CHAPTER II 

 THE PHYSICAL BASIS OF LIFE 



Science never destroys wonder, but only shifts it, higher 

 and deeper. Thomson. 



THE old saying that the materials forming the human body 

 change completely every seven years is a tacit recognition that 

 lifeless material, in the form of food, is gradually transformed 

 into similar living matter under the influence of the body. In- 

 deed, just as a geyser retains its individuality from moment 

 to moment though it is at no two instances composed of the 

 same molecules of water identically placed, so the living 

 individual is a focus into which materials enter, play a part 

 for a time, and then emerge to become dissipated in the 

 environment. But here the analogy stops. For in the 

 living organism the materials which enter as food, endowed 

 with POTENTIAL energy, are arranged and rearranged until 

 specific molecular aggregates result, which in turn are trans- 

 formed into integral parts of the organization of life itself. 

 However, to live is to work, and to work means expenditure 

 - the transformation of the potential into KINETIC energy - 

 with the result that materials in relatively simple form and 

 largely or entirely devoid of energy are returned to the 

 realm of the non-living. 



Thus we reach a fact of prime importance: so far as we 

 know, living matter is merely ordinary matter which has 

 assumed, for the time being, a peculiar condition in which it 

 displays the remarkable series of phenomena which we 

 recognize as LIFE. 



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