The gas in the jars was examined. That in the oxygene jar filled a space exactly equal to 12,7 cubic inches, and analised, was found to consist of 1,7 carbonic acid, 2,6 of nitrogene, and 8,4 of oxygene. So that absolutely, 2,1 cubic inches of oxygene and,4 of nitrogene had been consumed, and 1,7 of carbonic acid produced.
The gas in the atmospheric air jar was diminished nearly to 14,4, and consisted of 2,1 carbonic acid, 1,4 oxygene; and 10,9 nitrogene. So that 2,7 of oxygene and,5 of nitrogene, had been consumed by the mouse; and 2,1 of carbonic acid produced.
Hence it appears, that the mouse in atmospheric air consumed nearly one third more oxygene and produced nearly one fourth more carbonic acid in respiration in 55 minutes, than the other in an hour and quarter in oxygene. And if we consider the perpetual diminution of the oxygene of the atmospheric air; from which at last it became almost incapable of supporting the life of the animal; we may conclude, that the quantity of oxygene consumed by it, had the air been perpetually renovated, would have been much more considerable.
I design very shortly, to repeat these experiments, and to make others on the comparative consumption of oxygene and atmospheric air, by the larger quadrupeds. Whatever may be the results, I hope to be able to ascertain from them, why pure oxygene is incapable of supporting life.
VIII. Observations on the changes effected in the blood, by
atmospheric air and oxygene.
From the experiments of Mr. Cigna and Dr. Priestley,[202] it appears that the coagulum of the venous blood becomes florid at its surface when exposed to the atmosphere, though covered and defended from the immediate contact of air by a very thick stratum of serum.
Hence it is evident, that serum is capable of dissolving either the whole compound atmospheric air, or the oxygene of it.
Supposing what indeed is most probable from numerous analogies, that it dissolves the whole compound; it would follow, that the coloring of the coagulum of blood under serum, depended upon the decomposition of the atmospheric air condensed in the serum, the oxygene[203] of it combining with the red particles, and the nitrogene either remaining dissolved in the fluid, or being liberated through it into the atmosphere.
Now the circulating blood consists of red particles, floating in and diffused through serum and coagulable lymph.
In natural respiration, the red particles are rendered of a brighter tinge during the passage of the blood through the pulmonary veins. And as we have seen in the last sections, during respiration atmospheric air is decomposed; all the oxygene of it consumed, apparently a small portion of the nitrogene lost, and a considerable quantity of carbonic acid produced.