Respiration 1 79 



Wherever there is life, this process of oxidation is going 

 on, but more energetically in some tissues and organs than 

 in others. In other words, every tissue in the body is a source 

 of heat in proportion to the activity of its chemical changes. 

 The more active the changes, the greater is the heat pro- 

 duced, and the greater the amount of urea, carbon dioxide, 

 and water eliminated. 



The waste caused by this oxidation must be made good 

 by a due supply of food to be built up into protoplasmic 

 material. For the production of heat, therefore, food is 

 necessary. The oxidation process is not so simple and 

 direct as the statement of it might seem to indicate ; 

 but the ultimate result is as simple as in ordinary com- 

 bustion outside of the body, and the products are the 

 same. 



The continual chemical changes, then, chiefly by oxida- 

 tion of combustible materials in the tissues, produce an 

 amount of heat which is sufficient to maintain the tem- 

 perature 6f the living body at about 98^- Fahr. This 

 process of oxidation provides not only for the heat, but 

 also for the mechanical energy, required to carry on the 

 work of the body. 



270, Regulation of the Bodily Temperature. While bodily 

 heat is being continually produced, it is also as continually 

 being lost by the lungs, by the skin, and to some extent 

 by certain excretions. The blood, in its swiftly flowing 

 current, carries warmth from the tissues where heat is 

 being rapidly generated, to the tissues or organs in which 

 it is being lost by radiation, conduction, or evaporation. 

 Were there no arrangement by which heat could be dis- 

 tributed and regulated, the temperature of the body would 

 be very unequal in different parts and would vary at 

 different times. 



