NUTRITION. 



205 



plant has stored energy. Now that the wood or coal are 

 burned the energy is given oat, primarily as heat. But we 

 may convert the heat into electricity, the electricity into 

 light, or back again into heat if we wish. We get our 

 energy from food as the engine gets its energy from fuel. 

 This is saying nothing against the superiority of the 

 human body, and is not in the least degrading. We are 



ANIMALS 



AND PLANTS NOT 

 POSSESSING CHLOROPHYLL, 



WHICH DISINTEGRATE 

 COMPLEX CHEMICAL COM- 

 POUNDS, LIBERATING 

 ENERGY IN THE 

 PROCESS. 



PLANTS 

 POSSESSING CHLOROPHYLL 



INTEGRATE COMPLEX 



CHEMICAL COMPOUNDS, 



STORING UP SOLAR ENERGY 



IN THE PROCESS, 



THEY 



N H. 



Solar Energy 



Energy originally obtained from the sun radiated 

 by the animal (chiefly) into space as heat, and 

 thereby becoming ultimately unavailable 



Fig. 76 Relation of Plants and Animals. 



self-maintaining, self-directing, growing, living machines. 

 Still, starvation soon puts an end to our ability to produce 

 energy of any kind. 



The Utilization of Energy in the Body and in 

 Machines. Now, it is a well-recognized fact that in very 

 many machines only the smaller part of the energy is 

 directed to the end sought. Take a common candle. We 

 wish to get light from it. But most of the energy of the 

 candle is devoted to making heat, which in this case we do 

 not desire. In many machines there is great loss from 

 friction, from radiating heat, etc. Physiologists tell us that 

 the human body utilizes a larger portion of its energy than 



