126 VITALISM AND SCHOLASTICISM 



failed to consider the difficulty raised by the 

 intense heat engendered in these fragments 

 when they enter our atmosphere, a phenomenon 

 which we are familiar with in the shape of 

 " shooting stars." But it has been suggested 

 that the germs of life might have lain safely 

 concealed in deep cracks in the meteorites and 

 so on. A variant of this view is found in the 

 Arrhenius theory of Arrhenius put forward before the 

 existence of ultra-microscopic bacteria was 

 known, as it is to-day, and perhaps strength- 

 ened by that discovery. He postulated the 

 existence of vast quantities of such bodies in 

 space driven towards the earth by the action 

 of the waves of light, just as these impel the 

 vanes of Crookes' radiometer which we may 

 see spinning in a vacuum bulb in the windows 

 of instrument makers any sunny day. If these 

 germs were small enough they might attain a 

 great velocity ; in fact Arrhenius calculated that 

 they might travel from Mars in twenty days 

 and from ours to the nearest solar system 

 or of course vice versa in about nine thousand 

 years. 



From our point of view this discussion, 

 though interesting, is purely academic. To tell 

 us that the palm trees on a coral island sprang 

 from nuts washed up from some distant land 

 explains the palm trees on that particular 



