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Excited states of the nucleon were predicted by Wentzel already in 1940.Wentzel showed that such kind of states can be derived from models of mesonfield theory if they are treated above a certain coupling strength. Inparticular for a pseudo-scalar meson field theory such kind of states werederived by Pauli and Dancoff in 1942 with equal amount of spin and isospin.They can be understood as arising from excitation of the pionic cloud of thenucleon by which the main part of nuclear forces also is coming out. Theexcitation of these states also is the mechanism by which the pion-nucleonresonance scattering is originated which firstly was experimentally discoveredby Fermi in 1955.  In the following contribution a completion of the method of Wentzel and Pauli& Dancoff is sketched following a work of the author and treating thepion-nucleon resonance scattering. By means of a canonical and nonlineartransformation of variables the original meson field is split into a free mesonpart and a self field part of the nucleon. The transformation is defined suchthat the interaction between the compound nucleon system thus arising and thefree mesons vanish in the case of infinitely strong coupling. The solution ofthis field splitting problem is presented and the problem of calculating thepion-nucleon resonance scattering from this strong-coupling theory is treatedon this basis. Numerical results obtained from such a calculation arediscussed. For the sake of simplicity the symmetric pseudoscalarfixed-and-extended-source meson field theory is used and found that the lowestpion-nucleon resonance scattering is quite well reproduced with essentially thesame parameters necessary to reproduce the nucleon-nucleon-potential. Thepresent investigation will serve to guide more extended considerations in thisdirection.

Pion-Field Theoretical Description of the Delta^{++}(1236)-Resonance without QCD