636 FRAGMENTS OF SCIENCE. 



external to themselves, or an inherent force? Science 

 rejects the outside builder; let us, therefore, consider from 

 the other point of view the experience of the present year. 

 A low temperature had kept buck for weeks the life of the 

 vegetable world. But at length the sun gained power or, 

 rather, the cloud-screen which our atmosphere had drawn 

 between him and us was removed and life immediately 

 kindled under his warmth. But what is life, and how can 

 solar light and heat thus affect it? Near our elm was a 

 silver birch, with its leaves rapidly quivering in the 

 morning air. We had here motion, but not the motion of 

 life. Each leaf moved as a mass under the influence of an 

 outside force, while the motion of life was inherent and 

 molecular. How are we to figure this molecular motion 

 the forces which it implies, and the results which flow 

 from them? Suppose the leaves to be shaken from thu 

 tree and enabled to attract and repel each other. To fix 

 the ideas, suppose the point of each leaf to repel all the 

 other points and to attract the roots, and the root of each 

 leaf to repel all other roots but to attract the points. The 

 leaves would then resemble an assemblage of little 

 magnets abandoned freely to the interaction of their own 

 forces. In obedience to these they would arrange them- 

 selves, and finally assume positions of rest, forming a 

 coherent mass. Let us suppose the breeze, which now 

 causes them to quiver, to disturb the assumed equilibrium. 

 As often as disturbed there would be a constant effort on 

 the part of the leaves to re-establish it; and in making 

 this effort the mass of leaves would pass through different 

 shapes and forms. If other leaves, moreover, were at 

 hand endowed with similar forces, the attraction would 

 extend to them a growth of the mass of leaves being the 

 consequence. 



We have strong reason for assuming that the ultimate 

 particles of matter the atoms and molecules of which it is 

 made up are endowed with forces coarsely typified by 

 those here ascribed to the leaves. The phenomena of 

 crystallization lead, of necessity, to this conception of 

 molecular polarity. Under the operation of such forces 

 the molecules of a seed, like our fallen leaves in the first 

 instance, take up positions from which they would never 

 move if undisturbed by an external impulse. But solar 

 light and heat, which come to us as waves through space, 



