30 



OPTICAL ACTIVITY OF BIOL. MATERIAL 



TABLE 6 



The Distribution of the Optical Isomers of Limonene and of Its 

 Eacemic Form in Different Plants (Bartelt, 1910) 



terns, although one of them is usually found more often 

 than the other. 



7. Relative Configuration of Biological Material. The 

 results of numerous investigations undertaken to establish 

 the relative configuration of organic substances may be 

 summarized as follows. All biological isomers of amino- 

 acids possess the same relative configuration, Fischer and 

 Raske (1907) observed that from biological (-) serine can 

 be obtained biological (+) alanine and biological (-) cys- 



