OPTICAL ACTIVITY OF BIOL. MATERIAL 31 



tine. The suggestion that the reUitive configuration in all 

 biological isomers of amino-acids is identical was made by 

 Clougli (1918) ; it received confirmation from the work of 

 a number of later investigators (Freudenberg and Rhino, 

 1924; Langenbeck, 1925; Karrer and Ehrenstein, 1926; 

 Levene and Mardaschew, 1937 ; Pfeitf er and Christeleit, 

 1937). In general, it is established that the primary sub- 

 stances, although they rotate the plane of polarized light 

 in different directions, possess the same relative configura- 

 tion and form a definite "biological series" of optical 

 isomers. Their antipodes are excluded from participation 

 in living processes. Not all the potentialities of dissym- 

 metric configuration, therefore, are employed in the 

 organization of living systems. 



8. Asymmetry as a Criterion of the Organic Origin of 

 a Substance. From what has been said, it follow^s that 

 every deviation from the racemic state, that is, every 

 asymmetry of molecular aggregates represents actually a 

 specific attribute of biological systems, and we do not know 

 a single case when it would take place outside of living* 

 organisms or of the products of their activity. Conse- 

 quently, optical activity can be used as a criterion of the 

 biological origin of such natural products as petroleum. 

 Two theories of the origin of petroleum are generally held, 

 one attributing it to an inorganic, the other to an organic 

 source. The first suggestion concerning the inorganic, 

 volcanic origin of this so-called mineral oil is due to Hum- 

 boldt (1804). The theory of its organic origin is still 

 older (Lemery, 1675; Lomonosoff, 1761; Spielmann, 1774). 

 In its more modern form (see, e.g., Engler, 1906), this 

 theory implies that the fat contained in the dead bodies of 

 fishes, molluscs and other sea animals, and especially the 

 stable palmitic, stearic and oleinic acids are the ancestors 

 of petroleum. As a result of a breaking down of the chains 

 of carbon compounds under high pressure, hydrocarbons 

 with comparatively low boiling point could arise, a poly- 

 merization of which, during geological periods, resulted in 

 our present-day oil. It is also possible that in some cases 

 the initial substance was of vegetable origin. 



