1Q0 CHANGES PRODUCED Itf AIR BT RESPIR-ATION. 



Air repeatedly ters, into which exactly 30O cubic inches of atmospheric 

 respired. . » • 1 rru t t 



air were admitted. 1 he operator, having made an easy ex- 

 piration, applied his mouth to the cock at the lop of the bell 

 glass, and the time being noted, began to breathe; in less 

 than a minute he found himself obliged to take deeper and 

 deeper inspirations; and at last the efforts of the lungs to 

 take in air became so strong and sudden, that the glass was 

 in some danger of being broken against the side of the gaso- 

 meter. A great sense of oppression and suffocation was now- 

 felt in the chest, vision became indistinct, and after the second 

 minute his whole attention seemed to be withdrawn from sur- 

 rounding objects and fixed upon the experiment. He now 

 experienced that buzzin the ears which is noticed in breath- 

 ing nitrous oxide, and after the third minute had only suf- 

 ficient recollection to close the cock af eran expiration. This 

 secured the result of the experiment; but he became so per- 

 fectly insensible, that, on recovering, he was much surprised 

 at rinding his friend and the assistant on thetable in theactof 

 supporting him. It was noticed that he made thirty-five in- 

 spirations during the experiment. We now examined the 

 air which had been so treated. 



theaircxa- 100 parts contained 10 carbonic acid, 



rained, . , 



4 oxigen, 



86 azote, 



100 



In this experiment it is remarkable, that the air which had 

 been so often through the lungs should only have furnish- 

 ed 10 per cent of carbonic acid, while the air which passes 

 them but once contains from 8 to 8'5. 



Here the oxigen had lost 7 from L 21; and the azote had 



gained 7 upon 79* 



We knew by previous experiment*, that every cubic inch 

 of carbonic acid gas required exactly a cubic inch of oxigen 

 for its formation ; the ten parts of carbonic acid may there- 

 fore be reckoned as oxigen, which would make the constitu- 

 tion of 



* See the experiments on carbonic acid in the Society's Transactions, 

 •r our Journal, tol. XlX, p. 223. 



the 



