AND PERSONALITY 



enemies, better energy-releasing systems developed. The 

 demands of the plant for energy are constant, but the 

 demands of the animal for energy are not constant. 



To establish adaptive control of energy, special mecha- 

 nisms for the control of the speed of oxidation have been 

 evolved in animals. These mechanisms are the special 

 senses, the brain and communicating nerves, the heart, the 

 blood volume, the thyroid gland, the adrenal glands, and 

 the sympathetic system. These energy-controlling organs 

 and tissues are the means whereby energy is released in 

 this or that gland and in this or that combination of muscles 

 to enable the animal to secure food, to escape, and to 

 procreate. 



The transmitting system of animals includes the sensory 

 nerves of the organism, the nerves that control the volun- 

 tary muscles, and the sympathetic nerves that supply the 

 great network of blood vessels, which, in turn, are supplied 

 to each of the hundreds of millions of cells of the liver, the 

 thyroid gland, and the digestive system. These energy- 

 controlling systems constitute a network so vast and so 

 intricate that, were all the tissues of the body removed 

 except these nerve mechanisms, there would remain an 

 effigy of the body as a whole. Standing alone, without 

 accelerators or controllers, these nerve mechanisms would 

 work all day, all night, in danger, in hunger, in the presence 

 of prey or in the presence of mates but would not be able to 

 vary their speed and power. Little benefit would accrue 

 to an animal such as a man, a lion, or a zebra, if, having a 

 perfect mechanism for generating and distributing electric- 

 ity, it had no mechanism by which speed could be adap- 

 tively altered. Man would not be able to adapt his mechanism 

 to his changing requirements. The lion would not be able 

 to rush its prey. The zebra would not be able to meet the 

 energy requirements for escape. All animals would exist 

 at a constant energy level; they would be operated at a 

 given speed. The energy of these animals would be as 



17 



