35 



animal, at the moment of its introduction into tha 

 mixed gas, could possibly contain, in the state of 

 absorbed nitrogene gas, it appears;, that, after 

 the absorbed nitrogene gas was exhaled from the 

 blood, according to the above-mentioned law, for 

 the combination of mixed gases with liquids, a 

 fresh quantity of nitrogene gas was supplied at the' 

 expence of the constituent parts of the blood, 

 which seems to have a constant tendency to pro- 

 vide itself with nitrogene gas ; and this must again 

 be exhaled, in order to divide itself between the 

 blood and the gas in the lungs. Should this con- 

 jecture be supported by future observations, it 

 will, nevertheless, always be looked upon as a 

 peculiar and uncommon chemical process, that 

 nitrogene gas should be disengaged without any 

 particular change in the composition of the blood, 

 when we consider, that nitrogene is in general " 

 disengaged only by operations more or less de- 

 structive, such as, for instance, by the effect of 

 mineral acids. 



This is at present the extent of our information 

 about the change of the air by respiration. The 

 influence which the air exercises on the blood, 

 and the changes which are thereby produced in 

 the composition of the blood, are, as yet un- 

 XI 2 



