120 PHYSIOLOGY 



muscle and the oxidation of resulting products, occur. 

 From unstable compounds, stable compounds are 

 formed. These stable compounds are no longer of use 

 to the bodily machine so they are given off as wastes 

 through the excretory organs. The chemical actions 

 involved set free an enormous amount of heat which is 

 distributed through the body, or given off from its sur- 

 face. The disappearance of complex substances creates 

 a demand for food and oxygen which are brought to the 

 muscle through the quickening of the circulation and 

 respiration, and used for the manufacture of new com- 

 plex substances. 



