LIFE WITHOUT OXYGEN 



THE ANAEROBIC BEGINNINGS OF LIFE 



By CARL SNYDER 



In a previous essay in this journal l on the Physical Conditions 

 at the Beginnings of Life, it was briefly suggested that these 

 beginnings must have been in the absence of uncombined oxygen, 

 that is, in Pasteur's phrase, anaerobic. 2 At least five or six 

 convergent lines of evidence lead to this unexpected conclusion. 

 These are : 



i. That what appear to be the simplest forms of life are 

 anaerobic still and that the majority of lower organisms, both 

 plant and animal, can live under anaerobic conditions more or 

 less continuously. 



2. That the fundamental chemical processes of the cell in all 

 organisms, even the highest, are anaerobic, phenomena of oxida- 

 tion being of secondary or ulterior importance. 



3. That the relations of anaerobic and aerobic life are genetic 

 and that we have clear evidence of the gradual evolution of the 

 latter from the former, an increasing need of oxygen accompany- 

 ing an increasing complexity of chemical and morphological 

 organisation. 



4. That this increase in need of oxygen as complexity in- 

 creases is paralleled in the growth of the individual organism, 

 the ability to endure complete abstraction of oxygen varying 

 inversely with age and size. 



5. That the oxygen of the atmosphere appears to have been 

 formed exclusively by plant action. In the beginning there 

 was probably no oxygen free : if there had been any, it would 

 have been very quickly absorbed by the unoxidised substances 

 of the earth's crust or the quantity would have been so small as 

 to be practically negligible. 



1 Science Progress, April 1909, p. 579. 



s Cf. Weinland, Zeit.f. Biol. vols. 42 and 43 ; E. J. Lesser, " Das Leben ohne 

 Sauerstoff," Ergeb. d. Physiol. 742, 8, 1909. 



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