1921.] Recent Advances in Stereochemistry. 215 
in recent years must also be regarded as instances of molecular 
asymmetry. - 
Another instance of molecular asymmetry is furnished 
by 4-oximino-cyclohexane-carboxylic acid : 
COOH CH, — CH, 
Cc _— C=NOH 
Re 
which was resolved into the d-and 1-forms in 1910 by Miss 
Bain, now of Delhi, working under Mr. Mills at Cambridge. 
This discovery is of more than ordinary importance as it also 
furnished a proof for the validity of the views of Hantzsch and 
Werner on the isomerism of oximes. 
A problem of long standing was at last solved in 1914, 
when Pope and Read succeeded in obtaining chloroiodo- 
es i 
H 
tertiary amines has yet been effected. 
RELATION BETWEEN OPTICAL ACTIVITY AND CHEMICAL 
CONSTITUTION. 
and chemical constitution. We have as yet no clear idea why 
substances of enantiomorphous molecular configuration exhibit 
optical activity, but lack of knowledge on this point has not 
deterred the chemist from pursuing this study, which has 
resulted in the accumulation of large masses of quantitative 
data about optical activity. The complete correlation of these 
results must, however, await till we get from the Mathematical 
physicist a theory of optical activity comparable in quantita- 
tive completeness to the electromagnetic theory of light. : 
(a2) OPTICAL ACTIVITY IN HOMOLOGOUS SERIES : 
Numerous attempts have been made to discover Powe 
tion between optical activity and chemical constitution oe 
compound since Crum Brown and Guye independently in 189( 
