Formation of Organic Compounds 133 



first a large number of organic compounds similar to those that would make up 

 the first organism. Therefore, if it can be shown that the organic compounds 

 which make up hving systems cannot be synthesized under oxidizing conditions, 

 and if it can be shown that these organic componds can be synthesized under 

 reducing conditions, then one conclusion would be that the Earth had a reducing 

 atmosphere in its early stages and that life arose from the sea of organic com- 

 pounds formed while the Earth had this atmosphere. 



From a review of the hterature on electric discharges [24] and ultraviolet light 

 [25], from the result of the experiments described in this paper, and from the 

 first part of this discussion, one can see that organic compounds can be easily 

 synthesized under reducing conditions. 



There have been many attempts to synthesize organic compounds under 

 oxidizing conditions, usually from caibon dioxide and water, and these attempts 

 have almost always failed. A review of these attempts using ultraviolet Hght [26] 

 shows that success was claimed by some workers, but when their experiments 

 were repeated in other laboratories or when contaminating reducing agents 

 were removed, no organic compounds were synthesized. The action of electric 

 discharges on carbon dioxide and water has also resulted in failure [27]. Of course, 

 if a strong reducing agent such as Na or Mg is used, organic compounds can be 

 formed, but these reducing agents would not be present on the Earth with either 

 a reducing or an oxidizing atmosphere. High-energy radiations on ammonium 

 carbonate solutions might give organic compounds, but the presence of am- 

 monia would imply reducing conditions. 



There has been one successful synthesis of organic compovmds from carbon 

 dioxide and water using 40 milHon electron volt helium ions from a 60-inch 

 cyclotron [28, 29]. Formic acid was obtained in small yield, and if ferrous ion 

 was added to the solution as a reducing agent then a small yield of formaldehyde 

 was obtained in addition to formic acid. In view of the absence of a strong source 

 of high-energy particles, the small yields, and the very simple organic compounds 

 synthesized, it would seem that instead of showing that organic compounds 

 can be synthesized this experiment can best be interpreted to mean that organic 

 compounds cannot be effectively synthesized under oxidizing conditions. 



If any organic compounds should be synthesized under oxidizing conditions, 

 however difficult this may be, then the question of their stabihty arises. In the 

 presence of molecular oxygen the organic compounds would be oxidized rather 

 rapidly, especially in the presence of light [30]. An important reaction of the 

 oxygen would be the oxidative deamination of the amino acids. This reaction 

 is catalysed by blood charcoal and probably by many iron compounds [31]. The 

 oxidative deamination is a significant reaction even in the absence of catalysts 

 [32]. Oxygen would also attack aromatic compounds such as the purines and 

 pyrimidines, especially in the presence of light. These arguments make a strong 

 case that free oxygen must have been absent when the organic compounds were 

 formed and also absent during the development of heterotrophic organisms. 

 Shortly after the appearance of oxygen on the Earth the autotrophic organisms 

 would have to develop, for otherwise the nutrients would be rapidly exhausted. 



If the Strecker synthesis was the principal synthesis of amino acids on the 



