28 THE STORY OF LIFE'S MECHANISM. 



phenomena of life we have two entirely different 

 problems. The first is manifestly to account for 

 the existence of this machine, for such a com- 

 pleted piece of mechanism as a man or a tree 

 cannot be explained as a result of simple acci- 

 dent, as the existence of a rough piece of rock 

 might be explained. Its intricacy of parts and 

 their purposeful interrelation demands explana- 

 tion, and therefore the fundamental problem is 

 to explain how this machine came into existence. 

 The second problem is simpler, for it is simply 

 to explain the running of the machine after it is 

 made. If the organism is really a machine, we 

 ought to be able to find some way of explaining 

 its actions as we can those of a steam engine. 



Of these two problems the first is the more 

 fundamental, for if we fail to find an explana- 

 tion for the existence of the machine, our ex- 

 planation of its method of action is only partly 

 satisfactory. But the second question is the 

 simpler, and must be answered first. We cannot 

 hope to explain the more puzzling matter of the 

 origin of the machine unless we can first under- 

 stand how it acts. In our treatment of the sub- 

 ject, therefore, we shall divide it into two parts : 



I. The Running of the Living Machine. 

 II. The Origin of the Living Machine. 



