ANIMAL HEAT. 395 



this process, as in the essential fevers or extensive inflamma- 

 tions, the temperature of the body becomes an important 

 guide, particularly in prognosis. The clinical value of a 

 recognition of the temperature in disease has only been fully 

 appreciated within a few years, especially since the very 

 elaborate observations of Wunderlich, and other German 

 observers. 1 



The study of the temperature in different classes of ani- 

 mals presents very great interest, but the limits of a work 

 on pure human physiology restrict us to the phenomena as 

 observed in man, and in animals in which the processes of 

 nutrition are similar, if not identical. We shall therefore 

 treat of the subject from one point of view, and consider it 

 as follows : 



1. The normal temperature in the human subject, with 

 its variations in different parts of the body and at different 

 periods of life. 



2. The diurnal variations in the animal temperature, and 

 the relations of alimentation, digestion, respiration, nutri- 

 tion, exercise, and the nervous system. 



3. The means by which the temperature of the body is 

 kept within the limits necessary to the preservation of life 

 and health. 



Limits of Variation in the Normal Temperature in 

 jlfan. A great number of observations have been made 

 upon the normal temperature in the human subject under 

 different conditions ; but we shall cite those only in which all 

 sources of error in thermoinetry seem to have been avoided, 

 and in which the results present noticeable peculiarities. 

 One of the most common methods of taking the general tem- 

 perature has been to introduce a delicate thermometer, care- 

 fully protected from all disturbing conditions, into the axilla, 

 reading off the degrees after the mercury has become abso- 



1 HIRTZ, Chaleur dans Fetal de maladie. Nouveau dictionnaire de medecine, 

 Paris, 1867, tome vi., p. 772, et seq. 



