94 LECTURES ON BIOLOGY 



which it would be exposed during a journey lasting untold years 

 through the icy space entirely devoid of water. It is true that 

 in a former chapter we have become acquainted with living 

 organisms which exhibit an astonishing power of resistance to 

 all injurious influences of the external world, heat as well as 

 cold, and preserve latent life for a considerable time, but in all 

 these cases the span of life is not without limit, and even in the 

 most favourable cases restricted to a few years. 



But even though we cannot refute the cosmozoic hypothesis 

 on strictly scientific grounds just as science does not enable us 

 to prove that a divine creative act is an impossibility it appears 

 nevertheless highly improbable. To fall back upon it would 

 mean doing violence to reason, because we possess in the doctrine 

 of spontaneous generation (Urzengung} of the organisms a theory 

 which stands in better accord with the facts derived from 

 observation. 



We have thus come back once more to earth itself as the 

 place of the origin of life. As we have already seen, the 

 investigators of the earliest times had no difficulty in explain- 

 ing the spontaneous generation of even highly organized animals 

 insects, fishes, frogs and snakes and even in mediaeval times 

 a line of demarcation between inorganic matter and animated 

 nature was unknown. But the more science investigated the 

 nature of the living organisms, the clearer became the view 

 that, if any, only the most primitive unicellular organisms could 

 be considered from the point of view of abiogenesis. 



It is but a few decades ago that it was a universally accepted 

 dogma that infusoria were generated by infusions of water upon 

 hay, and that bacteria originated in putrifying flesh or other 

 fermenting matter by spontaneous generation. Even at the 

 end of the nineteenth century a French investigator, Pouchet, 

 endeavoured to produce such organisms artificially in the retort. 

 According to him it was only necessary to mix together the 

 various parts which composed the body of a living being' For 

 on the mixture it depends ' and to procure the most favourable 

 external conditions, in order to obtain unicellular organisms. 

 Truly an attempt worthy to be compared with those of the 

 alchemists. No one has so far succeeded in producing by syn- 



