46 



same as that of fishes. The oxygen absorbed by fishes exists 

 in a liquid ; the oxygen absorbed by the mammal foetus exists 

 also in a liquid, which is the blood of the mother. In fishes 

 and also in mammal foetuses, oxygen has to pass through many 

 membranes : in fishes, through the mucous membrane of the 

 bronchia and the membrane of the capillary vessels'; in the 

 mammal foetuses, through the membranes of the capillary vessels 

 of the maternal and the foetal placentas, and their mucous 

 coverings. After birth young mammals have an insufficient 

 power of breathing, and in this they are like the reptilia. They 

 are unable to absorb a sufficient quantity of oxygen to resist 

 the influence of cold ; and their power of retaining life when 

 deprived of oxygen, is comparable to that of the reptilia. 



This fact -has been well established by the experiments of 

 Buffon, Boyle, Ens, Roose, Haller, Fontana, Legallois, and 

 more particularly W. F. Edwards. Nevertheless, these eminent 

 experimenters have left many important questions without so- 

 lution, some of which I will examine here. 



In order to study the influence of temperature on the duration 

 of life in asphyxiated animals, W. F, Edwards dipped into 

 water, at different degrees of temperature, many animals of 

 different ages. Unhappily he did not take notice of the tem- 

 perature of the animals on which he experimented ; and we 

 will show that this circumstance is very important, because the 

 degree of that temperature at the instant when asphyxia begins, 

 has a considerable influence on the duration of life. Conse- 

 quently, to discover with exactitude the influence of the tempera- 

 ture of a medium, on animals deprived of breathing, it was 

 necessary to operate on animals at the same temperature. This 

 has been done neither by Edwards nor by any other physiologist. 



A. priori it is easy to acknowledge that the duration of life 

 in animals asphyxiated can be influenced by four capital circum- 

 stances : 1st. The degree of the temperature of the animals ; 

 2d. The degree of the temperature of the medium ; 3d. The 

 age of the animals ; 4th. Their species. 



Consequently four series of experiments were to be performed. 

 I have made them, and I propose to give here some of the results 

 I have obtained. The remaining shall be detailed in a special 

 paper. 



