registered, the operator continued to breathe 



in the 12th until a mark was made by his colleague upon 



the 



