CHANGES PRODUCED IN AIR BY RESPIRATION. }^J 



Cubic inches Cubic inches Results of the 



$o. Time. of common air of gas Deficiency. 1st ten experi- 



inspired. expired. ments. 



1. time not noted 3760 3741 19 



2. 11 minutes 390Q 3869 31 



3. lOf % 3624 3620 4, 



4. YOi 3570 3550 20 



5. 11 • 3685 3653 &2 



6. 11 * 3380 3355 2$ 



7. 10f 3180 3141 39 



8. 10* 336'0 3298 §2 



9- 10| 3290 3267 23 



10. 11 3580, 3543 37 



In this last experiment we ascertained, that the expired 08 of carbo- 

 gas contained 8 per cent of carbonic acid. n »c acid in the 



The breathing in these cases was as nearly natural as we The breaking 

 conceive it possible to. be in any apparatus: the operator was nearly natural 

 scarcely fatigued, and his pulse not raised more than about ^^ het 

 one beat in a minute; the respirations however were deeper 

 and fewer than natural, amounting only to about 58 in ele- ♦ 

 ven minutes, whereas from repeated observations at different 

 and distant times he makes 19 in a minute. The smallness A gre atcr de-" 

 of the deficiency surprised us very much, as, from the re- rkiency ex- 

 ports of other experimenters, we had been prepared to expect ' 

 a much greater loss. It might be objected, that the air was 

 rarefied by passing through the lungs; but this was almost 

 immediately counteracted by the mass of quicksilver in the 

 gasometers, which amounted at least to one hundred and 

 fifty pounds; and we have repeatedly noticed, that air un- 

 der these circumstances has suffered no perceptible diminu- 

 tion by standing for a considerable time; in one case, in 

 which air from the lungs was driven into the mercurial gas- 

 ometers for twenty-seven minutes, the temperature of the 

 quicksilver at the end of the experiment was not raised half 

 a degree of Farenheit's thermometer. The deficiency, in but eren this 

 our opinion, principally arises from the difficulty in bring- arises print- 

 ing the lungs precisely to the same state after, as before the f e ft ^i^the** 

 experiment; and it must be recollected, that the operator lungs. 

 commenced by a forcible expiration into the open air, but fi- 

 nished by a forcible expiration into the mercurial gasometer. 



Now, 



