SPONTANEOUS GENERATION AND EVOLUTION : CONCLUSION 365 



have fallen upon our earth and so have formed the first germs of life, 

 was first formulated by that chemical genius, Justus Liebig. It seems 

 certain that the state of glowing heat in which meteorites are, when 

 they come into our atmosphere, only affects the outer crust of these 

 cosmic fragments, and that living germs, which might be concealed in 

 the depths of their crevices and fissures, might therefore remain alive, 

 but nevertheless it is undoubtedly impossible that any germ should 

 reach us alive in this way, because it could neither endure the 

 excessive cold nor the absolute desiccation to which it would be 

 exposed in cosmic space, which contains absolutely no water. This 

 could not be endured even for a few days, much less for immeasurable 

 periods of time. 



But we have to take account, too, of an entirely general reason, 

 which lies in the fact that all life is transient, that it can be 

 annihilated, and is not merely mortal ! Everything that is dis- 

 tinctively organic may be destroyed to the extent of becoming- 

 inorganic. Not only may the phenomena of life disappear, and the 

 living body as such cease to be, but the organic compounds which 

 form the physical basis of all life are ceaselessly breaking up, and 

 they fall back by stages to the level of the inorganic. It seems to me 

 that we must necessarily conclude from this that the basis of Liebig's 

 idea was incorrect, that is, the assumption that ' organic substances 

 are everlasting and have existed from the first just in the same way 

 as inorganic substances.' This is obviously not the case, for a thing 

 that has an end cannot be everlasting ; it must have had a beginninu- 

 too, and consequently organic combinations are not everlasting, but 

 are transitory ; they come and go, they arise wherever the conditions 

 suitable for them occur, and they break up into simpler combinations 

 when these conditions cease to be present. It is only the elements 

 which are eternal, not their combinations, for these are subject to 

 more or less rapid continual change, whether they have arisen outside 

 of organisms or within them. 



It seems to me that these considerations destroy the foundations 

 of the hypothesis of the cosmic origin of life on our earth ; in any 

 case they leave the hypothesis without great significance ; for if we 

 could even admit the possibility of a transference of living organisms 

 from space, the question would only be pushed a little further back 

 by the assumption, and not solved, for the organisms thus brought in 

 must have had their origin on some other planet, since they are, ex 

 hypothed, not everlasting. 



Thus we are directed to our earth itself as the place of the origin 

 of the tellurian world of life, and I see no possibility of avoiding 



