In each of these experiments a certain absorption of the gas was always perceived, the water rising in the jar during the respiration of the animal. From them we learn
1st. That nitrous oxide is destructive when respired for a certain time to the warm-blooded animals, apparently previously exciting them to a great extent.
2dly. That when its operation is stopped before compleat exhaustion is brought on, the healthy living action is capable of being gradually reproduced, by enabling the animal to respire atmospheric air.
3dly. That exhaustion and death is produced in the small animals by nitrous oxide sooner than in the larger ones, and in young animals of the same species, in a shorter time than in old ones, as indeed Dr. Beddoes had conjectured a priori would be the case.
Most of the animals destroyed in these experiments were examined after death; the appearances in their organs were peculiar. To prevent unnecessary repetitions, an account of them will be given in the fourth section.
III. Effects of the respiration of Nitrous Oxide upon animals,
as compared with those produced by their immersion
in Hydrogene and Water.
Before the following experiments were made, a number of circumstances had convinced me that nitrous oxide acted on animals by producing some positive change in their blood, connected with new living action of the irritable and sensitive organs, and terminating in their death.
To ascertain however, the difference between the effects of this gas and those of hydrogene and non-respirable gases, I proceeded in the following way.
a. Of two healthy rabbits of about two months old, of the same breed, and nearly of the same size.
One was introduced into nitrous oxide. In a half a minute, it had fallen down apparently senseless. On applying my hand to the thorax, the action of the heart appeared at first, very quick and strong, it gradually became weaker, and in two minutes and half, the animal was taken out quite dead.