ANIMAL HEAT. 189 



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 hibernating 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 respi- 

 ration 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 

 atmospheric air for a considerable period. Spallanzani kept 

 a marmot, in this torpid state, immersed for four hours in car- 

 bonic acid gas, without its suffering any apparent inconveni- 

 ence. Dr. Marshall Hall kept a lethargic bat under water 

 for 16 minutes, and a lethargic hedgehog for 22& minutes ; and 

 neither of the animals appeared injured by the experiment. 



CHAPTER VIII. 



ANIMAL HEAT. 



THE average temperature of the human body in those in- 

 ternal parts which are more easily accessible, as the mouth 

 and rectum, is from 98.5 to 99.5 F. 



In different parts of the external surface of the human body 

 the temperature varies only to the extent of two or three de- 

 grees, when all are alike protected from cooling influences ; 

 and the difference which under these circumstances exists, 

 depends chiefly upon the different degrees of blood-supply. 

 In the arm-pit the most convenient situation, under ordinary 

 circumstances, for examination by the thermometer the aver- 

 age temperature is 98. 6 D F. 



The chief circumstances by which the temperature of the 

 healthy body is influenced are the following : 



Age. The average temperature of the new-born child is only 

 about 1 F. above that proper to the adult ; and the difference 

 becomes still more trifling during infancy and early childhood. 

 According to Wunderlich, the temperature falls to the extent 

 of about -J- to F. from early infancy to puberty, and by 

 about the same amount from puberty to fifty or sixty years 

 of age. In old age the temperature again rises, and approaches 

 that of infancy. 



Although the average temperature of the body, however, 



