165 



led to suppose, that neither the carbonic acid formed 

 in respiration, nor the nitrogen gas employed in that 

 process, would exert any positively destructive ope- 

 ration on the animal powers, since both of them 

 must, at all times, necessarily be present in the sys- 

 tem ; and seeing, moreover, that the abstraction of 

 oxygen gas alone is sufficient to account for the fa- 

 tal effects which ensue, it must be deemed unneces- 

 sary to resort to the supposed agency of any subor- 

 dinate cause. 



L3 



