THE OKIGIN OF LIFE 91 



but it is a limited eternity, an eternity which finds its end in 

 time. To what ends will fancy and speculation lead an otherwise 

 acute mind when it leaves the safe grounds of reality ! 



Apart from these considerations, natural science has very few 

 objections to Preyer's theory. He has a perfect right to define 

 life as he does, and no one can gainsay him if he regards molten 

 metal as animate ; though in that case he understands by life 

 something very different from what all other men mean by it. 

 But when all has been said, the whole fight is one about words. 

 In any case, Preyer's theory rests on the accurate perception 

 that, as Fechner had already demonstrated, there is no hard-and- 

 fast dividing line between organic and inorganic nature, but that 

 both are different phenomena of the same law. 



According to modern knowledge the conception of life is 

 identical with that of metabolism, and so far as our experience 

 goes this is always bound up with certain albuminoids. In that 

 case, however, neither sun nor any other astral body can be 

 called a living organism. Matter is eternal and indestructible. 

 But as it is certain that the earth will some day sink into the 

 icy night of death, so there was certainly once a time when no 

 life existed on earth nor could exist. The soil must first be 

 prepared before the seed can germinate. 



We are, therefore, again confronted with the alternative that 

 either life on earth is the result of spontaneous generation 

 (Urzengung], or that it originated on other bodies in the universe 

 from which it reached the earth. If this latter assumption, the 

 so-called cosmozoic theory, has few prominent supporters to-day, 

 we must nevertheless mention it, if only for the sake of the 

 famous men who have broken a lance on its behalf Sir William 

 Thomson (now Lord Kelvin), Liebig, and Helmholtz. According 

 to this hypothesis the first germs of life reached the earth hidden 

 in the crevices of meteorites, and then developed on earth. 



It was in the year 1871, at the Congress of the British Asso- 

 ciation, that Thomson, in his presidential address, endeavoured 

 to prove the scientific admissibility of his hypothesis. " When 

 we retrace," he said, " the physical history of the earth according 

 to strict dynamic laws we arrive finally at a red-hot molten 

 sphere upon which there was as yet no possibility for life to 

 exist. When afterwards conditions on earth became suitable 



