31 



before, till the gas over the liquid, and the part 

 absorbed by it, arrive at a certain degree of aequi- 

 libriunu As in all these experiments, the very 

 same respired air was constantly inhaled, it fol- 

 lows, that the relative quantity of nitrogene in the 

 air must have been increased, and thereby pro- 

 duced a double cause of mistakes, partly from the 

 gas, remaining in the 1 tings, containing more ni- 

 trogene ; and partly, from the circumstance, that 

 in proportion as the air in the lungs near the blood 

 contained more nitrogene, the blood itself, or ra- 

 ther the water in the blood, must absorb a new 

 quantity of nitrogene gas, in order to approxi- 

 mate to perfect saturation with this gas ; just as, 

 on the other hand, the blood, during the respira- 

 tion of gases, that contain no nitrogene, must con- 

 tinually return part of the nitrogene, which it had 

 absorbed before, which circumstance experience 

 has also fully confirmed. The cause of this mis- 

 take, therefore, did not originate in ah incorrect 

 or hasty experiment, but was the necessary 

 consequence of the state of the science at the 

 time. The experiments on respiration were last- 

 ly repeated by two English Chemists, ALLEN* 

 and PEPYS, on a larger scale, and with a preci- 

 sion, which far surpassed all examinations hither- 

 to made. In these experiments they had tlie 



