_f._ A goldfinch lived for near five minutes in a mixture of equal parts nitrous oxide and oxygene, without apparently suffering. Taken out, he appeared faint and languid, but finally recovered.[187] [187] Small birds suffer much from cold when introduced into gases through water. In this experiment, the goldfinch was immediately inserted into a large mouthed phial, filled with the gases, and opened in the atmosphere. VI. _Recapitulation of facts relating to the respiration of Nitrous Oxide, by warm-blooded Animals._ 1. Warm-blooded animals die in nitrous oxide infinitely sooner than in common air or oxygene; but not nearly in so short a time as in gases incapable of effecting positive changes in the venous blood, or in non-respirable gases. 2. The larger animals live longer in nitrous oxide than the smaller ones, and young animals die in it sooner than old ones of the same species. 3. When animals, after breathing nitrous oxide, are removed from it before compleat exhaustion has taken place, they are capable of being restored to health under the action of atmospheric air. 4. Peculiar changes are effected in the organs of animals by the respiration of nitrous oxide. In animals destroyed by it, the arterial blood is purple red, the lungs are covered with purple spots, both the hollow and compact muscles are _apparently_ very inirritable, and the brain is dark colored. 5. Animals are destroyed by the respiration of mixtures of nitrous oxide and hydrogene nearly in the same time as by pure nitrous oxide; they are capable of living for a great length of time in nitrous oxide mingled with very minute quantities of oxygene or common air. These facts will be reasoned upon in the next division. VII. _Of the respiration of Nitrous Oxide by amphibious Animals._ As from the foregoing experiments, it appeared that the nitrous oxide destroyed warm-blooded animals by increasing the living action of their organs to such an extent, as finally to exhaust their irritability and sensibility; it was reasonable to conjecture that the cold-blooded animals, possessed of voluntary power over respiration, would so regulate the quantity of nitrous oxide applied to the blood in their lungs as to bear its action for a great length of time. This conjecture was put to the test of experiment; the following facts will prove its error. _a._ Of two middle sized water-lizards, one was introduced into a small jar filled with nitrous oxide, over moist mercury, by being passed through the mercury; the other was made to breathe hydrogene, by being carried into it in the same manner.