The Origin of Life 37 



and seed. Thus seeds of leguminoses (Cassia bicapsu- 

 laris, Cytisus bifloms, Leucana leucocephala, and Tri- 

 folium arvense) had retained their power of germination 

 for eighty-seven years. Becquerel has shown that the 

 dryness of the membrane is very essential for such a 

 duration of life, since when dry it is impermeable for 

 gases and the slow chemical reactions inside the grain 

 become impossible. 



In the cosmic space there is no water vapour, no 

 atmosphere, and a low temperature, and there is hence 

 no reason why spores should lose appreciably more of 

 their germinating power in ten thousand years than in 

 six months. We must therefore admit the possibility 

 that spores may move for an almost infinite length 

 of time through cosmic space and yet be ready for ger- 

 mination when they fall upon a planet in which all 

 the conditions for germination and development exist, 

 e. g., water, proper temperature, and the right nutritive 

 substances dissolved in the water (inclusive of free 

 oxygen) . 



While thus everything is favourable to Arrhenius's 

 hypothesis, Becquerel raises the objection that the 

 spores going through space would yet be destroyed by 

 ultraviolet light. This danger would probably exist 

 only as long as the germ is not too far from a sun. The 

 difficulty is a real one since the ultraviolet rays have 

 a destructive effect even in the absence of oxygen. It 

 is possible, however, that there are spores which can 



