98 OF RESPIRATION. 



The average number of respirations in a minute in adults is 

 probably twenty. 



The common quantity of air taken in at each inspiration is 1G.5 

 cubic inches, and the quantity remaining after death in the lungs 

 of a stout adult man, about 100 cubic inches, according to Allen, 

 and Pepys. 



The quantity of aqueous vapour emitted by the lungs in expi- 

 ration may be about 20 oz. in '24 hours.* 



Camphor, phosphorus, ether, diluted alcohol, gases, and va- 

 rious odorous substances, when introduced into the system escape 

 in some measure by the lungs. 



(E) The experiment consisted in laying the lungs completely 

 bare, and supporting life by carrying on respiration artificially. 

 Hooke varied it by pricking the surface of the lungs and forcing 

 a continued stream of air through them. The following are the 

 words of Harvey : " It would appear that the use of expiration 

 is to purify and ventilate the blood, by separating from it these 

 noxious and fuliginous vapours." 



* Thomson, System of Chemistry, vol. iv. 



