70 EVOLUTION 



are more like termini than beginnings in 

 material evolution. 



It may be that what we call "living'* 

 evolved in Nature's laboratory from what 

 we call "not-living," for though prolonged 

 experiments have led biologists to adhere 

 dogmatically to the dictum "omne vivum e 

 vivo," this is not inconsistent with supposing 

 that spontaneous generation occurred in 

 favourable conditions very long ago. Ver- 

 worn has elaborated a suggestion due to the 

 great physiologist Pfliiger (1875), that the 

 cyanogen radical (CN) may have been the 

 starting-point of the proteid molecule which 

 is the essential part of the physical basis of 

 life. As cyanogen and its compounds arise 

 in an incandescent heat when the necessary 

 nitrogenous compounds are present, they may 

 have been formed while the earth was still 

 aglow; with their property of ready decom- 

 position they were forced into correlation 

 with various other compounds likewise due 

 to the great heat; when water was precipi- 

 tated upon the earth these compounds en- 

 tered into chemical relations with the water 

 and its dissolved salts and gases, and thus 

 originated extremely labile, very simple, un- 

 differentiated living substance, which per- 

 haps fed, as Sir Ray Lankester has suggested, 

 upon "antecedent steps in its own evolution." 



