LUCRETIUS AND HAECKEL 221 



tive substance, which in its original state of quiescence had the same mean consistency 

 throughout, divides or diflferentiates into two kinds. The centers of disturbance, 

 which positively exceed the mean consistency in virtue of the pyknosis or condensa- 

 tion, form the ponderable matter of bodies; the finer, intermediate substance, which 

 occupies the space between them, and negatively falls below the mean consistency, 

 forms the ether, or imponderable matter.. As a consequence of this division into 

 mass and ether there ensues a ceaseless struggle between the two antagonistic ele- 

 ments, and this struggle is the source of all physical processes. The positive pon- 

 derable matter, the element with the feeling of like or desire, is continually striving 

 to complete the process of condensation, and thus collecting an enormous amount 

 of potential energy; the negative, imponderable matter, on the other hand, offers 

 a perpetual and equal resistance to the further increase of its strain and of the fceling- 

 of dislike connected therewith, and thus gathers the utmost amount of acttial energy. 



The primal atoms of Lucretius are known well enough. They are 

 indestructible, eternal, indivisible — except metaphysically into mmimas 

 partes — of various shapes, infinite in number, moving continuously in 

 infinite space. The various qualities of material things are the results 

 of accidental combinations of the atoms, and we have seen that even 

 the human mind and soul are included in this reckoning. In view 

 of the importance of the atomic motion just mentioned, we may quote 

 the following : 



If you think that first-beginnings of things can lag and by lagging give birth to 

 new motions of things, you wander far astray from the path of true reason: since they 

 travel about through void, the first-beginnings of things must all move on either by 

 their own weight or haply by the stroke of another. For when during motion they 

 have, as often happens, met and clashed, the result is a sudden rebounding in an 

 opposite direction ; and no wonder, since they are most hard and of weight propor- 

 tioned to their solidity and nothing behind gets in their way. And that you may 

 more clearly see that all bodies of matter are in restless movement, remember that 

 there is no lowest point in the sum of the universe, and that first bodies have not 

 where to take their stand, since space is without end and limit and extends immeas- 

 urably in all directions round, as I haveehewn in many words and as has been proved 

 by sure reason. Since, then, this is a certain truth, sure enough no rest is given to 

 first bodies throughout the unfathomable void, but driven on rather in ceaseless and 

 varied motion they partly, after they have pressed together, rebound, leaving great 

 spaces between them, while in part they are so dashed away after the stroke as to leave 

 but small spaces between . And all that form a denser aggregation when brought together 

 and rebound leaving trifling spaces between, held fast by their own close-tangled 

 shapes, these form enduring bases of stone and unyielding bodies of iron and the rest 



