In the Luttinger model, right-hand-going particles moving at a constant vel
ocity c in ID maintain a constant distance apart, Therefore their interacti
on energy should be a trivial constant of the motion a whereas. in fact it
is not. This interaction affects the dispersion of all the elementary excit
ations in the model, hence the dynamics and thermodynamics. (Identical rema
rks hold for the left-handgoers.) The present paper explores the meaning of
this interesting Facet of Luttinger's model.