CHAPTER III 



THE ACTIVITIES OF LIVING BEINGS 



13. LIFE is a condition of activity. In the 

 body of one of the higher animals we see 

 activities manifested in various forms. Some 

 of these have already been referred to, but we 

 must now give a statement of those which 

 it is the special province of the physiologist 

 to explain. 



(1) Animal Heat. The body of an animal 

 (we may leave plants out of this discussion, 

 although much that will here be indicated 

 also applies to them) has a certain mean 

 temperature. In so called warm-blooded 

 animals, such as the birds and mammals, 

 the temperature of the body varies only 

 through a few degrees, even although there 

 may be very considerable variations in the 

 temperature of the surrounding medium. 

 Thus the temperature of the body of a man, 



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