74 THOUGHTS ON NATURAL PHILOSOPHY. 



the necessary conditions were given ; and it was 

 obliged to change its form and its composition in the 

 same measure as the external conditions of life 

 changed in the course of the earth's development. 

 It is only a portion of the earth's matter. The 

 combination of this matter into living substance was 

 as much the necessary product of the earth's develop- 

 ment as was the origin of water. It is an inevitable 

 result of the progressive cooling of the masses that 

 formed the earth's crust. Likewise, the chemical, 

 physical, and morphological characteristics of ex- 

 isting living substance are the necessary result of the 

 influence of the external conditions of life upon the 

 internal relations of past living substance. Internal 

 and external vital conditions are inseparably corre- 

 lated, and the expression of this correlation is life." 

 The whole being caused by material motion. When 

 the earth and its surroundings are sufficiently cold, 

 when material motion is too feeble for the mani- 

 festation of life, vital phenomena on this planet will 

 cease to exist. 



The subject is so vast and so exquisitely beautiful 

 that one might write for ever, and there is a danger 

 of eloquent gush ; but I spare the reader. 



Some persons may fear to amend the Newtonian 

 philosophy, lest some great catastrophe happen. 

 They may argue : " How can I give up this idea ? 

 What was to keep matter together before this uni- 

 verse was evolved, and what is to keep matter 

 together if the universe be destroyed ? " I think 

 that we can ease their minds. Space is illimitable, 

 and eternity has neither beginning nor end. Eternal 



