14 Dynamic Evolution 



forms. Of matter, we know some seventy- 

 odd kinds. How many kinds or forms of 

 energy there are we do not know. In the 

 inorganic world we have heat, light, electric- 

 ity, magnetism, chemism, and radio-activity. 

 In the organic world we have life, growth, 

 reproduction, muscular contraction, mental 

 power, ability to produce results, nervous 

 sensation, and a variety of others known 

 under the general and somewhat vague term 

 of vital forces. It is not material that we do 

 not know what these things are, or that 

 several of them may be the same thing under 

 different names. All that is essential to our 

 present considerations is that they are energy 

 as distinguished from matter, and are to be 

 measured by the factors for energy. Thus, 

 the life in a living body is not measured by 

 length, breadth, and thickness. By compar- 

 ing a live animal with a dead one we know 

 that it is life that gives motion to the body; 

 hence, by definition, life is energy. Our in- 

 ability to produce life from other forms of 

 energy is due to our ignorance and not to 



