But, as appears from the last section, there existed in the lungs before the inspiration of the nitrous oxide, about 32 cubic inches of gas, consisting of 23 nitrogene, 4,1 carbonic acid, and 4,9 oxygene, temperature being reduced to 59°. This gas must have been perfectly mingled with the nitrous oxide during the experiment; and consequently, the residual gas in the lungs after the experiment, was of the same composition as that in the airholder. Supposing it as before, to be about 32 cubic inches: from the rule of proportion, they will be composed of Nitrous oxide 14,7 Nitrogene 13,3 Carbonic acid 1,9 Oxygene 2,1 And the whole quantity of gas in the lungs and the airholder, supposing the temperature 59°, will equal 94 cubic inches, which are composed of Nitrous oxide 43,7 Nitrogene 39,0 Carbonic acid 5,2 Oxygene 6,1 ———— 94 But before the experiment, the gas in the lungs and airholder equalled 134 cubic inches, and these, reckoning for the common air, were composed of Nitrous oxide 100 Nitrogene, 24,3 Carbonic acid 4,1 Oxygene 5,6 Hence, it appears, that 56,3 cubic inches of nitrous oxide were absorbed in this experiment, and 13,7 of nitrogene produced, either by evolution from the blood, or decomposition of the nitrous oxide. The quantities of carbonic acid and oxygene approach so near to those existing after the respiration of hydrogene, that there is every reason to believe that no portion of them was produced in consequence of the absorption, or decomposition of the nitrous oxide. _b._ In Exp. 2, calculating in the same manner, before the first inspiration, a quantity of gas equal to 216,5 cubic inches at 47°, existed in the lungs and airholder, and these 216,5 cubic inches were composed of Nitrous oxide, 182,0 Nitrogene 24,9 Carbonic acid 4,1 Oxygene 5,5 —————— 216,5 After the compleat expiration, 160 cubic inches remained in the lungs and airholder, which was composed of Nitrous oxide 110,6 Nitrogene 36,3 Carbonic acid 6,8 Oxygene 6,3 Hence, it appears, that 71,4 cubic inches of nitrous oxide were absorbed in this experiment, and about 12 of nitrogene produced. The quantity of carbonic acid and oxygene is rather greater than that which existed in the experiments on hydrogene. _c._ From these estimations, I learned that a small quantity of nitrogene was produced during the absorption of nitrous oxide in respiration. It remained to determine, whether this nitrogene owed its production to evolution from the blood, or to the decomposition of a portion of the nitrous oxide.