in regard to Respiration, 263 



found letharg)' prevented them from profiting by it. They 

 did not absolutelv respire; that rising and falling occasioned 

 in their flanks during respiration was not remarked; the 

 case was the same in the open air. It is therefore evident, 

 that this partial consumption of oxygen gas was the conse- 

 quence of the absorption of this substance by the cutaneous 

 organ. 



It thence results, that this chemical power of absorbing 

 the oxygen of the atmosphere, belongs to these cold-blooded 

 animals when dead_, and that when living they exhibit the 

 same power, which is continued even when their bodies are 

 in a state of decomposition. 



In a word, this total suspension of respiration experienced 

 by these animals when exposed to a violent cold, becomes 

 uijsupportable to them and occasions their death, as I have 

 seen m my experiments ; so that this state of lethargy into 

 which they fall when in their burrows, which happens to 

 some small animals, and in general to amphibia, is always 

 accompanied with a weak principle of respiration, as I shall 

 show in its place in my work. 



Several worms, and' among them the greater part of the 

 testacea; many insects, among which systematic writers 

 place the Crustacea ; besides the immense family of fishes, have 

 their residence always in the water, and sometimes cease to live 

 in it. Will the faculty they have of appropriating to them- 

 selves oxygen when they remain exposed to the air, bemam- 

 tained in that fluid, because it is mixed therewith a quantity 

 of oxygen gas? I was inclined to think so; but to assure 

 myself of it, I made direct experiments. 



With this view I placed different kinds of these animals 

 when dead in tubes filled with water, above which I caused 

 a given measure of air to ascend. The oxygen gas of the 

 water communicated with that of the air. It appeared then 

 clear to mc, that if the former were absorbed, the second, 

 or at least a part of the air, without the water in the tube, 

 ought to replace tiiat kind of vacuum which might be pro- 

 duced in it, and re-establish the lost equilibrium. This took 

 place; and I must observe, that every time I made the expe- 

 riment on several individuals of these three classes, though 

 the experiments were very numerous, the air which covered 

 the water was deprived of its oxygen gas. 



I nuist mention also another observation which I made. 

 When, instead of these aquatic animals, I placed at a given 

 depth under the water terrestrial animals, or their parts, I 

 obtained the same destruction of the oxygen gas of the air 

 plaotd above it. This proves that the property which these 

 l\ 4 auiiiials 



