128 WHAT IS LIFE 



independent path. Whatever the new unit's energy 

 content, whatever the direction followed, and what- 

 ever the velocity of its motion, it is certain that there 

 is no interval between the time of the collision, the 

 closest approach and complete union of the positive 

 and negative electrons, and their shooting off on 

 their own path. And inevitably there will be further 

 collisions. 



The condition postulated (critical ionic concen- 

 tration) means the presence of many ions, hydrogen 

 ions and other ions, and that there are no appreciable 

 spaces between atoms (since in a liquid the molecules 

 presumably are in contact). Therefore the new unit, 

 into whatever path it is thrown, necessarily will 

 collide with atomic and ionic constituents. 



It is plain that under the conditions postulated the 

 only space to be found is the space in the atoms and 

 ions of the solution — intraatomic space. 



It is plain, too, that to a unit of the size of the new 

 unit, practically a mere point of force, the atom is an 

 open structure that consists mostly of empty space, 

 as it is to the beta-ray and to the alpha particle. 



But though the path of the new unit necessarily 

 would lead straight into or through atoms, and the 

 atom is an exceedingly open structure, it does not 

 follow that all atoms may be entered by it. It is 

 easily conceivable that some atoms may be penetrable 



