130 



s. L. MILLER 



Table 3 

 Ratios of products 



Since the production of aldehydes and hydrogen cyanide is sufficient to 

 account for the observed yield of amino acid, there can be little doubt that most 

 of the amino and hydroxy acids were formed from the nitrües in Rim i. How- 

 ever, these experiments do not exclude the possibility that a small percentage of 

 the amino acids was formed directly in the spark, entirely by radical reactions*. 



The synthesis of the products expected from acrylonitrile and the agreement 

 of the ratios of these products in the different runs provides strong indirect 

 evidence for the synthesis of /3-alanine and succinic acid by j3-addition, and in 

 turn that acrylonitrile or derivatives were synthesized in the electric discharges. 



If cyanate were formed in the electric discharge, then both urea and methyl- 

 urea could be expected of reaction with ammonia and methylamine (Wöhler 

 synthesis). The direct synthesis of the simple ureas in the electric discharge is 

 also quite reasonable. 



DISCUSSION 



Assuming that the Earth initially had a reducing atmosphere, do the experi- 

 mental results obtained in this very simple system show that amino acids or 

 other organic compounds would be present in the ocean ? The experiments on 

 the mechanism of the electric-discharge synthesis of amino acids indicate that 

 a special set of conditions or type of electrical discharge is not required to obtain 

 amino acids. Any process or combination of processes that yielded both alde- 



* The hydrogen cyanide concentration in the silent discharge case is too low to account 

 for the yield of amino acids unless the hydrolysis of the nitrilcs is more rapid than in 

 Run I. Hydrogen peroxide catalysis is a possibility. The ratios of products in the various 

 runs is strong evidence that the products were formed by the same mechanism. 



