PHILOSOPHY OF NATURE LEIBNITZ'S IDEAS. 41 



H. 



Leibnitz has thus led us on to the loftiest heights of 

 thought, the furthest bounds of speculation. Let us now 

 come down again with him to the special questions he has 

 explored and transmitted to modern science, which still 

 lacks the power to solve them all. We shall learn how 

 serviceable that science has found the general principles 

 settled by him as the grand laws of the world's order. 

 Leibnitz has the clearest and strongest sense of the diffusi- 

 bility of life. He defines exactly the characteristic which 

 lies at its base, that is, the incessant molecular replacement 

 of matter in the permanence of active forms, namely, of 

 souls. He holds that the minutest portion of matter con- 

 tains a world of creatures, lives, animated beings, actuali- 

 ties, souls. Every particle of matter is to be conceived of 

 as a garden full of plants, or a pond full of fishes ; but every 

 twig of each plant, every limb of each animal, every drop 

 in its humors, is again such a garden, or such a pond, full 

 of decreasingly minute lives, similar in kind. All these 

 bodies, he adds, move like rivers, in unresting flow* Por- 

 tions pass into them, and pass out of them, incessantly. In 

 this way the soul changes its bodies by very fine degrees, 

 and is never suddenly stripped of its organs ; vital proper- 

 ties are continuous, while the matter of life is transitory. 

 Leibnitz conjectured, consequently, that some animals must 

 have the faculty of multiplying by scission, like plants. 

 The discovery of polyps by Trembley, the facts of the mode 

 of increase in vorticelli, paramecias, and bursars and opa- 

 lines, since noticed, have justified the philosopher's guess. 



Descartes regarded animals as machines, as soulless 

 automata, made up of atoms the movements of which are 

 coordinated in the manner of those of plants. He denied 

 them intelligence, and supposed that the sensibility and in- 

 stinct noticed in them might be explained by purely me- 

 chanical causes. Leibnitz does not admit that there are 

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