133 



108. Mr Davy, however, taking for granted that 

 immense quantities of nitrogen gas enter into the 

 blood, observes, that " this being true, the quan- 

 tity of nitrogen produced in respiration, ought to be 

 increased in proportion as a greater quantity of ni r 

 trous oxide enters into combination with the blood *." 

 This he attempts to prove by experiment. Having 

 exhausted his lungs, he inspired the oxide out of a 

 silk bag, containing eight quarts of that gas, and thus 

 made nine respirations. The gas of the first expi- 

 ration was not preserved, but that of the seconc} 

 gave 29 of the oxide, and 1 7 parts nitrogen gas 5 

 the third was as 22 to 8 ; the fifth, as 27 to 6 ; the 

 seventh, as 23 to 7 ; and the ninth was as 26 to 1 1. 

 vSo far, therefore, from the nitrogen gas increasing 

 in proportion to the supposed combination of the 

 oxide with the blood, it observes nearly a decrea- 

 sing ratio ; and Mr Davy accordingly admits, that 

 the " results of these experiments are not so con- 

 clusive as could be wished f." He nevertheless 

 goes on to say, that " if any portion of nitrous 

 oxide were decomposed immediately by the red parr 

 tides of the blood, one should conjecture that the 

 quantity of nitrogen produced, ought to be greater 

 during the first inspirations, before these particles 

 became fully combined with condensed oxygen j." 

 And what is the fact from the experiments just re^ 

 lated ? Why, that in the second expiration, the ni- 

 trogen gas was 1 7 parts ; in the third only 8 ; and 

 in the fifth but 6 ; evidently showing that the greater 



Researches, p, 4-16. f Ibid - P- 418 - t Ibid P- 4<19 



