184 SESSION II. DISCUSSION 



S. L. Miller (U.S.A.) : 



In regard to the experiments of Pavlovskaya & Pasynskii I would like to comment 

 that their mixture of methane, carbon monoxide, water and ammonia is quite reducing. 

 Under geological conditions this mixture of gases would be stable only in the presence 

 of an appreciable pressure of hydrogen. In the experiments of Pavlovskaya & Pasynskii, 

 it is quite probable that some hydrogen was produced during the sparking. 



There is a question of the stability of carbon monoxide in a primitive atmosphere. 

 Carbon monoxide reacts at a significant rate with water in the presence of base to give 

 formate. Therefore, the carbon monoxide that was produced on the Earth would dissolve 

 in the ocean and the steady-state concentration would have been small. 



There have been several comments about the importance of sugars for the formation 

 of life. I should point out that polyhydroxy compounds, probably sugars, were produced 

 in my electric discharge experiments. This is reasonable since it is well known that 

 formaldehyde, which was produced in the spark, condenses in weakly basic solutions to 

 give 4-, 5- and 6-carbon sugars. We can expect that similar condensations would have taken 

 place in the primitive ocean. 



S. Fox (U.S.A.) 



Comments on the Origin of Optical Activity 



Many concepts of origin of optical activity have been considered. Many others from 

 the literature have not. One may particularly deserve serious consideration. If a compound 

 which occurs early in generalized biosynthetic pathways happens to crystallize in D and L 

 forms and then be separated by chance, then precipitation of one form by seeding can 

 occur. If this happens to be D-aspartic acid, for example, L-aspartic acid is left behind 

 in the primordial soup or paste. The primitive conversion of aspartic acid to other com- 

 pounds, e.g. alanine, would thus give L-alanine and a monoconfigurational biochemical 

 world would be triggered. 



This is more fully explained in a recent paper [i]. 



REFERENCE 



I. S. W. Fox, J. E. Johnson & A. Vegotsky, Science, 124, 923, 1956. 



A. G. Pasynskii (U.S.S.R.): 



In connection with Dr Miller's remarks I should like to state that the point is not that 

 the formation of amino acids could occur only in a hydrogen-containing atmosphere or 

 only in one containing CO; it probably took place under both conditions. Under the 

 actual experimental conditions used by Miller and ourselves the presence of free hydrogen 

 certainly was not necessary. 



A. Ya. Smirnova (U.S.S.R.): 



The Relationship between the Mineral and Organic Worlds 



It seems to me that in studying the pre-proteinaceous substances and their later trans- 

 formation into proteins with vital functions, more attention should have been paid to 

 certain supplementary factors. 



I am thinking of the similarity of many of the properties of complex compounds which 

 are not proteinaceous in nature, with the properties of proteins and other organic com- 

 pounds. 



I am referring, in the first place, to their high molecular weight, optical activity, 

 viscosity, stability, 5- and 6-membcrcd rings and great sensitivity to changes in pH and 



