131 



sorbed, and partially decompounded at 98% by a fluid 

 possessed apparently of uniform attractions *." To 

 this it may be replied, that the difficulty of decom- 

 posing a substance by some bodies, in certain cir- 

 cumstances, at a high temperature, is no proof that 

 it cannot be decomposed, by other bodies, in other 

 circumstances, at a low temperature. This oxide, 

 Mr Davy believes, to be in some manner decom- 

 posed by the blood during its circulation with that 

 iiuid : but, does the temperature of the blood ex- 

 ceed that of the lungs ? Even out of the body, and 

 in the ordinary temperature of the atmosphere, the 

 experiments of Mr Davy (97.) evince, that this 

 oxide can be partially decomposed by venal blood. 



107- According to the earliest and the latest ex- 

 periments of M. Lavoisier on the respiration of at- 

 mospheric air, its nitrogen gas was considered to be 

 in no respect affected by that function ; in which 

 conclusion Goodwyn, Menzies, and most other au- 

 thors, have acquiesced : and we have seen that this 

 gas is not affected by the growth of vegetables, 

 (5. 29.), nor by the respiration (73.) of the inferior 

 animals. Dr Priestley, however, at one time sup- 

 posed, that the oxygen gas passing the membrane of 

 the lungs, carried with it some part of the nitrogen 

 with which it was previously combined ; but, on the 

 suggestion of Sir Charles Blagden, he afterwards 

 thought it more probable that the deficiency of ni- 

 trogen gas was owing to the greater proportion of it 

 existing in the lungs after the process than before f. 



* Researches, p. 415. 



-\- Experiments on Air abridged, vol. iii. p. 380. 

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