20 OPTICAL ACTIVITY OF BIOL. MATERIAL 



the only one devoid of dissymmetry, and, in metabolic 

 processes, it is less important than the other amino-acids 

 which are dissymmetric. 



It is of interest to mention here that the elements of 

 which optically active compounds consist include twenty- 

 one of them, as follows (Lowry, 1935) : 



Metals 



B C N Be 



Al 



Cr Fe Co Ni Cu Zn 

 Ell Eh 



Ir Pt 



2. Asymmetry as a Specific Property of Protoplasm. It 

 is generally established that all the substances which are 

 produced in the laboratory or in nature, without the action 

 of living organisms, have right and left forms represented 

 in equal concentrations, the formation of both being equally 

 probable. It has never been observed, for example, that 

 in any quartz bed the right or the left crystals would pre- 

 dominate to any extent (Tromsdorff, 1937; Lemmlein, 

 1938). There is, of course, dissymmetry in individual 

 components, but no asymmetry in their aggregation. 



On the other hand, all basic chemical substances of which 

 living systems are made up or which are formed in connec- 

 tion with the activity of living systems, deviate from the 

 racemic state and are represented mainly by one antipode. 

 In other words, asymmetry is a specific attribute of living- 

 systems and an essential feature of their organization. 

 This is one of the most significant principles of experi- 

 mental biology ; it is based on a large number of observa- 

 tions accumulated within the last hundred years, since the 

 pioneer work of Pasteur. 



We shall study here, in some detail, which parts of living- 

 systems consist of racemic compounds and which parts 

 deviate from the racemic state and in what direction. It 

 will appear that the asymmetric state of protoplasmic 

 components is directly related to the role played by these 

 components in metabolic activity. 



