APPLIED PHYSIOLOGY 



structed into starch. Using starch as a basis, plants 

 construct fat and albumin and all other substances found 



in the plant. 



43. The sun's work 

 in reconstructing living 

 material. When oxygen 

 unites with the carbon and 

 hydrogen of the burning sub- 

 stances, heat and energy are 

 given out. Just as much 

 heat and force must be used 

 in tearing away the oxygen 

 as was ^iven out during the 

 oxidation. The sun furnishes 

 this heat and force. The 

 chlorophyll acting as the ma- 

 chine and using the sun's rays 

 for power, frees most of the 

 oxygen from the carbonic 

 acid gas and water, and gives 

 it back to the air. At the 

 same time it unites the re- 

 maining oxygen with the car- 

 bon and hydrogen to form living starch. Thus the real work of con- 

 struction is done by the sun. When the starch is oxidized, oxygen goes 

 back to the hydrogen and carbon, and the same 

 amount of heat is given off as was taken from 

 the sun when starch was formed. 



The heat of oxidation can be traced back to the 

 sun's heat stored up by living beings or beings 

 once alive. All the carbon of a tree is the car- 

 bonic acid gas of the air with its oxygen taken^ 

 away by the sun's force acting through chloro- 

 phyll. Coal is the carbon of trees changed in 

 form during ages of burial. 



Diagram of the restoration of oxygen to 

 the air after oxidation, and of the rebuilding 

 of burned material into living forms. 



Diagram of the stream 

 of material flowing through 



44. Conservation of energy. The 

 energy of the suns heat expended upon the plants in 



