THE PATH OF EVOLUTION 



chambers of their cells? we would find ourselves 

 in the position of a seeker after knowledge who 

 enters without an instructed guide the Laboratory of 

 a Chemist who is working upon the higher synthesis. 

 He sees the apparatus arranged, a heap of materials 

 provided, and also finds the finished educt prepared. 

 He can notice whether heat or cold is applied, whether 

 an increased or diminished pressure is made use of, 

 and if he is practiced in such manipulations, can 

 form a shrewd conjecture as to the connection between 

 the operations; but in the individual details much 

 will remain incomprehensible and much remain 

 unknown. Especially will his knowledge be defective 

 in respect to the nature of the materials used and of 

 the acting forces. Thus it is when we watch the 

 proceedings in the cell chambers wherein the chlo- 

 rophyll corpuscles manifest their activity. We see 

 the machinery for action, we know the salts and the 

 gases brought together for working, we know that 

 the sunbeams will be the impulsive force, and we 

 know what will be the finished products that the 

 chlorophyll corpuscles will put into their cells , but 

 how the active forces work, how it is that the sun- 

 beam is able to force the ultimate atoms to give up 

 their combinations to transport themselves apart and 

 away, and then soon after to appear in quiet and 



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