H. EYRING AND F. H. JOHNSON 7 



quartz and the tartrates, from racemic mixtures exemplifies fluctuations 

 where one optical isomer l)y nucleation gains the ascendancy and so forms 

 optically active crystals without, however, having the ability to effectively 

 destroy competitors. 



Our unfamiliarity with life in other worlds makes us unable to test our 

 assumption that independent biogeneses should yield I and d worlds sub- 

 stantially randomly. Goult (10), examining 1008 quartz crystals gathered 

 from six widely separated areas, found d and I quartz in the ratio 51.6 to 

 48.4. This approaches a random distribution and invites further experi- 

 mental and theoretical study. Systems like tartrates where the molecules 

 as well as the crystals are enantiomorphic will necessarily show very close 

 to equal frequency of occurrence of crystal types. 



SUMMARY 



The problem of biogenesis is discussed with reference to reaction rate 

 theory and the significance of optically active catalytic systems in the 

 living world. The facts that molecular systems in living organisms are 

 optically active, that different amino acids within an organism are con- 

 figurationally related, and that the various amino acids from different 

 species of organisms are likewise related, are indicative of a common ori- 

 gin in the remote past, from a single optically active template, probably 

 a ribonucleic acid molecule of greater length and configurational perfec- 

 tion than had previously occurred during some billion years of chemical 

 evolution. From reaction rate theory, it follows that the template was 

 formed in 10~^^ sec, the lifetime of the activated complex in any chemical 

 reaction. At this instant the world suddenly "went critical"; replication 

 of the template and the crude enzymes involved in its formation now oc- 

 curred within a shorter time than their own life spans. Simultaneously, 

 the door was slammed on competitors with a different type of optical ac- 

 tivity, and biological evolution began. An analogous event on some other 

 world might as easily have given rise to life characterized by the d- rather 

 than the I- type of optical isomer known in our world, the two types having 

 exactly the same chemical reactivity. In nuclear evolution, an analogous 

 turning point probably also occurred, so that it is natural to visualize 

 some other universe where positive electrons rotate about negative nuclei, 

 in contrast to the universe we know. 



Reaction rate theory, together with crude estimates of reactant concen- 

 trations, leads to a reasonable rate of appearance, at 300° absolute, of 

 the critical complex in biogenesis, according to known physical and chemi- 

 cal laws. With much greater concentrations, conditions could possibly be 

 found whereby optical activity would spontaneously arise in a sterile 

 system in a few days. 



