98 life's beginning on the earth 



Undoubtedly, Oparin's work deserves the highest recog- 

 nition due to his admirable attempt to explain the origin of 

 life as just one of the phases in the fate of carbon on our 

 earth. First there was the white-hot carbon vapor, then 

 came the carbides, then the carbon-hydrogen compounds; 

 later, after the earth had cooled, carbon had an opportunity 

 to display its extraordinary faculty to form an almost end- 

 less variety of different substances; thus, finally, structural 

 arrangements like the coazervate droplets and enzymes 

 were formed which gradually developed into living organ- 

 isms. 



Oparin attempts to trace as accurately as possible, the 

 character of all the different chemical changes during this 

 history of carbon. On the early earth with no oxygen in 

 the atmosphere, no "cellular respiration" but only fermenta- 

 tion was possible whereby carbon dioxide was given off into 

 the atmosphere. Subsequently, the enzyme chlorophyl in 

 the green plant cells appeared and free oxygen was given off 

 into the atmosphere. There is actual evidence available 

 that this was a very much later development since to this 

 day fermentative processes occur in all plants side by side 

 with the "assimilation" of carbon dioxide, which latter 

 process liberates atmospheric oxygen. Animal life which 

 depends on respiration in an oxygen-containing atmosphere 

 made its first appearance only after all these previous de- 

 velopments were well under way; it relied chiefly on the 

 great energy output resulting from processes of cellular 

 combustion. And what a long way it had to go before it 

 arrived at its present high stage! It is impossible to de- 

 scribe here all the chemical details which Oparin traces as 

 he maps out his gorgeous history of carbon, terminating in 

 life. 



In concluding, Oparin can justly claim that he has opened 

 a new outlook to "the colossal problem" of investigating 

 the stages of the evolution of life 1 as being chemically sepa- 



