In 1940, the theory leading to the prediction of optical activity in molecules having the 4, 5- dimethylphenanthrene nucleus was outlined, Since this time the prediction has been verified by the partial resolution of three compounds: 4, 5, 8-tri-methyl-1-phenanthrylacetic acidj4 4-(l- methylbenzo (c) phenanthryl)-acetic acid5 and 4 ',“', 6 ', 6”-tetramethyl-3, 4, 5, 6- dibenzphenanthrene-9, IO-dicarboxylic acid. 6 In each case the optically active forms ...