l8o ABIOGENIC ORGANIC-CHEMICAL EVOLUTION 



for the way in which these higher products of the reaction 

 were formed: 



(i) Hydrocyanic acid, amines, aldehydes, alcohols, most of 

 the volatile acids and acrylonitrile were formed in the elec- 

 tric discharge. The amino acids, hydroxy acids, some of the 

 fatty acids and the polymers only arose in solution. 



(2) All the substances which were found arose in the silent 

 discharges in the gaseous phase as the result of reactions 

 between free radicals and ions. 



Assuming the former hypothesis to be correct, Miller has 

 drawn up the following set of equations for the formation 

 of amino acids: 



R.CHO + NH3 + HCN^R.CHNHa.CN -|- H2O 

 R.CHNH2.CN -I- 2H20->R.CHNH2.COOH -1- NH3 



and hydroxy acids : 



R.CHO -1- HCN->R.CHOH.CN 

 R.CHOH.CN + 2H20^R.CHOH.COOH + NH3 



S. L. Miller's experiments were repeated and completely 

 confirmed by A. Pasynskii and T. Pavlovskaya."'^ According 

 to Pasynskii's calculations the value of Az for the formation 

 of alanine from methane, water and ammonia was 461004- 

 50-8t from which it may be seen that Az>o at all tempera- 

 tures. It follows that the reaction cannot occur spontaneously 

 but requires the extra energy of the electrical discharge. If, 

 however, the mixture of gases includes carbon monoxide, 

 Az for the reaction becomes — 52939 -f 153-4T and the re- 

 action is thermodynamically possible at ordinary tempera- 

 tures. This variant of Miller's reaction was reproduced 

 experimentally by Pasynskii and Pavlovskaya in an electric 

 field but the reaction has, so far, not been accomplished in 

 any other way. 



We have already shown that a far more potent source of 

 energy for the synthesis of organic substances on the primae- 

 val Earth than that of electric discharges was provided by 

 solar radiation, in particular by ultraviolet radiation. At 

 present the only chemical processes which are observed to 

 occur under natural conditions on the surface of the 



