SAND-HOPPERS 159 



fall on the hardest frozen bacillus, get at its chemical 

 structure, shake it to pieces, destroy it. Hence Sir James 

 Dewar argues that, whilst it would appear that the ex- 

 treme cold of space would not kill a minute living germ, 

 and prevent it passing from planet to planet, or from 

 remotest space to our earth, yet one thing which is more 

 abundant in space than within the shell of our atmosphere 

 is absolutely destructive to such minute particles of living 

 matter, even when hard-frozen, and that is intense light, 

 the ultra-visible vibrations of smallest wave-length. 



A dance on the seashore : a sketch by Edward Forbes (1841). 





