220 GRAVITY, LIGHT AND CALORIC. LiECT. XT. 



They saw a young girl remain for twelve minutes in an 

 oven, the temperature of which was 128 centig. [ = 

 262-4 Fahr. ]. Delaroche and Berger introduced rabbits, 

 cats, and several other vertebrated animals, into an oven 

 heated to from + 56 to + 65 centig. [ = l32-8 to 149 

 Fahr.]. The animals died at the expiration of some 

 minutes. These observers concluded, from a great number 

 of experiments, that vertebrated animals, when exposed to 

 a dry atmosphere heated to 4- 45 centig. [ = 113 Fahr.,] 

 are near the extreme limit of temperature in which they are 

 capable of living. It appears, then, that man alone is en- 

 dowed with the faculty of supporting a higher temperature ; 

 indeed, besides the instance already mentioned, there exists 

 others, of the truth of which no doubt exists. 



Dobson tells us of a young man who remained for 

 twenty minutes in an oven heated to + 98-88 centig. 

 [ = 210 Fahr. ;] his pulse, which was usually sixty-five, 

 was, when he came out, a hundred and sixty-four. Berger 

 supported, for seven minutes, an atmosphere at -f 109 

 centig. [ = 228-2 Fahr.,] and Blagden was enclosed in 

 one heated to + 127 centig. [ = 260-6 Fahr.]. 



But it is different if the heated air be saturated with 

 aqueous vapour. Berger could remain only twelve minutes 

 in a vapour bath whose temperature was raised from + 

 45-25 to 53-75 centig. [ = 113-45 to 128-75 Fahr.]. 

 The temperature which a man can support when in heated 

 water, is still less than that which he is capable of enduring 

 in a vapour bath. We shall soon see what are the causes 

 of this difference. 



It was important to ascertain the variations in the tem- 

 perature of animals exposed to different degrees of heat. 

 If we limit ourselves to the ordinary variations of tempera- 

 ture of climates and seasons, the heat of the human body 

 is not perceptibly modified. The numerous experiments of 



