“…Moncrieff, 1951;Beets, 1957Beets, , 1964Ruzicka, 1957;Stoll, 1957;Amoore, 1962). The chemical properties remain unaltered within each series that have the same 'functional group' (Beets, 1957(Beets, , 1964 but are different for the different series of homologous substances. The results of the 'cross-comparison' of the present experiments demonstrate that the substances within one series give much higher chi-square values than do the odours from different series, although they had nearly the same molecular weight.…”