2 TEMPORAL ORGANIZATION IN CELLS 



such as the cistron, the zymon, the repHcon, etc., must emerge those charac- 

 teristics which are the recognized attributes of Uving cells. But here the biolo- 

 gist faces a situation quite unlike that which existed in the physical science of 

 Boltzmann's day. On the one hand there is nothing analogous to Newtonian 

 mechanics describing the microscopic "motion" of molecular and macro- 

 molecular activities in cells. On the other hand there is no well-formulated set 

 of relations between the general properties of cells which could correspond to 

 phenomenological thermodynamics. All that there is in biology is a set of 

 concepts such as organization, adaptation, regulation, competence, homeo- 

 stasis, etc., which must carry an enormous burden of more or less intuitive 

 understanding and experience about the essential principles of biological 

 structure and function. Although some of these concepts have been analysed 

 into more exact notions which could lead to quantititative definitions satis- 

 fying to some extent their intuitively-perceived content, there is certainly no set 

 of relations which order them into phenomenological laws of cellular biology. 



The only biological science which has in fact a general law of a quantitative 

 nature derivable from microscopic properties is population genetics. Here 

 R. A. Fisher's (1930) fundamental principle of natural selection, defined in 

 terms of the variance of gene frequencies in a population of organisms breeding 

 sexually, occupies a place as central to this field of study as the law of maximum 

 entropy in physics. A dynamic substructure for this principle, which thus 

 occupies a place analogous to Newtonian mechanics for physical systems, 

 has been derived by Kimura (1958). The interesting fact about this principle 

 of natural selection or law of maximum "fitness" is that it was formulated 

 quantitatively only after a mathematical theory of gene frequency distributions 

 in randomly-mating populations had been worked out. It was not an estab- 

 lished quantitative law prior to its introduction in connection with a specific 

 mathematical theory, although Darwin's principle of the survival of the fittest 

 was clearly the qualitative precursor. Here we have a case, then, of a biological 

 law which received quantitative, exact definition only after the "elementary 

 particles" of heredity — the genes — had been discovered and used as the micro- 

 structure for a mathematical theory which described the motion and the inter- 

 action of these hereditary particles, to use the language of dynamics. As 

 compared with the historical development of physical science, the pattern of 

 discovery and deduction was reversed: first the properties of the microscopies 

 units were established (at least those incorporated in the Mendelian laws of 

 inheritance), and then the macroscopic law was deduced in quantative form. 



We may now ask if this pattern will also be followed in cell biology. That is 

 to say, will quantitative macroscopic principles of cell behaviour be discovered 

 in connection with the mathematical theories which are now beginning to 

 emerge, based on our present understanding of the molecular organization of 

 living cells? And will these principles be in accord with our rather vague 

 notions about the nature of cell structure and function in the same way that 

 Fisher's fitness principle satisfies and gives precise to Darwinian notions about 

 survival in natural populations? Or will essentially new and unexpected 

 macroscopic principles be deduced which will develop an intuitive content 



