COSMIC PHILOSOPHY 



Phenomena apparently at variance with it — 

 such as the occasional discovery of animalcules 

 in closed vessels — were disposed of by the 

 hypothesis, devised by Spallanzani, that the 

 atmosphere is full of invisible germs which can 

 penetrate through the smallest crevices. This 

 hypothesis is currently known as "pansperma- 

 tism," or the " theory of omnipresent germs," 

 or (less cumbrously) as the " germ-theory." 



Now, as concerns the germ-theory, to which 

 appeal is unhesitatingly made whenever the 

 question of spontaneous generation is discussed, 

 it must be admitted to be extremely plausible ; 

 yet we must not forget that it has never been 

 actually demonstrated : it has not been proved 

 that the germ-theory can do all that its advo- 

 cates require it to do. It may well be the case 

 that the air is everywhere full of germs, too 

 small to be seen, which are capable of giving 

 rise to all the organisms of which there is any 

 question in the controversy about spontaneous 

 generation ; nevertheless this has not been rig- 

 orously demonstrated. The beautiful researches 

 of Professor Tyndall have indeed proved that 

 the atmosphere is everywhere filled with solid 

 particles, in the absence of which it would not be 

 luminous ; and it is fair to suppose that among 

 these particles there are always to be found 

 some which are the germs of monads and bac- 

 teria. Still this can hardly be taken for granted ; 

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