224? RESPIRATION. 



Dr. Edwards advances, contrary to Morozzo z , that every warm- 

 blooded animal perishes instantly a when placed in the air in 

 which another has died through want of renovation, and that all 

 of the same class among them deoxidize it equally, though in dif- 

 ferent times. This time will occasionally differ i, notwithstanding 

 the size of the body and the movements of the chest be equal in 

 them, and the carbonic acid removed as quickly as formed. The 

 young deoxidize it more slowly than adults ; and the young, if 

 quite deprived of air, die later than adults. b Indeed, Buffon found, 

 and Dr. Le Gallois and Dr. Edwards have confirmed his discovery, 

 that new-born animals of many species, as dogs and rabbits, will 

 live a long time without air, even after they have been allowed to 

 respire. This period lessens as the animal's temperature rises 

 with age ; and in those whose temperature is at birth high, as 

 guinea-pigs, it is very short. 6 They live longer than adults also 

 in a limited quantity of air. d Amphibious animals likewise live 

 long without air. e 



Persons have been said to be able, by habit, to live without air 

 a considerable time. Death generally occurs at the latest in one 

 or two minutes, when respiration is suspended; but by habit 

 some few divers of the swimming school at Paris can remain under 

 water three minutes. f If the system is in an extraordinary nerv- 



hydrogen and azote appear to destroy by the mere exclusion of oxygen ; carbonic 

 acid by poisoning, but, if not diluted with rather more than double its bulk of 

 common air, it will not pass the glottis. Sulphuretted hydrogen instantly 

 poisons : carbonic oxide is fatal less quickly, and the venous blood accumulates 

 within, and the animals are very hot. Nitrous oxide intoxicates quickly, briefly, 

 and without consequent exhaustion, and appears to be absorbed by the blood 

 (see Sir Humphry Davy's Researches, &c.) ; but it destroys at length, and sooner 

 than pure oxygen, according to Mr. Broughton : the blood is thin, and con- 

 tinues fluid. Drowning destroys life only by the exclusion of air ; and, as the 

 glottis closes, little or no water nothing often but frothy mucus is found in 

 the air-passages. Yet Professor Meyer asserts, that he has seen the fluid in 

 which the animal was drowned, generally, in the lungs, in his experiments. 



z Journal de Physique, t. xxv. p.. 102. sqq. One reason that an animal will 

 live in air in which another has died, is, that it comes fresh and strong into it, 

 and therefore resists the poison better than its enfeebled predecessor. 



Me'moires de VAcadtmie des Sciences. 1789. p. 573. 



1. c. p. 184. sqq. 



Edwards, 1. c. p. 191. sqq. 



1. c. p. 513. sqq. 



Sir Anth. Carlisle, Phil. Trans. 1805. 



Edwards, 1. c. p. 269. Mr. Brydone (Tour through Sicily and Malta) fre- 



