BOTANY FOR YOUNG PEOPLE. 25 



must be in some measure immaterial, and 

 we can only recognize its existence by its effects. 



L. But I do not comprehend how you can 

 tell about that which you cannot see. 



E. Here is my watch; can you tell what 

 makes it go? 



L. Yes; the mainspring. I perceive what 

 you mean : that when I am witnessing a set 

 of actions I should think there must be some 

 cause sufficient to produce these actions, even 

 though that cause is hidden. 



E. You understand me perfectly. There 

 are two kinds of powers in nature, the Life 

 Powers and the Mechanical forces, and these 

 are in perpetual opposition. A good example 

 of this is shown in the case of two seeds, one of 

 which has had an electric spark passed through 

 it in order to destroy its powers. Place both 

 in a warm moist place, and watch the effects. 

 The dead seed soon rots and disappears, while 

 the very warmth and moisture that caused it to 

 decompose excites the living one to grow. 

 A violent contest is evident, the effect of which 

 is seen by the sprouting of a plant that hangs 

 out its rlowery banners in token of victory. 

 The Mechanical Forces, from destroying every 



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