Physical vs. Statistical Origin of Optical Activity in Nature

Physical vs. Statistical Origin of Optical Activity in Nature 

As has already been shown, several quite different mechanisnts may operate in optically selective biosynthesis and, given the initial presence of an optically active substance, there is no difficulty in accounting for the perpetuation of asymmetry through a subsequent chain of biosyntheses. But we have still to face the thorny problem of the production of the initial directing agent in an optically active state, and we may conclude this survey by considering the relative merits of the two rival mechanisms which have been proposed to account for this. 

The first of these—the intervention of an unsymmetrical physical directive agency such as circularly polarized light—has already been considered when dealing with absolute asymmetric syntheses and decompositions. Of recent years, however, attention has been widely directed to the statistical treatment of material systems and processes. Spiers (136), for example, has advanced arguments in support of the statistical or chance deviation mechanism a statistical approach to the problem has also been advocated by Mills (102). It has much to commend it. The basic idea is that, in an aggregate of dissymmetric molecules, synthesized in vitro under 

If this is so, and if Mills s arguments supporting the greater efficiency of reaction between optically pure systems as contrasted with racemic systems are justified, then this admittedly very slight statistical departure from strict numerical equality 

One must, however, admit the justice of Mills s skepticism of an explanation based wholly on the action of circularly polarized light. Only 

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VI. Physical vs. Statistical Origin of Optical Activity in Nature. 104... 

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