  An experimental motivated QCD analysis of the behaviour of the Adler
D-function in the Euclidian region is described. It is stressed that by taking
account of $b$-quark mass-dependent $\alpha_s^2$-effects one obtains better
agreement between theoretical predictions and experimentally motivated
behaviour of the D-function at large Euclidian momentum transfer. A more
detailed analysis of QCD predictions, including information on quark and gluon
condensates, requires more precise data on $e^+e^-\to{hadrons}$, particularly
in the region $E<M_{J/\Psi}$ and $M_{J/\Psi}<E<3.6 GeV$. use of experimental
determination of the D-function to test the generalized Crewther relation is
outlined.
