CHAPTER X 



HEREDITY 



WHEN the sea is calm one sees in the sand near the 

 shore the same undulations that ripple the surface 

 of the water, that in its turn reproduces the 

 undulation of the air that strikes and blows upon 

 its surface. We cannot test the undulations of the 

 air, these not being sensible to the touch ; but their 

 impression on the water or the sand is readily 

 perceptible by the organs of vision. Here sight is 

 an amplification and complement of touch, just as 

 the microscope enlarges the power of vision. 



In the same way every organism, crystal, plant, 

 or animal reflects, like the sand of the sea, the 

 impression that the indefinite rhythm of universal 

 mechanics makes on every organic substance. Men 

 cannot perceive the rhythm of this mechanics any 

 more than the rhythm of the undulations of the 

 air on striking the surface of the water. But as 

 observation reveals to us in a thousand instances 

 this concomitance of undulations in sand, water, 



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