THE first definite proof of the existence of optically active compounds in which the optical activity is due to asymmetric atoms other than carbon atoms was given by Pope and Peachey (Trans., 1899,'75, 1127), when they resolved Wetiekind's a-phenyl benzylmethylallylammoniurn iodide into dextro-and {avo-rotatory forms in which the activity is caused by the asymmetzy of the quinqrievalent nitrogen atom. Up to the present time, ...