66 THE ORIGIN OF LIFE 



may call it, it affords us, as we may venture to think, 

 the true keynote of the vast field which we are 

 compelled to cover : that instability of molecular 

 structure, disintegration, and decay, as concomitants' 

 of their opposites, constitute, however simplified, 

 the fundamental principles of luminosity not less 

 than those of life ; "a continuous adjustment of 

 internal to external relations," when, as in the case of 

 fluorescence, the external environment is that of 

 similar but smaller particles ; the violet and ultra- 

 violet radiations giving rise to the formation of these 

 unstable molecular groups, which, in their turn, 

 disintegrate, radiating all the while intensely the 

 energy which was stored up in their formation. 



The aether must be considered part of the en- 

 vironment, else we should find ourselves dealing 

 with only one aspect of the question, or with one 

 part of Nature. The absorption of radiant energy of 

 one period and the emission of that of another are 

 accompanied by a molecular shuffling, of a catalytic 

 nature, as in the case of metabolic transmutations. 



It is when we come to deal with flame that the 

 presence of catalytic actions will be most apparent : 

 whilst the facts which relate to luminous, or phos- 

 phorescent plants, insects, and bacteria will serve to 

 make the analogy almost complete. But not alto- 

 gether so. For the luminosity of gases, highly 

 rarefied, presents many difficulties, which are not so 

 easily to be surmounted ; and, therefore, whilst 

 following in detail the great work of the last ten 

 years, of ionisation in such media, we must point 



