610 FUNCTIONS OF ANIMALS. 



breathed for some time without destroying the animal, but death 

 ensues at last, provided their action be long enough continued. 

 To this class belong the nitrous oxide and oxygen gas.* 4. The 

 fourth set may be breathed any length of time without injuring 

 the animal. Air is the only gaseous body belonging to this class. 



Let us now endeavour to state the phenomena of respiration 

 with as much precision as possible : 



1. From the experiments of Messrs Allen and Pepys, it ap- 

 pears that the lungs of a stout man about five feet ten inches 

 high, after a full expiration, still retain 108 cubic inches of air. f 

 The previous determination of Goodwyn very nearly agrees with 

 this. He reckoned the air in the lungs after an expiration, to 

 be 109 cubic inches.:]: 



In order to discover the capacity of the lungs, I made twelve 

 individuals, young men from fourteen to thirty-three years of 

 age, make a full inspiration and then expel from the lungs as 

 much air as they could. The following table exhibits the results : 



1. . 100 cubic inches. 



2. ... 140 



3. . . 163 



4. ... 180 



5. . . 193 



6. ... 200 



7. :>: ^ . 200 



8. .,,.>. . . 200 



9. . . 200 



10. . . . 200 



11. . . 210 



12. . . 250 



The individual who could expel only 100 cubic inches of air 



* Perhaps also nitrous gas might have the same effect, if it could be breathed 

 by an animal whose lungs contained no oxygen. 



f Phil. Trans. 1809, p. 410. J Goodwyn on Respiration, p. 27. 



Mr Thackrah mentions a tall young cornet who was able to throw out 10| 

 pints of air from his lungs. If he means wine pints, as is likely, the quantity 

 thus thrown out was 296 cubic inches. See Thackrah on the effects of different 

 arts, trades, and professions on health, p. 16- He reckons the average in adults 

 to be 219 cubic inches. He says that the capacity of the female chest is less 

 than that of the male, which he ascribes to the wearing of tight stays. The 

 mean quantity of air thrown out of the chest of ten females aged 18, and in 

 good health, by a forced expiration, was 3 pints, or only 10 i cubic inches. 

 Ibid. p. 96. 



