654 SESSION VII. DISCUSSION 



their functions are based on physical properties such as their relatively low thermal 

 conductivity, their specific gravity of less than one, their liquid state and their lubricating 

 properties and on chemical properties such as their ability to produce a considerable 

 amount of energy and water on oxidation. 



Thus, as the complexity of structure and number of functions of organisms increased 

 during the course of evolution, the use of substances belonging to any particular group 

 extended to an ever-increasing number of fields (within each organism). 



M. Calvin: Being a cross between a biologist and a biochemist I should like to confirm 

 and amplify the suggestion put forward by Prof. Bernai on behalf of another department 

 of science. I should hke to direct the attention of physical chemists and organic chemists 

 to a large field of which we have absolutely no understanding, namely to the behaviour 

 of coacervatcd colloids. 



It is not a question of simply taking any mixture of polymers and seeing whether a 

 coacervate can be made from it. I am speaking of a detailed understanding of the physico- 

 chemical nature of the phenomenon. It is necessary to find out what molecular forces take 

 part in the separation of a second phase out from a very dilute solution of substances of 

 high molecular weight, how these new phases change the physical and chemical properties 

 of the small molecules within the coacervates, how they affect the interaction of these 

 molecules with one another and with the larger molecules associated with this new phase. 



A. E. Braunshteïn: I must comment on the inconsistency of the attempts of some 

 scientists to identify the transition from non-living material to life with the appearance 

 of particular, extremely complicated, forms of organic compounds, as if their molecules 

 were endowed with the property of 'life' by virtue of their having particular physical and 

 chemical characteristics. The ability of protein molecules, under certain conditions, to 

 incorporate or even exchange individual amino acid residues is just as decisive as the 

 importance of nucleic acids as a factor determining the specific direction of the biosyn- 

 thesis of proteins, they are necessary prerequisites if proteins and nucleic acids are to be 

 able to form the major components of multimolccular living systems. These character- 

 istics do not, however, give any reason for considering molecules of protein or desoxy- 

 ribose nucleic acid in the isolated state as 'living molecules'. 



The transition to life only occurs when these compovmds and many other substances are 

 unified into complicated systems with an internal organization, capable of growth and of 

 specific self-reproduction by means of an exchange of substances with the external en- 

 virormient. I should Uke to emphasize that there is one gap to be found in the programme 

 of our Symposium. Although we have listened to a number of communications on the 

 original conditions for the synthesis of amino acids and polypeptides, no new material 

 has been laid before the Symposium concerning the conditions for the abiogenic synthesis 

 of carbohydrates, especially of complicated carbohydrates, or concerning the possibilities 

 for the synthesis of organic phosphorus compounds, in particular nucleotides. It is, at 

 present, more difficult for us to imagine clearly how nucleotides or polymers of nucleic 

 acid could have been formed abiogenically, than it is for us to imagine the formation of 

 polymers such as proteins. Strictly speaking, we have no more experimental evidence for 

 the direct synthesis of carbohydrates than Butlerov's model involving the condensation 

 of formaldehyde. 



I call upon those who are interested in this problem to take up the making of models 

 in the field of the biosynthesis of organic phosphorus compounds, especially macroergic 

 compounds and polymers which could lead to the synthesis of nucleic acids from inorganic 

 polyphosphates. We should then be able to reopen the discussion on a more precise basis. 



A. G. PasynskiI: If our respected Chairman is, as he puts it, a cross between a biologist 

 and a biochemist, then I should like to intervene as a cross between a physical chemist and 

 a biochemist. It seems to me that the study of the growth of complexity of substances in 

 the course of evolution, which has made such great advances during the past years, is 

 only one aspect of the evolutionary process. At the same time as the increase in complexity 

 of substances there have arisen definite relationships, definite networks of reactions 

 between these substances —an increase in complexity, not merely of the substances, but 

 also of the network of chemical reactions. Nevertheless, this aspect of the matter has so 

 far been quite insufficiently studied. The difficulty, which has been formulated in to-day's 

 discussion, in understanding how a more or less uniform collection of substances could 



