AXIMAL HEAT. 231 



in the respiratory efforts, may also be ascribed the 

 greater length of time persons have been found to bear 

 submersion without being killed, when in a state of in- 

 toxication, poisoning by narcotics, or during insensibility 

 from syncope. 



It is to the accumulation of carbonic acid in the blood, 

 &nd its conveyance into the organs, that we must, in the 

 first place, ascribe the phenomena of asphyxia. For when 

 this does not happen, all the other conditions may exist 

 without injury ; as they do, for example, in hybernating 

 warm-blooded animals. In these, life is supported for 

 many months in atmospheres in which the same animals, 

 in their full activity, would be speedily suffocated. During 

 the periods of complete torpor, their respiration almost 

 entirely ceases ; the heart acts very slowly and feebly ; the 

 processes of organic life are all but suspended, and the 

 animal may be with impunity completely deprived of atmo- 

 spheric air for a considerable period. Spallanzani kept a 

 marmot, in this torpid state, immersed for four hours in 

 carbonic acid gas, without its suffering any apparent in- 

 oonveniencs Dr. Marshall Hall kept a lethargic bat under 

 water for 1 6 minutes, and a lethargic hedgehog for 22 J 

 minutes ; and neither of the animals appeared injured by 

 the experiment. 



CHAPTER VIII. 



ANIMAL HEAT. 



THE average temperature of the human body in those 

 internal parts which are most easily accessible, as the mouth 

 and rectum, is from 98-5 to 99-6 F. 



In different parts of the external surface of the human 

 body the temperature varies only to the extent of two or 

 three degrees, when all are alike protected from cooling 



