178 THE ORIGIN OF LIFE 



incandescent planet by its intense vital activity, and 

 were not able to return again into tbe hot liquids 

 wbich gradually decreased in quantity because of 

 the progressive decrease in temperature of the 

 earth's crust — we maintain that after this had 

 occurred, protoplasm must necessarily have remained 

 over. The heavy metals, once organic elements, 

 no longer melted, and did not return into the 

 circulation from which they had been east out. 

 They are the signs of the rigor mortis of the 

 gigantic, cooling, primeval organisms, whose breath 

 perchance was luminous iron-vapour, whose blood 

 was liquid metal, and whose food was meteorites." 

 It is at this juncture that we may begin to 

 realise the bearing of physical forces upon this 

 state of matter. For although Preyer's statements 

 may appear now, as they did at the time he made 

 them, somewhat fantastic and crude by adverse 

 critics ; yet from the views herein expressed, they 

 appear to be quite in harmony with the physical 

 theory of metabolism in inorganic as well as in 

 organic substances. The phenomena of catalysis 

 seem to take part in such simpler reactions as in 

 the phenomena of flames, and in those of fluores- 

 cence and phosphorescence. These phenomena are 

 distinctly of the nature of a building up and break- 

 ing down of more or less unstable molecular groups. 

 So that it may be said that here at last we have 

 metabolic action in its simplest form ; each little 

 aggregate acting as an individual for a time, and 

 then, having played its part in the process, dis- 



