MOLECULAR AGGREGATION 265 



enables the phosphorescent molecule to remain intact 

 for a much longer time. 



We may regard, therefore, in the light of 

 these facts, the effect of glycerine or gelatin on 

 such liquids, as a confirmation of the hypothesis 

 that the luminosity is stored up in newly formed 

 molecules produced by the action of the more 

 refrangible rays. 



A cell with a radio-active nucleus would, it 

 appears, be the seat of such molecular aggregations 

 and disintegrations, and in a certain sense of 

 metabolism too ; since such molecular metabolism 

 to which luminosity is akin must result in a medium 

 in which a radio-active particle is immersed. 



