ORIGIN AXD MAINTEN. OF OPT. ACTIVITY 53 



long' periods of time on racemic compounds would initiate 

 optical activity. 



More recently Kuhn and Braun (1929) and Kulni and 

 Knopf (1930) have shown that, in laboratory experiments, 

 when circularly polarized light is used in the photochemi- 

 cal decomposition of racemates, it causes the appearance 

 of optically active isomers. 



Ritchie (1933) and later Langenbeck and Triem (1936) 

 supported the hypothesis just described. 



The second explanation of the origin of optical asym- 

 metry (cf., Pearson, 1898; Fitzgerald, 1898; Bartrum, 

 1898; Errera, 1898; Kipping and Pope, 1898; Byk, 1925; 

 Mills, 1932) is based on the assumption that the equality 

 of the right and left components represents a statistical 

 mean value around which fluctuations occur. Kipping and 

 Pope (1898) observed, for example, that, while the occur- 

 rence of either right or left component, in crystallization 

 experiments, furnished a mean value of 50.08% ± 0.11, 

 the proportion varied from 24.14/^ to 77.36% in separate 

 experiments (46 of them). An inequality of the right or 

 the left form of a substance might have originated acci- 

 dentally in this manner when some living systems were in 

 formation and this inequality might have spread by asym- 

 metric catalysis (Strong, 1898). 



Lately Spiers (1937) supported the chance deviation 

 hypothesis of the origin of asymmetry. 



7. General Survey of the Problem of the Origin and 

 Maintenance of Optical Asymmetry. The various stages 

 in the development and maintenance of the asymmetric 

 state are represented diagramatically in Fig. 4. 



Let us note, first, that there are two levels of stability 

 for the state of symmetry or asymmetry: 1. the level of 

 thermodynamic stability which characterizes the racemic 

 state ; 2. the level of protoplasmic stability which is main- 

 tained by living matter. In inorganic nature, the race- 

 mates are stable because they possess the least amount of 

 free energy. In living nature, optically pure forms are 

 stable because they are the most advantageous in natural 



