MICROBE AND LIFE 



nexion Urcy has also pointed to the mighty electrical discharges that 

 characterized this epoch, and it is certainly of interest to note that 

 Miller shortly afterwards reported that under the influence of this 

 agency amino acids are soon detectable in the above-mentioned sys- 

 tem. If, furthermore, it is realized that these photo- and electrochemi- 

 cal processes must have proceeded for periods of many hundred million 

 years, the conclusion seems almost irrefutable that gradually enormous 

 quantities of organic matter must have accumulated in the primitive 

 oceans. Moreover, as a result of the production of radicals by the 

 above-mentioned agents it may safely be assumed that quite divergent 

 types of organic substances must have originated through conden- 

 sation reactions. Amongst these the building blocks of present-day 

 cellular constituents must surely have been present. In the absence 

 of life these compounds could persist in the aqueous medium, so that 

 gradually the oceans became solutions of organic compounds. 



It is this proto-solution that lends itself to making a spontaneous 

 appearance of an utterly primitive form of life conceivable. In illus- 

 trating this I shall follow H. J. Muller's recently published discourse. 

 First of all, this geneticist stresses the fact that the most essential com- 

 ponents of life are the genes, the hereditary units that possess the power 

 of multiplication under certain conditions, as revealed during every 

 cell division. Chemically they can be characterized as nucleic acids, 

 substances that are composed of numerous building blocks of, for the 

 rest, a small number of types. The virtually unlimited diversity in 

 arrangement of these building blocks determines the differences be- 

 tween individual nucleic acids, and consequently the specificity of the 

 multifarious cells. In a sense we may therefore say that life, reduced to 

 its ultimate essence can be viewed as a nucleic acid that attracts new 

 building blocks, arranges these in accordance with its own pattern, 

 and in this manner creates its physico-chemical image. 



Bernal has pointed out that particular clays have the property of 

 adsorbing very diverse organic molecules in a regular fashion, and 

 also can function as catalysts of reactions that lead to a condensation 

 of the adsorbed molecules. In this manner the first nucleic acid may 

 have been generated. Under conditions that nowadays are still real- 

 ized in every living cell, but have as yet been insufficiently elucidated, 

 building blocks could have grouped themselves in regular order, ulti- 

 mately causing the formation of a second molecule. This ordering in 



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