SESSION V. DISCUSSION 491 



Zh. Ïordanov (Bulgaria): 



Even before the second World War, but especially since it. Academician Oparin's 

 theory has been widely known in Bulgaria. This is due to Academician Oparin's con- 

 sistent, materialistic approach to the solution of the problem and to the convincing 

 nature of the chemical and geological arguments. 



I believe that it is the chemistry of coacervates which will lead us closer to a solution of 

 the phenomenon of life. It is this which I see as the practical significance of Oparin's 

 theory : the experimental reproduction of the phenomenon of life should be brought about 

 by means of coacervates. 



As a histologist and cytologist I am convinced that many of the appearances seen in 

 cells and tissues and many morphological peculiarities are completely consistent with the 

 coacervate theory. Take for example the yolk globules of egg-cells. Irrespective of whether 

 they can develop into cells or not, everyone who has studied their origin, histochemical 

 and physicochemical properties and their transformations under natural and experimental 

 conditions has been able to convince himself that the key to an understanding of the 

 essential nature of these formations, which are complex systems of proteins, lipids and even 

 enzymes, could be found in a study of their behaviour in terms of coacervates. Like my 

 teacher. Academician Khadzhiolov, I believe that, as well as studying the coacervate 

 state of substances, we must consider another similar state of substances in the cell. 

 Khadzhiolov, who has made important histological investigations of the lipids in tissues, 

 showed, long ago, that the metabolism and activity in the organism of many substances, 

 which are important from a biological point of view (fat-soluble vitamins, hormones, 

 etc.), may be brought about by means of a transition from the fat-soluble to the water- 

 soluble state. In the course of various functional manifestations of cells and when they 

 are becoming adapted to the conditions of tissue culture, there appear within them mor- 

 phologically pecuHar lipid inclusions which may 'disappear' in the presence of other 

 so-called hydrotropic substances, becoming water-soluble. This is an important process 

 and is characteristic of the living system. 



The present Symposium has shown that the problem of the origin of life on the Earth 

 has passed beyond the stage of a purely theoretical treatment. It has important tasks 

 ahead of it and their accomplishment will prepare, at some future time, for the production 

 under laboratory conditions of the first artificial living system. As has been shown earlier, 

 this will require the concerted efforts of scientists working in different fields — biochemists, 

 biologists, cytologists, geologists and astronomers. 



G. M. Frank (U.S.S.R.): 



In the light of considerations which have been put forward to-day I should like to call 

 attention to what I consider to be a very important peculiarity, namely the motility of the 

 structures of living things. 



If disturbances of structure disorganize metaboUc processes one may, logically, easily 

 admit that a modification of structure is necessary for another form of the course of 

 metabolic processes. To this extent it is permissible to speak of the structural regulation 

 of chemical processes. 



Even at an early stage of the development of living matter one may observe one of its 

 most important properties, namely irritability. This is manifest in the simplest living 

 system, where it is clearly shown by corresponding changes in metabolic processes and 

 structural reorganization. 



Therefore, when speaking of the interdependence of chemical mechanism and structure 

 I should like to emphasize not merely the presence of determinate structural organization, 

 but also the presence of a certain degree of motility of structures. This motility is most 

 clearly to be seen in such a perfect structural chemical mechanism of motion as muscle. 

 However, as may be shown by many examples, the ability to move is not a particularly 

 specialized or limited function. One should regard it as the development of some general 

 property. 



In this connection I should like to put forward just one example. As we have succeeded 



