366 r«- J- Anderson, A Discussion on the interchange of Gases in the Lungs. 



aperture, but as the aperture is wider at the beginning of expiration 

 than at the beginning of inspiration the expiratory murmur is less 

 marked, although continuous with the inspiratory murmur of the aus- 

 cultator. 



It requires in ordinary experiments with perforated membrane 

 considerable pressure to force air through a small aperture in it. 



It will take ten seconds to fill a flask 500 cc. with air at a 

 pressure of 75 mm. Hg. and a longer time at a lower pressure through 

 a 1 mm. aperture. It is, however, probable if there be no obstacle 

 that the air alveoli fill without difficulty. Then the velocity of the 

 air may come into question; the rate of flow of the air into an in- 

 fundibulum cannot be much more rapid than 2 inches per second, a 

 less considerable rate of flow of blood than this is supposed to affect 

 the diffusion capacity of the intestine. Then the vibratory effect of 

 the air is an element that may come also to count in the phenomenon, 

 whether the vibratory effect of waves rating at 40 — 60 per second, 

 as given by some, would be effective in shaking the carbonic acid out 

 of the membranes of the air cells and determining further combination 

 is open to question. It has lately been proved that a gas may ad- 

 here to glass even if the latter be burned or boiled. 



